10 August 2021 - As the poultry industry continues to reduce the use of antibiotics in production, an undesired consequence has been the rise of opportunistic intestinal diseases. Necrotic enteritis – which is caused by an overgrowth of the Clostridium perfringens bacterium in the small intestine – is one of the industry’s most economically significant, costing more than $6 billion annually.
The increase in incidence and the continued push to limit antibiotic use means that, in order to successfully manage the disease, a multifaceted approach is necessary.
To find out what this could look like, we spoke to Dr Katie Hilton, Technical Service Manager at Danisco Animal Nutrition (IFF) about how the company is combining its research into the disease with its expertise in nutrition and gut health to help producers rear healthier, more resilient and cost-effective flocks.
[Feedinfo] Why does Danisco Animal Nutrition (IFF) consider necrotic enteritis to be an important topic for poultry research?
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Katie Hilton |
[Katie Hilton] As the global poultry market continues to grow and its contribution to food security and nutrition is magnified, it is increasingly important to assess the impact of diseases that compromise poultry productivity and welfare. The growing prevalence of necrotic enteritis (NE) and its severity over the past years, together with the transition to a No Antibiotic Ever (NAE) production, raises the question on how to prevent and/or control NE outbreaks. |
NE severely impairs digestion and intestinal absorption of nutrients, reducing weight gain while increasing feed conversion rate (FCR) and mineral excretion in manure. This ultimately poses a sustainability challenge. Moreover, NAE production means a reduction in the use of therapeutic solutions for bird health, meaning limiting the disease’s impact when it arises is more challenging. Poultry producers are left without one of the key tools to fight this unpredictable disease, hence alternative strategies are of the utmost importance and part of Danisco Animal Nutrition’s priorities.
[Feedinfo] What makes it such a complex disease?
[Katie Hilton] NE is a complicated problem to solve because of its diverse aetiology. It is caused by Clostridium perfringens which can produce toxins and enzymes, ultimately causing enteric lesions. Since C. perfringens is naturally found in the poultry’s gut, researchers have spent years determining what triggers this opportunistic behaviour. NE onset has been linked to different predisposing factors such as physical damage of the gut, diet and co-infection (namely coccidiosis).
More accurately, NE infection in poultry is caused by C. perfringens type A, which produces the alpha toxin, and to a lesser extent type C, which produces both alpha toxin and beta toxin. In more recent years the Net-B toxin has been identified as a major contributor to disease progression. These toxins can cause damage to the small intestine, potential translocation to livers and further lesion development, which not only reduces bird performance and weight gain, but also leads to mortality and condemnations.
This disease is present in two distinct forms, which further contributes to NE complexity: acute clinical disease or subclinical condition. The clinical disease is characterised by a sudden increase in flock mortality. While wet litter can be an early indicator of this form of the disease, there are often no early warning signs.
The subclinical form, which became more prevalent in recent years, shows no obvious clinical signs and has no peak in mortality, making it very difficult to identify. Left undetected and untreated, subclinical NE causes the highest economic losses in the poultry industry as consequence of chronic intestinal damage resulting in poor digestion and absorption, decreased weight gain, and increased FCR. Additionally, intestinal damage can allow the bacteria to infiltrate the body and reach the liver, which can increase the likelihood of condemnations at processing.
[Feedinfo] What can you share about Danisco Animal Nutrition’s own research efforts on the issue of NE? Why is modelling the disease important?
[Katie Hilton] The most logical approach in our vision is to tackle conditions that are known to cause NE outbreaks – to act preventively rather than reactively – and focus on the multiple factors that, when combined, create the perfect environment for C. perfingens’ proliferation.
This is where Danisco Animal Nutrition’s nutribiotic approach stands out: By studying the bird’s gut structure and immune function, microbiome, and nutrition, as well as identifying the tools and practices to manipulate its microorganisms, we can develop approaches that contribute to a favourable nutribiotic state and help manage NE. Poultry producers can then use the results to put in place sustainable and more cost-effective production programmes in today’s limited antibiotic use environments.
Our research addresses the conditions and specifics of real farm scenarios, and this is where modelling the disease becomes so important. By mimicking the production conditions, models help us better understand the disease and shed light, for instance, on how and why some animals get the clinical form of the disease and others remain in a subclinical stage.
Backed by state-of-the-art biotechnological approaches, such as metagenomics tools, we can compare the diversity of microbiome profiles between highly susceptible flocks with those of less susceptible flocks over time. This allows us to understand the interactions between nutrition, microbiome, and gut and immune function – what we define as nutribiosis – and the effects of the disease on the overall intestinal environment. Nutribiosis has become an integrated part of the innovation work we do at Danisco Animal Nutrition and by using the model approach, we can test the robustness of the bird’s nutribiosis and understand how the disease affects it.
[Feedinfo] How have changes in the management of coccidiosis affected NE? Are changes to production trends (for example, the increase in NAE systems) having an impact?
[Katie Hilton] Research has identified coccidiosis, an infectious protozoan disease caused by the genus Eimeria, as a predisposing factor for NE, with coccidiosis often pre-existing or occurring simultaneously with NE outbreaks. Coccidiosis used to be managed using chemicals, ionophores and vaccines. Yet, with the transition to NAE production and the ban of some products, control strategies were re-evaluated. At first, these NAE environments posed a threat to NE control, but new coccidiosis management strategies ultimately benefit C. perfringens control.
