A study on the replacement of dietary protein with synthetic amino acids lysine and methionine shows the effects on growth performance and feed costs in finishing pigs. Cross breed finishing pigs (LWxLYxDr) weighing 60 kilograms were fed four formulas: negative control (NC; basal diet without synthetic amino acid; 14% protein), positive control (PC; basal diet with 0.45% lysine 0.10% methionine; 14% protein), and protein replacement feed containing 0.60% lysine 0.15% methionine (T1; 13% protein) and 0.65% lysine 0.15% methionine (T2 The results showed that there were no statistically significant differences in daily feed intake and average daily gain between groups (P > 0.05) , but the groups that contained dietary lysine and methionine showed significantly lower feed conversion ratio and feed cost per gain than the negative control group (P < 0.05). The FCR values of the NC, PC, T1 and T2 groups were 3.60, 3.12, 3.21, and 3.32, and FCG values were 46.70, 41.46, 42.12, and 42.95 respectively. In conclusion, lysine and methionine are important for growth and can be used to replace the protein level in feed without having
a negative effect on productive performance of finishing pigs