by Inge Heinzl, Editor, and Marisabel Caballero, Global Technical Manager Poultry, EW Nutrition

What is your most crucial key feed performance indicator? We posted this question on an online professional platform and got more than 330 answers from professionals in the industry:

• 55 % of the respondents considered feed efficiency or feed conversion rate (FCR) the key indicator, and
• 35 % listed feed cost / kg produced as their most important indicator.

As feed represents 60-70 % of the total production costs, feed efficiency has a high impact on farm profitability – especially in times of high feed prices. Furthermore, for the meat industry, an optimal FCR is essential for competitiveness against other protein sources. Finally, for food economists, feed efficiency is connected to the optimal use of natural resources (Patience et al., 2015).

In this article, we explain the factors that influence feed efficiency and show options to support animals in optimally utilizing the feed – directly improving the profitability of your operation.

How to measure the feed conversion rate

The FCR shows how efficiently animals utilize their diet for maintenance and net production. In the case of fattening animals, it is meat production; for dairy cows, it is milk, and for layers, it is egg mass (kg) or a specific egg quantity.

The feed conversion rate is the mathematical relation obtained by dividing the amount of feed the animal consumed by the production it provided. The FCR is an index for the degree of feed utilization and shows the amount of feed needed by the animal to produce one kg of meat or egg mass, or, e.g., 10 eggs.

When comparing the FCRs of different groups of animals (e.g., from different houses or farms), some considerations are important:

• Feed consumed is not feed disappeared: Due to differences in feeder design and feeder adjustment, these two values can differ by 10-30 %. If FCR is calculated for economic purposes, the wasted feed must be included, as it causes costs and must be paid by the farmer. However, if FCR is calculated for scientific purposes (e.g., a performance trial), only the feed consumed should be included.
• Even if they are same-aged animals, individuals or groups differ in weight. Hence, they have different requirements for maintenance and also diverging quantity left for production. To avoid mistakes, weight-corrected FCR can be used.
• Nutrient utilization also depends on genotype and sex; thus, comparisons should consider these factors as they also influence weight gain and body composition (Patience et al., 2015).

Many factors influence the FCR

There are internal and external factors that influence feed efficiency. Internal factors originate in the animal and include genetics, age, body composition, and health status. In contrast, external factors include feed composition, processing, and quality, as well as the environment, welfare enrichment, and social aspects.

1. Species

Different species have different body sizes and physiology and, therefore, vary in their growth and maintenance requirements, impacting their efficiency in converting the feed.

Table 1: FCRs of different species

Compared to terrestrial animals, for example, fish and other aquatic animals have a low FCR. Being poikilothermic (animals whose body temperature ranges widely), they don’t spend energy on maintaining their body temperature if the surrounding water is within their optimal range. As they are physically supported by water, they also need less energy to work against gravity. Furthermore, carnivorous fish are offered highly digestible, nutrient-dense feed, which lowers their requirements in quantity. Omnivorous fish, on the other hand, also consume feedstuffs not provided by the producer (e.g., algae and krill), which is not considered in the calculation. Broilers are the only farm animals achieving a similar FCR.

2. Sex, age, and growth phase

Sex determines gene expression related to the regulation of feed intake and nutrient utilization. Males have a better feed conversion and put on more lean meat than females and castrates, which grow slower and easier run to fat.

Young animals have a fast growth rate and are offered nutritionally dense feed; hence, their FCR is lower. When the animal grows and gains weight, its energy requirement for maintenance increases and its growth rate and the feed nutrient density diminish.

Table 2: FCR during different life phases of pigs (based on Adam and Bütfering, 2009)

3. Health and gut health

Health decisively impacts feed conversion. An animal that is challenged by pathogens reduces its feed intake and, thus, decreases growth. Additionally, the body needs energy for the immune defense, the replacement of damaged or lost tissue, and heat production, in case of fever. As many immune components are rich in protein, this is the first nutrient to become limited.

An imbalance in the gut microbiome also impacts feed conversion: pathogenic microorganisms damage tissues, impair nutrient digestion and absorption, and their metabolic products are harmful. Furthermore, pathogens consume nutrients intended for the host and continue to proliferate at its expense.

4. Environment

The environment influences the way the animals spend their maintenance energy. According to Patience (2012), when a 70 kg pig is offered feed ad libitum, 34 % of the daily energy is used for maintenance. For each °C below the thermoneutral zone, an additional 1.5% of feed is needed for maintenance. In heat stress, each °C above the optimum range decreases feed intake by 2%. Therefore, the feed needs to be denser to fulfill the requirement, or the animal will lose weight. Social stress also influences animal performance, especially chronic stress situations. Keeping the animals in their thermoneutral zone and mitigating the impact of stressors means more energy can go towards performance.

5. Feed quantity, composition, and quality

The feed is the source of nutrients animals convert into production. So, it’s natural that its quality and composition, and the availability of nutrients affect feed efficiency.

Better FCR by increasing nutrient density and digestibility

Higher energy content in the diet and better protein digestibility improve FCR. Saldaña et al. (2015) assert that increasing the energy content of a diet led to a linear decrease of the average daily feed intake but improved FCR quadratically. The energy intake by itself remained equal. However, these diet improvements also increase costs, and a cost-benefit analysis should be conducted.

Feed form and particle size play an important role

Feed processing can improve nutrient utilization. Particle size, moisture content, and whether the feed is offered as pellets or mash influence feed efficiency. Reducing the particle size leads to a higher contact surface for digestive enzymes and higher digestibility. Chewning et al. (2012) tested the effect of particle size and feed form on FCR in broilers. They found that pellet diets enable better FCRs than mash diets – one reason is the lower feed waste, another one the smaller feed particle size in the pelleted feed. Comparing the different tested mash diets, the birds receiving feed with a particle size of 300 µm performed better than the birds getting a diet with 600 µm particles.

Richert and DeRouchey (2015) show that pigs’ feed efficiency improved by 1.3 % for every 100 µm when the particle size was reduced from 1000 µm to 400 µm , as the contact surface for the digestible enzymes increased. In weaning piglets of 28-42 days, the increase of particle size from 394 µm to 695 µm worsened FCR from 1.213 to 1.245 (Almeida et al., 2020). There is a flipside to smaller particle size as well, however: high quantities of fines in the diet can lead to stomach ulceration in pigs (Vukmirović et al., 2021).

Non-starch polysaccharide (NSP)-rich cereals worsen FCR

The carbohydrates in feedstuffs such as wheat, rye, and barley are not only energy suppliers, and if not managed well, the inclusion of these raw materials can deteriorate feed conversion. Vegetable structural substances such as cellulose, hemicellulose, or lignin (e.g., in bran), are difficult or even impossible to utilize as they lack the necessary enzymes.

Figure 1: Contents of arabinoxylan and ß-glucan in grain (according to Bach Knudsen, 1997)

Additionally, water-soluble NSPs (e.g., pectins, but also ß-glucans and pentosans) have a high water absorption capacity. These gel-forming properties increase the viscosity of the digesta. High viscosity reduces the passage rate and makes it more difficult for digestive enzymes and bile acids to come into contact with the feed components. Also, nutrients’ contact with the resorptive surface is reduced.

Another disadvantage of NSPs is their “cage effect.” The water-insoluble NSPs cellulose and hemicellulose trap nutrients such as proteins and digestible carbohydrates. Consequently, again, digestive enzymes cannot reach them, and they are not available to the organism.

Molds and mycotoxins impair feed quality, but also animal health

Molds reduce the nutrient and energy content of the feed and negatively impact feed efficiency. They are dependent on active water in the feed and feed ingredients. Compared to bacteria, which need about 0.9-0.97 Aw (active water), most molds require only 0.86 Aw.

Table 3: Comparison of 28-day-old chicks performance fed not-infested and molded corn

Besides spoiling raw materials and feed and reducing their nutritional value, molds also produce mycotoxins which negatively impact animal health, including gut health. They damage the intestinal villi and tight junctions, reducing the surface for nutrient absorption. In a trial with broiler chickens, Kolawole et al. (2020) showed a strong positive correlation between the FCR and the exposure to different mycotoxins. The increase in levels of toxin mixtures resulted in poor FCR. Williams and Blaney (1994) found similar results with growing pigs. The animals received diets containing 50 % and 75 % of corn with 11.5 mg nivalenol and 3 mg zearalenone per kg. The inclusion of contaminated corn led to a deterioration of feed efficiency from 2.45 (control) to 3.49 and 3.23.

Oxidation of fats also affects feed quality

DDGS (distiller’s dried grains with solubles), by-products of corn distillation processes, are often used as animal feed, especially for pigs. The starch content is depleted in the distillation process and thus removed. The fat, however, is concentrated, and DDGS reach a similar energy content as corn.

Pigs also receive fats from different sources (e.g., soybean or corn oil, restaurant grease, animal-vegetable blends), especially in summer. Due to heat, the animals eat less, so increasing energy density in the feed is a possibility to maintain the energy intake.  The high fat content, however, makes these feeds susceptible to oxidation at high temperatures.

The oxidation of feedstuffs manifests in the rancidity of fats, destruction of the fat-soluble vitamins A, D, and E, carotenoids (pigments), and amino acids, leading to a lower nutritional value of the feed.

Use adequate supplements to enhance FCR

The feed industry offers many solutions to improve the FCR for different species. They usually target the animal’s digestive health or maintain/enhance feed quality, including increasing nutrient availability.

1. Boost your animals’ gut health

Producers can improve gut health by preventing the overgrowth of harmful microorganisms and by mitigating the effects of harmful substances. For this purpose, two kinds of feed additives are particularly suitable: phytomolecules and products mitigating the impact of toxins and mycotoxins.

Phytomolecules help stabilize the balance of the microbiome

By preventing the proliferation of pathogens, phytomolecules help the animal in three ways:

1. They prevent pathogens from damaging the gut wall
2. They deter and mitigate inflammation
3. By inhibiting the overgrowth of pathogens, they promote better nutrient utilization by the animal

Only a healthy gut can optimally digest feed and absorb nutrients.

