Abstract: The aim of the study was to investigate the effect of dietary protein levels on meat quality so as to find the suitable dietary protein level according to the best meat quality by Fuzzy Comprehensive Judgment Model. Ninety pigs were randomly allotted into five groups fed diet containing different protein levels. There were eighteen pigs in each group with three replicates. Six pigs were used in per replicates. The experiment was designed by single factor random arrangement. The dietary protein levels were high high protein（HHP,18%, 16% and 14%）, high medium protein（HMP, 17%, 15% and 13%）,medium medium protein（MMP, 16%, 14% and 12%）, medium low protein（MLP, 15%, 13% and 11%）and low low protein（LLP, 14%, 12% and 10%）respectively during 15-30, 30-60 and 60-100 kg body weight. The dietary energy level, trace element and amino acids content in one group during different growth stages were constant. The meat quality traits were measured when the pigs were slaughtered at 30, 60 and 100 kg body weight. Fuzzy Comprehensive Judgment Model was analyzed to make sure the suitable dietary protein level to attain the best meat quality in Wujin pigs during different growth stages. The results showed that dietary protein level affected obviously the muscle pH value, water holding capacity, shear force, cooking loss and drip loss during the different growth stages, the differences were significant among high, medium and low groups (P<0.05 or P<0.01). The marbling score increased with the reducing of dietary protein level and which was significant between low and high dietary protein levels (P<0.05). The muscle crude protein contents increased with the dietary protein level increasing and the difference was significant at 100 kg (P<0.05). However, the contents of muscle crude fat, intramuscular fat and inosine monophosphate reduced with dietary protein level enhancing, and the differences were significant among high, medium and low groups during different growth stages (P<0.05 or P<0.01). Fuzzy Comprehensive Judgment Model was analyzed basing on the marbling score, shear force and drip loss which represented the meat quality. The suitable dietary protein levels were 15.88%, 14.13% and 11.42% during 15-30, 30-60 and 60-100 kg body weight from the fitting curve in order to attain the best meat quality in Wujin pigs. The present results could provide scientific materials for the reasonable feeding of Wujin pigs to improve meat quality.

Key words: dietary protein, meat quality, intramuscular fat, Wujin pigs