Today, coccidiosis management is mostly performed through controlling nutritional factors, chemical coccidiostats and vaccination, which can help manage the risk of proliferation of C. perfringens and avoid NE outbreaks. This shows the importance of having an integrated, comprehensive strategic approach to control and prevent both diseases, utilising measures such as coccidiosis monitoring and improved farm management, as well as applying scientific insights onto farms.
[Feedinfo] How do housing and nutrition impact NE?
[Katie Hilton] We know that NE is a contagious disease and that an intestinal environment that favours the growth of C. perfringens is a key risk factor for it developing. These two factors are vital to better understand the impact of housing conditions and nutrition on the incidence and mitigation of NE. In addition, C. perfringens has the ability to form resistant spores that can survive in soil, waste water, faeces and feeds. This highlights the role of the flock’s housing conditions in preventing disease spread and outbreaks. Ensuring the sanitation of drinker lines and proper litter treatment and management (including keeping litter moisture below 25%), guaranteeing proper ventilation and cleaning are valuable tools to prevent the spread of NE.
When it comes to nutrition, research shows the benefits of a correct feed approach in maintaining gut health and tackling NE disease. Studies have identified a link between high levels of crude protein/undigested protein and C. perfringens counts. As an opportunistic microbe, C. perfringens can easily take advantage of undigested protein to fuel its own population increase. But crude protein is not the only enemy in the NE battle; the undigestible, water-soluble, non-starch polysaccharides (NSPs) found in wheat, rye, oats and barley increase the prevalence and severity of NE with negative impacts on growth performance, gut microbiota, FCR and, in general, bird health. In this context, feed enzymes such xylanase, protease and phytase play an important role by enhancing digestion and breaking down of NSPs, proteins and phytate, increasing nutrient absorption, controlling intestinal irritation and reducing the opportunity for microbial proliferation. Data also shows that high levels of calcium, as well as the use of small particle limestone or highly soluble calcium, impact the levels of C. perfringens. To avoid unwanted effects, calcium levels must be closely monitored in finished feed.
[Feedinfo] How big is the challenge of NE for poultry producers, and what should they be doing differently to address the issue?
[Katie Hilton] Knowing that sub- and clinical disease incidence affects up to 40% of production flocks highlights NE as a substantial challenge for producers. Aside from production losses, farmers must also deal with increased mortality, reduced bird welfare and extension of the age at market weight (due to poor nutrient absorption and slower growth). Nevertheless, there are strategies that could be implemented to prevent or mitigate the consequences of an outbreak, which can be divided in farm management and feed management. The first refers to litter treatment and all sanitary measures, as well as other preventive measures such as coccidiosis vaccination. As for feed management, the measures comprise all nutrition-related optimisations and quality control of ingredients, guaranteeing that birds are receiving the nutrients they need. We also know that a balanced microbiota plays a vital role in inhibiting the colonisation of potential pathogens, so it is key to make strategic decisions regarding feed ingredients and additives. Adding enzymes, Direct Fed Microbial products (DFM, probiotics), phytogenics or betaine, for instance, improves digestion of the feed – and therefore the absorption of nutrients – contributes to a balanced microbiota and improves growth uniformity in flocks.
[Feedinfo] Why does Danisco Animal Nutrition believe it is important to take a holistic approach to understanding NE?
[Katie Hilton] Nutrition, microbiome and gut health are crucial to prevent and mitigate NE disease, but these areas have been traditionally looked at in a siloed way. At Danisco Animal Nutrition we take a more holistic approach, which considers how everything that is fed to an animal combines and interacts in the gastrointestinal tract. We bring together microbiology, biochemistry, genomics, bioinformatics and immunology to understand how to improve gut function and promote a favourable nutribiotic state that helps birds be more resilient, particularly when exposed to bacteria.
Throughout many years and backed through research, we have developed a strong nutritional health portfolio of solutions available to our customers. Built to increase farmers’ profitability, improve animal performance, animal welfare and gut health, Danisco Animal Nutrition’s products include probiotics, phytogenics, natural betaine and enzymes. Our continuous investment to grow this portfolio shows our ongoing commitment to our customers and our willingness to contribute to a more sustainable and strong industry.
[Feedinfo] Beyond organising the necrotic enteritis seminar at PSA 2021, Danisco Animal Nutrition also presented several pieces of research at the conference. Can you briefly tell us about it?
[Katie Hilton] The seminar on managing the facets of necrotic enteritis was a great opportunity to discuss the disease and the scientific advances we have witnessed recently. At PSA 2021, we presented seven abstracts, from which I would like to underline five: three presenting studies on Axtra® PHY GOLD, our novel phytase, superior bioefficacy in broilers and turkeys, and independent studies on maintaining performance in broilers using inorganic phosphorus free diets for the whole cycle; and two assessments of the variation in limestone grit originating from North and South America and its implications for laying hen and broiler nutrition.
Published in association with Danisco Animal Nutrition (IFF)