In trials testing the phytogenic Activo product range, supplemented animals showed the following FCR improvements compared to non-supplemented control groups (Figure 2).  Note that phy­tomolecules also have a digestive effect that contributes to the FCR improvements:

Figure 2: FCR improvements for animals receiving Activo

Products mitigating the adverse effects of toxins

Both mycotoxins and bacterial toxins negatively impact gut health. Mycotoxins are ingested with the feed; bacterial toxins appear when certain bacteria proliferate in the gut, e.g., gram-negative bacteria releasing LPS or Clostridium perfringens producing NetB and Alpha-toxin.

Products that mitigate the harmful effects of toxins help to protect gut health and maintain an optimal feed efficiency, as shown with a trial conducted with Mastersorb Gold:

Table 4: Trial design, the impact of Mastersorb Gold on broilers challenged with zearalenone and DON-contaminated feed

Figure 3: Average FCR for broilers, with or without zearalenone and DON challenge, with or without Mastersorb Gold supplementation

2. Improve nutrient utilization

Maximum use of the nutrients contained in the feed can be obtained with the help of feed additives that promote digestion. Targeting the animal, selected phytomolecules are used for their digestive properties. Focusing on the feed, specific enzymes can unlock nutrients and thus improve feed efficiency.

Phytomolecules support the animal’s digestive system

Phytomolecules promote optimal digestion and absorption of nutrients by stimulating the secretion of digestive juices, such as saliva or bile, enhancing enzyme activity, and favoring good GIT motility (Platel and Srinivasan, 2004). FCR improvements thanks to the use of a phy­tomolecules-based product (Activo) are shown in figure 2.

Enzymes release more nutrients from feed

Enzymes can degrade arabinoxylans, for example. Arabinoxylans are the most common NSP fraction in all cereals – and are undigestible for monogastric animals. Enzymes can make these substances available for animals, allowing for complete nutrient utilization.  Additionally, nutrients trapped due to the cage effect are released, altogether increasing the energy content of the diet and improving FCR.

3. Be proactive about preserving feed quality

The quality of feed can deteriorate, for instance, when nutrients oxidize, or mold infestation occurs. Oxidation by-products promote oxidative stress in the intestine and may lead to tissue damage. Molds, in turn, take advantage of the nutrients contained in the feed and produce mycotoxins. Both cases illustrate the importance of preventing feed quality issues. Feed additives such as antioxidants and mold inhibitors mitigate these risks.

Antioxidants prevent feed oxidation

Antioxidants scavenge free radicals and protect the feed from spoilage. In animals, they mitigate the adverse effects of oxidative stress. Antioxidants in pig nutrition can stabilize DDGS and other fatty ingredients in the feed, maintaining nutrient integrity and availability. Figure 4 shows the FCR improvement that a producer in the US obtained when using the antioxidant product Santoquin in pork finisher diets containing 30% DDGS.

Figure 4: FCR improvement in pigs receiving Santoquin (trial with a Midwest pork producer)

In DDGS-free diets, which are more common in poultry production, antioxidants also help optimize FCR, as shown by the results of a comprehensive broiler field study in 2015 (figure 5).

Figure 5: FCR in broilers receiving Santoquin, compared to a non-supplemented control group

Inhibiting molds and keeping feed moisture

To round off the topic of feed quality preservation, one should consider mold inhibitors, which also play an essential role. Used at the feed mill, these products blend two types of ingredients with their different modes of action: surfactants and organic acids. Surfactants bind active water so that the moisture of the feed persists, but fungi cannot survive. Organic acids, on the other hand, have anti-fungal properties, directly acting against molds. Both actions together prevent the reduction of energy in the feed, keeping feed efficiency at optimal levels.

Conclusion

The improvement of feed efficiency ranks as one of the most, if not the most, critical measures to cope with rising feed costs. By achieving optimal nutrient utilization, producers can make the most out of the available raw materials.

The feed industry offers diverse solutions to support animal producers in optimizing feed efficiency. Improving gut health, mitigating the negative impact of harmful substances, and maintaining feed quality are crucial steps to achieving the best possible FCR and, hence, cost-effective animal production.

References

Adam, F., and L. Bütfering. “Wann Müssen Meine Schweine an Den Haken?” top agrar. top agrar online, October 1, 2009. https://www.topagrar.com/schwein/aus-dem-heft/wann-muessen-meineschweine-an-den-haken-9685161.html.

Almeida, Leopoldo Malcorra, Vitor Augusto Zavelinski, Katiucia Cristine Sonálio, Kariny Fonseca da Silva, Keysuke Muramatsu, and Alex Maiorka. “Effect of Feed Particle Size in Pelleted Diets on Growth Performance and Digestibility of Weaning Piglets.” Livestock Science 244 (2021). https://doi.org/10.1016/j.livsci.2020.104364.

Chewning, C.G., C.R. Stark, and J. Brake. “Effects of Particle Size and Feed Form on Broiler Performance.” Journal of Applied Poultry Research 21, no. 4 (2012): 830–37. https://doi.org/10.3382/japr.2012-00553.

Gaines, A. M., B. A. Peerson, and O. F. Mendoza. “Herd Management Factors That Influence Whole Feed Efficiency.” Essay. In Feed Efficiency in Swine, edited by J. Patience, 15–39. Wageningen Academic, 2012.

Kolawole, Oluwatobi, Abigail Graham, Caroline Donaldson, Bronagh Owens, Wilfred A. Abia, Julie Meneely, Michael J. Alcorn, Lisa Connolly, and Christopher T. Elliott. “Low Doses of Mycotoxin Mixtures below EU Regulatory Limits Can Negatively Affect the Performance of Broiler Chickens: A Longitudinal Study.” Toxins 12, no. 7 (2020): 433. https://doi.org/10.3390/toxins12070433.

Patience, J. F. “The Influence of Dietary Energy on Feed Efficiency in Grow-Finish Swine.” Essay. In In Feed Efficiency in Swine, edited by J. Patience, 15–39. Wageningen Academic, 2012.

Patience, John F., Mariana C. Rossoni-Serão, and Néstor A. Gutiérrez. “A Review of Feed Efficiency in Swine: Biology and Application.” Journal of Animal Science and Biotechnology 6, no. 1 (2015). https://doi.org/10.1186/s40104-015-0031-2.

Platel, K., and K. Srinivasan. “Digestive Stimulant Action of Spices: A Myth or Reality?” Indian J Med Res, pp 167-179 119 (May 2004): 167–79. http://www.ncbi.nlm.nih.gov/pubmed/15218978

Richert, B. T., and J. M. DeRouchey. “Swine Feed Processing and Manufacturing.” Pork Information Gateway, September 14, 2015. https://porkgateway.org/resource/swine-feed-processing-and-manufacturing/.

Saldaña, B., P. Guzmán, L. Cámara, J. García, and G.G. Mateos. “Feed Form and Energy Concentration of the Diet Affect Growth Performance and Digestive Tract Traits of Brown-Egg Laying Pullets from Hatching to 17 Weeks of Age.” Poultry Science 94, no. 8 (2015): 1879–93. https://doi.org/10.3382/ps/pev145.

Vukmirović, Đuro, Radmilo Čolović, Slađana Rakita, Tea Brlek, Olivera Đuragić, and David Solà-Oriol. “Importance of Feed Structure (Particle Size) and Feed Form (Mash vs. Pellets) in Pig Nutrition – A Review.” Animal Feed Science and Technology 233 (2017): 133–44. https://doi.org/10.1016/j.anifeedsci.2017.06.016.

By Dr. Inge Heinzl, Editor, EW Nutrition

Nowadays, intensive livestock farming with high stocking densities causes stress in the animals and affects the immune system^{9, 13}. The increase in respiratory diseases with associated losses and costs is only one of the consequences. Due to antimicrobial resistance, antibiotics should only be used in critical cases, so effective alternatives are requested to support the animals.

Respiratory problems are a conjunction of several factors

It already has a name: PRDC or the Porcine Respiratory Disease Complex describes the cooperation of viruses, bacteria, and non-infectious factors such as environmental conditions (e.g., insufficient ventilation), stocking density, management (e.g., all-in-all-out only by pens and not for the whole house) and pig-specific factors such as age and genetics, altogether causing respiratory issues in pigs. Non-infectious factors such as high ammonia levels weaken the immune system and lay the foundation for, e.g., mycoplasmas which damage the ciliated epithelial cells in the upper respiratory tract, the first line of defense, and pave the way for PRRS viruses. They, on their part, enter the respiratory tract embedded in inhaled dust. There, they harm the macrophages and breach a further barrier of defense. Another pathfinder is the Porcine Circovirus 2 (PCV2), which destroys specific immune cells and leads to a generally higher susceptibility to infectious agents. Bacteria such as Pasteurella multocida or Streptococcus suis further on can cause secondary infections^{7, 20, 22}. Also, the combination of mycoplasma hyopneumoniae and porcine circovirus, both typically low pathogenic organisms, leads to severe respiratory disease¹⁵.

Restricted respiratory function impacts growth

The main tasks of the respiratory tract are to take in oxygen from the air and to pump out the CO₂ entailed by the catabolism of the tissue. In pigs, however, the respiratory tract is also responsible for thermoregulation, as pigs don’t have perspiration glands. The animals must get rid of excessive heat by rapid breathing. If the respiratory function is affected due to disease, thermoregulatory capacity is reduced. The resulting lower feed intake leads to decreased growth performance and less economic profit¹⁷. One of the first studies concerning this topic was conducted by Straw et al. (1989)²¹. They asserted that, with every 10 % more affected lung tissue, daily gain decreased by about 37g. This negative correlation between affected lung tissue and weight gain could be confirmed by Paz-Sánchez et al. (2021)¹⁸. They saw that animals with >10% lung parenchyma impacted by cranioventral bronchopneumonia needed a longer time to market (208.8 days vs. 200.8 days in the control), showed a lower carcass weight (74.1 kg vs. 77.7 kg in the control group) and, therefore, also a lower daily gain (500.8 g/day compared to 567.2 g/d). In another study, Pagot and co-workers (2007)¹⁶ observed 7000 pigs from 14 French farms. They saw a significant negative correlation (p<0.001) between the prevalence of pneumonia and growth and a weight gain loss of about 0.7 for each point of pneumonia increase.

