101 Supplementation of valine, isoleucine, and tryptophan may overcome the negative effects of dietary excess leucine in high protein corn protein when fed to weanling pigs

Abstract

Abstract Inclusion of high protein corn protein (HPCP) in diets for weanling pigs may result in diets with excess Leu being formulated, which may reduce growth performance. However, it was hypothesized that the negative effect of using HPCP in diets for weanling pigs may be overcome if diets are fortified with crystalline Val, Trp, and (or) Ile. A total of 320 weanling pigs were randomly allotted to 10 dietary treatments in a randomized complete block design. Day 1 to 14 was phase 1 and d 15 to 28 was phase 2. Within each phase, a corn-soybean meal control diet and 2 diets based on corn and 10% HPCP or corn and 20% HPCP were formulated. Seven additional diets were formulated by adding Val, Ile, Trp, Val and Ile, Val and Trp, Ile and Trp, or Val, Ile, and Trp to the diet with 20% HPCP. Fecal scores were recorded every other day. Blood samples were collected on d 14 and d 28. Data were analyzed using the PROC MIXED of SAS; diet was the fixed effect and block and replicate within block were random effects. Inclusion of 10 or 20% HPCP in diets reduced (P < 0.05) final body weight (BW) on d 28, and also reduced (P < 0.05) average daily gain (ADG) and average daily feed intake (ADFI) in phase 2 and for the overall experiment (Table 1). However, pigs fed the HPCP diet supplemented with Val, Ile, and Trp had a greater (P < 0.05) final BW and ADG in phase 2 and for the overall experiment than pigs fed the HPCP diets without AA or with Ile, Trp, or Ile and Trp, and results for this diet were not different from results for the control diet. Fecal scores in phase 2 were reduced (P < 0.05) if 20% HPCP was included in the diets except if Ile and Val were also included (Table 2). On d 28, pigs fed the diet with 20% HPCP and only Val, Val and Trp, or Val, Trp, and Ile had reduced (P < 0.01) blood urea N compared with pigs fed the control diet or the other HPCP-based diets, and pigs fed the control diet and the diet with 20% HPCP and Val, Ile and Trp had a greater (P < 0.05) albumin concentration than pigs fed the other diets (Table 3). Thus, the increased catabolism of Val, and reduced Trp transport into the brain that are caused by excess Leu from HPCP may be overcome by adding Val, Ile, and Trp to HPCP-based diets. In conclusion, up to 20% HPCP may be included in diets for weanling pigs without affecting growth performance or blood characteristics if diets are fortified with extra Val, Ile, and Trp.