Evaluation of the effects of branched chain amino acids and corn-distillers dried grains by-products on the growth performance, carcass and meat quality characteristics of pigs

Studies were conducted to evaluate the effects of corn byproducts high-protein died distillers grain (HP-DDG), and dried distillers grain with solubles (DDGS), and branched chain amino acids (BCAA) on the growth performance and meat quality of pigs. The first study evaluated the combined effect of dietary level of DDGS and HP-DDG on the growth performance of wean-finish pigs and carcass and pork quality characteristics. This study demonstrated that DDGS can be included at up to 30% in diets (without HP-DDG) without compromising growth performance of wean-to-finish pigs. However, growth performance was increasingly compromised at higher inclusion levels of both co-products and belly firmness was negatively affected by increasing levels of both DDGS and HP-DDG. A second experiment was designed to define the minimum CP level and whether non-essential amino acids become limiting in low crude protein diets for late finishing pigs. The results of this study demonstrated that late finishing pigs can be fed diets with 9.76% crude protein level supplemented with 0.32 % L-Lys HCL and other essential amino acids without affecting growth rate and that non-essential amino acids were not limiting in the low crude protein diets evaluated. A third study was designed to recreate the negative effects on growth performance of feeding diets with 30% HP-DDG inclusion level and to test if the negative effect of feeding high HP-DDG levels on growth performance can be reproduced by adding excess branched chain amino acids (leucine, isoleucine, and valine) to standard corn-soybean meal based diet. The results show that the reduction in the growth rates of growing pigs fed diets with 30% HP-DDG inclusion levels may be due to the dietary excesses of leucine present in diets with HP-DDG at 30% inclusion levels. The same effect was not present in finishing pigs. In general, growth performance and belly quality are compromised at higher inclusion levels of both HP-DDG and DDGS. The results of the last studies indicate that leucine level may play an important role on the reduction of the growth performance of pigs fed 30% HP-DDG inclusion levels.