Plant extracts support pigs with different modes of action

People have always used herbal substances to cure illnesses, be it willow bark for pain, chamomile for anti-inflammation or an upset stomach. Ribwort and thyme are used as cough suppressants, and eucalyptus and menthol help you breathe better. What is good for humans can also be used for pigs. To use plant extracts efficiently, it is crucial to know their specific modes of action. Due to their volatile nature, essential oils can directly reach the target site, the respiratory tract, via inhalation¹.

1.   Plant extracts can act as an antimicrobial

Many essential oils show some degree of antimicrobial activity. So, the oils of, e. g., oregano, tea tree, lemongrass, lemon myrtle, and clove are effective against a wide range of gram-positive and gram-negative bacteria. LeBel et al. (2019)¹² tested nine different oils against microorganisms causing respiratory issues in pigs. They found the oils of cinnamon, thyme, and winter savory the most effective against Streptococcus suis, Actinobacillus pleuropneumoniae, Actinobacillus suis, Bordetella bronchiseptica, Haemophilus parasuis, and Pasteurella multocida, with MICs and MBCs from 0.01 to 0.156%.

Not only the direct bactericidal effect is important. 1,8 cineol, e.g., although often considered to have only marginal or no antimicrobial activity¹⁰, effectively causes leakage of bacterial membranes² and allows other harmful substances to enter the bacterial cell. However, cineol possesses noted antiviral properties.

2.  Plant extracts can have mucolytic, spasmolytic, and antitussive effects

In the case of respiratory disease, mucolytic and spasmolytic characteristics of phytomolecules are decisive in allowing efficient respiration. Mucolytic substances dissolve the mucus, make it more liquid and facilitate the removal from the respiratory tract by the ciliated epithelium. As liquifying the mucus with essential oils or phytomolecules is related to local irritation, dosage and application form are of the highest importance⁵.

The “cleanup” is called mucociliary clearance. There are also substances that do not dissolve the mucus but stimulate the mucociliary apparatus itself and increase mucociliary transport velocity¹.

Spasmolytic activity on airway smooth muscle is shown, for example, by menthol⁸ or the essential oil of eucalyptus tereticornis⁴. Menthol showed antitussive effects¹¹.

3.   Plant extracts can have immune-modulatory and anti-inflammatory effects

If animals are suffering from a respiratory disease or are in danger of catching one, a supportive influence on the immune system is helpful. One thing is to make vaccination more effective. Mieres-Castro et al. (2021)¹⁴ figured out that the combined application of influenza vaccine and cineol to mice resulted in a longer survival time, less inflammation, less weight loss, a lower mortality rate, less pulmonary edema, and lower viral titers after a challenge with the virus seven days after the vaccination than the mice without cineol.

On the other hand, if the animals are already ill, strengthening their immune defense is essential. Li et al. (2012)¹³ showed that interleukin-6 concentration was lower (p<0.05) and the tumor necrosis factor-α level was higher (p<0.05) in the plasma of pigs fed a diet with 0.18% thymol and cinnamaldehyde than in the negative control group. Also, the lymphocyte proliferation for pigs fed the diet with thymol and cinnamaldehyde increased significantly compared with the negative control (p<0.05).

4.   Plant extracts can act as an antioxidant

There are respiratory diseases in which reactive oxygen species (ROS) play an important role. In these cases, the antioxidant activity of phytomolecules is of interest. Here again, Li et al. (2012)¹³ asserted that a diet with 0.18% thymol and cinnamaldehyde increased the total antioxidant capacity level (p<0.05) in pigs compared to a negative control group.

Can Baser & Buchbauer (2010) described eucalyptus oil containing 1,8-cineole, the monoterpene hydrocarbons α-pinene (10–12%), p-cymene, and α-terpinene, and the monoterpene alcohol linalool, is used to treat diseases of the respiratory tract in which ROS play an important role.

5.   Plant extracts reduce the production of ammonia

High concentration of ammonia in the pig house stresses the pigs’ respiratory tract and makes them susceptible to disease. Ammonia develops when feces and urine merge and the enzyme urease degrades them. Yucca extract, containing a high percentage of saponins, can reduce ammonia emissions in animal houses. Ehrlinger (2007)⁵ supposes that the glyco-components of the saponins bind ammonia and other harmful gases. Another explanation can be the decreased activity of urease shown in a trial with rats¹⁹ or the reduction of total nitrogen, urea nitrogen, and ammonia nitrogen in sow manure³.

6.   Plant extracts often show diverse modes of useful action against respiratory issues

Due to their natural task – protecting the plant – essential oils typically do not show only one beneficial activity for us. Camphene, for example, in Thymus vulgaris, shows expectorant, spasmolytic, and antimicrobial properties and is used in treating respiratory tract infections. Menthol can be effectively used in cases of asthma due to its bronchodilatory activity on smooth muscle, its interaction with cold receptors, and the respiratory drive. Menthol acts antitussive in low concentration, gives the impression of decongestion and reduces respiratory discomfort and sensations of dyspnea.

Cineol, on its part, acts antimicrobial, antitussive, bronchodilatory, mucolytic, and anti-inflammatory. It promotes ciliary transport and improves lung function^{1, 6}. Mucolytic, antioxidant, antiviral, and antibacterial activity is ascribed to thymol⁵.

Trial shows: phytomolecules help to keep respiratory diseases in check

A field study was conducted on a Philippine piglet farm with a history of chronic respiratory issues during the growing phase, with a morbidity of about 10-15%. In this study, a supplement for water containing phytomolecules that support animals against respiratory diseases (Grippozon) was tested. For the trial, 360 randomly selected 28-day-old pigs (average weight: 6.64±0.44 kg) were divided into two groups with 6 replications per group and 30 piglets per replication. All piglets came from sows raised antibiotic-free, and the piglets received antibiotics neither upon weaning except in case of symptoms (scouring: Baytril-1 mL/pig;  respiratory disease: Excede – 1mL/pig). All piglets received the same feed and a regular water therapy regimen:

Control group: no additional supplements
Grippozon group:  Addition of 250 mL of Grippozon per 1000 L of water

As parameters, the incidence of respiratory disease, final weight, daily gain, FCR, and antibiotic cost, were recorded.

The phytomolecules-containing product reduced the incidence of respiratory diseases by 52 %, leading to a 53% lower cost for antibiotic treatment. The animals showed better growth performance (600 g higher average weight and 13 g higher average daily gain), altogether resulting in an extra cost-benefit of 1.76 US$ per pig.

Reduction in disease and medication ensures healthier pigs in the Grippozon-supplemented group, reflected by better performance.

We have means at hand to reduce the use of antibiotics

Respiratory disease is a big problem in pigs. Due to the still high occurrence of antimicrobial resistance, it is essential to reduce antibiotic use as much as possible. Phytomolecules offer the possibility to strengthen the animals’ health so that they are less susceptible to disease or support them when they are already infected. With the help of phytomolecules, we can reduce antibiotic treatments and help keep antibiotics effective when their use is indispensable.

