| The Lueyang black-bone chicken is a unique germplasm resource in China,with not only good meat quality,but also unique physical appearance.In this experiment,we evaluated the selection effect of Lueyang black-bone chicken meat line based on the results of seven consecutive generations,compared the selection effect of weight traits in each generation,and fitted the growth pattern curve of Lueyang black-bone chicken using Gompertz model to determine its growth turning point;Phenotypic correlations were performed for weight and body size indicators using SPSS 26.0 software;heritability was estimated for each weight trait at each week of age using the MCMCglmm installation package of R language(4.2.0)software;in addition,the KSAP technique was used to validate the effect of SNPs loci for two genes(MSTN and KLF7)from the initial screening on subsequent generations and to correlate different genotypes with week of age The association analysis was carried out between different genotypes and body weight of 8 W.The results showed that:1.After seven consecutive generations of selection,the weight of meat-type Lueyang black-bone chicken at 4,8,and 12 weeks in P7 generation was significantly higher than that in P1 and P2 generations(P < 0.05),and the weight traits gradually improved with the generations.As the generations increased,the uniformity of the population gradually increased,the coefficient of variation decreased,and the uniformity of the breeding population was significantly improved,which proved that the effect of generational selection was significant;2.The growth curves of Lueyang black-bone chicken for each generation were fitted using the Gompertz model.The results showed that,as the generations of selection breeding proceeded,the inflection point age of the breeding group gradually decreased while the inflection point weight gradually increased,and the inflection point age of hens decreased from 8.16 W in P1 generation to 7.25 W in P7 generation,and the inflection point weight of P1 generation 618.22 g increased to 698.24 g in P7 generation;the inflection point age of roosters decreased from 8.76 W in P1 generation to 7.81 W in P7 generation,and the inflection point weight of P1 generation 706.96 g to 1084.10 g in the P7 generation,and the effect of group selection and breeding is obvious;3.The heritability of body weight traits at all weeks was higher than 0.2,which was medium heritability.Genetic and phenotypic correlation analysis showed that body weight was significantly and positively correlated with tibia length,body slope length and tibia circumference(P < 0.05);the correlation between body weight at 8 weeks of age and other weeks of age was higher in hens,and that between body weight at 12 weeks of age and other weeks of age was higher in males,so the period from 8 weeks of age to 12 weeks of age has important reference value for the late selection of breeders;4.The SNP locus c.A233 G on the MSTN gene was significantly associated with the 8 W body weight of Lueyang black-bone chicken;the SNP locus c.C1022 T on the KLF7 gene was significantly associated with the 8 W body weight,and it was speculated that the above two loci could be used as molecular genetic markers for the selection of meat traits in Lueyang black-bone chicken.In summary,in the breeding work of meat-line Lueyang black-bone chicken,the uniformity of the population has been significantly improved and the breeding effect is very significant.Meanwhile,during the breeding process,the growth rate of Lueyang black-bone chicken gradually increased,the inflection point age decreased,and the inflection point of weight increased.The study also found that two SNP loci(MSTN: c.233 A > G,KLF7:c.1022 C > T)can serve as molecular genetic markers for selecting meat traits in Lueyang black-bone chicken,which can accelerate the breeding process.These results provide a scientific theoretical basis for further breeding work of Lueyang black-bone chicken and theoretical guidance for the industrial development of Lueyang black-bone chicken. |
PDF Full Text Request