Respiratory Challenges: Breathing Space for Antibiotic Reduction?

Clinical signs of respiratory disease in chickens include coughing sneezing and rales 1

Sub-therapeutic doses of antibiotic growth promoters (AGPs) were used for more than 50 years in poultry production to achieve performance targets – until growing concerns arose regarding antibiotic resistance (Kabir, 2009) and decreasing efficacy of antibiotics for medical purposes (Dibner & Richards, 2005).

Isolates of ESBL-producing E.coli from animals, farmworkers, and the environment were found to have identical multidrug resistance patterns (A. Nuangmek et al., 2018). There is also evidence that AMR strains of microorganisms spread from farm animal to animal workers and beyond. Global AMR fatalities are increasing and might reach 10 million by 2050 (Mulders et al., 2010, Trung et al., 2017, Huijbers et al., 2014).

In light of this, certain AGPs have already been banned, and there is a strong possibility of future restrictions on their use worldwide. Bans are effective: the MARAN report 2018 shows that lower antibiotics usage following the EU ban on AGPs has reduced resistant E.coli in broilers. Another positive consideration is the market opportunities that exist for antibiotic residue-free food.

However, the key element that poultry producers need to get right for antibiotic reduction to be successful is respiratory health management. This article looks at why respiratory health is a particular challenge – and how phytogenic solutions can help.

A closer look at the chickens’ respiratory system

The respiratory tract is equipped with a functional mucociliary apparatus consisting of a protective mucous layer, airway surface liquid layer, and cilia on the surface of the ciliated cells. This apparatus produces mucus, which traps the inhaled particles and pathogens and propels them out of the airways. This mechanism, called the mucociliary clearance, is the primary innate defense mechanism of the respiratory system.

High stocking density combined with stressful environmental factors can negatively influence birds’ immune systems (Heckert et al., 2002; Muniz et al., 2006), making them more susceptible to respiratory disease. When a bird suffers from respiratory disease, which is nowadays usually complicated by a co-infection or secondary bacterial infection, there is an excess production of mucus that results in ciliostasis and, therefore, in an impaired mucociliary clearance. The excess mucus in the tract obstructs the airways by forming plagues and plugs, resulting in dyspnea (hypoxia) and allowing the invasive bacteria to adhere and colonize the respiratory system.

The build-up of mucus in the respiratory tract severely reduces oxygen intake, causing breathlessness, reduced feed intake, and a drop in the birds’ energy levels, which negatively impacts weight gain and egg production. Respiratory problems can result from infection with bacteria, viruses, and fungi, or exposure to allergens. The resultant irritation and inflammation of the respiratory tract leads to sneezing, wheezing, and coughing – and, therefore, the infection rapidly spreads within the flock.


Clinical signs of respiratory disease in chickens heat stressRelatively high stocking density is the norm in poultry production

Low or no antibiotics: how to manage respiratory disease?

Unsurprisingly, respiratory diseases in poultry are a major cause of mortality and economic loss in the poultry industry. For Complicated Chronic Respiratory Disease (CCRD), for instance, although the clinical manifestations are usually slow to develop, Mycoplasma gallisepticum (MG), in combination with E. coli, can cause severe airsacculitis. Beside feed and egg production reduction, these problems are of high economic significance since respiratory tract lesions can cause high morbidity, high mortality, and significant carcass condemnation and downgrading.

Producers need to pre-empt the spread of respiratory pathogens, react quickly to alleviate respiratory distress and maintain the mucociliary apparatus’ functionality. Traditionally, treatment options are based on antiviral, anti-inflammatory, and antibiotic drugs. Can the poultry industry limit losses from respiratory infections without excessive recourse to antibiotics?

Indeed, a sudden reduction in antibiotic usage comes with a risk of impaired performance, increased mortality, and impaired animal health and welfare. The impact has been quantified as a 5% loss in broiler meat production per sq. meter (Gaucher et al., 2015). Effective antibiotics reduction requires a combination of innovative products and suitable consultancy services to manage poultry gut health, nutrition, flock management, biosecurity, and, particularly, respiratory health.

Non-antibiotic alternatives to control diseases and promote broiler growth, such as organic acids (Vieira et al., 2008), probiotics (Mountzouris et al., 2010), prebiotics (Patterson & Burkholder, 2003), and essential oils (Basmacioğlu Malayoğlu et al., 2010) have been the subject of much research in recent years.