References

1. Can Baser , K. Hüsnü, and Gerhard Buchbauer. Handbook of Essential Oils: Science, Technology, and Applications. Boca Raton, FL: Taylor & Francis distributor, 2010.
2. Carson, Christine F., Brian J. Mee, and Thomas V. Riley. “Mechanism of Action of Melaleuca Alternifolia (Tea Tree) Oil on Staphylococcus Aureus Determined by Time-Kill, Lysis, Leakage, and Salt Tolerance Assays and Electron Microscopy.” Antimicrobial Agents and Chemotherapy 46, no. 6 (2002): 1914–20. https://doi.org/10.1128/aac.46.6.1914-1920.2002.
3. Chen, Fang, Yantao Lv, Pengwei Zhu, Chang Cui, Caichi Wu, Jun Chen, Shihai Zhang, and Wutai Guan. “Dietary Yucca Schidigera Extract Supplementation during Late Gestating and Lactating Sows Improves Animal Performance, Nutrient Digestibility, and Manure Ammonia Emission.” Frontiers in Veterinary Science 8 (2021). https://doi.org/10.3389/fvets.2021.676324.
4. Coelho-de-Souza, Lívia Noronha, José Henrique Leal-Cardoso, Francisco José de Abreu Matos, Saad Lahlou, and Pedro Jorge Magalhães. “Relaxant Effects of the Essential Oil of Eucalyptus Tereticornisand Its Main Constituent 1,8-Cineole on Guinea-Pig Tracheal Smooth Muscle.” Planta Medica 71, no. 12 (2005): 1173–75. https://doi.org/10.1055/s-2005-873173.
5. Ehrlinger, Miriam. “Phytogene Zusatzstoffe in der Tierernährung.” Dissertation, Tierärztliche Fakultät LMU, 2007.
6. Gelbe Liste Online. “Gelbe Liste Pharmindex Online.” Gelbe Liste. Accessed January 20, 2023. https://www.gelbe-liste.de/.
7. Hennig-Pauka, Isabell. “Atemwegserkrankungen: Schutz fängt schon bei Ferkeln an.” Der Hoftierarzt, January 13, 2021. https://derhoftierarzt.de/2021/01/atemwegserkrankungen-schutz-faengt-schon-bei-ferkeln-an/.
8. Ito, Satoru, Hiroaki Kume, Akira Shiraki, Masashi Kondo, Yasushi Makino, Kaichiro Kamiya, and Yoshinori Hasegawa. “Inhibition by the Cold Receptor Agonists Menthol and ICILIN of Airway Smooth Muscle Contraction.” Pulmonary Pharmacology & Therapeutics 21, no. 5 (2008): 812–17. https://doi.org/10.1016/j.pupt.2008.07.001.
9. Kim, K.H., E.S. Cho, K.S. Kim, J.E. Kim, K.H. Seol, S.J. Sa, Y.M. Kim, and Y.H. Kim. “Effects of Stocking Density on Growth Performance, Carcass Grade and Immunity of Pigs Housed in Sawdust Fermentative Pigsties.” South African Journal of Animal Science 46, no. 3 (2016): 294–301. https://doi.org/10.4314/sajas.v46i3.9.
10. Kotan, Recep, Saban Kordali, and Ahmet Cakir. “Screening of Antibacterial Activities of Twenty-One Oxygenated Monoterpenes.” Zeitschrift für Naturforschung C 62, no. 7-8 (2007): 507–13. https://doi.org/10.1515/znc-2007-7-808.
11. Laude, E.A., A.H. Morice, and T.J. Grattan. “The Antitussive Effects of Menthol, Camphor, and Cineole in Conscious Guinea-Pigs.” Pulmonary Pharmacology 7, no. 3 (1994): 179–84. https://doi.org/10.1006/pulp.1994.1021.
12. LeBel, Geneviève, Katy Vaillancourt, Philippe Bercier, and Daniel Grenier. “Antibacterial Activity against Porcine Respiratory Bacterial Pathogens and in Vitro Biocompatibility of Essential Oils.” Archives of Microbiology 201, no. 6 (2019): 833–40. https://doi.org/10.1007/s00203-019-01655-7.
13. Li, Xue, Xia Xiong, Xin Wu, Gang Liu, Kai Zhou, and Yulong Yin. “Effects of Stocking Density on Growth Performance, Blood Parameters and Immunity of Growing Pigs.” Animal Nutrition 6, no. 4 (2020): 529–34. https://doi.org/10.1016/j.aninu.2020.04.001.
14. Mieres-Castro, Daniel, Sunny Ahmar, Rubab Shabbir, and Freddy Mora-Poblete. “Antiviral Activities of Eucalyptus Essential Oils: Their Effectiveness as Therapeutic Targets against Human Viruses.” Pharmaceuticals 14, no. 12 (2021): 1210. https://doi.org/10.3390/ph14121210.
15. Opriessnig, T., L. G. Giménez-Lirola, and P. G. Halbur. “Polymicrobial Respiratory Disease in Pigs.” Animal Health Research Reviews 12, no. 2 (2011): 133–48. https://doi.org/10.1017/s1466252311000120.
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17. Pallarés Martínez, Francisco José, Jaime Gómez Laguna, Inés Ruedas Torres, José María Sánchez Carvajal, Fernanda Isabel Larenas Muñoz, Irene Magdalena Rodríguez-Gómez, and Librado Carrasco Otero. “The Economic Impact of Pneumonia Processes in Pigs.” https://www.pig333.com. Pig333.com Professional Pig Community, December 14, 2020. https://www.pig333.com/articles/the-economic-impact-of-pneumonia-processes-in-pigs_16470/.
18. Paz-Sánchez, Yania, Pedro Herráez, Óscar Quesada-Canales, Carlos G. Poveda, Josué Díaz-Delgado, María del Quintana-Montesdeoca, Elena Plamenova Stefanova, and Marisa Andrada. “Assessment of Lung Disease in Finishing Pigs at Slaughter: Pulmonary Lesions and Implications on Productivity Parameters.” Animals 11, no. 12 (2021): 3604. https://doi.org/10.3390/ani11123604.
19. Preston, R. L., S. J. Bartle, T. May, and S. R. Goodall. “Influence of Sarsaponin on Growth, Feed and Nitrogen Utilization in Growing Male Rats Fed Diets with Added Urea or Protein.” Journal of Animal Science 65, no. 2 (1987): 481–87. https://doi.org/10.2527/jas1987.652481x.
20. Ruggeri, Jessica, Cristian Salogni, Stefano Giovannini, Nicoletta Vitale, Maria Beatrice Boniotti, Attilio Corradi, Paolo Pozzi, Paolo Pasquali, and Giovanni Loris Alborali. “Association between Infectious Agents and Lesions in Post-Weaned Piglets and Fattening Heavy Pigs with Porcine Respiratory Disease Complex (PRDC).” Frontiers in Veterinary Science 7 (2020). https://doi.org/10.3389/fvets.2020.00636.
21. Straw , B. E., V. K. Tuovinen, and M. Bigras-Poulin. “Estimation of the Cost of Pneumonia in Swine Herds.” J Am Vet Med Assoc. 1989 Dec 15;195(12):1702-6. 195, no. 12 (December 15, 1989): 1702–6.
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By Technical Team, EW Nutrition

A variety of stressors simultaneously occur at weaning, making this probably the most challenging period in pig production. During weaning, we commonly see altered gut development and gut microbiome, which increases piglets’ vulnerability to diseases. The most classic clinical symptom resulting from these stressors is the occurrence of post-weaning diarrhea. It is a sign that something went wrong, and piglet development and overall performance may be compromised (Guevarra et al. 2019).

Besides weaning, an unavoidable practice in pig production, the swine industry has been facing other changes. Among them, the increased pressure to reduce the use of antimicrobials stands out. Antimicrobials are often associated with improved piglet performance and health. Their usage has been reduced worldwide, however, due to the threat of antimicrobial resistance that affects not just animal health but also human health (Cardinal et al., 2019).

Reduce antimicrobials and post-weaning diarrhea: can piglet nutrition achieve both?

With these drastic changes for the piglets and the global swine industry, producers must find solutions to keep their farms profitable — especially from a nutritional perspective. Our last article presented two feed additives that can be part of an antibiotic-free concept for post-weaning piglets. This article will highlight a few essential nutritional strategies that swine producers and nutritionists must consider when formulating post-weaning feed without or with reduced amounts of antimicrobials.

What makes weaning so stressful for piglets?

Producers, nutritionists, and veterinarians all agree that weaning is a tough time for piglets (Yu et al., 2019) and, therefore, a challenge to all those involved in the pig production chain. Although there is a global trend towards increasing weaning age, generally speaking, animals are still immature when going through the weaning process. They face several physiological, nutritional, and environmental changes (figure 1).

Figure 1. Factors associated with weaning can compromise piglet well-being and performance

Most of these changes become “stressors” that trigger a cascade of reactions affecting the balance and morphology of the intestinal microbiome (figure 2). The outcome is a decrease in the piglets’ well-being and, in most cases, performance. We need to clearly understand how these stressors affect pigs to develop effective strategies against post-weaning growth impairments, especially when no antimicrobials are allowed.

Figure 2. Schematic diagram illustrating the effects of stress in weaned piglets (adapted from Jayaraman and Nyachoti, 2017)

Weaning support starts before weaning

The use of creep feed has been evaluated and even criticized for many years. Some operations are still reluctant to use such a feed due to its high cost and amount of labor on the farm, with manually providing feed and cleaning feeding trays. In addition, some questions have been raised regarding the ideal composition of the creep feed – how much complexity should we add to this special diet?

Therefore, the benefits of creep feed are under re-evaluation, not only considering piglet physiology per se, but also feed characteristics and different feeding programs. Recent studies have questioned highly complex creep feed formulations. Creep feed is being called “transition feed” (Molist, 2021) – i.e., that meal which is complementary to sows’ milk and not a replicate of it, helping piglets during the period of changing its main source of nutrients. We must, therefore, look at it as a way of making piglets familiar with solid feed, as highlighted by Mike Tokach during the 2020 KSU Swine Day. Dr. Tokach also mentioned that the presence of feeders in the lactation pen could stimulate the exploratory behaviors of the piglets. Combined, these practices can lead to a higher feed intake and performance during the nursery phase.

Towards a pragmatic stance on creep feed

Heo et al. (2018) evaluated three different creep feed types: a highly digestible creep feed, weaning feed as creep feed, and sow feed as creep feed until weaning. Piglets receiving the highly digestible creep had higher feed intake during the second to the last week pre-weaning (14 to 21 days of age) and higher ADG during the last week pre-weaning (21 to 28 days of age). This resulted in a trend for higher weaning weight. However, these benefits did not persist after weaning when all piglets received the weaning feed.

Guevarra et al. (2019) also suggested that the abrupt transition in piglet nutrition to a more complex nutrient source can influence shifts in the gut microbiota, impacting the absorptive capacity of the small intestine. Yang et al. (2016) evaluated 40 piglets from eight litters during the first week after weaning. They found that the change in diet during weaning reduced the proliferation of intestinal epithelial cells. This indicates that this period affects cellular macromolecule organization and localization, in addition to energy and protein metabolism. These results suggest that “similarity” in feed pre- and post-weaning may contribute more to the continuity of nutrient intake post-weaning than a highly complex-nutrient dense creep feed.

Nutritional strategies without antibiotics: focus on pig physiology

As mentioned, it is crucial to avoid a drastic drop in feed/nutrient intake after weaning compared to pre-weaning levels. In a classic study, Pluske et al. (1996) showed the importance of high intake levels on villus weight (used as a reference for gut health, cf. graph 1). Although not desirable, the reduction should be considered “normal” behavior.

Imagine these recently weaned piglets, facing all these stressors, having to figure out within this new group of peers when it is time to eat, where to find food, why water and food now come from two distinct sources… Therefore, management, feeding, water quality, and other aspects play important roles in post-weaning feed intake (figure 3).

Graph 1. Villus height following different levels of feed intake (M = maintenance) post-weaning (a.b.c bars with unlike superscript letters are different at P<0.05). (From Pluske et al., 1996.)

From a nutritional perspective, piglets at weaning experience a transition from milk (a high-fat, low-carbohydrate liquid) to a plant-based diet (a solid, low-fat, and high-carbohydrate diet) (Guevarra et al., 2019). Even when previously introduced to solid feed, it is still difficult for their enzymatic system to cope with grains and beans.

One of the consequences of the lower digestibility capacity is an increase of undigested nutrients. Harmful bacteria thrive and cause diarrhea, reducing even further an already compromised feed intake. This cycle must be broken with the support of formulations based on piglet physiology.

