| Abstract: | This study investigated the effects of amino acids (AA) supplementation in low‐crude protein (CP) diets on the growth performance and carcass characteristics in late‐finishing gilts. Ninety gilts (93.8 ± 5.5 kg) were randomly allotted to one of the five diets which consisted of a normal‐CP (137 g/kg) or four low‐CP (105 g/kg) diets for 28 days. The low‐CP diets were supplemented with lysine + threonine + methionine (LCM), LCM + tryptophan (LCT), LCT + valine (LCV) or LCV + isoleucine (LCI), respectively. Non‐significant difference in average daily gain (ADG) was obtained in gilts receiving the control and LCV diet, which was higher than that of gilts fed the LCM diet (p < .05). The additions of crystalline AA in the low‐CP diet resulted in the improvements in ADG (linear and quadratic effect, p < .05) and fat‐free lean gain (quadratic effect, p < .05) and influenced the valine concentration (linear and quadratic effect, p < .05) and proportion of saturated fatty acid (linear effect, p < .05) in longissimus muscle. The results indicated that the valine supplementation could further improve the performance in 94 to 118 kg gilts fed the 105 g/kg CP diet. |
