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Effect of dietary inclusion level of high-protein distillers grains (HP-DDG) and of dietary excesses of branched chain amino acids (BCAA) on the growth performance of pigs
Previous research has shown a negative effect of feeding high levels of HP-DDG on growth performance of pigs. The objectives of this research were to firstly recreate the negative effects on growth performance of feeding diets with 30% HP-DDG inclusion and, secondly, investigate if this negative effect could be reproduced by adding excess BCAA (Leu, Iso, and Val) to corn-soybean meal based diets. Two studies, 1 with growing and 1 with finishing pigs (initial BW 42.36 ± 2.84 kg and 101.7 ± 2.86 kg, respectively) were carried out as RCBD with the same 6 dietary treatments: 1) Positive Control (corn-soybean meal based diet); 2) Positive Control + supplemental Leu, Iso and Val; 3) Positive Control + supplemental Leu and Iso; 4) Positive Control + supplemental Leu; 5) Negative Control (30% HP-DDG inclusion); and 6) Negative Control + supplemental Val. For Trt. 2, 3, and 4, the respective synthetic BCAA were added to give the same total digestible levels as Trt. 5; Trt. 6 had the same Val:Leu ratio (0.56) as Trt. 1 by the addition of supplemental Val to the diet for Trt. 5. Diets were formulated to the same ME content (3.37 Mcal/kg); digestible lysine levels were 1.04 and 0.64% for Study 1 and 2, respectively. Both studies used 72 individually-housed pigs (12 replications) that were given ad libitum access to feed and water. In both studies, there was no effect (P > 0.05) of dietary treatment on final BW, ADFI, and G:F. In Study 1, the addition of BCAA’s to dietary Treatments 2, 3 and 4 at the same digestible amino acid levels as Treatment 5 (2.00% Leu, 0.64% Iso, and 0.77% Val) resulted in a 8.7% reduction (P < 0.05) in average daily gain compared with Treatment 1 (0.977, 1.016, 0.992, 1.004 Vs 1.090 kg, respectively, SEM 0.231; P < 0.05). In Study 2, Trt. 2, 3, 4, 5, and 6 had similar ADG (P > 0.05) than the Positive Control (Trt. 1). These results suggest that the negative effect on growth rate resulting from feeding diets with 30% HP-DDG can be recreated in growing, but not finishing, pigs by the addition of BCAA to corn-soybean meal based diets and that this reduced growth rate may be due to a dietary excess of leucine.
Keywords:
branched chain amino acids, pigs, high protein dried distillers grain