Effect of betaine and arginine in lysine-deficient diets on growth, carcass traits, and pork quality1

Forty entire male pigs from a commercial crossbreed (Duroc × Large White × Landrace) were used to investigate the individual or combined effects of betaine and Arg supplementation in Lys-deficient diets on growth performance, carcass traits, and pork quality. Pigs with 59.9 ± 1.65 kg BW were randomly assigned to 1 of 5 dietary treatments (n= 8). The 5 dietary treatments were normal Lys and CP diet (0.51% Lys and 16% CP; control), reduced Lys and CP diet (0.35% Lys and 13% CP), reduced Lys and CP diet with betaine supplementation (0.33%), reduced Lys and CP diet with Arg supplementation (1.5%), and reduced Lys and CP diet with betaine and Arg supplementation (0.33% betaine and 1.5% Arg). Pigs were slaughtered at 92.7 ± 2.54 kg BW. The Lys-deficient diets (–35% Lys) increased intramuscular fat (IMF) content by 25% (P= 0.041) and meat juiciness by 12% (P= 0.041) but had a negative effect on growth performance (P< 0.05) of pigs. In addition, Lys-deficient diets increased L* (P= 0.005) and b* (P= 0.010) muscle color parameters and perirenal fat deposition (P< 0.001) and decreased both HCW (P= 0.015) and loin weight (P= 0.023). Betaine and Arg supplementation of Lys-deficient diets had no effect on IMF content but increased (P< 0.05) overall pork acceptability. Arginine supplementation also increased (P= 0.003) meat tenderness. Differences in fatty acid composition of pork were not detected among dietary treatment groups. However, oleic acid was positively correlated (P< 0.05) with IMF content, juiciness, flavor, and overall acceptability of meat. Data confirm that dietary CP reduction enhances pork eating quality but negatively affects pigs' growth performance. Moreover, it is suggested that betaine and Arg supplementation of Lys-deficient diets does not further increase IMF content but improves some pork sensory traits, including overall acceptability.