Effects of amino acid supplementation of sorghum based diets for the growing pig

Six experiments utilizing 284 pigs were conducted to determine the effects of amino acid supplementation of sorghum-soybean meal diets for growing pigs. Experiment 1 diets consisted of: (1) basal diet, 13.8% protein; (2) threonine balanced diet + .18% lysine; (3) threonine deficient diet + .30% lysine; and (4) as three + .07% threonine. Pigs fed diet 4 gained faster (P<.05) and were more efficient than pigs fed diet 3. The amino acid analysis in experiment 2 and 3 indicated isoleucine was second limiting. Test diets were as follows: (1) basal diets, 15.99% protein; (2) isoleucine balanced diet + .11% lysine; (3) isoleucine deficient diet + .166% lysine; and (4) as three + .05% isoleucine. Results of experiment 2 and 3 showed no differences in growth and feed efficiency for all diets except for the third experiment. During the last 14 days of this study, pigs fed diet 2 grew faster and were more efficient in their gain/feed ratio (P<.05). No differences resulted in PUN values in experiment 2. Test diets for experiment 4 consisted of: (1) basal diets, 13.36% protein; (2) threonine balanced diet + .18% lysine; (3) threonine deficient diet + .32% lysine; and (4) as three + .061% threonine. Pigs fed the basal diet grew faster (P<.05). Diets used in experiment 5 and 6 were: (1)basal sorghum diet, 9.18% protein + .25% lysine; (2) basal + .128% isoleucine and .25% lysine; (3) basal + .128% isoleucine with .25% lysine and .039% threonine; and (4) as three + .266% methionine. Experiment 5 revealed that pigs fed diet 3 grew faster (P<.05) and produced the lowest PUN values. Experiment 6, a metabolism study, again showed that diet 3 was superior to the other three treatments as these pigs retained the most nitrogen.