Effects of Dietary Digestible Energy Levels on Meat Quality in Wujin Pig

The aim of the study was to investigate the effects of diet composition and digestive energy levels on meat quality of Wujin pig and find out the suitable dietary energy levels according to the best meat quality by fuzzy comprehensive judgment model. Ninety pigs were randomly divided into 5 groups that were fed with diets containing 14.22, 13,60,12.98, 12.36 and 11.74 MJ/kg of digestive energy. There were 18 pigs in each group with 3 replicates and each replicate contained 6 pigs.Randomized block design with single factor was adopted in the experiment. The energy level of group Ⅲ (with digestive en-ergy of 12.98 MJ/kg) was designed according to the feeding standard energy requirement of Chinese meat-fat type of growth-finishing pigs, while the energy level of group Ⅰ (with digestive energy of 14.22 MJ/kg) was designed according to feeding standard of NRC (1998) growth-finishing pigs. The energy level of group Ⅰ(with digestive energy of 13.60 MJ/kg)was designed between groupⅠand Ⅲ. The energy levels of group Ⅳ and Ⅴ were designed under the energy level of group Ⅲ.The gradient of each adjacent energy level was 0.62 MJ/kg. The dietary crude protein, trace element and amino acids con-tents in each group during different growth stages were basically constant. The meat quality was measured when the pigs were slaughtered with the body weight of 30, 60 and 100 kg. Fuzzy comprehensive judgment model was adopted to analyze and determine the suitable dietary energy level to attain the best meat quality of Wujin pig during different growth stages.The results showed that the muscle pH, water holding capacity, shear force, cooking loss and drip loss were significantly af-fected by the diet composition and digestive energy levels during different growth stages. The differences were significant a-mong group Ⅰ, Ⅲ and Ⅴ (P<0.05 or P<0.01). The marbling of meat was significantly different among each group when the body weight of pigs were 60 and 100 kg(P<0.05). The muscle crude protein contents increased with the decrease of di-etary energy level and the difference was significant when the body weight was 100 kg (P<0.05). However, the muscle e-ther extract, intramuscular fat and inosine monophosphate contents reduced with the decrease of dietary energy level. The differences were significant among groups Ⅰ,Ⅲ and Ⅴ during different growth stages (P<0.05 or P<0.01). The applica-tion of fuzzy comprehensive judgment model was based on the marbling, shear forcer and drip loss which represented the meat quality. According to synthetically evaluation, the suitable dietary energy levels were determined as 13.10, 13.08 and 13.11 MJ/kg when the body weight were 30, 60 and 100 kg. The study results could provide scientific basis for the reasona-ble feeding and the improvement of meat quality of Wujin pig.