Post-weaning feed must support digestion and nutrient absorption, including the largest possible share possible of high-quality, digestible ingredients, with low anti-nutritional factors. High-performing feed also integrates functional amino acids, functional carbohydrates, and additives to support the intestinal mucosa and gut microbiome.

Figure 3. Supporting piglets with effective solutions

Crude protein – more of the same?

Levels of crude protein in piglet feed have been in the spotlight for quite some time. The topic can be very controversial where the exact percentage of crude protein in the final feed is concerned. Some nutritionists pragmatically recommend maximal levels of 20% in the weaner feed. Others go a bit lower, with some formulations reaching 17 to 18% total crude protein. Levels above 20% will incur high costs and may accentuate the growth of pathogenic bacteria due to a higher amount of undigested protein in the distal part of the small intestine (figure 4).

Figure 4. The dynamics of crude protein levels in piglet feed

What is not open for discussion, however, is the quality of the protein used, in terms of:

• digestibility,
• the total amount of anti-nutritional factors, and
• the correct supply of essential and non-essential amino acids (particularly lysine, methionine, threonine, tryptophane, isoleucine and valine).

The critical role of digestibility

High-digestibility ingredients for piglets need to deliver minimum 85% digestibility. In most cases, to reach high biological values (correlating to high digestibility), these ingredients typically undergo different processing steps, including heat, physical, and chemical treatments. Animal by-products (such as hydrolyzed mucosa, fish meal, spray-dried plasma) and processed vegetable sources (soy protein concentrate, extruded grains, potato protein) can be used in high amounts during this phase. They will notably reduce the total amount of undigested protein reaching the distal part of the intestine, with 2 main benefits:

• Less substrate for pathogenic bacteria proliferation (and therefore lower incidence of diarrhea)
• Lower nitrogen excretion to the environment

It is common knowledge that certain storage proteins from soybean meal (for instance, glycinin and B-conglycinin) can cause damage to piglets’ intestinal morphology and trigger the activation of the immune system. However, it is normal practice to introduce this ingredient to piglets around weaning so that the animals can develop a certain level of tolerance to such compounds (Tokach et al., 2003). In Europe, where most diets are wheat-barley based, soybean meal is included in levels varying from 3 to 9% in the first 2 diets, with gradual increases during the nursery phase.

Amino acids and protein: manage the balance

When the supply and balance between essential and non-essential amino acids is concerned, reducing total crude protein brings indeed complexity to the formulations. The concept of ideal amino acid should be expanded, ideally, to all 9 essential amino acids (lysine, methionine, tryptophan, threonine, valine, isoleucine, leucine, histidine, and phenylalanine). In most cases, formulations go up to the 5^th or 6^th limiting amino acid. Lawor et al. (2020) suggest 2 practical approaches to avoid deficiencies when formulating low-protein piglet feed:

• Maintain a maximum total lysine to crude protein ratio in the diet of 7.1 to 7.4%
• Do not exceed the SID lysine to crude protein ratio of 6.4%

Some conditionally essential amino acids (e.g. arginine, proline, and glutamine) also play critical roles in diets with reduced crude protein levels. Glutamine is especially interesting. When supplemented in the feed, it can be used as a source of energy by the intestinal epithelium and, therefore, prevent atrophy and support nutrient absorption, resulting in better growth post-weaning (Hanczakowska and Niwińska, 2013; Watford et al., 2015)

The importance of the buffer capacity of the feed – supporting the enzymatic system

Given the move towards antibiotic reduction, this topic is more relevant than ever to nutritionists worldwide. The acid-binding capacity (also known as buffering capacity) of the feed directly affects the capacity of the stomach to digest protein. Hence, buffer capacity is of utmost importance in antimicrobial-free diets as it influences the growth of pathogenic bacteria (Lawlor et al., 2005).

In short, the acid-binding capacity is the resistance of an ingredient or complete feed to pH change. For piglet feed/feed ingredients, it is normally measured by the acid-binding capacity at pH4 (ABC-4). A higher ABC-4 equates to a higher buffering capacity. Feed with a high ABC-4 would require large amounts of gastric acid for the pH of the stomach to reach 4 and below. As the post-weaned piglet has limitations on producing and secreting acid, the stomach pH would stay high and, thus, less favorable for protein digestion.

The recommendation is to have a complete feed based on single ingredients with low ABC-4 values and to use additives that further reduce the ABC-4 value (such as organic acids). According to Molist (2020), post-weaning feed must have an ABC-4 that is lower than 250-300 meq/kg.

Talking about fiber

Dietary fibers are also known for regulating intestinal health in both humans and animals. Chen et al. (2020), for example, examined the effects of dietary soluble fibers (inulin) and insoluble fibers (lignocellulose) in weaned piglet diets for four weeks. Results showed that combining those fibers can positively influence nutrient digestibility, gut microbiota composition, intestinal barrier functions, and growth performance (table 1 ).

Table 1. Effects of dietary fiber supplementation on piglet growth performance (adapted from Chen et al., 2020)

How to reduce antimicrobials? Understand the roles of piglet physiology and nutrition

Swine producers might think that “How can I reduce antimicrobial use on my farm?” and “How can I improve the performance of piglets at weaning?” are two separate questions. However, that is not always the case. Answers based on a deep understanding of physiology and nutrition dynamics help piglets overcome the challenges encountered during weaning – and, thus, lessen the need for antimicrobial interventions.

In this article, we have explored the basic principles that are the basis for ensuring the performance and health of the post-weaning piglet. Although we do not have a singular solution for eliminating antimicrobials on our pig farms, we can count on a group of robust and integrated nutritional strategies. By integrating factors ranging from management to feed additives, these solutions can improve piglet health and performance throughout their lives.

To know more about Gut health products click here.

Piglet weaning is a critical period. When not properly managed, it leads to decreased performance, diarrhea, and sometimes mortality. 

The six areas of intervention in our infographic will help pig producers manage these stressors, avoid diarrhea, and maintain piglet health and performance. 

Antimicrobial resistance is a natural process but this is accelerated by inappropriate prescribing of antimicrobials, poor infection control practices and the unnecessary use of antimicrobials in agriculture (Barber and Sutherland, 2017).

Antimicrobial resistance – a threat to humanity

Resistance to specific antibiotics occurs through mutations that enable the bacteria to withstand an antibiotic treatment. One mechanism is the production of enzymes degrading or altering the antibiotic, rendering them harmless. The elimination of entrances for antibiotics or the development of pumps discharging them is another possibility. A further option is the elimination of the targets the antibiotic would attack.

So-called “resistance genes” are responsible for resistance. These genes can be transferred from one bacterium to another and also from beneficial bacteria to harmful ones. When antibiotics are used, “normal” bacteria are killed; the resistant ones survive and have all possibilities to proliferate. The Dutch Government has been tracking resistant bacteria in poultry flocks for the last two decades. A clear correlation between antibiotic use and the percentage of resistance could be observed. The good thing: according to the 2020 MARAN report (De Greeff et al., 2020), by reducing the use of antibiotics, the occurrence of resistances can be pushed back.

Figure 1. Sales of antibiotics from 1999 to 2016 and the development of resistances (MARAN report, 2018)

Antibiotic use in animal production

In pig production, antibiotics are often used in stressful situations such as weaning or moving. Antibiotics decrease the pathogenic pressure in animals and help them overcome these critical periods. Disadvantage: Antibiotics do not differentiate between good and bad but between susceptible and resistant. Therefore, also the beneficial gut flora gets destroyed through antibiotic treatment, and resistance is spread.

After the ban of antibiotic growth promoters in Europe in 2006, the US has also made considerable efforts to reduce the use of antibiotics.

Is performance at risk without antibiotics?

When antibiotics are taken out of livestock production, measures in different areas must be implemented to keep performance and profitability high. Without supporting the animals by other means, they will get sick and even die in acute cases. Subclinical disease forms reduce their feed intake, and growth performance consequently decreases. According to literature, losses due to decreased average weight gain can be up to $40 per pig (Hao et al., 2014).

Goal: reducing antibiotics while maintaining performance

To support pigs, especially during the afore-mentioned critical periods, alternatives focusing on the maintenance of gut health and, therefore, also overall health must be chosen. This goal can only be achieved by balancing the intestinal flora with reducing pathogenic bacteria occurrence.

Phytomolecules are an effective solution

Phytomolecules are produced by plants to defend themselves against predators or pathogens. Farmers use the substances in animal feeds to support digestion, improve palatability, but also to reduce pathogenic pressure (Baser and Buchbauer, 2010).

In animal feeding, different application forms are available:

• As premixes containing microencapsulated phytomolecules with a slow release. This version is mixed into the feed in the feed mill and constitutes continuous long-term support for the animals. Due to microencapsulation, the active substances are released where they are needed – in the gut.
• As liquid complementary feeds for the application via the waterline. The application of the liquid form to the animals can be decided from one day to the other. It is an optimal additional tool to support the pigs in challenging situations such as weaning.

Scientific trials show: In-feed phytomolecules support performance

A trial conducted at the Federal University of Lavras (Brazil) evaluated if phytomolecules as a regular diet component can deliver the same effects on growth performance as AGPs in pig production.

For the trial, 108 castrated newborn male pigs were allocated to 3 groups (control, AGP (antibiotic growth promoters), and Activo). Pigs were weaned at 23 days of age with an average weight of 6.3 kg. They were fed a 3-phase diet (nursery, growing, and finishing). The inclusion rates of the additives (antibiotics and phytomolecules-based product – Activo) are shown in table 1.

On days 0, 1, and 2 of the experiment, the animals were challenged by applying a solution containing 10⁷ CFU of E. coli K88, producing the toxins LT, Sta, and bST. Additionally, during the two last days before the growing phase, the animals were exposed to 5h of heat stress, using infrared lamps and closed windows. The parameters weight gain, final weight, FCR, and gut flora composition in the cecum were evaluated.

Table 1. Inclusion rate of the additives in the feed
AGP: Antibiotic growth promoter; Activo: product based on phytomolecules, microencapsulated (EW Nutrition)

Results

The results of this trial are shown in figure 2.

