Maximizing the use of supplemental amino acids in corn-soybean meal diets for 20- to 45-kilogram pigs1,2

Abstract

Four experiments were conducted to determine the Lys requirement, the maximum amount of supplemental Lys that does not decrease growth performance, and to determine the order of limiting AA beyond Lys, Thr, Trp, and Met in a corn-soybean meal diet for 20- to 45-kg pigs. All experiments were conducted for 27 to 28 d with purebred or crossbred barrows and gilts, which were blocked by initial BW. Treatments were replicated with 4 to 6 pens of 4 to 6 pigs per pen. In all experiments, pigs and feeders were weighed on d 0, 14, and 27 or 28. At the beginning and end of all experiments, blood samples were obtained from all pigs to determine plasma urea N (PUN) concentrations. In Exp. 1, 0.830, 0.872, 0.913, and 0.955% standardized ileal digestible (SID) Lys was fed, whereas 0.747, 0.788, 0.830, 0.872, and 0.913% SID Lys was fed in Exp. 2. Broken-line analysis requirement estimates could not be estimated from any response variable in Exp. 1, but in Exp. 2, using ADG and PUN, the estimated SID Lys requirement was 0.83%. In Exp. 3, 0, 0.118, 0.191, 0.264, and 0.335% supplemental Lys was added to achieve 0.83% SID Lys in all diets, and Thr, Trp, and Met were supplemented to maintain Thr:Lys, Trp:Lys, and TSAA:Lys of 0.65, 0.18, and 0.60, respectively. Based on ADG, ADFI, and G:F, up to 0.23% supplemental Lys can be added along with supplemental Thr, Trp, and Met without negatively affecting growth performance; PUN was linearly decreased (P < 0.001) by supplemental Lys. In Exp. 4, treatments were 1) positive control (PC) without supplemental AA, 2) negative control (NC) with 0.335% supplemental Lys + 0.140% l-Thr + 0.035% l-Trp + 0.117% dl-Met, 3) NC + 0.044% l-Val, 4) NC + 0.021% l-Ile, and 5) NC + 0.044% l-Val + 0.021% l-Ile. Individual addition of Val and Ile did not improve (P > 0.10) ADG or G:F compared with the NC. The combined addition of Val + Ile resulted in ADG that was intermediate between the PC and NC diets but not different from either diet (P > 0.10); G:F was not improved (P > 0.10) to that observed in pigs fed the PC diet. The PUN was not different (P > 0.10) among pigs fed diets with supplemental AA but less (P < 0.10) than pigs fed the PC. The results of this research indicate that the Lys requirement for 20- to 45-kg pigs is 0.83% SID Lys, up to 0.23% supplemental Lys (0.29% l-Lys·HCl or 0.45% l-Lys·SO(4)) can be added along with supplemental Thr, Trp, and Met without negatively affecting growth performance, and another AA besides Val and Ile may be limiting growth performance in a corn-soybean meal diet with 0.335% supplemental Lys.

Utilization of crystalline or protein-bound lysine for growth and carcass traits of barrows and gilts fed individually or in groups1

“…Dietary treatments did not affect ADFI, indicating that Lys source or concentration did not affect feed intake. This is in agreement with the results of Roux et al (2011), who reported that ADFI was not affected by supplemental Lys addition from a crystalline source in diets fed to 20-to 45-kg pigs. Lopez et al (1994) evaluated a group of gilts from 71 to 102 kg in a thermoneutral environment and fed control and ideal diets, in which Lys concentration was limiting (0.65%), and reported that ADFI was not different for gilts fed the intact diet compared with gilts fed the ideal protein diet.…”

Growth performance of 20- to 50-kilogram pigs fed low-crude-protein diets supplemented with histidine, cystine, glycine, glutamic acid, or arginine1

“…Previous studies within our research group have shown that grower pigs (20 to 50 kg) fed a low-CP diet supplemented with 0.34% Lys along with Thr, Met, and Trp had reduced growth performance compared with pigs fed a positive control (PC) diet with no supplemental AA (Roux et al, 2011). Growth performance was improved with the supplementation of He and Val; however, G:F was less than that of pigs fed the PC.…”

“…To achieve a Met:Cys of 50:50, L-Cys was supplemented to the diet to replace dietary Met. The quantity of Gly supplemented was done to achieve 1.35% Gly -I-Ser, which has been reported previously to provide growth performance similar to that of pigs fed the PC diet (Roux et al, 2011).…”

Effects of sex and dietary lysine on performances and serum and meat traits in finisher pigs

“…Also, Jin et al (2010) found an impairment of ADG and FCR with 30% of Lys restriction over a control diet containing 6 g total Lys/kg. Some authors have used the blood urea content to define Lys requirements (Roux et al, 2011), although not always successfully (Cameron et al, 2003), depending on the supply of non-limiting AAs relative to Lys. In the current study, the formulation of diets for similar content of ideal protein prevented the response of serum urea to dietary Lys.…”