Study polymorphism growth hormone secretagogue receptor gene and its association with blood parameters and carcass traits in Zell and Shal sheep breeds

Molecular genetics selection on individual genes is a promising method to genetically improve economically important traits in livestock. Growth hormone secretagogue receptor (GHSR) gene secreted by the stomach that has two important functions: the stimulation of the growth hormone production and the stimulation of feed intake. In this study, the association between gherlin receptor gene polymorphism (GHSR) with blood parameters and carcass traits in Zell and Shal sheep breeds were studied using PCR-SSCP and DNA sequencing.

Genomic DNA was extracted from 51 adipose tissue samples using phenols chloroform method. The exon 2 (452 bp) of GHSR gene was amplified with designed specific primers. The single stranded conformation polymorphism (SSCP) patterns of PCR product were studied using 12% Acrilamid gel and silver staining method. In the present study, after revealing genotype of animals for the GHSR locus, this data along with data related to studied traits were analyzed by the least-squares method as applied in the General Linear Model (GLM) procedure of SAS 9.2 program.
sequencing show a novel single nucleotide polymorphism in this gene on the nucleotide position 3278 converting T to C.

This SNP had a significant effect on red meat trait (P<0/05), carcass pH (P<0/002) and ash (P<0/06) in Zel and Shal breed in such a way that the CT genotype was more desirable than TT genotype in red meat and carcass pH traits. The value of least square means of the CC genotype was higher than CT genotype in ash trait. Breed had significant effect on hot carcass weight (P <0/0001), carcass yield (P <0/04), pH (P <0/01), shear force (P <0/001), water holding capacity of the first day (P <0/05), LDL (P <0/02), b * (P <0/0001), l * (P <0/007). The results showed that sex had a significant effect on hot carcass weight (P <0/0008), PH (P <0/01), water holding capacity on the first day (P <0/05) and LDL (P <0/02) traits. The effect of Males was higher effect than females on hot body weight and water holding capacity on the first day. The females had higher effect in LDL, b * and l * traits. In this study there was no significant association between SNP and saturated and unsaturated fatty acids traits.

The results showed that the gherlin receptor gene (GHSR) could be regarded as a possible candidate gene for selection in Zell and Shal sheep breeds