Concerning growth performance, the group fed the phytomolecules-based product Activo showed a 4.36 kg higher final weight after 126 days than the group provided AGPs (p=0.11), resulting in a 3.28 kg higher weight gain (p=0.21) and a 13 points better feed conversion.

Figure 2. Data of growth performance including final weight, weight gain and FCR adjusted to 100kg

The evaluation of some bacteria naturally occurring in the gut flora showed that, in contrast to the antibiotic prophylaxes, Activo has no negative impact on E. coli, Lactobacillus and Bifidobacterium. However, the antibiotic group showed a slight decrease in the population of Lactobacilli (Figure 3).

Figure 3. Impact of antibiotics and phytomolecules (Activo) on the composition of the gut flora

This trial shows Activo increasing growth performance and feed conversion without any negative impact on gut flora. The addition of phytomolecules (Activo) to the feed is documented as optimal long-term support instead of antibiotic growth promoters.

Trial shows: Phytomolecules support animals in critical situations like weaning

In a trial conducted in the USA, a product containing phytomolecules and organic acids (Activo Liquid, EW Nutrition) was compared to an antibiotic for controlling bacterial diseases in US pig production (Mecadox). For the trial, a total of 360 weanling pigs, about 19 days old and weighing 5.70 kg, were divided into four groups. Each group consists of 9 pens with 10 animals per pen. All groups were fed a 3-phase diet.

To the different trial groups, the following products were added (table 2):

These performance parameters were evaluated: live weight, daily gain, daily feed intake, feed:gain ratios, and mortality.

Table 2. Feeding and inclusion of the additives

Results

The results of the trial are shown in figure 4. Concerning growth, no significant differences could be seen between the groups, only numerical differences. Live weight in the antibiotic group was 25.95 kg, and in the Activo Liquid groups, it ranges from 25.77 kg (shortest period of application) to 26.20 kg (see below). This resulted in calculated values for an average daily gain of 473 g in the Mecadox fed animals and 463 to 487g in the Activo Liquid groups. Due to a lower feed intake per kg of weight gain, all groups fed Activo Liquid showed a significantly (p=0.05) better feed conversion than the Mecadox group.

Figure 4. Live weight in the groups fed the antibiotic Mecadox and the phytomolecules-based product Activo Liquid for different periods
Average daily gain in the different trial groups
Average daily feed intake in the different trial groups (P=0.05)

Concerning mortality, the group fed Activo Liquid for 5 days showed the lowest mortality rate of 1.1% (figure 5).

Figure 5. Feed:gain ratio in the different trial groups (P=0.05) & Mortality rates

Considering all parameters, the group fed Activo Liquid for five days provided the best results: numerically the lowest mortality rate, highest daily gain, and one of the two lowest feed:gain ratios. This trial concludes that Activo Liquid with an application period of five days can safely replace antibiotic growth promoters in the diet. Therefore, Activo Liquid is an interesting tool to additionally support pigs during critical periods of life.

Phytomolecules help keep health and performance together

The trials conducted with two types of phytomolecules-based products show that phytomolecules efficiently support pigs to achieve their genetic potential. A basic supply of these substances within the feed yields results similar to those of animals receiving antibiotic growth promoters (AGPs). In challenging situations like weaning, additional short-term supply is recommended, which can be done with liquid products via the waterline.

With this strategy, the use of antibiotic growth promoters and, therefore, antibiotics in general can be drastically reduced. This approach can help decrease antimicrobial resistance and, not to be forgotten, accommodates final customers’ requests for the lower usage of antibiotics in livestock.

References

Barber, Sarah, and Nikki Sutherland. “O’Neill Review into Antibiotic Resistance.” House of Commons Library, March 6, 2017. https://commonslibrary.parliament.uk/research-briefings/cdp-2017-0074/.

Baser, Kemal Hüsnü Can, and Gerhard Buchbauer. Handbook of Essential Oils: Science, Technology, and Applications. Boca Raton, FL: Taylor & Francis distributor, 2010.

Davies, Dame Sally. “Antibiotic Resistance ‘Big Threat to Health’.” BBC News. BBC, November 16, 2012. https://www.bbc.co.uk/news/health-20354536.

De Greeff, S.C., A.F. Schoffelen, and C.M. Verduin. “MARAN Reports.” WUR. National Institute for Public Health and the Environment – Ministery of Health, Welfare and Sport, June 2020. https://www.wur.nl/en/Research-Results/Research-Institutes/Bioveterinary-Research/In-the-spotlight/Antibiotic-resistance/MARAN-reports.htm.

Hao, Haihong, Guyue Cheng, Zahid Iqbal, Xiaohui Ai, Hafiz I. Hussain, Lingli Huang, Menghong Dai, Yulian Wang, Zhenli Liu, and Zonghui Yuan. “Benefits and Risks of Antimicrobial Use in Food-Producing Animals.” Frontiers in Microbiology 5, no. Art. 288 (2014): 1–11. https://doi.org/10.3389/fmicb.2014.00288.

Marquardt, Ronald R, and Suzhen Li. “Antimicrobial Resistance in Livestock: Advances and Alternatives to Antibiotics.” Animal Frontiers 8, no. 2 (2018): 30–37. https://doi.org/10.1093/af/vfy001.

O’Neill, J. “Tackling Drug-Resistant Infections Globally.” Review on Antimicrobial Resistance. Wellcome Trust / HM Government, May 19, 2016. https://amr-review.org/sites/default/files/160518_Final%20paper_with%20cover.pdf.

The benefits imprinted by genetics with more piglets/sows can be lost along the way to weaning. What can decrease performance and increase mortality in such cases? Why do higher litter sizes so often correlate with higher mortality?

Amongst naturally occurring mycotoxins, the five most important ones are aflatoxin, ochratoxin, deoxynivalenol, zearalenone, and fumonisin. Their incidence varies with the different climates, the prevalence of plant cultures, the occurrence of pests, and the handling of harvest and storage. Worldwide, farmers faced various and sometimes extremely high mycotoxin contamination in their feed materials in 2021. In the following, we show the major challenges in five main regions.

Asia faced high aflatoxin contamination

In Asia, high temperatures and humidity favor Aspergillus growth in grains. As a result, 95 % of the samples in South Asia and three-quarters of the samples in the China and the SEAP region (Indonesia, Philippines, Vietnam) showed aflatoxin contamination. The average contamination being higher than the threshold for all farm animals represents an increased risk for their health and performance.
In China and the SEAP region, also DON and T-2 were highly prevalent. Showing an incidence of more than 60%, they pose a severe risk when combined with aflatoxin.

Fumonisins afflicted the LATAM region

In Mexico, Central and South America, fumonisin contamination prevailed with an incidence of almost 90% at average levels that can be considered risky for swine and dairy. Together with incidence levels of around 60% found for DON and T2, fumonisin may act synergically in the animals, raising the risk for health and performance.
The Fusarium species linked to these mycotoxin contaminations occur in the grains on the field. Amongst others, insect damage, droughts during growing, and rain at silking favor their development.

Trichothecenes prevailed in North America

Contamination with trichothecenes (DON and T2) is the rule in the United States. The interaction of these mycotoxins is at least additive. The damage they cause to the gut opens the door to dysbiosis and disease, decreasing performance and profitability.
Also in this case, the responsible molds for the contamination are Fusarium species that develop when grains are in the field. As with fumonisins, the molds are favored by insect damage, moderate to warm temperatures and rainfall.

Fusarium toxins contaminated grain in the MEA region

Fusarium toxins such as Fumonisin, DON, and T2 prevail in the region of Egypt, Jordan, and South Africa. In combination, these mycotoxins have additive effects at the intestinal level, which increases the risk of dysbiosis in poultry.

A challenging year with long-term repercussions

Since mycotoxin contamination affects animal health, measures must be taken to provide the best protection. Besides improving agricultural practices in the field, smart in-feed solutions and mold inhibitors can be used in stored grain. These measures help producers preserve feed quality after a troubled year for crops around the world.

By Technical Team, EW Nutrition

In modern swine production, one of the key aspects for success is a balanced diet. This essentially means ensuring that the animal meets its daily nutritional requirements for maintenance, growth, and reproduction. In order to provide an appropriate diet and safe feed for the animals, the sensory and nutritional characteristics of the feed must be preserved and issues like the oxidation of the feed must be avoided.

This article aims to highlight why oxidation in  feed can become a big concern for swine producers, what the problems resulting from oxidation in pig feed are, and present practical solutions to improve feed quality and pig performance by controlling the oxidation.

Feed oxidation: What are the dangers?

In pig diets, various sources of lipids are added to increase caloric density, provide essential fatty acids, improve feed palatability, improve pellet quality, and reduce dust (Keer et al., 2015). Some of the feed ingredients are more susceptible to oxidation because of their physical and chemical characteristics, such as milled grains and ingredients of animal origin and vegetable oils with a high content of polyunsaturated fatty acids.

Oxidative rancidity is a type of lipid deterioration. In the oxidation process, the free radicals react with lipids and proteins and induce cellular and tissue damage.

Some consequences of oxidative deterioration are the destruction of fat-soluble vitamins, supplemental fats, and oils. Preserving these ingredients is crucial because fats and oils provide a high quantity of energy and essential fatty acids. At the same time, vitamins, such as those present in vitamin premixes, are indispensable for optimal animal growth and performance.

The oxidation process also results in by-products with strong unpleasant taste and odor, and even toxic metabolites. In addition, oxidized feed has less protein, amino acids, and energy content. All these factors are relevant when resources, in the current scenario of high prices of feed ingredients and inputs, might be wasted due to poor feed management.

Performance losses caused by oxidation

Lipid oxidation can incur several losses regarding the pigs’ performance. Feeding oxidized lipids significantly decreases growth rate, feed intake and efficiency, immune function, and weight gain efficiency in pigs, especially in breeding animals, since the exposure occurs over long periods.

