Feed evaluation in poultry

The food-feed competition between human and livestock pushes the poultry industry to find substitutions for lost feed resources. Substitutions, such as agricultural by-products may contain high amounts of fibre. Various physicochemical characteristics of dietary fibres can differently affect digesta rheology and passage rate in the gastrointestinal tract (GIT) of chickens, thereby, as a consequence, affecting nutrient digestibility. The interaction between these characteristics on the process of digestion along the GIT of chickens, however, is still a gap of knowledge. This project aims to understand the role of dietary fibres varying in fermentability and physicochemical properties on digesta characteristics and transit through the GIT, endogenous losses, and microbial colonization in chickens in three experiments. It is expected that this process can affect nutrient digestibility, GIT health and development, and excreta properties. To prove this hypothesis, therefore, in the first experiment, we will compare the digestion and digesta transport in birds of various genetic strains (high vs low productive laying hens), when fed diets containing coarse vs fine particles. In the second experiment, we will study the effect of dietary fibres with different physicochemical characteristics on passage rate, endogenous losses, and nutrient digestibility in broiler chickens. In the third experiment, we will further observe various fibres (as a result from experiment 2) with various physicochemical properties on digesta transit dynamics.