Emily Marshall, Alltech Europe
In a post-COVID-19 world, many things in the poultry industry are inevitably likely to change. With social distancing being implemented and a limited workforce for farms and processing plants, the industry is in an accelerated period of technological adaptation. Despite all this, bird health and welfare will still be critical for efficient production. On this basis, gut health should remain at the forefront of producers’ minds when trying to help their birds perform to their genetic potential.
Good gut health is vital for a bird to reach its genetic potential
The importance of good gut health
Gut health can mean different things to different people. But, when taking a holistic approach, gut health must be described as not just the absence of pathogens, but the maintenance and optimisation of gastrointestinal (GI) structure and integrity to enable birds to reach their full genetic potential sustainably.
Despite the broiler and turkey industry focusing on feed conversion ratio (FCR) and weight gain, and the laying and breeder industry focusing on eggs/bird, hatchability and shell strength, all of these measures have an intrinsic link to gut health. It can be thought of as one of the fundamentals of efficient performance. The gut is the organ that allows feed to be digested and absorbed into components that can pass from the gut lumen into the bloodstream to be used by the body in metabolic processes, including growth and egg production. Any issues can lead to inefficiencies and gut health can be thought of as a bottleneck to operations.
Many factors can influence gut health status, including disease pressure, bird age, feed and the associated anti-nutritional factors, external factors like temperature or humidity and the microbiota. Most of these factors are controllable. However, by implementing gut health programmes in flocks, any potentially detrimental impacts can be minimised. With more research around this topic, it has become more evident that the GI tract has direct and substantial implications on other bodily systems. One crucial area of focus has been the interaction between gut health and immunity.
Gut health and immunity
These organisms interact together in a delicate balance, like the rainforest ecosystem. Each organism occupies its own, niche environment, and as the microbiota is a multitude of species, and each species has its own substrate, microbes directly aid food digestion, making it easier for the bird to absorb nutrients.
The microbiota, as non-self organisms, help to educate the immune system as to what is a threat and what can be ignored, meaning that responses to things such as feed changes are minimised. This is important, as immune responses often lead to inflammation, causing excessive mucus production. This is then an extra barrier for nutrients to pass through before being absorbed, reducing efficiencies. Immune responses also use a lot of energy, and so minimising unnecessary action reduces expenditure, giving the bird more energy for growth or egg production.
Microbial populations also produce metabolites. Metabolites, in turn, aide the maintenance of a healthy, diverse microbial population. Volatile fatty acids (VFAs) are metabolites of certain beneficial bacterial species. Butyrate, for example, has been shown to have positive effects on immunity, through modulation of intestinal epithelial cells and leukocytes. Therefore, not only does having a diverse microbiota aide in immune system development, which will make it more robust for times of real challenge, but also helps improve the efficiency of digestion and absorption. This, in turn, aids performance, such as improved feed conversion or more eggs.
How do we improve gut health?
Promoting gut health is paramount in ensuring that flocks are reaching their full genetic potential. Dr. S. Collett of the University of Georgia has created a model encompassing the key factors influencing gut health — the ‘Seed, Feed, Weed Concept’. Conscious of the parameters facing commercial operations, the programme is designed to be sustainable, holistic, farm-specific and cost-effective. Obtained results are measurable, ensuring that benefit can be quantified.
Dr. Collett describes the concept, using crops as an example: sowing seeds of the plants that you want to grow, feeding them for optimal growth and weeding out other plants that may prevent your crop growing optimally. Seeding is done using a probiotic, which ensures that the chick’s nearly sterile gut is colonised by beneficial organisms as soon as possible. These organisms are then fed with an organic acid. Beneficial organisms are acidophiles, meaning that they thrive in acidic conditions. Organic acids are preferable, as they remain associated for longer, keeping pH low and allowing the active component to reach the place where it will be most effective. In contrast, pathogenic species tend to be alkaliphiles, and so promoting a low pH inhibits their growth.
Finally, a product, such as Actigen, is used, which acts as the ‘Weed’ part of the programme. Derived from the Saccharomyces cerevisiae yeast strain, it helps maintain gastrointestinal integrity and stability.
The importance of an early start
For both layers and broilers, getting gut health right early on is fundamental to later performance. Villi surface area is vital for transferring nutrients into the bloodstream. In birds, there is a lag phase, where surface area development through increased cellular differentiation cannot keep up with the growth of the bird. This happens between 2–5 days. If nutrients are not digested and absorbed, they pass through into the caeca, where bacteria ferment them into absorbable forms. If protein is not absorbed higher up in the tract, and high levels are present in the caeca, then pathogenic organisms can use it as a substrate for growth. This is a problem throughout life but is especially important in young birds as their microbiota has not yet fully developed, so there is limited competition for resources, giving unfavourable organisms the upper hand early on. If we can start birds on a gut health programme from day one, it aides with gut structural and microbial development, meaning that potential issues are minimised, and older birds’ performance is not impaired.
The industry is changing at a rapid rate, both in terms of scientific research and technological advancements. Producers must adapt to overcome challenges. As the research builds, it is becoming ever clearer that optimal gut health has huge positive impacts on production and performance. It is also abundantly clear how and why challenges are exacerbated by poor gut health. The question becomes how much is poor gut health costing you, and why are you not doing anything about it?
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