“The ‘Seed, Feed, Weed’ concept is a comprehensive programme developed in order to improve the gut health of birds, whether breeder, broiler or layer. Improved performance has been measured across all types of birds, however if good gut health can be established in the breeding population this will provide the biggest benefit to chick and hence bird performance.”
Poultry Technical Coordinator
Alltech Europe
Gut health is the limiting factor in poultry production, regardless of species. Improving gut health will directly impact performance, and, as a result, it should be at the forefront of producers’ minds. The gut is the first portal of entry for a vast array of pathogens, and it interacts with all other bodily systems. As such, there is no silver bullet for improving gut health status; management, genetics, nutrition and additives can all play a part.
THE SEED, FEED, WEED CONCEPT
Profitability is key when discussing implementation of any changes on farm. Conscious of the parameters facing commercial operations the ‘Seed, Feed, Weed’ programme has been designed in order to be sustainable, holistic, farm specific and cost effective.
Results obtained are measurable, ensuring benefit can be quantified. The concept can be visualised using crops as an example, sowing seeds of the crops that you want to grow, fertilising the crops for optimal growth and weeding out other plants that may prevent your crop growing at its optimum.
SEEDING THE GUT WITH FAVOURABLE ORGANISMS
In a natural environment, the chick’s gut would be seeded with the microorganisms from the mother’s GI tract through vertical transmission. Also due to nest hatching, they would spend their early life in an environment containing the mother’s faeces, allowing transfer of her microbiome and colonisation of the chick’s gut.
Modern farming practices remove eggs and place them into an artificial environment for hatching, reducing the opportunity for transfer of microbiota to being transovarial or due to shell contamination. Many studies have shown that even low doses of favourable bacteria can significantly improve resistance to pathogen colonisation. ‘Seeding’ the day-old chick’s gut with a probiotic ensures that a diverse population of microflora is able to develop, creating the framework for good gut health to build upon. As the egg shell contaminant is the first seed stock for the chick, the importance of vertical transmission cannot be overlooked. Altering the microbiome of the breeder stock is the first opportunity to influence the gut health of the chick, feeding Mannan Rich Fractions (MRF, Alltech Inc. USA) to the breeder has been shown to positively alter the microflora in both the breeder herself and her offspring.
FEEDING A FAVOURABLE ENVIRONMENT
Once a favourable population of microorganisms has been established in the gut, it is important to ensure that the surrounding environment is optimal for their growth and replication. Most beneficial microflora are acid tolerant, and therefore grow best at lower pH, whereas potentially pathogenic organisms such as Clostridia and Campylobacter are intolerant to acidic conditions. Feeding a buffered weak organic acid compound provides a competitive disadvantage to the unfavourable bacteria, allowing organisms beneficial to gut health to prosper. Using a weak acid ensures that it is not inactivated whilst passing through the proventriculus and gizzard, allowing it to reach the small intestine and provide maximum benefit. As colonisation of the gut with favourable bacteria continues, organisms attach to the epithelial gut lining and form an interlinked mat over the surface creating a barrier, preventing pathogens access to attach and colonise. With reduced pathogen colonisation there would be reduced disease pressure, and so the need for antibiotic usage is lowered.
WEEDING OUT UNFAVOURABLE ORGANISMS
Through using ‘Seed’ and ‘Feed’ we can establish a healthy population of microorganisms in the gut, however throughout the life of the bird there will be stressors which cause slight alterations to the gut environment, for example after vaccination, post thin or coming into lay. It is vital to maintain favourable gut conditions with the correct balance of microbial species throughout the life of the bird, in order to prevent challenges causing a decline in performance.
Balance is maintained through the ‘Weed’ principle, feeding with a selective exclusion product, such as an MRF, which removes the unfavourable bacteria. For a pathogen to cause disease it first needs to adhere to the gut epithelial lining. It does this via type-1 fimbriae projections which recognise specific carbohydrate molecules on the gut cell wall. Once attached the pathogen is able to replicate which can then lead to inflammation, alteration of villi structure and a reduction in absorption in the bird.
MRF products are competitive inhibitors of pathogenic bacteria, through binding to the type-1 fimbriae, preventing them binding to the epithelium. The agglutinated bacteria are then excreted. MRF products have also been shown to improve absorptive capacity through increasing villi height and surface area and improving villi to crypt ratio, allowing an improved absorption of nutrients leading to improved performance. ‘Weeding’ programmes, such as those using MRF products, are an important factor in reducing antibiotic usage whilst also maintaining microbial diversity, promoting good gut health. Historically antibiotics were used to remove unfavourable organisms from the bird, however due to their non-specific nature whilst ‘weeding’ pathogens other beneficial organisms were also removed. As the gut is recolonised post antibiotic use microbial diversity is greatly reduced leading to the issues discussed above which arise from lack of diversity.
The ‘Seed, Feed, Weed’ concept is a comprehensive programme developed in order to improve the gut health of birds, whether breeder, broiler or layer. Improved performance has been measured across all types of birds, however if good gut health can be established in the breeding population this will provide the biggest benefit to chick and hence bird performance.
Poultry meat and eggs are currently experiencing a boom. In order to keep up with production requirements, birds are often fed protein-rich feed. Due to low retention times, the protein is often not fully digested, meaning that nutrients reach the hindgut. This can then act as a substrate for unfavourable bacteria to replicate, causing dysbacteriosis and gut health issues. Dysbacteriosis is extremely common among all poultry species and is most easily noticed by looking for foamy yellow/orange caecal droppings in the shed. One means of monitoring gut health is by using Alltech’s new Manure Online Scoring System, which enables producers to easily compare shed to shed, or even variation within sheds through time.
As discussed, gut health is the limiting factor in performance, so careful consideration should be given to improve it. It is extremely difficult to manage something without first monitoring it, requiring a system to be implemented to measure, monitor and maintain gut health status. Improving gut health will benefit overall health status, and there are many means to do so. Management practices, such as ventilation and heating, are key to enabling optimal gut health, and programmes such as Seed, Feed, Weed give an all-encompassing and, most importantly, cost-effective way of doing so.
About Emily Marshall
Marshall graduated from the University of Nottingham with a degree in Biology. Since graduating she has held a number of roles in retail, both commercial and technical, and now works at Alltech as Technical Coordinator for Poultry. Emily works on Alltech’s Gut Health Platform and acts as technical support for Alltech’s European poultry team.
