The present study aimed to evaluate the effects of varying standardized ileal digestible Lysine:Threonine (SID Lys:Thr) ratio in the diet on the performance and meat quality of finishing pigs. Methods:In total 192 crossbred pigs [(Landrace × Yorkshire) × Duroc, 17weeks old], with an initial median body weight (BW) of 70.6± 3.9 kg were used in an 8-wk trial. Pigs were randomly allotted to one of six dietary treatments based on their initial BW and sex (8 replications; 4 pigs per pen, 2 barrows and 2 gilts). The pigs in the 6 treatments were fed diets having different

With the development of industrial synthetic amino acid technology, supplementary feed grade amino acids have become available for use in livestock diets. A portion of dietary crude protein replacement in poultry and swine diets with grain and synthetic amino acid has been reported to reduce feed cost, and it contributes in the reduction of

This study was conducted to evaluate the supplementation of glutamic acid (Glu) to reduced protein diets on the performance of weanling pigs. One hundred and eighty crossbred weanling pigs ([Yorkshire × Landrace] × Duroc, 21 d old) having similar body weight (BW) of 6.45 kg were randomly allotted to 1 of 6 dietary treatments (5 pigs per pen [2 barrows and 3 gilts]; 6 pens per treatment) based on BW and sex during a 6-week trial. Dietary treatments consisted of positive control (PC) diet formulated to have 226.9, 205.6, and 188.8 g crude protein (CP) during phases 1, 2, and 3, respectively, and negative control (NC) diets with 20 g CP reduction from PC diets and addition of Glu with increasing levels, resulting in the calculated Lys-to-Glu ratios of 1:2.25, 1:2.30.1:2.35, 1:2.40, and 1:2.45, designated as NC, NC1, NC2, NC3, and NC4, respectively. The BW of pigs receiving PC diet was higher ( P < 0.05) than those receiving NC diet at d 7, 21 and 42. A higher ( P < 0.05) average daily gain (ADG) from d 1 to 7, 8 to 21, 22 to 42 and during the overall experiment period was observed in pigs fed PC than NC diet. Pigs fed NC diets including the graded level of Glu linearly increased ( P < 0.05) BW at d 42, ADG and gain-to-feed ratio (G:F) during the overall experimental period. In addition, trends in linear increase in BW ( P = 0.056) at d 7 and ADG from d 1 to 7 and d 22 to 42 (linear effect, P = 0.081, P = 0.058 respectively) were observed. A tendency in the linear increment of NH 3 ( P = 0.082) at d 21 and linear reduction in methyl mercaptans ( P = 0.054) emission at d 42 was observed in pigs fed NC diets supplemented with graded level of Glu. In conclusion, supplementing the reduced protein diet with Glu enhanced the growth performance in weanling pigs suggesting that supplementation of Glu can compensate the reduction of 2% CP in the basal diets.