Phytogenic solutions: proven efficacy

Essential oils, which are extracted from plant parts, such as flowers, buds, seeds, leaves, twigs, bark, wood, fruits, and roots, have a particularly well-established track record of medicinal applications. Efforts have centered on phytomolecules, the biologically active secondary metabolites that account for the properties of essential oils (Hernández et al., 2004; Jafari et al., 2011).

Studying these properties is challenging: essential oils are very complex natural mixtures of compounds whose chemical compositions and concentrations are variable. For example, the concentrations of the two predominant phytogenic components of thyme essential oils, thymol and carvacrol, have been reported to range from as low as 3% to 60% of the whole essential oil (Lawrence and Reynolds, 1984).

Another well-researched example is eucalyptus oil. The essential oils of eucalyptus species show antibacterial, anti-inflammatory, diaphoretic, antiseptic, analgesic effects (Cimanga et al., 2002) and antioxidant properties (Lee and Shibamoto, 2001; Damjanović Vratnica et al., 2011). The oils are mainly composed of terpenes and terpene derivatives in addition to some other non-terpene components (Edris, 2007). The principal constituent found in eucalyptus is 1,8-cineole (eucalyptol); however, other chemotypes such as α-phellandrene, ρ-cymene, γ-terpinene, ethanone, and spathulenol, among others, have been documented (Akin et al., 2010).

eucalyptol respiratory challengesClose-up of eucalyptus leaf oil glands and
the molecular structure of eucalyptol
C10H18O (red = oxygen; dark grey = carbon; light grey = hydrogen)

Antimicrobial activity

In modern intensive broiler production, bacterial diseases such as salmonellosis, colibacillosis, mycoplasmosis, or clostridia pose serious problems for the respiratory system and other areas. Analyses of the antibacterial properties of essential oils have been carried out by multiple research units (Ouwehand et al., 2010; Pilau et al., 2011; Solorzano- Santos and Miranda-Novales, 2012; Mahboubi et al., 2013; Nazzaro et al., 2013; Petrova et al., 2013).

Phenols, alcohols, ketones, and aldehydes are clearly associated with antibacterial activity; the exact mechanisms of action, however, are not yet fully understood (Nazzaro et al., 2013). Essential oils’ antimicrobial activity is not attributable to a unique mechanism but instead results from a cascade of reactions involving the entire bacterial cell (Nazzaro et al., 2013). However, it is accepted that antimicrobial activity depends on the lipophilic character of the components.

The components permeate the cell membranes and mitochondria of the microorganisms and inhibit, among others, the membrane-bound electron flow and thus the energy metabolism. This leads to a collapse of the proton pump and draining of the ATP (adenosine triphosphate) pool. High concentrations may also lead to lysis of the cell membranes and denaturation of cytoplasmic proteins (Nazzaro et al., 2013; Gopi et al., 2014).

According to current knowledge, lavender, thyme, and eucalyptus oil, as well as the phytomolecules they contain, show enhanced effects when combined with other essential oils or synthetic antibiotics (Sadlon and Lamson, 2010; Bassole and Juliani, 2012; Sienkiewicz, 2012; de Rapper et al., 2013; Zengin and Baysal, 2014).

Minimum inhibitory concentration (MIC) of some essential oil components against microorganisms in vitro

Table Minimum Inhibitory Concentration Mic Of Some Essential Oil Components

Immune system boost I: improved production of antibodies

Some essential oils were found to influence the avian immune system positively, since they promote the production of immunoglobulins, enhance the lymphocytic activity, and boost interferon-γ release (Awaad et al., 2010; Faramarzi et al., 2013; Gopi et al., 2014; Krishan and Narang, 2014). Placha et al. (2014) showed that the addition of 0.5g of thyme oil per kg of feed significantly increased IgA levels.

Awaad et al. (2010) experimented on birds vaccinated with the inactivated H5N2 avian influenza vaccine. The experiment revealed that adding eucalyptus and peppermint essential oils to the water at a rate of 0.25 ml per liter resulted in an enhanced cell-mediated and humoral immune response.

