Enzymes and Phytochemicals in Chicken Diets: The Influence of Enzymes and Phytochemicals in Chicken Diets on Performance, Nutrient Utilisation and Gut Microbiota

The thesis reports studies conducted to investigate the influence of dietary components on the performance and gut microbial fermentative characteristics of chickens. These investigations were done with nutritional studies and an in vitro fermentation assay developed during the course of this study. The in vitro microbial fermentation assay developed was able to predict the influence of antimicrobial feed additives quite effectively. However, the interpretation of the in vitro effects in vivo has to be done with caution due to the complex nature of the chicken gut. Nevertheless the in vitro fermentation assay can be used as an effective screening tool prior to in vivo studies. The studies in this thesis concluded that the interaction between the diet, additives and the gut microflora is extremely complex and optimal performance of the broiler depends very much on the type of microorganisms that colonise the gut which in turn is influenced by the materials available in the chicken gut. In depth studies are required to investigate the identity of key gut microorganisms that may be exploited via nutritional means for the benefit of the chicken.