Effects of Dietary Combinations of Vitamin A, E and Methionine on Growth Performance, Meat Quality and Immunity in Commercial Broilers

The experiment was conducted to study the effect of dietary combinations of vitamin A (VA), vitamin E (VE) and methionine (Met) on growth performance, meat quality and immunity in commercial broilers. Ross chicks (n=3,630) were allocated to five experimental treatments with three replicates per diet. The dietary treatments were: VA 8,000 IU, VE 10 IU (diet 1); VA 12,000 IU, VE 10 IU (diet 2); VA 8,000 IU, VE 100 IU (diet 3); VA 12,000 IU, VE 100 IU (diet 4) and; VA 12,000 IU, VE 100 IU/kg diet and 20% Met higher than other groups (diet 5). The Met content in diet 1 to diet 4 were as per the requirement suggested by NRC. Separate vitamin premixes were prepared for each treatment diet as per the requirement of study. The 35 d study revealed significantly (p<0.0001) higher weight gains in broilers fed diet 3 and diet 5, than in the rest of the groups during starter phase (0-3 weeks) only. The feed intake did not vary significantly at all phases of study, but feed efficiency was significantly (p<0.05) lower in diet 1 during starter and overall phase (4-5 weeks). The bone strength and bone composition, except bone calcium, remained unaffected due to experimental diets studied after 35 d of experimental feeding. The thio-barbituric acid reactive substances (TBARS) were significantly (p=0.0013) lower in the breast meat in group 5, followed by group 3, than in the rest of the groups. The immune studies conducted, antibody titers to sheep red blood cells, thickness index to phytohaemagglutinin-P, and heterophil: lymphocyte ratio, did not show any significant difference among treatments. It could be concluded that supplementation of VA, VE and Met at higher levels could be beneficial to broilers only during the starter phase. (Asian-Aust. J. Anim. Sci. 2005. Vol 18, No. 4 : 516-523)