Polymorphisms Of A-FABP And SCD1Genes In Longdong Beef Cattle And Its Relationship With Meat Quality Trait

Zaosheng cattle in Gansu province have a long history of domestication andhybridization improvement and are well-adapted to the production environments inGansu. Consequently, Zaosheng cattle formed Longdong beef cattle group which haveexcellent production characteristics, such as good forage utilization, good growth onforage-based rations, and good meat quality. Longdong beef cattle include Zaoshengcattle and their hybrid modified groups which are distributed in Qingyang and Pingliang.However, genetic improvement in carcass quality in Longdong beef cattle is desirable inorder to increase net income. Therefore, the objective of this study was to identifypolymorphisms is genes related to fat metabolism and deposition and evaluate carcassquality in the different genotypes identified. Identification of polymorphisms in A-FABPand SCD1genes was done using PCR-SSCP, DNA sequencing and DNA sequenceanalysis in five Zaosheng cattle groups (Qingyang group, QZ; QZ and its hybrid withSouth Devon group, QZ×N; Pingliang group, PZ; PZ and its hybrid with Qinchuancattle group, PZ×Q; PZ and its hybrid with Simmental group, PZ×S). Polymorphismsfromexon2、3、4ofA-FABP gene and the exon5ofSCD1gene were identified and usedin this study. The associations between single nucleotide polymorphisms (SNPs) andcarcass and meat quality traits of the five cattle groups were analyzed by mixed modelleast squares procedures using general linear model. Results fromthis studywill be usefulin identification of genotypes with positive influences on economically-important traitsthat will be useful in marker-assisted-selection (MAS) and improvement of Longdongbeef cattle. Results were shown as follows:1. For the A-FABP gene, three genotypes in exon2and exon3were detected,respectively. Sequence analysis revealed nucleotide substitutions in exons2and3,c.280A>G site and c.408G>C site, respectively. For the SCD1gene, two genotypes(CC and CT) representing two specific alleles (C and T) in exon5were detected, withsequence analysis revealing one nucleotide substitution, c.878C>T.2. At the c.408G>C locus in exon3of A-FABP, polymorphism informationcontent (PIC) of Qingyang and Pingliang cattle were lesser genetic variation andpolymorphism. The others were abundant genetic diversity in these loci within different groups.3. For the c.280A>G of the A-FABP locus, there were significant effects onDressing percentage, Net meat percentage and WBSF (P<0.05or P<0.01). Forc.408G>C locus of the A-FABP gene, there were significant effects on Carcass weight,Dressing percentage, Net meat percentage, Loin muscle area, pressing loss, WBSF,Retort cooking and pH(P<0.05or P<0.01), and it could be the candidate gene for thecarcass and meat quality traits in Longdong beef cattle.4. For the c.878C>T locus of SCD1gene, the SNPs did not influence carcass andmeat quality traits (P>0.05).