Saleh et al. (2014), who applied thyme and ginger oils in quantities of 100mg and 200mg per kg of feed, respectively, observed an improvement in chickens’ immunological blood profile through increased antibody production. Rehman et al. (2013) stated that the use of herbal products containing eucalyptus oil and menthol in broilers showed consistently higher antibody titers against NDV (Newcastle disease virus), compared to untreated broilers.

Immune system boost II: better vaccine responses and anti-inflammatory effects

Essential oils are also used as immunomodulators during periods when birds are exposed to stress, acting protectively and regeneratively. Importantly, the oils alleviate the stress caused by vaccination (Barbour et al., 2011; Faramarzi et al., 2013; Gopi et al., 2014). The study by Kongkathip et al. (2010) confirmed the antiviral activity of turmeric essential oil.

In recent years studies have been carried out on the use of essential oils in conjunction with vaccination programs, including those against infectious bronchitis (IB), Newcastle disease, and Gumboro disease. The results of the experiments show that essential oils promote the production of antibodies, thus enhancing the efficacy of vaccination (Awaad et al., 2010; Barbour et al., 2010; Barbour et al., 2011; Faramarzi et al., 2013).

Essential oils contain compounds that are known to possess strong anti-inflammatory properties, mainly terpenoids, and flavonoids, which suppress the metabolism of inflammatory prostaglandins (Krishan and Narang, 2014). Also, other compounds found in essential oils have anti-inflammatory, pain-relieving, or edema-reducing properties, for example, linalool from lavender oil, or 1,8-cineole, the main component of eucalyptus oil (Peana et al., 2003).

Immune system boost III: antioxidant effects and radical scavenging

An imbalance in the rate of production of free radicals or removal by the antioxidant defense mechanisms leads to a phenomenon referred to as oxidative stress. A mixture of Oregano (carvacrol, cinnamaldehyde, and capsicum oleoresin) was found to beneficially affect the intestinal microflora, absorption, digestion, weight gain and also to have an antioxidant effect on chickens (Bassett, 2000).

Zeng et al. (2015) indicated the positive effect of essential oils on the production of digestive secretions and nutrient absorption. They reduce pathogenic stress in the gut, exert antioxidant properties, and reinforce the animal’s immune status.

Inside the cell, essential oils can serve as powerful scavenger preventing mutations and oxidation (Bakkali et al., 2008). Studies have demonstrated the concentration-dependent free radical scavenging ability of oils from eucalyptus species (Kaur et al., 2010; Marzoug et al., 2011; Olayinka et al., 2012). Some authors attribute the strong antioxidant capacity of essential oils to their phenolic constituents and synergistic effect between tannins, rutin, thymol, and carvacrol, and probably 1, 8-cineole. Moderate DPPH radical scavenging activity reported by Edris(2007), El-Moein et al. (2012), and Kaur et al. (2011).

Vázquez et al. (2012) have demonstrated the potential of the phenolic compounds in eucalyptus bark as a source of antioxidant compounds. The study showed that eucalyptus had ferric reducing antioxidant power in the ranges 0.91 to 2.58 g gallic acid equivalent (GAE) per 100 g oven-dried bark and 4.70 to 11.96 mmol ascorbic acid equivalent (AAE) per 100 g oven-dried bark, respectively (see also Shahwar et al., 2012). Moreover, Eyles et al. (2004) were able to show superoxide dismutase (SOD)-like activity for different compounds and fractions isolated from wood extracts.

Last but not least: positive effects on the respiratory system

In poultry production houses, especially in summer, high temperatures and low humidity increase the amount of air dust. Under such conditions, respiratory tract disorders in broiler chickens, including the deposition of particulates, become more frequent and more severe.

Clinical signs of respiratory disease in chickens include coughing, sneezing, and rales

Clinical signs of respiratory disease in chickens include coughing, sneezing, and rales

Thyme oil, thanks to the phytomolecules thymol and carvacrol, supports the treatment of respiratory disorders. These substances smooth tightened muscles and stimulate the respiratory system. An additional advantage lies in their expectorant and spasmolytic properties (Edris, 2007).

These properties are also seen in essential oils such as eucalyptus and peppermint, which contain eucalyptol and menthol. They thin out the mucus and facilitate its removal from the airways. As a result, the airways are cleared and breathing during inflammation becomes easier (Durmic and Blache, 2012).

