Abstract

Laith Sofian Younis, Saad Tawfik Rasheed, Qusay Mohammed Aboud, Mustafa Salah Hasan, Ali Aziz Abid..

This study performed to test the influence of β subunit polymorphisms for inhibin A (αβ) and Activin A (ββ) on the superovulation characteristic. Also to investigate the effect of β subunit polymorphisms on inhibin and FSH concentration during the estrus phase for Singleton birth (SB) and Dizygotic twin birth (DZTB) cows.
Thirty-six mature pregnant Iraqi Holstein Friesians cows were utilized, in the confined period (between July 2018-June 2019), these cows were equally disconnected into two groups according to a type of birth; SB cows and DZTB cows. The DZTB trait indicates that superovulation has occurred. Five pairs primers were utilized to magnificate the whole exon 2 of the β sheet of inhibin A and Activin A by polymerase chain reaction (PCR) after extracting the DNA from blood specimens. The single nucleotide polymorphism (SNPs) were detected through sequencing by matching with the Bos taurus inhibin subunit beta A, NCBI Gene ID: 281867 and Ensembl gene browser ENSBTAT00000066382.1.
The data analysis revealed presence of four missense SNPs in exon 2; G(554)S, G(866)R, C(883)S, A(877)R, and 3 prime UTR variant C(1865)Y. The first four SNPs caused amino acid changes, while the fifth wasn't encode amino acid. Two genotypes were detected for each SNP; (GG and GC), (GG and GA), (CC and CG), (AA and AG), (CC and CT) for G(554)S, G(866)R, C(883)S, A(877)R, and C(1865)Y loci respectively.
Higher significant increase (P<0.01) were showed in mutant genotypic frequencies as a compared with the wild in A(877)R and C(1865)Y loci, a significant variance (P<0.05) were registered between the genotypic frequencies of A(877)R locus, while non-significant variation were noticed between the G(554)S and G(866)R genotypes.
The distribution of genotypic frequencies according to type of birth; the genotypic frequencies for mutant genotypes of recorded a higher significant increment (P<0.01) in dizygotic twin birth cows when compared with the wild genotypes of the G(554)S, G(866)R and A(877)R loci, a significant rise (P<0.05) were viewed in mutant genotypes of the C(883)S C(1865)Y loci. While, higher significant rise (P<0.01) were detected in wild when compared with mutant genotypes in C(883)S, A(877)R, C(1865)Y, and a considerable enhance (P<0.05) in wild against the mutant genotypes in G(554)S and G(866)R for SB cows groups.
In addition, a significant rise (P<0.05) in ovulation rate (calving rate) were noticed in heterozygote mutant genotypes of C(883)S and A(877)R loci.
The hormonal evaluation revealed that measured inhibin A was lower in the DZTB group than SB cows groups at the estrus phase. While the finding showed that mean FSH concentration were higher in the DZTB than SB cows groups.
The distribution of hormonal concentration according to genotypes revealed that the inhibin A concentration was lower (P<0.05) in the mutant heterozygote genotype against wild homozygote genotype in A(877)R locus, otherwise, the FSH level recorded a significant rise (P<0.05) in the mutant heterozygote genotypes when compared with wild homozygote genotypes in C(883)S and A(877)R loci.
In conclusion, the exon II SNPs affect positively on superovulation, besides, C(883)S and A(877)R SNPs affect the calving rate. Furthermore, the finding reported that inhibin A was lesser in DZTB cows than in the SB cows, while, FSH was higher in DZTB cows when compared with SB cows. Moreover, A(877)R SNP contributes to inhibin A concentration (mutant genotypes decrease inhibin A level), C(883)S and A(877)R SNPs participate in the increase of FSH level. The bovine superovulation trait can be enhanced via genetic selection for specific genetic markers. The detected Inhibin βA/Activin A SNPs especially C(883)S and A(877)R can be considered as genetic markers to improve the superovulation in cows for embryo transfer and long term genetic selection.
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