Effects of Dietary Protein and Corticosterone on Mixed Function Oxidase in Liver and Immunity in Male Broilers.

Abstract

Three experiments were undertaken to determine if dietary protein and corticosterone affect hepatic microsomal mixed function oxidase (MFO) system and immunoresponses in male broiler chicks. In Experiments 1 and 2, chicks (14 days of age) were fed on 11.5 or 23% protein diet supplemented with 0, 5 or 50 ppm corticosterone for 14 days. In Experiment 3, chicks (20 days of age) were given 10, 20 or 40% protein diet supplemented with 0 or 10 ppm corticosterone for 12 days. Dietary corticosterone increased the content of cytochrome P-450 in chicks fed on the 11.5% protein diet, but not on the 23% protein diet. Cytochrome P-450 in chicks fed the 40% protein diet with 10 ppm corticosterone is lower as compared to that in chicks fed the diet without corticosterone. The activity of NADPH-cytochrome c reductase increased linearly with dietary corticosterone or protein. Antibody titer to Sheep Red Blood Cell in chicks fed on the 40% protein diet was lower than that in chicks fed on the 10 or 20% protein diet. The corticosterone administration did not affect the titer. The titer to Brucella canis was decreased by the administration of corticosterone, but not by an increase in dietary protein contents. The results suggest that dietary corticosterone activates the MFO system in hepatic microsomes, while the degree of the activation of the MFO is dependent on dietary protein contents, and also suggest that effects of dietary protein and corticosterone on antibody production may be different from type of antigen used though decreasing protein and increasing corticosterone in the diets reduces organ weight related to immunity.