Poultry GIT-Pillar of Poultry Performance and Health
The gastrointestinal tract (GIT) health impacts poultry productivity. It is known to be the pillar of poultry success. The poultry microbiome has myriad functions which range from protection against pathogens and nutrients production, to host immune system development. Healthy poultry birds possess a natural resistance to infection. Since optimum performance and growth rate are central to animal production, the host-microbiome relationship remains integral.
A healthy gut ensures:
- Proper digestion and absorption of valuable feed nutrients
- Less wastage of nutrients
- Minimum foul odour.
- Provides resistance against entero-pathogens
- Checks mortality and morbidity losses
- Optimizes feed conversion ratio.
Figure 1 : The gastrointestinal tract of a chicken.
Apart from nutrient absorption and digestion, three important part of gut function are gut integrity, gut immunity, and gut microbiome. Intestinal integrity may be described as the intactness of the intestine in maintaining its structure and function or simply an unimpaired and sound intestine.
Gut integrity maintains a strong barrier of defense. Physical barriers protect against the entry of foreign materials and organisms into the bloodstream and access to other viscera thus helping intestinal integrity. On occasion due to improper nutrition or an unhygienic environment, when the load of foreign invaders increases these barriers are breached.
1. Mucus (Mucus: material secreted by intestinal cells) acts as a barrier to bacterial and fungal invasion.
2. Gut epithelial cells (enterocytes): These cells form a semi-permeable surface that selectively allows passage of fluid, electrolytes, and dissolved nutrients. Every epithelial cell in the digestive tract is part of a continuous physical barrier. When organisms and toxic agents damage epithelial cells, the integrity of this protective barrier is broken.
3. Fluid secretion: fluid having large amounts of water mixed with electrolytes. The fluid in the upper small intestine is protective and keeps bacteria in suspension and washes them downstream.
4. Vascular supply: supply under the gut epithelial layer serves to rapidly dilute and carry away any agents or chemicals (endogenous or exogenous) that may breach the mucosal barrier.
Gut integrity can be affected by physical barriers Stress factors, Feed toxins and toxicants, dietary factors, health status and gut microflora.
Gut Immunity: Poultry GIT can be considered an immune organ. GALT (Gut associated lymphoid tissue ) is a secondary immune organ and developed early stage in birds life.
Gut microbiome: Consists of species of bacteria, protozoa and fungi in the GIT.
Early life and Gut health
Early life care is an important factor in maximizing profits from broiler operations. Early nutrition mainly in the first 7 days of life for broilers may program the birds’ systems and set a pattern for growth and productivity. A larger percentage of early growth (upto 5 times the growth rate of other tissues) occurs in the digestive tract and those organs involved in digestion. If digestive growth is hampered during this period, overall growth rate may be compromised. Newly hatched chicks are more prone to gut infections as its natural defence is yet to be strengthened. So proper care should be taken during this period.
Functions of Gastrointestinal Tract
Role of Environment in Poultry Gut health:
Role of Dietary Factors in Improving Intestinal Integrity
1. Quality feed ingredients: Supplementation of quality feed ingredients helps in maintaining natural gut health. Mycotoxins which are present in most of feed raw materials like Aflatoxin, Fumonisins, T2, DON, Zearalenone, Ochratoxins affect the gut integrity thereby affecting the gut health and giving rise to bacterial issues like E coli and Clostridium which is directly correlated with the presence of multiple mycotoxins. .
2. Processed feed: Many incriminating factors of feed are destroyed due to processing.
3. Pelleted feed: Pelleting provides scope for utilization of high fibre feed resources. Use of steam- pelleted feed seems to be of value in maintaining gut health.
4. Feed additives: Like Anticoccidials and Ionophores Coccidiosis, a managemental disease, causes devastating losses to the poultry industry. Other feed additives which can help maintain gut health are organic acids, probiotics, prebiotics, mycotoxin binders etc.
Conclusion: To summarise, gastrointestinal tract is the key organ that converts feed to meat and eggs. It is largest organ exposed to foreign matters and serves as first line of defence. GIT is continuously exposed to multiple foreign materials and irritants. Regardless of the level of hygiene and biosecurity imposed at production level, poultry will be exposed to multiple infections and toxic agents through the feed and environment.
Aerobic and anaerobic bacteria, toxin-producing fungi, and protozoan parasites (coccidian) are challenging to be eliminated from poultry production units.
Because of the potential development of antibiotic resistant human pathogenic bacteria, the use of antibiotics, have come under increasing scrutiny and feed safety concerns in the food chain. Hence, today’s intensive animal agriculture industry must adapt to producing poultry and take care of holistic factors that affect gut health right from maintaining biosecurity ,early chick health and also by implementing nutritional strategies that would strengthen the gut health by securing gut integrity, gut immunity and gut microbiome .
