A Comparative Study On The Production Performance,Egg Quality And Immune Function Of Fast And Slow Feathered Hens Of Tianfu Green-shelled Laying Hens

In poultry production,the mating speed gene is often used to establish the unique male and female lines.The establishment of early-and later-feathering lines through phenotypic identification and molecular identification assisted selection is a technology widely used in chicken breeding.Previous studies have shown that there are some differences in performance between early-and later-feathering strains,which vary from variety to variety.Tianfu Green shell laying hens is a strain being cultivated in Sichuan Agricultural University.Our research group found that the progeny of Tianfu green shell laying hens had improved the production performance,and at the same time,different feather types were separated.Therefore,this experiment selected Tianfu green-shelled layer hens as the research object to carry out the identification of fast and slow feathers,and compared the differences in egg production performance,egg quality and immune performance of fast and slow feather hens,aiming to reveal the influence of fast and slow feathers on production performance,and provide a data basis for the selection and supporting utilization of Tianfu green-shelled laying hens.The main contents and research results are as follows:(1)Phenotypic identification of fast and slow feathers in 1000 chicks of Tianfu green shell laying hens,420 early-feathering and 150 later-feathering were obtained,and 120 early-feathering and 120 later-feathering were obtained by re-examination.The accuracy of early-and later-feathering was further determined by molecular identification method.The results showed that the consistency rate of early-feathering molecular identification and phenotypic identification was 98.33%.The molecular identification of later-feathering was 97.50% consistent with phenotypic identification.(2)The comparison of the early growth performance of hens with different feathered types showed that there was no significant difference in body weight between hens in the fast feather group and the slow feather group at the first 3 weeks of age(P>0.05).;After birth,the weight of the slow feather group at 25 weeks to 43 weeks was significantly higher than that in the fast feather group(P<0.01).Meanwhile,After3 weeks of age,the tibia length of hens in the slow feather group was longer than that in the fast feather group,and the differences in the 4th,11 th,14th and 16 th week age groups were statistically significant(P<0.05).(3)The comparison of laying performance and egg quality of hens showed that the laying age of hens in the early-feathering group was about one day earlier than that in the slow feathering group,and the overall laying rate,laying weight,laying number at 300 days and 300-day weight of hens in the early-feathering group were higher than those in the later-feathering group,while the broken egg rate was significantly lower than that in the later-feathering group.At the same time,for egg quality,the eggshell thickness,egg weight,protein height and Haugh unit of the early-feathering group were higher than those of the slow feathering group at the beginning and peak of laying,but lower than those of the later-feathering group at the late laying,and the differences between the two groups were not significant(P> 0.05).(4)The results showed that the Ig A content in serum of the early-feathering group was slightly higher than that of the later-feathering group at the early stage of laying,and the difference was not significant(P>0.05),and Ig G and Ig M contents were lower than those of later-feathering group.The contents of Ig A,Ig G and Ig M in serum of early-feathering group were significantly higher than those of later-feathering group(P< 0.01).Meanwhile,the expression levels of IFN-γ gene and interleukin-6(IL-6)gene in the ovarian matrix of the early-feathering group were significantly higher than those of the later-feathering group(P< 0.01).(5)The expression levels of CDK2 and Cyclin D1 and PCNA in ovarian stroma were significantly higher than those of slow feathered hens(P<0.05),the expressions of apoptotic genes Bax,Caspase 3 and Caspase 9 in ovary and uterus of early-feathering chickens were higher than those of later-feathering chickens.In addition,the expression levels of hormone-related genes FSHR,St AR and FOXL2 in later-feathering chicks were higher than those in early-feathering chicks,but the differences were not significant(P>0.05),and the expressions of LHR,ESR1,FOXL2 and St AR in earlyfeathering ovaries were significantly higher than those in later-feathering ovaries(P<0.05).In conclusion,the early growth performance of later-feathering hens was better than that of early-feathering hens,and the laying performance and immune performance of early-feathering hens were better than that of later-feathering hens.