Another positive effect of the terpenoid compounds used in commercial preparations for poultry is that they disinfect the bronchi, preventing respiratory infections (Awaad et al., 2010; Barbour et al., 2011; Mahboubi et al., 2013). Barbour and Danker (2005) reported that the essential oils of eucalyptus and peppermint improved the homogeneity of immune responses and performance in MG/H9N2-infected broilers.

Grippozon: the phytogenic solution for respiratory health

Grippozon is a liquid composition with a high content of essential oils, which are combined to systematically prevent and ease respiratory diseases. The formulation is derived from the research on essential oils’ effectiveness against respiratory pathogens that are common in animal farming. Grippozon exhibits a synergistic action of all its components to optimally support animal health. It contains a high concentration of active components; both their quantity and quality are guaranteed to deliver results.

Application of Grippozon

Grippozon application can be flexibly adapted to most common housing systems. It is fully water-soluble for use in the drinking line and it is also possible to nebulize a diluted solution in air.

The dose recommendation in drinking water usually amounts to 100ml to 200ml per 1000 liters of drinking water (Grippozon administration has not been reported to affect water consumption). The active substances in Grippozon adhere to mouth mucosa and become volatile in the breathing air later on. Therefore Grippozon can enter the respiratory system indirectly as well. The volatile compounds also spread into the whole barn air and, thus, indirectly via breathing into the respiratory system (and farmers notice the smell of essential oils when Grippozon is applied through in the waterline)

Grippozon can also be used as a spray at a rate of 200ml/10 liters of water for 2000 birds, twice daily on 2-3 days a week. This produces a very effective nebulization effect and offers faster respiratory relief to birds.

Grippozon is an impactful tool for managing respiratory problems. Thanks to its effective mucolytic and relaxant activity, Grippozon gives symptomatic relief to the birds during high-stress periods of respiratory diseases. Mucus in the trachea works as media for the proliferation of bacteria and viruses, so by thinning the mucus, Grippozon slows down the proliferation of bacteria and the spread of disease. Grippozon helps in improving air quality and air intake. It can also be used to stimulate the immune response during vaccination.

Ruturaj Patil – Product Manager Phytogenic Liquids
Kowsigaraj Palanisamy – Global Validation Trial Manager

References available on request

Challenging times for broilers? Phytomolecules, not antibiotics, are the answer

BROILER PIC Aviagen Drinking Stable 2 01 2015

Challenging times for broilers? Phytomolecules, not antibiotics, are the answer
by Ajay Bhoyar, Global Technical Manager, EW Nutrition

Anyone working with today’s fast-growing broiler chicken knows that it is a sensitive creature – and so is its gut health. Thanks to continuous improvements in terms of genetics and breeding, nutrition and feeding, as well as general management strategies, broiler production has tremendously upped performance and efficiency over the past decades. It is estimated that, between 1957 and 2005, the broiler growth rate increased by over 400%, while the feed conversion ratio dropped by 50%.

These impressive improvements, however, have come at the cost of intense pressure on the birds’ digestive system, which needs to process large quantities of feed in little time. To achieve optimal growth, a broiler’s gastrointestinal tract (GIT) needs to be in perfect health, all the time. Unsurprisingly, enteric diseases such as necrotic enteritis, which severely damages the intestinal mucosa, hamper the intestines’ capacity to absorb nutrients and induce an inflammatory immune response.

The modern broiler’s gut – a high-performing, but sensitive system

However, in a system as high performing as the modern broiler’s GIT, much less can lead to problems. From when they are day-old chicks up to slaughter, broilers go through several challenging phases during which they are more likely to show impaired gut functionality, e.g. after vaccinations or feed changes. Good management practices go a long way towards eliminating unnecessary stressors for the animals, but some challenging periods are unavoidable.

The transition from starter to grower diets is a classic situation when nutrients are very likely to not be well digested and build up in the gut, fueling the proliferation of harmful microbes. Immunosuppressive stress in combination with an immature intestinal microflora results in disturbances to the bacterial microbiota. At “best”, this entails temporarily reduce nutrient absorption, in the worst case the birds will suffer serious intestinal diseases.