The ingestion of products resulting from the oxidative deterioration of fatty acids leads to irritability of the intestinal mucosa, diarrhea, and, in extreme cases, can result in liver degeneration and cell death. DeRouchey et al. (2004) observed reduced growth rates in pigs that are fed rancid white grease. Ringseis et al. (2007) reported that feeding oxidized sunflower oil increased oxidative stress markers in the small intestine of pigs, while Boler et al. (2012) reported that feeding pigs oxidized corn oil reduced growth performance (Table 1). Lu et al. (2014a) reported signs of liver damage in pigs subjected to dietary oxidative stress, increasing plasma bilirubin content, and enlarged liver size.

Table 1. Effects of dietary corn oil quality and antioxidant inclusion on barrow performance (Source: Boler et al., 2012)

There are some theories as to why oxidized feed causes such effects. According to Dibner et al. (1996), vitamins and polyunsaturated fatty acids deteriorate in the absence of antioxidants, and oxidized fats and their byproducts can negatively affect cells, resulting in changes in membrane permeability, viscosity, secretory activity, and membrane-bound enzyme activity. These primary effects lead to observable systemic effects. In order to prevent these damaging consequences, antioxidants have become a widely used alternative.

The power of antioxidants

Chemical antioxidants (Table 2) are added to animal feeds to delay fat and vitamin oxidation, which keeps the diet palatable and helps prolong the feed’s shelf life, ultimately maintaining the quality of the ingredients (Jacela et al., 2010). They prevent the binding of oxygen to free radicals. Dietary antioxidants have also been used in several species of animals to replace vitamin E, which is known for its antioxidant powers. Antioxidants are highly applicable in warm climates, when high levels of fat are added to the diet, and in areas where byproducts high in unsaturated fats are commonly used.

Table 2. Commonly used chemical antioxidants

Lu et al. (2014b) studied the effects of dietary supplementation with a blend of antioxidants (ethoxyquin and propyl gallate) on carcass characteristics, meat quality, and fatty acid profile in finishing pigs fed a diet high in oxidants. They reported that the inclusion of antioxidants minimized the effects of the high oxidant diet. The treatments including antioxidants, whether combined with vitamin E or not, had positive results in carcass weight, back fat, loin characteristics, and extractable lipid percentage.

Fernandez-Duenas (2009) studied the use of antioxidants in feed containing fresh or oxidized corn oil and its effects on animal performance, the oxidative status of tissues, meat quality, shelf life, and the antioxidant activity of skeletal muscle of finishing pigs. They reported that barrows fed with diets with the antioxidant blend showed increased feed efficiency. Orengo et al. (2021) showed that feeds protected with antioxidants could compensate for low vitamin E supply with regard to growth performance in the starter phase. Hung et al., 2017 theorized that the impacts on growth performance are likely related to the lack of adequate antioxidant capacity of the diet and oxidative stress status.

As literature and application results show, the use of antioxidants in pig feed is crucial to minimize adverse effects from oxidized feed and allow the animals to express their full performance potential.

SANTOQUIN: preserving feed quality

From a practical standpoint, swine producers must consider some criteria for selecting a good antioxidant, which must preserve feed components, be nontoxic for humans and pigs, show effectiveness at very low concentrations, and be economically sustainable.

Considering those major characteristics, EW Nutrition offers a range of antioxidant solutions for the preservation of feed ingredients and feeds for poultry and swine through their SANTOQUIN product line. Santoquin is a feed preservative that protects supplemental fats, oils, meals, and vitamin premixes and protect feed from oxidation. Santoquin provides unsurpassed protection from oxidative rancidity, and it has proven effects against oxidation in feeds (Figure 1) ensuring the prolonged shelf life of feeds, especially during suboptimal storage conditions, such as those with high environmental temperature and elevated levels of moisture.

Figure 1. Antioxidant efficacy and competitiveness. SANTOQUIN MAX feed preservative is a proprietary antioxidant blend that effectively prolongs the shelf life of feed and feed ingredients by reducing oxidation rate.

Studies have been conducted to show the beneficial effects of Santoquin. Ethoxyquin, contained in Santoquin, has been used in the swine industry for over five decades and has been shown to improve growth performance and markers of oxidative status in pigs (Dibner et al., 1996). Ethoxyquin is also known for being the most efficacious and cost-effective antioxidant. Lu et al. (2014b) showed that the addition of an antioxidant blend (ethoxyquin and propyl gallate) protected pigs fed with a high-oxidant diet from oxidative stress more efficiently than vitamin E supplementation (Figure 2).

Figure 2. Concentrations of vitamins A and E across treatments in the plasma (A) and muscle (B). HO: high oxidant diet containing 5% oxidized soybean oil (peroxide value at approximately 180 mEq/kg of oil, 9 mEq/kg in the diet) and 10% of a PUFA source (providing approximately 55.57% of crude fat that contains docosahexaenoic acid [ DHA] at 36.75%, and 2.05% DHA in the diet); VE: the HO diet with 11 IU/kg of added vitamin E; AOX: the HO diet with an antioxidant blend (ethoxyquin and propyl gallate, 135 mg/kg); VE+AOX: the HO diet with both vitamin E and antioxidant blend; SC: a standard corn–soy control diet with nonoxidized oil and no PUFA source. The HO pigs were switched to the SC diet after day 82 as an intervention for poor health and performance. The samples came from two pigs from each pen. The VE treatment lost 1 replicate during the feeding phase and transportation period (n = 4), while in other treatments, n =5. (Source: Lu et al., 2014b)

Conclusion

The negative effects of oxidation in pig feed can result in diets with lower biological energy value. To avoid that, antioxidants help maintain intestinal health, ensure a safe food intake, preserve the ingredients and resources used in pig production. Overall, antioxidants help swine producers improve feed conversion and achieve more productive animals and lower mortality caused by toxicity. At the end of the day, the use of antioxidants is associated with better profitability.

References

Boler, D. D., Fernández-Dueñas, D. M., Kutzler, L. W., Zhao, J., Harrell, R. J., Campion, D. R., Mckeith, F. K., Killefer, J., & Dilger, A. C. (2012). Effects of oxidized corn oil and a synthetic antioxidant blend on performance, oxidative status of tissues, and fresh meat quality in finishing barrows. Journal of Animal Science, 90(13), 5159–5169. https://doi.org/10.2527/jas.2012-5266

DeRouchey, J. M., Hancock, J. D., Hines, R. H., Maloney, C. A., Lee, D. J., Cao, H., Dean, D. W., & Park, J. S. (2004). Effects of rancidity and free fatty acids in choice white grease on growth performance and nutrient digestibility in weanling pigs. Journal of Animal Science, 82(10), 2937–2944. https://doi.org/10.2527/2004.82102937x

Dibner, J. J., Atwell, C. A., Kitchell, M. L., Shermer, W. D., & Ivey, F. J. (1996). Feeding of oxidized fats to broilers and swine: Effects on enterocyte turnover, hepatocyte proliferation and the gut associated lymphoid tissue. Animal Feed Science and Technology, 62(1 SPEC. ISS.), 1–13. https://doi.org/10.1016/S0377-8401(96)01000-0

Fernández-dueñas, D. M. (2009). Impact of oxidized corn oil and synthetic antioxidant on swine performance, antioxidant status of tissues, pork quality, and shelf life evaluation.

Hung, Y. T., Hanson, A. R., Shurson, G. C., & Urriola, P. E. (2017). Peroxidized lipids reduce growth performance of poultry and swine: A meta-analysis. Animal Feed Science and Technology, 231, 47–58. https://doi.org/10.1016/j.anifeedsci.2017.06.013

Jacela, J. Y., DeRouchey, J. M., Tokach, M. D., Goodband, R. D., Nelssen, J. L., Renter, D. G., & Dritz, S. S. (2010). Feed additives for swine: Fact sheets–flavors and mold inhibitors, mycotoxin binders, and antioxidants. Journal of Swine Health and Production, 18(1), 27-32.

Kerr, B. J., Kellner, T. A., & Shurson, G. C. (2015). Characteristics of lipids and their feeding value in swine diets. Journal of Animal Science and Biotechnology, 6(1), 1-23. https://doi.org/10.1186/s40104-015-0028-x

Lu, T., Harper, A. F., Zhao, J., Estienne, M. J., & Dalloul, R. A. (2014). Supplementing antioxidants to pigs fed diets high in oxidants: I. Effects on growth performance, liver function, and oxidative status. Journal of animal science, 92(12), 5455-5463. https://doi.org/10.2527/jas.2013-7109

Lu, T., Harper, A. F., Dibner, J. J., Scheffler, J. M., Corl, B. A., Estienne, M. J., Zhao, J., & Dalloul, R. A. (2014b). Supplementing antioxidants to pigs fed diets high in oxidants: II. Effects on carcass characteristics, meat quality, and fatty acid profile. Journal of Animal Science, 92(12), 5464–5475. https://doi.org/10.2527/jas.2013-7112

Orengo, J., Hernández, F., Martínez-Miró, S., Sánchez, C. J., Peres Rubio, C., & Madrid, J. (2021). Effects of commercial antioxidants in feed on growth performance and oxidative stress status of weaned piglets. Animals, 11(2), 1–13. https://doi.org/10.3390/ani11020266

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Over the past 60 years, antibiotics have played an essential role in the swine industry as a tool that swine producers rely on to control diseases and to reduce mortality. Besides, antibiotics are also known to improve performance, even when used in subtherapeutic doses. The perceived overuse of antibiotics in pig production, especially as growth promoters (AGP), have raised concerns from governments and public opinion, regarding the emergence of multidrug-resistant bacteria, adding a threat not only to animal but also human health. The challenges raised regarding AGPs and the need for their reduction in livestock led to the development of combined strategies such as the “One Health Approach”, where animal health, human health, and the environment are interlaced and must be considered in any animal production system.

In this scenario of intense changes, swine producers must evaluate strategies to adapt their production systems to accomplish the global pressure to reduce antibiotics and still have a profitable operation.

