摘要：The effects of addition of fats to the diet on some liver and serum parameters of fattening bulls were examined in breeding conditions. Twenty-four Brown Swiss calves, average weight of 275 kg, were assigned to three groups and fed the following mixed feeds for 183 days: I, control without added fat (CON); II, 2.5% vegetable oil contained (CSO); III, 2.5% animal fat contained (TAL). In the study, the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT) and lactate dehydrogenase (LDH) were measured. The serum concentrations of total protein (TP), albumin, glucose, cholesterol, triglyceride, urea, creatinine, calcium, phosphorus, magnesium, sodium and potassium and the concentration of liver glycogen and protein were determined. This study showed that both at the end of the backgrounding and the finishing period, differences for enzyme activities of AST, ALT, GGT and LDH, concentrations of TP, albumin, creatinine, Ca, P, Mg, Na and K among the groups were not statistically significant. However, glucose values were significantly higher (P< 0.05) in TAL in both periods. Urea and P were significantly lower in vegetable oil in the backgrounding period while cholesterol and tryglyceride concentrations were significantly lower with vegetable oil in the finishing period. On the other hand, feeding bulls on the diet including animal fat caused a significant increase of the liver glycogen level (P< 0.01). Liver protein was not influenced by fat addition.
