Comparative Study On Carcass,Meat Quality And Muscle Fiber Traits Of Three Hybrid Commercial Pigs

Pork is the main source of animal protein for Chinese people,and its qualit y has attracted more and more attention.Pork quality is a comprehensive trait affected by many factors.Terminal male parents provide 50% genetic materials for commercial pigs,which has a significant impact on meat quality.Myofibers and intramuscular fat are the main components of muscle,which are directly related to the tenderness,flavor,and juiciness of lean meat.In the present study,we measured growth traits,carcass traits,and meat quality traits for 1166 commercial pigs,including Duroc♂×(LR×LW)♀(hereinafter referred to as"DLY")(400),Pidu boars♂×(LR×LW)♀(hereinafter referred to as―PDLY‖)(332 heads),Pietrain♂×(LR×LW)♀(hereinafter referred to as"PLY")(434 heads),and collected all related phenot ypic data.Moreover,we anal yzed m yofiber histological characteristics by using slicing technology,and analyzed the correlation between myofiber traits and meat quality traits.By comparing the growth,carcass,meat qualit and muscle fiber traits among different hybrid combinations,the following results are obtained:(1)In the three different hybrid combinations,the initial weight order is:PDLY>DLY>PLY,the initial weight of the PDLY is 1.63±0.018kg and the PDLY has the highest dail y weight gain,0.729±0.003kg/day.The DLY has the highest slaughter rate(0.739±0.001).The average daily gain of sows is significantly greater than that of steerers,whereas the slaughter rate of steerers is greater than that of sows.PLY have the smallest body length,101.1±0.960cm.The eye muscle area of PLY is significantly larger than that of DLY and PDLY(P=3.49e-02).The carcass weight of steers(99.3±0.238kg)is larger than that of sows,and the backfat thickness of the barrow is extremely significantly larger than that of the sow.But the eye muscle area of the barrows is small.As for the meat quality traits,the intramuscular fat content of the DLY(2.31±0.039)is extremel y significa ntl y higher than that of PDLY and PLY.The DLY has the least moisture content,which is 73.24±0.048.The intramuscular fat content of barrows is extremely significantly higher than that of sows and the drip loss of steers is significantly lower than that of sows.(2)Analysis of the phenot ypic characteristics of muscle fibers:the average area of the muscle fibers of the PDLY is 6229±123μm~2,the average length of the muscle fiber is 88.7±0.92μm,and the average diameter of the muscle fiber is 67.2±0.64μm,all of which are significantly lower than the DLY and PLY.The phenot ypic values of myofiber traits in barrows are lower than that of sows.The average myofiber value is extremely significantly correlated with the feeding age.Myofiber area is extremely significantly negatively correlated with body weight(r=-0.01,0.01<P≤0.05)and is positively correlated with 48h drip loss of muscle..(3)The proportion of type I myofibers is significantly positively correlated with intramuscular fat,and it is significantl y negatively correlated with the value of the flesh color.The proportion of type I myofibers in the high intramuscular fat content group is higher than that in the low intramuscular fat content group,which means the increase in the number of type I muscle fibers is beneficial to the deposition of intramuscular fat.The proportion of type I myofibers in DLY is significantly higher than that of the PDLY and PLY,and the intramuscular fat content of the hybrid combination DLY is the highest among the three hybrid combinationsAccording to the results of study,when considering the growth traits only,the birth weight and the average daily gain of PDLY is larger,and the overall economic benefit is better.However,as for meat quality,DLY has higher intramuscular fat content,higher slaughter rate,lower drip loss and better comprehensive phenotype.By analyzing the type of muscle fiber in high and low intramuscular fat content group,it is found that type I myofiber had a positive effect on intramuscular fat deposition.The results of this study provide an important reference for the selection of terminal male parent and meat quality breeding in commercial pig production.