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Impact of colonic antiperistalsis due to dietary structure on microbial growth, N efficiency and gut health in broilers

Gepubliceerd op
9 december 2014

This PhD research aims to investigate the physiological relevance of reflux from the colonic/caecal region back into the ileum and if such backflow mechanism could be positively influenced by a proper gut development and functioning, resulting from feeding coarse diets at a low CP level. The outcome of this research may shed light on the quantitative relevance of the avian N-recycling mechanism to the performance and health of protein-depleted broilers, as well as a possible solution to economic efficiency of broiler diets since protein carrying feedstuffs are expensive dietary ingredients in feed formulation.

For decades, nutritional improvements have been focussed to satisfy the effectively high nutrient uptake required by modern broilers. It must be said, however, that much is still unclear. For example, the ceca play an important role in nitrogen (N) economy of broilers, especially when fed a protein deficient diet. This could occur through the action of colonic antiperistalsis; which is the reflux of urinary constituents and small undigested feed particles from the cloaca, through the colon and into the caeca. However, despite concerted efforts by poultry scientists, the exact colonic recycling mechanism and nutritional relevance of the caeca remains unclear, especially the quantitative importance of it. Moreover, it seems possible that synthesized caecal contents (e.g. microbial protein) might be refluxed back to the ileum where further degradation and subsequent absorption will occur.

Nowadays, broilers are usually fed easily degradable pellets (mainly consisting of finely ground feed ingredients) based on the concept of increased exposure of feed substrates to digestive enzymes, thereby leading to improved nutrient digestibility. However, these pellets move quickly along the gut upon ingestion, thereby impairing extensive contractions and gut motility. On the other hand, a more coarse diet is likely to be more efficiently digested, as a result of improved gut development and functioning. A very important effect of a structured particle stimulation is an increase in the refluxing properties of the upper part of the gut, due to its positive correlation to the relative gizzard size and its improved grinding capacity. It is questioned whether a more structured diet also enhances refluxing properties of the hind gut region (N-recycling).

Kazeem Akinloye obtained his BSc degree in Agriculture general from Njala University, Sierra Leone and MSc. degree in Animal Sciences from Wageningen University, the Netherlands. He is currently pursuing his PhD degree at the Animal Nutrition Group, Wageningen University with a part scholarship from the Lagos State Government, Nigeria.