Phytomolecules – the intelligent alternative to antibiotics

To safeguard performance during stressful periods, poultry producers need to anticipate them and proactively provide effective gut health support. For many years, this support came in the form of antibiotic growth promoters (AGP): administered prophylactically, they were effective at keeping harmful enteric bacteria in check. However, due to grave concerns about the development of antimicrobial resistance, non-therapeutic antibiotics use has been banned in many countries. Alternatives need to focus on improving feed digestibility and strengthening gut health, attacking the root causes of why the intestinal microflora would become unbalanced in the first place.

Phytomolecules are secondary metabolites active in the defense mechanisms of plants. Studies have found that certain phytomolecules stimulate digestive enzyme activities and stabilize the gut microflora, “leading to improved feed utilization and less exposure to growth-depressing disorders associated with digestion and metabolism” (Zhai et al., 2018). With other trials showing positive effects on broilers’ growth performance and feed conversion, the research indicates that phytomolecules might also specifically support chickens during challenging phases.

The effect of phytomolecules on broilers during a challenging phase

A study was conducted over a period of 49 days on a commercial broiler farm of an AGP-free integration operation in Japan. The farm reported gut health challenges in the second and third week of the fattening period due to vaccinations and changes to the animals’ diets. The trial included 15504 Ross 308 broilers, divided into two groups. The negative control group included a total of 7242 birds, kept in another house.

All the birds were fed the standard feed of the farm. The trial group (8262 birds) received Activo® Liquid, which contains a synergistic combination of phytomolecules, administered directly through the drinking water. Activo® Liquid was given at an inclusion rate of 200ml per 1000L of water (3.3 US fl oz per gallon of stock solution, diluted at 1:128), from day 8 until day 25, for 8 hours a day.

The results are summarized in Figure 1:

Figure 1: Improved broiler performance for Activo® Liquid group (day 49)

Improved broiler performance for Activo Liquid group

The Activo® Liquid group clearly showed performance improvements compared to the control group. Livability augmented by 1.5%, while the feed conversion rate improved by 3.2%. This resulted in a more than 5% higher score in terms of the performance index.

Challenging times? Tackle them using phytomolecules

Poultry producers take great care to eliminate unnecessary sources of stress for their birds. Nonetheless, during their lifecycle, broiler chickens face challenging periods during which the balance of the intestinal microflora can easily become disturbed, with consequences ranging from decreased nutrient absorption to full-blown enteric disease.

The trial reviewed here showed that, after receiving Activo® Liquid, broilers raised without AGPs showed encouraging performance improvements during a challenging phase of feed changes and vaccinations. Likely thanks to the activation of digestive enzymes and a stabilization of the gut flora, the broilers showed improved livability and feed conversion, thus delivering a much more robust performance during a critical phase of their lives. In times where the non-therapeutic use of antibiotics is no longer an option, phytomolecules allow poultry farmers to effectively support their animals during challenging times.


Photo Source: Aviagen

Adedokun, Sunday A., and Opeyemi C. Olojede. “Optimizing Gastrointestinal Integrity in Poultry: The Role of Nutrients and Feed Additives.” Frontiers in Veterinary Science 5 (January 31, 2019): 348.

Jamroz, D., T. Wertelecki, M. Houszka, and C. Kamel. “Influence of Diet Type on the Inclusion of Plant Origin Active Substances on Morphological and Histochemical Characteristics of the Stomach and Jejunum Walls in Chicken.” Journal of Animal Physiology and Animal Nutrition 90, no. 5-6 (March 23, 2006): 255–68. 

Tavárez, Marcos A., and Fausto Solis De Los Santos. “Impact of Genetics and Breeding on Broiler Production Performance: a Look into the Past, Present, and Future of the Industry.” Animal Frontiers 6, no. 4 (October 1, 2016): 37–41.

Zhai, Hengxiao, Hong Liu, Shikui Wang, Jinlong Wu, and Anna-Maria Kluenter. “Potential of Essential Oils for Poultry and Pigs.” Animal Nutrition 4, no. 2 (June 2018): 179–86.

Zuidhof, M. J., B. L. Schneider, V. L. Carney, D. R. Korver, and F. E. Robinson. “Growth, Efficiency, and Yield of Commercial Broilers from 1957, 1978, and 20051.” Poultry Science 93, no. 12 (December 2014): 2970–82. 


