Amino Acid Supplementation to All-Corn Diets for Pigs

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Abstract
A series of three experiments was designed to study the effect of amino acid supplementation of low-protein, all-corn diets on weight gain and carcass measurements of growing pigs. Finishing pigs (50 to 100 kg.) fed corn diets containing 10% protein supplemented with L-lysine-HCl and L-tryptophan gained more rapidly and efficiently than pigs fed unsupplemented corn diets. Rate of gain, efficiency of feed utilization and carcass measurements were not significantly different from those of pigs fed a 12% corn-soybean meal diet. At a level of 0.22% L-lysine supplementation, addition of 0.02% L-tryptophan was as effective as additions of 0.04 and 0.06%. A response to lysine supplementation was obtained only with the simultaneous addition of tryptophan. With pigs weighing 47 kg. initially, supplementation of corn-glucose diets (7.6% protein) with 0.37% lysine and 0.06% tryptophan significantly reduced area of the l. dorsi, increased back fat and decreased total serum protein, despite the fact that daily gain was not significantly lower than that of pigs fed a 20.5% corn-soybean meal diet. Supplemental levels of 0.28% L-lysine and 0.04% L-tryptophan at 7.6% protein resulted in a lower average daily gain than obtained with the higher level of supplementation. Carcass measurements and serum protein of pigs fed the two low-protein diets were not significantly different. The corn-glucose diet reduced by about one-third the amino acids supplied by corn when it makes up 95% of the diet. Feeding unsupplemented corn diets during the early growth period (9 kg.) resulted in complete growth failure. L-lysine and L-tryptophan additions to the all-corn diet at levels of 0.22 and 0.04%, respectively, produced an average daily gain to 100 kg. of 0.56 kg., and the level of performance with respect to gain, efficiency of feed utilization and area of the l. dorsi was below that of pigs fed 20.5% protein corn-soybean meal diets (average daily gain, 0.79 kg.). When pigs fed the all-corn diet for 31 days were transferred to the 20.5% corn-soybean meal diet, performance was similar to that of pigs fed the same diets from the beginning (average daily gain, 0.80 kg.). Copyright © 1968. American Society of Animal Science . Copyright 1968 by American Society of Animal Science