Objective  Effects of reduced-protein diet with a lysine addition on the growth and the content and composition of intramuscular amino acids and fatty acids of pigs at finishing stage were determined to optimize the feeding at hog farms．

  Method  Ninety Landrace x Large White x Duroc pigs with an initial body weight of 59.5±3.6 kg were randomly divided into 3 groups with 10 pigs in each of 3 replicates. As control, Group 1 was fed on forage containing 16.58% crude protein (CP) and 0.71% digestible lysine (DLy). Group 2 and Group 3 were treatments on diets of 14.58% and 12.53% CP, respectively, with a 0.71% DLy addition. The feeding lasted for 40 d prior to slaughtering for chemical analysis on longissimus muscles.

  Result   Compare to control, the pigs in the treatment groups showed no significant differences on the average daily gain (ADG) or feed/gain ratio (F/G) (P＞0.05). Neither the content or the composition of intramuscular amino acids and fatty acids in the longissimus muscles differed significantly among the 3 groups (P＞0.05).

  Conclusion   The results suggested that, so long as the DLy supply in the forage was kept constant at the adequate level, a reduction of CP up to 12.53% in the pig diet would not significantly alter the growth or the nutritional and eating quality of the pork meat.