Serum biochemistry and carcass of broilers, in natural heat conditions, supplemented with organic zinc and vitamin E

The objective of this study was to evaluate the effect of organic zinc and vitamin E on diets for broilers exposed to natural cyclic heat conditions, from 1 to 21 days of age, on carcass and cut yield, skin resistance and serum biochemistry. A total of 600 male and female Ross 308 chicks were used and distributed in a completely randomized design in a factorial scheme. The treatments consisted on inclusion of organic zinc (0 and 120 mg/kg) in association with vitamin E (0, 300 and 600 mg/kg) in the birds' diets. The carcass yield was higher with 120 mg of organic zinc/kg when compared to the treatment without the mineral. Serum triglycerides decreased with 300 mg and 600 mg of vitamin E supplementation. There was interaction between the levels of zinc and vitamin E promoting the fall of blood albumin levels. Organic zinc provides higher carcass yield and vitamin E, associated or not with zinc, improves the serum biochemistry of broiler chickens under natural cyclical heat conditions up to 21 days of age.