Effect Of Castration On Meat Traits And MRNA Expression Of Meat Quality Related Genes In Huainan Male Chicken

The castrated rooster, whose testis was extirpated and loses sexual function, has aseries of different traits in feather color, comb size, feed conversion rate, productivityperformance, slaughter performance and meat quality. In this study, Huainan Chicken, afamous chicken breed in Anhui Province, was selected to estimate the effects of castrationon production performances and meat quality.The Huainan Chickens selected in the research are mixed sibs. At day46, they weredivided into two groups contain the castrated group, whose members were castrated andcontrol group, which operated on but uncastrated. The chicken in the two groups wereslaughtered at12,16, and weeks of age, respectively, and the carcass traits, meatquality,and PPAR-α, MSTN and MyoG gene mRNA expression pfofile were analyzed.The results showed:1. growth and slaughter performance: there was no difference(P>0.05) in body weight and slaughter rate between two groups during the whole studyperiod; At16wks of age, percent of eviscerated body was higher (P <0.05) than controlgroup.At20wks of age, leg muscle rate of catratated were higher (P <0.05) than controlgroup.At16and20wks of age, abodominal fat percentage of catratated were higher (P <0.01) than control group.2. muscle fiber development: chicken in castrated group of breastmuscle and leg muscle at wk16, muscle fiber diameter were13%and16%lower than incontrol group, respectively (P <0.05) and muscle fiber density of breast muscle was26%higher (P <0.01), meanwhile, the muscle fiber density of leg muscle increased by20%atweek20;3. On meat quality, The shear force of muscle was significantly declined (P<0.05)of leg by58%and breast by55%at the age of16weeks,the shear force of muscle wassignificantly declined (P<0.05) of leg by32%and breast by25%at the age of20weeks;4.The intramuscular fat of chicken in castrated group were34%higher (P <0.05) than thosein control group at20weeks, while there were no apparent difference between them inIMP content;5.The relative expression level of PPAR-α and MyoG was significantlyhigher of chicken in castrated group than those in control group (P<0.05) at the age16weeks and20weeks and the level was upgraded with age;6. Of chicken in both groups,the relative expression level of PPAR-α mRNA in liver had a remarkable positivecorrelation with caul fat rate(P<0.05), while MSTN mRNA remarkable negative with caulfat rate(P<0.05) and MyoG mRNA extremely remarkable with caul fat rate(P<0.01).In conclusion, castration affected insignificantly the growth rate of roosters ofHuainan Chicken while greatly improves the tenderness and intramuscular fat percentage, which attributes partly to the expression level of meat quality associated genes such asPPAR-α, MSTN and MyoG.