Measurement And Analysis Of Meat Performance Of Ningdu Yellow Chicken

Ningdu yellow chicken is a high-quality local broiler in China,which has the characteristics of small size,early sexual maturity,fresh and tender meat,and Buddha’s hands-like tail feathers.In the past two decades,Ningdu yellow chicken industry has developed steadily.However,the average body weight of Ningdu yellow chicken at marketing age has an increasing trend in recent years,and the number of chickens with upturned tail has increased.In order to investigate the effect of the change of body weight and appearance on meat quality,the meat-related traits of different Ningdu yellow chickens and other three commercial yellow chicken breeds were measured in this study,with a view to make a comprehensive evaluation of the meat performance of Ningdu yellow chickens.1.The meat performance of Ningdu yellow chickens with different body weights.Thirty Ningdu yellow chickens at 120-days-old reared under the same conditions were divided into light body weight(LW)group,medium body weight(MW)group and heavy body weight(HW)group according to their body weight.The growth,carcass and meat quality traits of 10 chickens in each group were measured.Seven,six and five chickens were selected from each group,respectively,to measure the chemical composition,amino acid content and fatty acid composition of breast muscle.Results: The breast muscle of Ningdu yellow chicken preserved the characteristics of high crude protein and amino acid content.There were no significant differences in carcass trait,muscle chemical composition and amino acid content indexes among Ningdu yellow chicken populations with different body weights(P>0.05),while there were significant differences in fatty acid composition ratio.The proportions of arachidonic acid in LW group were significantly higher than those in HW group,and the proportions of oleic acid and linolenic acid were significantly lower than those in HW group(P<0.05).2.The meat quality of Ningdu yellow chickens with different tail typesThree individuals with drooping tail and three individuals with upturned tail were selected from the aforementioned groups,respectively,which were recorded as the drooping tail group(9 individuals)and the upturned tail group(9 individuals).Result: The percentage of abdominal fat,the pH value of breast muscle and the content of arachidonic acid in the drooping tail group were significantly higher than those in the upturned tail group(P<0.05),and the ash content of breast muscle in the drooping tail group was significantly higher than that in upturned tail group(P<0.05).3.Histological characteristics of muscle fibers in different parts of breast muscle of Ningdu yellow chickenSix Ningdu yellow chickens with 300-days-old were selected to collect the chest muscle on the right pectoralis major(top,middle,bottom),the middle of right pectoralis minor and the middle of left pectoralis major,marked with group A,group B,group C,group D and group E,respectively.The conventional paraffin section method was used to determine the diameter and density of muscle fiber,number of fibers in muscle bundle,endomysium thickness and perimysium thickness.Meanwhile,shear force values of left pectoralis major and pectoralis minor were measured.The results showed that the number of fibers in muscle bundle in group D is higher than the other four groups(P<0.05),the thickness of endomysium is higher than that of group A,B and C(P<0.01),higher than group E(P<0.05).The shear force of pectoralis major muscle was significantly higher than that of pectoralis minor muscle(P<0.01).4.Comparison of meat quality between Ningdu yellow chickens and other yellow chickens sold in the marketFour kinds of yellow-feathered broilers with different growth rates were purchased,including Wannan yellow chickens(about 240 days of age),Ningdu yellow chickens(110～120 days of age),Zhanjiang yellow chickens(80～90 days of age)and Dwarf yellow chickens(60～70 days of age).Results: the crown length,crown height,slaughter rate,ratio of leg,breast pH value of Ningdu yellow chicken were significantly higher than those in other three breed chicken(P<0.05).The half-eviscerated rate of Ningdu yellow chickens is significantly higher than that in Wannan yellow chicken(P<0.05),24 h drop water loss rate is significantly lower than that in Wannan yellow chicken and Zhanjiang yellow chicken(P<0.05),muscle fiber diameter is significantly lower than that in Wannan yellow chicken and Dwarf yellow chicken(P<0.05).In conclusion,Ningdu yellow chicken preserves the characteristics of high content of crude protein,amino acid and thin muscle fiber.There were no significant differences in most meat quality traits among different body weights and tail type of Ningdu yellow chickens.However,the proportions of arachidonic acid,arachidonic acid in LW group were significantly higher than those in HW group,and the proportions of oleic acid and linolenic acid were significantly lower than those in HW group.Therefore,it is important to pay close attention to the changes of body weight.