Effects Of Pre- And Post-morten Factors On Growth Performance,Slaughter And Carcass Characteristics And Meat Quality Of Pig

The present study is to determine the effects of pre- and post-mortem factors on growth performance, slaughter and carcass characteristics and pork quality by slaughtering 648 pigs. The pre-mortem factors are breed, gender, slaughter weight and diet, and the post-morten factors are chilling, ageing and moisture enhancement. The growth performance was determined by the weight of the growth, average daily gain and average daily intake; the slaughter and carcass characteristics was carried out by the percentage of the lean yield and cutout, as well as the composition of the carcass; and the meat quality was evaluated by the value of pH, color, texture, proximate analyses and the eating quality.The result indicated that the percentage of lean yield, picnic and ham, as well as the content of intramuscular fat and the scores of marbling in Duroc are the highest(P<0.05),however, the content of body cavity fat, subcutaneous fat and intermuscular fat are the lowest(P<0.05). Meanwhile, the content of IIB fiber type, PUFA and n-3 are the highest in Duroc(P<0.05). Iberian has the highest percentage of belly, body cavity fat,subcutaneous fat and intermuscular fat, and the highest fat hardness(P<0.05). However,the purge loss, drip loss and cook loss in Iberian are the lowest(P<0.05), which account for the highest scores of tenderness, juiciness and overall palatability(P<0.05).Meanwhile, Iberian has the lowest length and diameter of sarcomere, content of IA and IIA fiber type(P<0.05), but the highest content of n-6/n-3(P<0.05). The average daily gain in Lacombe the period from pen to W1, as well as the average feed intake and the weight of lean yield are the highest(P<0.05). Furthermore, the Lacombe has the highest value of shear force, purge loss, drip loss and cook loss, as well as the content of moisture and PUFA/SFA(P<0.05).Barrows has the higher weight in every growth period, average daily gain and average feed intake than gilts(P<0.05). However, gilts has higher percentage of lean yield, weight of lean yield and ham, but lower loin than barrows(P<0.05). Thepercentage of body cavity fat, subcutaneous fat and intermuscular fat in barrows are higher(P<0.05), whereas the value of hue, shear force, as well as the content of intramuscular fat and the fat hardness in gilts are lower(P<0.05), which contribute to the highest scores of marbling, tenderness, juiciness, flavor and overall palatability in barrows(P<0.05). Meanwhile, gilts has higher content of moisture and protein,PUFA/SFA and n-6/n-3(P<0.05), but lower content of SFA、MUFA and PUFA(P<0.05).The pig in group of 140 kg has higher weight in every growth period, average daily gain and average feed intake(P<0.05). The cooler loss, percentage of lean yield and ham has significant decreased(P<0.05), however, the percentage of belly has significant increased as the slaughter weight increased(P<0.05).The pig in group of 140 kg has higher content of body cavity fat, subcutaneous fat and intermuscular fat(P<0.05), but lower content of lean than the pig in group of 120kg(P<0.05). The higher slaughter weight has account for the lower value of pH(P<0.05), but higher value of shear force and drip loss(P<0.05). As the slaughter weight increased, the content of moisture has decreased significantly(P<0.05), but the content of intramuscular fat and fat hardness has increased significantly(P<0.05), which account for the significant increasing in scores of marbling, but decreasing in tenderness and juiciness(P<0.05).The pigs in D3 have the lowest value of pH(P<0.05), but higher value of chroma than the pigs in D1(P<0.05). The value of shear force, purge loss, drip loss and cook loss and fat hardness in the pig of D3 are the highest(P<0.05), which account for the lowest scores of initial juiciness(P<0.05). However, the content of IA fiber type in pig of D3 was the lowest(P<0.05), whereas the content of IIB fiber type was the highest(P<0.05).The blast chilling has made the value of pH, chroma, as well as the purge loss and cook loss decreased significantly(P<0.05), but made the value of shear force and drip loss increased significantly(P<0.05). Meanwhile, the sensory quality also expressed the same result, which indicated the higher fat hardness and juiciness, but lower scores of tenderness, respectively(P<0.05). The pork after moisture enhancement has shown the lower value of shear force(P<0.05), but higher purge loss and drip loss, which result in the highest scores of tenderness and initial juiciness(P<0.05). In addition, the longer ageing time could make the value of shear force, purge loss, drip loss and cook lossdecreased significantly(P<0.05), which account for the higher scores of tenderness and juiciness(P<0.05). However, as the ageing processing, the scores of flavor desirability,flavor intensity and overall palatability has decreased significantly(P<0.05).Therefore, Duroc has advantage feed intake conversion, percentage of lean yield and the content of intramuscular fat. Iberian has exhibited the highest content of carcass fat and the highest scores of sensory quality. Lacombe has indicated the highest growth performance and weight of lean yield, but lowest sensory quality. Meanwhile, barrows has advantage growth performance, fat content and characteristics, as well as sensory quality, however, gilts has advantage percentage of lean yield and the content of fatty acid. Pig in group of 140 kg has advantage growth performance, but poor percentage of lean yield, as well as the scores of tenderness and juiciness. In addition, D3 has account for the poor texture of the pork. Blast chilling has contributed to higher juiciness, but lower tenderness. Both moisture enhancement and ageing have significantly improved the sensory quality, however, the scores of flavor and overall palatability has decreased as the ageing processed. Thus, it is important to determine a point which is able to balance the value of shear force and the water holding capacity in chilling, and tenderness,juiciness and flavor in ageing, respectively.In addition, the present study indicated that the lower pH value could account for the lower water holding capacity, as well as the increasing of the L and the value of the shear force. The meat that had higher content of the moisture had lower content of the fat.Meanwhile, the lower content of the fat could make the fat hardness, the score of the marbling, tenderness, juiciness and flour lower.