Polymorphism Of CRBP4, OCX-32, VLDLR And CTSDC Gene And Its Correlation With Egg Quality Traits In Lingkun Chicken

In this study, we analyzed F3 and F4 two generations in 300-day-old egg productions,500-day-old egg productions and 300-day-old’s egg quality traits by Lingkun chicken. Meanwhile, SNPs of CRBP4, OCX-32, VLDLR and CTSD gene were screened by direct DNA sequencing and the correlation with egg production traits were analyzed to detect the molecular marker of the traits. The results showed that egg production traits may be closely related to the expression of CRBP4, OCX-32, VLDLR and CTSD gene, and can be used as a molecular marker for egg production traits in MAS breeding of Lingkun chicken, which provided a theoretical basis for Lingkun chicken breeding. Results were obtained as follows:1.300-day-old’s and 500-day-old’s egg production were counted, and 300-day-old’s egg quality traits were determined in F3 and F4 two generations of Lingkun chicken. Comparing the two generations’ egg production data, we found the 300-day-olds egg production and yolk ratio significantly different (P<0.05); eggshell thickness, yolk color and haugh unit was very significant difference(P<0.01); the difference of other traits was not significant.2. Through correlation analysis between F3 and F4 two generations’egg production traits, results found in two generations,300-day-olds egg production and 500-day-olds egg production was extremely significant positive correlation (P< 0.01); eggshell thickness and eggshell strength was extremely significant positive correlation (P< 0.01); albumen height and Haugh unit was extremely significant positive correlation (P< 0.01); yolk weight and egg yolk ratio was extremely significant positive correlation (F<0.01).3. A total of 12 SNPs were detected through direct PCR sequencing. Three SNPs of CRBP4 are A337C、G2727A、A2847G, three SNPs of OCX-32 are G6566A、 A6612G、A6760T, one SNPs of VLDLR is C13444T, five SNPs of CTSD are T2614C、C9445T、C9457、C9475T、T11028C. And C13444T, C9457T, T1 1028C SNPs deviated from the equilibrium state of Hardy-Weinberg (P<0.05), the remaining sites are in the Hardy-Weinberg equilibrium.4. The SNPs of exon 2,5 of CRBP4 gene:according to least square analysis, AA and AC genotypes of A337C mutation site is superior to CC in 300-day-olds egg production (P<0.05). On G2727A and A2847G mutation site, GG genotype is superior to AA in egg weight (P<0.05), GG genotype is superior to AA in egg shape index (P<0.05), GG genotype is superior to AA in albumen height (P<0.05).5. The SNPs of exon 5 of OCX-32 gene:according to least square analysis, AA genotype of A6566G mutation site is superior to GG in albumen height (P<0.05). On A6612G and A6760T mutation site, GG genotype is superior to AG in egg yolk weight (P<0.05).6. The C13444T mutation site of VLDLR gene:according to least square analysis, C13444T mutation site is significantly correlation with the haugh unit, yolk weight, egg ratio (P<0.05); In haugh unit, ZTW genotype is significantly higher than the ZCW genotype individual mean (P<0.05); the yolk weight and egg yolk ratio, ZCW genotype is significantly higher than that of ZTW individual mean (P<0.05).7. The SNPs of exon 3,7,9 of CTSD gene:according to least square analysis, CC and CT genotypes of T2614C mutation site is superior to TT in albumen height (P<0.05); TT genotype is superior to CT in haugh unit (P<0.05). C9445T and C9475T mutation sites are significantly correlation with 500-day-old egg production and egg weight (P<0.05), CC genotype is superior to CT (P<0.05). CC genotype of C9457T mutation site is superior to TT in egg weight (P<0.05). CT genotype of T11028C mutation site is superior to TT in albumen height (P<0.05).