SNPs Detection Of Chicken CALB1 Gene And Their Association With Egg Quality

Eggshell quality is an important economic trait for eggs poultry.Calcium binding protein is an important protein that regulates calcium transport in the body.CALB1,Calbindin-D28 k,is a soluble protein located in cytoplasm of Ca BP.It can be combined with Ca2+ to directly regulate Ca2+ transport and mediate regulation.Participates in various physiological functions of Ca2+.In this study,Jining Bairi chickens was used as the test material.560 eggs were collected from 43-week-old hens.The egg quality traits such as egg weight,egg shape index,shell thickness,shell strength,shell weight,yolk weight,albumen weight,albumen height,yolk color,Haugh unit,percentage of shell,percentage of yolk and percentage of albumen were measured.The 5 ? regulatory region SNPs of CALB1 gene were detected and correlated with egg quality traits.The main findings are as follows:(1)The average egg weight of Jining Bairi chickens is 44.04±0.15 g,the shell thickness is 0.31±0.03 mm,the shell strength is 38.13±0.29N/cm2,the egg shape index is 1.31±0.00,and Haugh unit is 61.17±0.30.The percentage of shell,percentage of yolk,and percentage of albumen were 9.90%,37.60%,and 52.52%.The coefficient of variation of the egg shape index is the smallest,at 4.06%;the coefficient of variation of shell strength and albumen height are the largest,both exceeding 15%.The traits with a coefficient of variation between 5% and 10% are percentage of shell,percentage of yolk and percentage of albumen.The coefficient of variation of the other traits were between 10% and 15%.Egg weight was highly positively correlated with shell weight,yolk weight,and protein weight,with correlation coefficient of 0.60,0.61 and 0.85(P<0.01).Shell strength was moderately positively correlated with shell thickness and shell weight,with correlation coefficients of 0.40 and 0.50(P <0.01);shell strength was highly positively correlated with percentage of shell,with correlation coefficient of 0.58;Haugh unit showed a strong positive correlation with albumen height,and the correlation coefficient up to 0.92(P<0.01).(2)In this experiment,560 eggs from Jining Bairi chickens were used.A total of 25 SNPs were detected in the CALB1 5 'regulation,which is rich in polymorphisms,including 16 low polymorphisms(PIC<0.25);9 polymorphisms(0.25<PIC<0.5),which are-958,-919,-751,-735,-710,-664,-614,-541,-516,and the number of effective alleles is between 1.40-1.97.Of the 25 polymorphic loci,10 loci(-958,-751,-735,-710,-689,-664,614,-541,516,-425)significantly deviate from Hardy-Weinberg equilibrium(P<0.05).(3)A total of 10 SNPs were detected to have a significant effect on egg quality?A total of 6 SNPs loci-949,-879,-725,-682,-541,-516 have significant effects on eggshell quality.The-725 locus significantly affected shell thickness.AA type was 3.33% thicker than AG type.The-682 locus had a significant effect on the percentage of shell.The CG type percentage of shell was 4.04% higher than the CC type.Four loci(-919,-879,-541,-516)significantly affected the egg shape index.Comparing egg shape index of different genotypes,-919 locus CT type is better than CC type,-879 locus CT type is better than TT type,-541 locus CC type is more than CG type,and-516 locus GG type is more than AG type.It was 2.33%,3.13%,2.31%,and 1.54% higher.The two loci of-541 and-516 were linked,and the construction of haplotype revealed that there was also a significant interaction effect between haplotype GA and CG(P <0.05),and the egg shape index decreased by 0.03%.(4)Ali Baba 2.1 online software was used to predict the change of transcription factor binding sites at the 6 polymorphic loci that significantly affect egg quality before and after mutation.The transcription factor changed from RAP1 to C / EBP;the binding site before and after mutation at-725(A?G)was GCN4 and AP-1;the transcription factor before mutation at-682(C?G)was only Sp1,and the mutation Sp1 and RAP1 followed;mutation of A-G at-516 locus caused the transcription factor at that site to change from GR to GATA-1.Changes in bound transcription factors may affect the expression level of CALB1 gene.Using Meth Primer 1.0 for methylation prediction of the 1040 bp region of the 5 'regulatory region,it was found that there is a Cp G island in this region,with 6 locus at-293,-290,-284,-267,-248 and-132.In this region,6 polymorphic locus that significantly affect egg quality are not in the Cp G island.In summary,eggs of Jining Bairi Chickens are small in weight and high in shell strength,especially the percentage of yolk is high.Most egg quality traits such as eggshell strength and albumen height have a higher degree of variation.A total of 25 SNPs were detected in the 5 ? regulatory region of CALB1 gene,in which the loci of-919,-879,-725,-682,-541,and-516 have a significant influence on egg shell traits.