Selection On Meat Quality Traits And Its Genetic Correlation With Reproduction Traits In Beijing-You Chicken

With the records of 4 generations up-selection lines for IMP (inosine-5'-monophosphate) and up- and down-selection lines for IMF (intramuscular fat content) which had been established in Beijingyou chicken by Institute of Animal Science in Chinese Academy of Agricultural Sciences, the genetic parameters of the IMF, IMP and other meat quality traits were estimated using a MTDFREML procedure, the effects of genetic selection for IMF and IMP on their contents in muscle, the carcass traits as well as the reproduction traits in different generations and the selection responses of IMF and IMP were investigated in order to testify the validity of selection methods. It would provide references for the development of broiler quality breeding.The results for genetic parameters estimation showed: heritabilities of IMP and IMF were 0.24 and 0.12 respectively and less than middle; among other traits analyzed, the heritability of comb weight percentage was the highest, the following was the heritabilities of abdominal fat percentage, breast meat yield and body weight on 90d, being 0.54, 0.52 and 0.40 respectively; leg meat yield and egg yield in 43 weeks had the moderate heritabilities, being 0.27 and 0.26 respectively.IMF exhibited positive correlation with IMP (rA=0.13); IMP and IMF were positively correlated with body weight (rA=0.14, 0.28) and lowly negatively correlated with the egg yield in 43 weeks (rA=0.04, -0.09); IMF was moderately negatively correlated with the breast meat yield and leg meat yield (rA=-0.15), moderately positively correlated with the abdominal fat percentage and comb weight percentage (rA=0.29, 0.14); IMP was moderately negatively correlated with AFP (rA=-0.28), moderately positively correlated with CWP rA=(0.21), not significantly correlated with BMY and LMY (rA=0.04, rA= -0.05); body weight on 90d exhibited no significant correlation with AFP and CWP (rA= -0.01, 0.01); body weight on 90d and CWP exhibited moderately positive correlations with egg yield in 43 weeks (rA=0.28, 0.18).The results of the selection responses showed the realized heritability (h2R=0.305,0.17) and realized genetic correlations (rA=0.23 and 0.38) of IMP and IMF were higher than the estimated values; In the process of up-selection for IMP, IMF contents was improved slightly, however, when experiencing the divergent selection for IMF, IMP contents decreased and changed more sharply in the process of down-selection than that in the process of up-selection. The egg yields of G3 lines in 43 weeks showed the egg yields of all selection lines increased through the family selection for IMP and IMF; egg yields in up-selection line for IMP and in down-selection line for IMP increased more greatly, by 18.4% and 12.6 respectively; egg yield in up-selection for IMP changed a little (0.8%).In conclusion, it was possible to increase the contents of IMP and IMF in chicken by sib family selection. Up-selection for IMP and IMF could be conducted simultaneously in one population in order to improve the taste and flavor of chicken. Up-selection for IMF resulted in increased fatness and reduced egg yield, indicating that when breeding new line for meat quality, the lines for meat quality and reproduction should be established respectively, then new line was bred through hybridization. It could make sure the improvements of comprehensive performances in breeding chicken and commercial chicken.