Beyond AGPs: Controlling necrotic enteritis through gut health optimization

BROILER PIC Aviagen Drinking Stable 1 01 2015

antibiotic reduction phytomolecules necrotic enteritis


Antibiotic growth promoters (AGPs) have routinely been used in intensive poultry production for improving birds’ performance. However, in recent years, reducing the use of antibiotics in animal production has become a top priority, due to concerns about the development of antibiotic-resistant bacteria and mounting consumer pressure. Multiple countries have introduced bans or severe restrictions on the non-therapeutic use of antibiotics, including in the US, where the Food and Drug Administration has implemented measures to curb the use of antibiotics since 2017.

However, the removal of AGPs poses challenges for poultry performance, including reduced feed efficiency, decreased daily weight gain, as well as higher mortality. Moreover, the withdrawal of AGPs in feed is widely recognized as one of the predisposing factors for necrotic enteritis (NE). NE is one of the most common and economically important poultry diseases, with an estimated global impact of US$ 5 to 6 billion per year. As a result of withdrawing AGPs, the usage of therapeutic antibiotics to treat NE has increased. To break out of this vicious cycle and to secure the efficiency of poultry production, alternatives are needed that combat NE where it starts: in the gut.


Necrotic enteritis: a complex disease

NE is caused by pathogenic strains of Clostridium perfringens (CP): ubiquitous, gram-positive, spore-forming anaerobic bacteria. The spores of CP can be found in poultry litter, feces, soil, dust, and contaminated feed. Low levels of different CP strains are naturally present in the intestines of healthy birds, kept in check by a balanced microbiome. However, when gut health is compromised, pathogenic strains can proliferate at the expense of unproblematic strains, resulting in clinical or sub-clinical NE.

Animals suffering from the clinical form show symptoms such as general depression, reluctance to move, and diarrhea, with mortality rates of up to 50%. Infected birds suffer from degenerated mucosa lesions in the small intestines. Even in its “mild”, subclinical form, which often goes unnoticed, the damage to the animals’ intestinal mucosa can result in permanently reduced performance and consequent economic losses for the producer.

Certain predisposing factors have been found to enable the proliferation of pathogenic strains in the gastrointestinal tract. Diet is a key example: the composition of the gut flora is directly linked to feed composition. High inclusion rates of cereals (barley, rye, oats, and wheat) that contain high levels of non-starch polysaccharides (NSPs), high levels of indigestible protein, and inclusion of proteins of animal origin (e.g. fishmeal) have been shown to predispose birds to NE.

A range of diseases (e.g. chicken infectious anemia, Gumboro, and Marek’s disease), but also other factors that have immunosuppressive effects, such as heat or cold stress, mycotoxins, feed changes, or high stocking density, render birds more susceptible to intestinal infections. The single most prominent predisposing factor for the occurrence of NE is the mucosal damage caused by coccidiosis.

Gut health is key to combating necrotic enteritis

To control NE, a holistic approach to optimizing the intestinal health of poultry is needed. It should take into account not only parameters such as diet, hygiene, and stress, but should also make use of innovative tools.

Phytomolecules, also known as secondary plant compounds, are essentially plants’ defense mechanisms against pathogens such as moulds, yeasts, and bacteria. Studies have demonstrated the antimicrobial effects of certain phytomolecules, including against antibiotic-resistant pathogens. Phytomolecules have also been found to boost the production of digestive enzymes, to suppress pro-inflammatory prostaglandins and have antioxidant properties. These features make them a potent tool for optimizing gut health, potentially to the point of replacing AGPs.

Can phytomolecules mitigate the impact of necrotic enteritis?

To study the impact of phytomolecules on the performance of broilers challenged with a NE-causing CP strain, a trial was conducted at a US-based research facility. In this 42-day study, 1050 male day-old Cobb 500 broiler chicks were divided into 3 groups, with 7 replicates of 50 chicks each.

On the first day, all animals were vaccinated against coccidiosis through a live oocyst spray vaccination. The experimental diets met or exceeded the National Research Council requirements, and were fed as crumbles/pellets. On days 19, 20, and 21, all pens, except the negative control group, were challenged with a broth culture of C. perfringens. A field isolate of CP known to cause NE (originating from a commercial broiler operation) was utilized as the challenge organism. On day 21, three birds from each pen were selected, sacrificed, group weighed, and examined for the degree of present NE lesions.