Many of these concerns focus on piglet nutrition, since the use of sub-therapeutic levels of antimicrobials as growth promotors is still a regular practice for preventing post-weaning diarrhea in many countries (Heo et al., 2013; Waititu et al., 2015). Taking that into consideration, this article serves as a practical guide to swine producers through AGP removal and its impacts on piglet performance and nutrition Three crucial points will be addressed:

1. Why is AGP removal a global trend?
2. What are the major consequences for piglet nutrition and performance?
3. What alternatives do we have to guarantee optimum piglet performance in this scenario?

AGP removal: a global issue

Discussions on the future of the swine industry include understanding how and why AGP removal became such important topic worldwide. Historically, European countries have led discussions on eliminating AGP from livestock production. In Sweden, AGPs were banned from their farms as early as 1986. This move culminated into a total ban of AGPs in the European Union in 2006. Other countries followed same steps. In Korea, AGPs were removed from livestock operations in 2011. The USA is also putting efforts into limiting AGPs and the use of antibiotics in pig farms, as published in guidance revised by the Food and Drug Administration (FDA, 2019). In 2016, Brazil and China banned Colistin, and the Brazilian government also announced the removal of Tylosin, Tiamulin, and Lincomycin in 2020. Moreover, countries like India, Vietnam, Bangladesh, Buthan, and Indonesia have announced strategies for AGP restrictions (Cardinal et al., 2019; Davies and Walsh, 2018).

The major argument against AGPs and antibiotics in general is the already mentioned risk of the development of antimicrobial resistance, limiting the available tools to control and prevent diseases in human health. This point is substantiated by the fact that resistant pathogens are not static and exclusive to livestock, but can also spread to human beings (Barbosa and Bünzen, 2021). Moreover, concerns have been raised in regard to the fact that antibiotics in pig production are also used by humans – mainly third-generation antibiotics. The pressure on pig producers increased and it is today multifactorial: from official regulatory departments and stakeholders at different levels, who need to consider public concerns about antimicrobial resistance and its impact on livestock, human health, and the sustainability of farm operations (Stein, 2002).

It is evident that the process of reducing or banning antibiotics and AGPs in pig production is already a global issue and increasing as it takes on new dimensions. As Cardinal et al. (2019) suggest, that process is irreversible. Companies that want to access the global pork market and comply with increasingly stricter regulations on AGPs must re-invent their practices. This, however, is nothing new for the pig industry. For example, pig producers from the US and Brazil have adapted their operations in order to not use ractopamine to meet the requirements from the European and Asian markets. We can be sure, therefore, that the global pig industry will find a way to replace antibiotics.

With that in mind, the next step is to evaluate the consequences of AGP withdrawal from pig diets and how that affects the animals’ overall performance.

Consequences in piglet health and performance

Swine producers know very well that weaning pigs is challenging. Piglets are exposed to many biological stressors during that transitioning period, including introducing the piglets to new feed composition (going from milk to plant-based diets), abrupt separation from the sow, transportation and handling, exposure to new social interactions, and environmental adaptations, to name a few. Such stressors and physiological challenges can negatively impact health, growth performance, and feed intake due to immune systems dysfunctions (Campbell et al. 2013). Antibiotics have been a very powerful tool to mitigate this performance drop. The question then is, how difficult can this process become when AGPs are removed entirely?

Many farmers around the world still depend on AGPs to make the weaning period less stressful for piglets. One main benefit is that antibiotics will reduce the incidence of PWD, with subsequent improved growth performance (Long et al., 2018). The weaning process can create ideal conditions for the overgrowth of pathogens, as the piglets’ immune system is not completely developed and therefore not able to fight back. Those pathogens present in the gastrointestinal tract can lead to post-weaning diarrhea (PWD), among many other clinical diseases (Han et al., 2021). PWD is caused by Escherichia coli and is a global issue in the swine industry, as it compromises feed intake and growth performance throughout the pig’s life, also being a common cause for losses due to young pig death (Zimmerman, 2019).

Cardinal et al. (2021) also highlight that the hypothesis of a reduced intestinal inflammatory response is one explanation for the positive relationship between the use of AGPs and piglet weight gain.  Pluske et al. (2018) point out that overstimulation of the immune system can negatively affect pig growth rate and feed use efficiency. The process is physiologically expensive in terms of energy and also can cause excessive prostaglandin E2 (PGE2) production, leading to fever, anorexia, and reduction in pig performance. For instance, Mazutti et al. (2016) showed an increased weight gain of up to 1.74 kg per pig in animals that received colistin or tylosin in sub-therapeutic levels throughout the nursery. Helm et al. (2019) found that pigs medicated with chlortetracycline in sub-therapeutic levels increased average daily gain in 0.110 kg/day. Both attribute the higher weight to the decreased costs of immune activation determined by the action of AGPs on intestinal microflora.

On the other hand, although AGPs are an alternative for controlling bacterial diseases, they have also proved to be potentially deleterious to the beneficial microbiota and have long-lasting effects caused by microbial dysbiosis – abundance of potential pathogens, such as Escherichia and Clostridium; and a reduction of beneficial bacteria, such as Bacteroides, Bifidobacterium, and Lactobacillus (Guevarra et al., 2019; Correa-Fiz, 2019). Furthermore, AGPs reduced microbiota diversity, which was accompanied by general health worsening in the piglets (Correa-Fiz, 2019).

It is also important to highlight that the abrupt stress caused by suckling to weaning transition has consequences in diverse aspects of the function and structure of the intestine, which includes crypt hyperplasia, villous atrophy, intestinal inflammation, and lower activities of epithelial brush border enzyme (Jiang et al., 2019). Also, the movement of bacteria from the gut to the body can occur when the intestinal barrier function is deteriorated, which results in severe diarrhea and growth retardation. Therefore, nutrition and management strategies during that period are critical, and key gut nutrients must be used to support gut function and growth performance.

With all of that, it is more than never necessary to better understand the intestinal composition of young pigs and finding strategies to promote gut health are critical measures for preventing the overgrowth and colonization of opportunistic pathogens, and therefore being able to replace AGPs (Castillo et al., 2007).

Viable alternatives for protecting the piglets

The good news is that the swine industry already has effective alternatives that can replace AGP products and guarantee good animal performance.

Immunoglobulins from egg yolk (IgY) have proven to be a successful alternative to weaned piglet nutrition. Investigations have shown that egg antibodies improve the piglets’ gut microbiota, making it more stable (Han et al., 2021). Moreover, IgY optimizes piglet immunity and performance while reducing occurrences of diarrhea caused by E. coli, rotavirus, and Salmonella sp. (Li et al., 2016).

Phytomolecules (PM) are also potential alternatives for AGP removal, as they are bioactive compounds with antibacterial, antioxidant, and anti-inflammatory characteristics (Damjanović-Vratnica et al., 2011; Lee and Shibamoto, 2001). When used for piglet diet supplementation, phytomolecules optimize intestinal health and improve growth performance (Zhai et al., 2018).

Han et al. (2021) evaluated a combination of IgY (Globigen^® Jump Start, EW Nutrition) and phytomolecules (Activo^®, EW Nutrition) supplementation in weaned piglets’ diets. Results from that study (Table 1 and 2) showed that this strategy decreases the incidence of PWD and coliforms, increases feed intake, and improves the intestinal morphology of weaned pigs, making that combination a viable AGP replacement.

Table 1. Effect of dietary treatments on the growth performance of weaned pigs challenged with E. coli K88 (SOURCE: Han et al., 2021).

Table 2. Effect of dietary treatments on the post-weaning diarrhea incidence of weaned pigs challenged with E. coli K88 (%) (SOURCE: Han et al., 2021).

A trial conducted at the Institute of Animal Sciences of the Chinese Academy of Agricultural Sciences, China, supplemented weaning pigs challenged by E. coli K88 with a combination of PM (Activo^®, EW Nutrition) and IgY (Globigen^® Jump Start). The trial reported that this combination (AC/GJS) showed fewer diarrhea occurrences than in animals from the positive group (PC) during the first week after the challenge and similar diarrhea incidence to the AGP group during the 7th and 17th days after challenge (Figure 1).

Figure 1 – Incidence of diarrhea (%). NC: negative group, PC: positive group, AGP: supplementation with AGP, AC/GJS: combination of PM (Activo, EW Nutrition) and IgY (Globigen Jump Start).

The same trial also showed that the combination of these non-antibiotic additives was as efficient as the AGPs in improving pig performance under bacterial enteric challenges, showing positive effects on body weight, average daily gain (Figure 2), and feed conversion rate (Figure 3).

Figure 2 – Body weight (kg) and average daily gain (g). NC: negative group, PC: positive group, AGP: supplementation with AGP, AC/GJS: combination of PM (Activo, EW Nutrition) and IgY (Globigen Jump Start).

Figure 3 – Feed conversion rate. NC: negative group, PC: positive group, AGP: supplementation with AGP, AC/GJS: combination of PM (Activo, EW Nutrition) and IgY (Globigen Jump Start).

The multiple benefits of using IgY in piglet nutrition strategies are also highlighted by Rosa et al. (2015), Figure 4, and Prudius (2021).

Figure 4. Effect of treatments on the performance of newly weaned piglets. Means (±SEM) followed by letters a,b,c in the same group of columns differ (p < 0.05). NC (not challenged with ETEC, and diet with 40 ppm of colistin, 2300 ppm of zinc, and 150 ppm of copper). Treatments challenged with ETEC: GLOBIGEN® (0.2% of GLOBIGEN®); DPP (4% of dry porcine plasma); and PC (basal diet) (SOURCE: Rosa et al., 2015).

Conclusions

AGP removal and overall antibiotic reduction seems to be the only direction that the global swine industry must take for the future. From the front line, swine producers demand cost-effective AGP-free products that don’t compromise growth performance and animal health. Along with this demand, finding the best strategies for piglet nutrition in this scenario is critical in minimizing the adverse effects of weaning stress. With that in mind, alternatives such as egg immunoglobulins and phytomolecules are commercial options that are already showing great results and benefits, helping swine producers to go a step further into the future of swine nutrition.

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