Heat stress is one of the most important factors affecting the productivity of poultry farming. Higher productivity also means different nutritional requirements for the animals. This results in changes in nutritional requirements, which include a higher amount of antioxidants. The main objectives of the M.Sc. thesis were to investigate whether the addition of feed additives such as vitamin E (VE), vitamin C and selenium (Se) has an antioxidant effect and whether these additives affect the histological structure of the gastrointestinal tract in broilers exposed to heat stress. The nutritional experiment included 100 one-day-old male broilers divided into five groups according to nutritional and heat exposure treatment. The groups were NNRC (neutral barn, NRC recommendations), VNRC (stress, NRC recommendations), VNRC + PUFA (stress, NRC recommendations, added oil), VECSe (stress, ROSS recommendations, added VE, C and Se), VECSe + PUFA (stress, ROSS recommendations, added VE, C, Se and oil). During the experiment, we weighed broilers, measured feed intake, and recorded mortality. We slaughtered 60 birds, 12 from each experimental group. We measured the mass of each part of the gastrointestinal tract, the viscosity in small intestinal content, and the pH of the small intestine, colon and caecum, determined the concentration of volatile fatty acids (VFA) in the content of small intestine and caecum, and performed histological measurements in two parts of the gastrointestinal tract: the height of villi and the depth of crypts in the jejunum of the small intestine and the depth of crypts in the caecum. We can conclude that the addition of various antioxidants only partially affected the growth of animals and the concentration of VFA in the caecum, but had no effect on the concentration of VFA in the small intestine and the histological structure of the gastrointestinal tract.
|
