Effects of Season, Dietary Protein Supplement and Biotin on Performance and Pyruvate Carboxylase Activity in Livers of Poults

Two trials were conducted to study the effects of protein supplements and biotin level of rations on rate of growth, occurrence of symptoms of biotin deficiency and pyruvate carboxylase activity in livers of poults. Three protein supplements were compared in rations with and without added biotin (220 μg./kg. of ration). When meat and fish meal were used as the protein supplement in a ration, without supplemental biotin, rate of growth of poults was lower than normal; more than 50% of the poults developed symptoms of a biotin deficiency; and pyruvate carboxylase activity in their livers was low. Addition of biotin markedly reduced the incidence of deficiency symptoms, and resulted in more than a 70% increase in pyruvate carboxylase activity in livers of 3 week old poults in both trials, but failed to improve rate of growth. When soybean meal was included in the protein supplement used, the poults in the groups without supplemental biotin were almost free of deficiency symptoms, grew rapidly and had a higher level of pyruvate carboxylase activity in their livers than those receiving meat meal and fish meal. Addition of biotin to the ration containing meat-fish-soybean meal protein supplement increased pyruvate carboxylase activity in livers of poults by 33% in the early hatched poults and by 50% in the later hatched ones. The corresponding increases when soybean meal and fish meal supplied all of the protein supplement were 18% and 16% respectively.