The positive control group received no supplements. The trial group received a synergistic combination of two phytogenic products containing standardized amounts of selected, microencapsulated phytomolecules: an in-feed phytogenic premix (Activo®, EW Nutrition GmbH) and a liquid complementary feed supplied via the drinking water (Activo® Liquid, EW Nutrition GmbH). The products were given at inclusion rates corresponding to the manufacturer’s baseline antibiotic reduction program recommendations (Figure 1):

Figure 1: Trial design

The trial results indicate that the addition of phytomolecules helps to mitigate the impact of NE on broilers’ performance. The group receiving Activo® and Activo® Liquid showed a better feed conversion (Figure 2) compared to the positive control group (NE challenge, no supplement). Also, better lesion scores were noted for animals receiving phytomolecules (0.7 and 1) than for the positive control group (1.6).

The most significant effect was observed concerning mortality: the group receiving Activo® and Activo® Liquid showed a 50% lower mortality rate than the positive control group (Figure 3). These results clearly indicate that phytomolecules can play an important role in mitigating losses due to NE.

Figure 1: Adjusted FCRActivo + Activo Liquid vs control

Figure 2: Lesion scores and mortalityNecrotic Enteritis mortality

Tackling necrotic enteritis in a sustainable way

In an age of AGP-free poultry production, a concerted focus on fostering animals’ gut health is key to achieving optimal performance. This study strongly demonstrates that, thanks to their antimicrobial, digestive, anti-inflammatory and antioxidant properties, phytomolecules effectively support birds’ intestinal health when challenged with NE. The inclusion of Activo® and Activo® Liquid, two phytogenic products designed to synergistically support birds during critical periods, resulted in improved feed conversion, better lesion scores, and 50% lower mortality.

In combination with good dietary, hygiene, and management practices, phytomolecules are therefore a potent tool for reducing the use of antibiotics: including Activo® and Activo® Liquid in their animals’ diets allows poultry producers to reduce the incidence of NE, to mitigate its economic impact in case of outbreaks, and therefore to control NE in a sustainable way.

By by Ajay Bhoyar, Global Technical Manager, and  T. van Gerwe, Global Technical Director, EW Nutrition


Antonissen, Gunther, Siska Croubels, Frank Pasmans, Richard Ducatelle, Venessa Eeckhaut, Mathias Devreese, Marc Verlinden, Freddy Haesebrouck, Mia Eeckhout, Sarah De Saeger, Birgit Antlinger, Barbara Novak, An Martel, and Filip Van Immerseel. “Fumonisins Affect the Intestinal Microbial Homeostasis in Broiler Chickens, Predisposing to Necrotic Enteritis.” Veterinary Research 46, no. 1 (September 23, 2015): Article 98. doi:10.1186/s13567-015-0234-8.

Moore, Robert J. “Necrotic Enteritis Predisposing Factors in Broiler Chickens.” Avian Pathology 45, no. 3 (May 31, 2016): 275-81. doi:10.1080/03079457.2016.1150587.

Tang, Karen L., Niamh P. Caffrey, Diego B. Nóbrega, Susan C. Cork, Paul E. Ronksley, Herman W. Barkema, Alicia J. Polachek, Heather Ganshorn, Nishan Sharma, James D. Kellner, and William A. Ghali. “Restricting the Use of Antibiotics in Food-producing Animals and Its Associations with Antibiotic Resistance in Food-producing Animals and Human Beings: A Systematic Review and Meta-analysis.” The Lancet Planetary Health 1, no. 8 (November 6, 2017): 316-27. doi:10.1016/s2542-5196(17)30141-9.

Van Immerseel, Filip, Julian I. Rood, Robert J. Moore, and Richard W. Titball. “Rethinking Our Understanding of the Pathogenesis of Necrotic Enteritis in Chickens.” Trends in Microbiology 17, no. 1 (2009): 32-36. doi:10.1016/j.tim.2008.09.005.

Wade, Ben, and Anthony Keyburn. “The True Cost of Necrotic Enteritis.” PoultryWorld. October 09, 2015. Accessed August 19, 2019.

 Source Photo: Aviagen