Influence of basic and branched chain amino acid interactions on the lysine and valine requirements of young turkeys.

Two experiments were conducted to determine the influence of amino acid interactions on the lysine and valine adequacy of a low protein diet fed to Large White turkeys from 7 to 19 days of age. Corn-soybean meal diets containing 22 and 30% protein served as controls in both experiments. Test diets involved supplementation of the 22% protein diet with several essential amino acid mixtures. Each diet was fed ad libitum to two pens of eight males and two pens of eight females in each of three trials, except that the 22% protein control diet was fed to four and two pens of each sex per trial in Experiments 1 and 2, respectively. Experiment 1 varied the levels of lysine (0, .60, and 1.20%) and arginine (0, .64, and 1.28%) included in the amino acid mixture. A decrease in supplemental lysine from .60 to 0% reduced weight gain and feed efficiency by 8.6 and 2.4%, respectively. The lysine deficiency was not exacerbated by arginine supplementation up to 179% of the requirement. The effects of altering the leucine (0, .54, and 1.08%) and isoleucine (0 and .4%) contents of the amino acid mixture on the valine requirement were investigated in Experiment 2. Leucine and isoleucine supplementation of diets containing 1.25% valine acted independently to reduce weight gain and feed intake, but the depressions were reversed with the addition of .44% valine. Maximum weight gain and feed efficiency were not achieved with diets containing 1.25% valine and no added leucine or isoleucine, which were indicative of a true valine deficiency in the basal 22% protein diet.(ABSTRACT TRUNCATED AT 250 WORDS)