| In this study,pure line Jilin black chickens were used as materials to study the characteristics of growth and development,slaughter characters,meat quality and blood biochemical characters of Jilin black chickens,and analyze the correlation,so as to provide reference for the research on germplasm characteristics of Jilin black chickens,breed breeding,feeding management and breed evaluation.The body weight of 0-21weeks,the body size of 6 weeks and the body size of 7-21 weeks were measured.At 21weeks of age,some chickens were randomly selected for slaughter test,and the meat quality was measured.The blood of wing vein was collected one week before slaughter.The results are as follows:1.Fitting analysis of growth curve of Jilin black chickenThe body weight of Jilin black chicken was similar to that of hen before 7 weeks of age,and the difference increased after 7 weeks of age.From 0 to 21 weeks old,the average body weight of cocks was always higher than that of hens.The average body weight of 21-week-old rooster was 2353.53g and that of hen was 1907.14g,the difference was significant.The fitting degree(R~2)of the three growth curve models of Logistic,Gompertz and Bertallanffy are all more than 0.99.the three mathematical models can well describe the growth and development law of Jilin black chicken,but through the comprehensive comparison of the mature weight,inflection point week age and inflection point weight predicted by the three models,it is considered that the Gompertz model is the most suitable to describe the growth and development law of Jilin black chicken.The turning point weight of Jilin black chicken fitted by Gompertz model was 1120.6g and 927.1g,the age of inflection point was 10.54g and 10.94weeks,and the mature weight was 3046g and 2520g,respectively.2.Correlation Analysis between body weight and some body size traits of Jilin black chickenThere were significant positive correlations between body weight and body size traits such as oblique length,chest width,pelvic width,tibia length and shank circumference of Jilin black chickens at 6 and 13 weeks of age,respectively(P<0.05).3.Correlation analysis between partial body size traits and slaughtering traits of Jilin black chickenSlaughter rates of 21-week-old Jilin black chicken were 88.55±1.21%and 91.20±1.33%,respectively,and the eviscerated rate were 69.36±1.57%and 63.77±2.83%,respectively.The results showed that Jilin black chicken had good meat performance.The correlations between body size traits and slaughtering traits of Roosters and hens measured at the age of 21 weeks were analyzed,and their significance was tested.Among the body size traits of 21-week-old Jilin black chickens,the correlation coefficients of body oblique length and chest depth with carcass weight,full clean body weight,semi-clean chamber weight and leg weight were the highest,while the correlation coefficients between breast width,shank circumference and carcass weight,full clean body weight,semi-clean chamber weight and leg weight were the highest.The results showed that the slaughtering performance of rooster could be improved indirectly by the selection of oblique length and chest depth,and the slaughtering performance and early breeding of hens could be predicted by chest width and shank circumference.4.Analysis of muscle quality of Jilin black chickenAt the age of 21 weeks,there was no significant difference in drip(storage)loss,shear force and cooked meat rate of leg muscle between male and female(P>0.05).The cooked meat rate of breast muscle of Jilin black chicken was 68.14±4.42%and70.77±1.95%respectively,and the water loss rate of leg muscle was 21.57±4.30%and25.32±4.58%,respectively.the water loss rate of breast muscle was 32.44±3.27%and36.95±3.5%,respectively.There were significant differences in chest muscle cooked meat rate and leg muscle water loss rate between male and female(P<0.05),and extremely significant difference in chest muscle water loss rate between male and female(P<0.01).5.Correlation Analysis between Blood biochemical traits and body size traits of Jilin black chickenOnly some blood biochemical traits of Jilin black chicken were correlated with body size traits,and there were differences between males and females.There was a significant positive correlation between serum TBIL and pelvic width and tibial circumference,as well as between HDL-C and tibial circumference(P<0.05),but there was no significant correlation among other indexes(P>0.05).HBDH of hens was positively correlated with body weight,oblique length,chest width and shin length(P<0.01),and the correlation coefficient between HBDH and body weight was the highest,which was 0.532.CK was significantly(P<0.05)or significantly positively correlated with all body size traits(P<0.01).The experiment shows that TBIL and HDL-C can be used as indirect selection indexes of pelvis width and shin circumference,respectively.Hens selected HBDH as genetic markers for indirect breeding such as body weight and body length.6.Correlation analysis between blood biochemical traits and slaughtering traits There were some differences between males and females in the correlation between blood biochemical traits and slaughtering traits of Jilin black chicken.There was a significant negative correlation between TCHO and abdominal fat weight,a significant negative correlation between UA and leg muscle weight(P<0.05),a significant positive correlation between LDH and abdominal fat weight(P<0.05),and no significant correlation between other indexes.HDL-C of hens was positively correlated with half-bore weight,full-bore weight and wing weight(P<0.01).There was a significant positive correlation with leg weight and chest muscle weight(P<0.05),and the correlation coefficient between HDL-C and wing weight was the highest,which was 0.588.The results show that UA of cock can be used as an indirect selection criterion for leg muscle weight,and HDL-C of hen can be used as an indirect selection criterion for half-clean bore weight,full-clean bore weight,wing weight,leg weight and chest muscle weight. |
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