Weanling pigs fed diets containing high-protein corn co-products

Hans Stein

High-protein distillers dried grain with solubles (HP-DDGS) and other high protein corn co-products have been developed in recent years and most of these ingredients are produced by fractionating corn coproducts from the ethanol industry. High protein corn co-products contain between 40 and 50% crude protein, and therefore, may be used in diets for pigs instead as a source of amino acids. Indeed, it is possible to formulate diets for pigs based on corn and HP-DDGS or other corn co-products, but such diets will contain more than twice as much leucine as recommended. Results of recent research have demonstrated that there is a negative relationship between dietary leucine and brain synthesis of serotonin, which results in reduced feed intake of pigs fed diets containing excess leucine. As a consequence, pigs often have reduced growth performance if fed diets with high concentrations of corn protein. Excess leucine in diets for pigs also influences metabolism of isoleucine and valine, which results in a deficiency of these amino acids for protein synthesis, and therefore, reduced growth performance of pigs. However, it is possible to counteract the negative effects of the high leucine concentrations in corn co-products by adding crystalline sources of tryptophan and valine to the diets. Therefore, we hypothesize that corn protein may be used as the primary source of amino acids in diets for weanling pigs if diets are fortified with crystalline amino acids. As a consequence, it is possible that high-protein corn co-products can be used in diets without influencing growth performance or intestinal health of weanling pigs. However, at this time, limited research has been conducted to confirm the hypothesis.