Ratio needs of arginine relative to lysine of male broilers from 28 to 42 days of age during a constant, elevated environmental temperature regimen

Abstract

SUMMARY The digestible Arg (dArg)-to-digestible Lys (dLys) ratio of broilers exposed to a constant, elevated ambient temperature was evaluated in commercial high-yielding male broilers. Common starter and grower diets were fed to all broilers from 0 to 28 d of age. Experimental diets were provided from 28 to 42 d of age. The experimental test diets were formulated with corn, soybean meal, corn distillers dried grains with solubles, and an animal by-product blend. The diets were formulated to satisfy all nutrient recommendations, with the exception of dArg. To create the experimental finisher diets, 2 experimental diets were formulated to contain 0.95 and 1.24% dArg and a common dLys level of 0.95%. These 2 diets were then blended to create 5 intermediate dArg:dLys levels (7 treatment diets in total), which were fed from 28 to 42 d of age. A diet made exclusively with conventional ingredients, with a dArg:dLys ratio of 107%, served as a positive control. Body weight gain was unaffected by the 7 experimental diets. Feed efficiency was improved in the experimental diets when the dArg:dLys ratio was 110%. However, no difference was observed for this parameter when compared with the FE of the control diet (dArg:dLys = 107%). Carcass traits were unaffected by the experimental treatments. Therefore, an adequate dArg:dLys ratio during a period of constant, elevated temperature was satisfied at a minimum of 110%.