The experiment was conducted to determine the effects of four amino acids (lysine, methionine, threonine and tryptophan) supplementation on growth performances and serum antibody titers to Gumboro disease (IBD, infectious bursal disease) in broiler chickens. Chicks were randomly assigned to 5 dietary groups (5 chicks/group as 12 replicates of 5 chicks) in a complete randomised experimental design. Group I served as control group, was fed a diet without any supplementation. Groups II and III were supplemented 10% of four amino acids (lysine, methionine, threonine and tryptophan) of the recommended requirements for 45 and 42 days, respectively. Meanwhile, Groups IV and V were supplemented 20% of four amino acids (lysine, methionine, threonine and tryptophan) of the recommended requirements for 45 and 42 days, respectively. The supplementation was started at 3 days of age in chicks. The chickens were vaccinated against Gumboro disease at day 12 and day 19. The antibody titer of the chickens in each group was assayed using IBD anti-body ELISA. Besides, the live body weight, average feed intake and feed conversion (FCR) were determined at 0, 21, 42 and 84 days of age. The results showed no significant different between groups in performance parameters such as body weight and FCR. However, the present work showed highest dose of lysine, methionine, threonine and tryptophan supplementation for 42 days may be improved feed intake and immune response of chicken against Gumboro disease vaccination. | Effects of lysine, methionine, threonine and tryptophan on growth performance and serum antibody titers to Gumboro disease of color-feathered chickens
