Estimation of genetic parameters for contents of intramuscular fat and inosine-5'-monophosphate and carcass traits in Chinese Beijing-You chickens.

This study was conducted to estimate genetic parameters of meat quality-related traits by a MTDFREML procedure, using 1,069 purebred Beijing-You full-sib male chickens derived from the first 2 generations of divergent selection for the percentage of intramuscular fat (IMF) and selection for increased inosine-5'-monophosphate content (IMP) in breast meat. The results show that estimated heritability of IMP was moderate (0.23), and heritability of IMF was low (0.11). Other traits with high heritabilities, ranging between 0.56 and 0.79, were BW, abdominal fat weight (AFW), breast meat yield, ratio of breast meat yield to evisceration weight (BMP), leg muscle yield, comb weight, and ratio of comb weight to BW (CWP). Moderate heritabilities for the ratio of AFW to BW (AFP) and leg muscle yield to evisceration weight were estimated, 0.24 and 0.32, respectively. Lower significant phenotypic correlations of IMP with BMP and ratio of leg muscle weight to evisceration weight were discovered (P < 0.05), whereas IMF exhibited slightly positive, though significant, phenotypic correlations with BW (0.11) and AFP (0.27). Genetic correlations of IMP with BW and CWP were negative (-0.38 and -0.62, respectively), whereas a high positive genetic correlation was found between IMP and BMP (0.57). It was found that IMF had high genetic correlations with BW (0.75) and AFW (0.66) and moderate correlations with AFP (0.32) and CWP (0.40). A low positive genetic correlation was estimated between IMP and IMF (0.27). In conclusion, both IMP and IMF contents in chicken meat have the potential to be increased through genetic selection with little or no positive effect on BW. Furthermore, close managerial control of growth rate (and BW) will be needed to assure high quality of chicken meat so that increased IMP and IMF can be obtained with less abdominal fat deposited.