Association of AHSG and BHMT Gene Polymorphisms with Fatty Acid Composition and Cholesterol in Sheep

Abstract

Alpha2-Heremans-Schmid Glycoprotein (AHSG) and Betaine-Homocysteine S-Methyltransferase (BHMT) genes are excellent candidate genes that affect fatty acid composition in sheep. The aim of this study was to identify and analyze the association of Alpha2-Heremans-Schmid glycoprotein (AHSG) and Betaine Homocysteine Methyltransferase (BHMT) gene polymorphisms with fatty acid composition and cholesterol in lambs. This study was conducted in two stages, identification of AHSG and BHMT gene polymorphisms and their associations with fatty acid composition and cholesterol in sheep. This study used a total of 67 rams of 12 months with average body size of 25-30 kg, consisted of 20 heads of Javanese Fat-Tailed (JFT) sheep, 17 heads of Javanese Thin-Tailed (JTT) sheep, 10 heads of Composite Garut (CG) sheep, 10 heads of Compass Agrinak (CA) and 10 Barbados Black Belly Cross (BC) sheep. Identification of AHSG and BHMT gene polymorphisms was performed using Polymerase Chain Reaction - Restriction Fragment Length Polymorphism (PCR-RFLP) method. Association of AHSG and BHMT genotypes with fatty acid traits and cholesterol was performed by T-TEST of MINITAB program. AHSG and BHMT genes were polymorphic with three genotypes (GG, GA, and AA) and genotype CC, CT, and TT, respectively. The SNP of AHSG (g.198655287 (G>A) was in Hardy-Weinberg Equilibrium, except in Composite Garut (CG), Compass Agrinak (CA) and Barbados Black Belly Cross (BC) sheep breeds while the SNP of BHMT (g.9947372 C>T) was in Hardy-Weinberg Equilibrium in all sheep breeds, except in Javanese Fat-Tailed (JFT) sheep breed. The SNP g.198655287 (G>A) SNP of AHSG gene was significantly (P<0.05) associated with different saturated fatty acids, unsaturated fatty acids while g. 9947372 (C>T) SNP of BHMT gene was significantly (P<0.05) associated with heptadecenoic acid (C17:1), myristoleic acid (C14:1) and stearic acid (C18:0). Individuals with AA genotype had a higher content of unsaturated fatty acids, especially monounsaturated fatty acids (MUFAs) compared to individuals with GG genotypes, also individuals with AA genotypes had more average values of EPA compared to individuals with GG genotypes and higher content of DHA compared to individuals with GA individuals while for BHMT gene, individuals with genotype CT had higher mean value of stearic acid (C18:0), myristoleic acid (C14:1) and heptadecenoic acid (C17:1). Both genes were not significantly (P>0.05) associated with cholesterol content in all sheep breeds. SNP g. 198655287 (G>A) of AHSG gene and SNP g. 9947372 (C>T) of BHMT may be useful candidate markers for selecting and producing sheep meat having desirable and healthy fatty acids.