Energy metabolism and lactation performance of primiparous sows as affected by dietary fat and vitamin E.

In this thesis different levels of dietary fat (37, 43, 75 and 125 g/kg DM, respectively) and vitamin E (from 14 to 151 mg α-tocopherol/kg diet) in the lactation diet, were studied for their effect on the energy metabolism, and lactation performance of primiparous sows. The effects of different levels of vitamin E (13, 48 and 136 mg α-tocopherol/kg diet, respectively) and types of dietary fat (50 g/kg sunflower oil or animal fat) in gestation and lactation diets, on some immunological parameters of sows and piglets were also investigated. It was found that a high level of fat in the lactation diet decreased daily heat production of sows. As a consequence the energetic efficiency of milk production was improved. A high dietary fat level increased the milk fat output. The daily quantity of milk from sows was not influenced by the different levels of dietary fat, nor by the vitamin E in the diet. The high level of dietary vitamin E in the pregnancy and lactation diets had no consistent effect on the measured parameters of the cell-mediated and humoral immunity of lactating sows. The results of present studies indicate that vitamin E levels in sows' diets can improve some immunological variables in piglets. The fat sources had no consistent effect on the immunological parameters teste