Abstract: Forty-eight finishing pigs (Duroc×Landrace×Yorkshine) were randomly allocated to two groups with three replicates of each. All of pigs were fed with the same basal corn-soybean meal diet, one supplemented with 0.1% galacto-mannan-oligosacharrides (GMOS) and the other supplemented with 50mg/Kg chlortetracycline (CTC). At the end of the feeding trial for 46 days, six hogs from each replicate were slaughtered for collecting the slaughter performance and meat quality. The results were as follows: 1) Addition of 0.1% GMOS in basal diet could increase the daily weight gain by 10.2%（P<0.05）, decrease the average daily feed intake by 25.2%（P<0.01）and improve feed conversion rate by 13.2% （P<0.01）as compared with the 50mg/Kg CTC diet；2) Addition of 0.1% GMOS in basal diet could decrease backfat thickness and skin thickness by 15.6% and 11.5%, enhance the fat-free lean by 2.94% as compared with the 50mg/Kg CTC diet, but all were not significant in statistical sense (P>0.05); 3) Compared with the addition of 50mg/Kg CTC, addition of 0.1% GMOS in basal diet could significantly increase blood sugar level by 120%（P<0.05）, decrease the total cholesterol level by 3.86%(P>0.05) and decrease the triglyceride level by 42.6% (P>0.05); 4) Compared with the addition of 50mg/Kg CTC, addition of 0.1% GMOS in basal diet could significantly decrease the indole content in pig muscle（P<0.05）, however, it had not significantly influenced the other meat quality indices.

Key words: galacto-mannan-oligosacharrides, chlortetracycline, finishing pigs, serum biochemical indices, pork quality