Response of broiler chickens to dietary energy and lysine levels in a warm environment.

Two trials were conducted to determine the response of 23- to 47-day-old broiler chickens to dietary lysine and energy levels when reared in a 26.7 C environment. Broiler finishing diets, which contained 3100, 3175, 3250, or 3325 kcal ME/kg of feed were fed in combination with either .308 or .322% lysine/Mcal (kg) with a constant 18.7% dietary protein. Male and female body weights were not statistically different (P less than .05) among dietary energy levels when both sexes were fed .308% lysine/Mcal (kg). When the male chicks were fed .322% lysine/Mcal (kg), body weights increased with increasing dietary energy level. Feed utilization also increased with increasing dietary energy level when broilers were fed either .308 or .322% lysine/Mcal (kg). These data suggest that the body weight response to dietary energy level when broilers were reared in a warm environment will occur only when adequate amino acid levels are employed. The dietary energy requirement is at least 3250 kcal ME/kg of feed when 23- to 47-day-old broilers are fed .322% lysine/Mcal (kg) and reared in a hot environment but appeared to be lower when broilers were fed .308% lysine/kg of feed.