Ratio of total sulfur amino acids to lysine for finishing pigs.

Abstract

We conducted two experiments to determine the optimum ratio of total sulfur amino acids (TSAA) to Lys for late finishing pigs. In Exp. 1, 50 barrows and 50 gilts were allotted to treatments with three replicates of three or four pigs per replicate in a randomized complete block (RCB) design within a split-plot arrangement of treatments. Sex was the whole plot and TSAA:Lys ratio was the subplot. Average initial and final BW were 77 and 111 kg. Barrows and gilts were fed diets formulated to contain .55 and .65% Lys, respectively. The ratios of TSAA:Lys were .50, .55, .60, .65, and .70. Diets met or exceeded an ideal amino acid pattern for all indispensable amino acids (except TSAA), and all diets were isonitrogenous and equal in electrolyte balance. In Exp. 2, 60 gilts were allotted to five treatments with four replicates of three gilts each in a RCB design. Average initial and final BW were 74 and 110 kg. Gilts were fed diets formulated to contain .65% Lys. The ratios of TSAA:Lys were .35, .425, .50, .575, and .65. In Exp. 1, there were no TSAA:Lys ratio effects (P > .10) for ADG, final BW, percentage muscle, longissimus muscle area, carcass length, percentage fat-free lean (PFFLEAN), lean gain per day (LGD), total fat (TOFAT), percentage TOFAT (PTOFAT), fat gain per day (FGD), lean:fat, retained energy in TOFAT as ether extractable lipid (RE-F), retained energy (RE), or serum urea N (SUN). Feed intake (ADFI) was greater (quadratic, P < .05) for pigs fed .70 TSAA:Lys than for pigs fed any other treatment. Hot carcass weight, psoas muscle weight, 10th rib fat thickness, dressing percentage, fat-free lean (FFLEAN), and retained energy in FFLEAN as protein (RE-P) responded inconsistently to TSAA:Lys ratio, resulting in cubic (P < .09) effects. In Exp. 2, ADFI (linear, P < .08), TOFAT (linear, P < .05), PTOFAT (linear, P < .07), FGD (linear, P < .05), RE-F (linear, P < .05), RE (linear, P < .05), and SUN (linear, P < .02; quadratic, P < .01) decreased as TSAA:Lys ratio increased. Also, gain:feed (GF) (linear, P < .01; quadratic, P < .04), PFFLEAN (linear, P < .04), and lean:fat (linear, P < .04) increased as TSAA:Lys ratio increased. One-slope, broken-line regression models estimated required ratios of TSAA:Lys of .44 (SUN), .40 (ADG), .47 (ADFI), .45 (GF), .45 (FFLEAN), .44 (LGD), .65 (TOFAT), .65 (FGD), .44 (RE-P), .65 (RE-F), .65 (RE), and .57 (lean:fat). Thus, for growth and muscling traits of late finishing pigs, the optimum ratio of TSAA:Lys is less than the current proposed ratio (.65), but to minimize fat accretion, the ratio is .65.

Relações metionina mais cistina digestível: lisina digestível em dietas suplementadas com ractopamina para suínos em terminação

“…Os resultados de ganho de peso foram semelhantes aos encontrados por Knowles et al (1998) (2005), que não constataram variação significativa na conversão alimentar dos suínos em terminação, em razão do aumento da concentração de metionina + cistina na ração. De forma contrária, Santos et al (2007) verificaram melhora na conversão alimentar de suínos em terminação à medida que a concentração de metionina + cistina aumentou até o nível estimado de 0,506%, correspondente à relação met+cis:lis de 0,63.…”

“…Knowles et al (1998) observaram incremento na quantidade de carne magra na carcaça com o aumento da relação met+cis:lis até 0,55, no qual a quantidade de carne magra na carcaça passou a diminuir. Esses resultados contrariam, no entanto, os descritos por Santos et al (2007), que verificaram aumento da quantidade de carne magra na carcaça de suínos com o aumento da relação met+cis: lis até 0,63.…”

“…Resultados similares foram obtidos por Loughmiller et al (1996a) e Santos et al (2007), que também não observaram efeito do aumento da relação met+cis:lis na ração sobre o peso de carcaça. Em outro trabalho, Knowles et al (1998) relataram efeito cúbico do peso de carcaça em resposta ao aumento da relação met+cis:lis.…”

“…Estes resultados corroboram os relatos de Loughmiller et al (1996b), Knowles et al (1998) e Santos et al (2007, que também não observaram efeito da elevação da relação de met+cis:lis na dieta sobre a porcentagem de carne magra dos animais.…”

Evaluation of various sulphur amino acid to lysine ratio for growing-finishing pigs fed antibiotic-free diets

“…Although the optimum proportion of sulphur amino acid (SAA, Met and Cys) to lysine for growing-finishing pigs has been widely investigated in recent years (Hahn & Baker 1995;Knowles et al 1998;Loughmiller et al 1998;Zhang et al 2015), the SAA requirement varies depending on response criteria and health status of pigs. According to NRC (2012), the proposed ratio of standardised ileal digestible (SID) SAA to lysine for 50-100 kg pigs ranges from 0.56 to 0.60.…”