Effects Of ACSL5 Gene On Carcass Traits And Triglyceride Of Fat Synthesis Pathway In Beef Cattle

Acyl coenzyme A long-chain 5 synthetase(ACSL5),a member of ACSLs gene family,plays a key role in beta-oxidation of fatty acids and triglycerides metabolism.However,it is not clear that if ACSL5 play a similar role in fat deposition and carcass traits in cattle.In this study,we tested the association between ACSL5 and lipids metabolism in individual and cellular level in cattle,aiming to reveal the gene function of ACSL5 and to find a new molecular marker in cattle breeding system.For finding a new molecular marker,we investigated 78 beef and carcass traits of 354 Chinese Simmental cattle.Then PCR-RFLP was used for detecting gene type of SNPs in ACSL5.For revealing the gene function in bovine preadipocyte,we constructed and electorporated PBI-CMV3-ACSL5 and sh RNA-ACSL5 to respectively overexpress and knockdown ACSL5 in cells,then triglycerides content in cells was investigated to reveal the relationships between ACSL5 expression level and triglycerides synthesis.Results showed that we detected 2 SNPs in ACSL5 flanking sequence,g.33185918G>A and g.33186348C>T,which showed significantly influence to both beef and carcass traits in Chinese Simmental herds.For g.33185918G>A,compared with individuals with AA genotype,individuals with G-bearing genotype(TC heterozygotes or T allele homozygotes)were showed a greater weight of the rumen,omasum and testes and a higher fat color score(7.48±0.91 kg,3.94±0.59 kg,0.69±0.13 kg,and 2.97±0.74,respectively,p<0.05),which was also related to a higher p H of beef(5.91±0.78 kg,p<0.01).For g.33186348C>T,compared with CC genotype the T-bearing genotypes(TC heterozygotes or T allele homozygotes)were associated with a greater weight of the liver(6.33±1.24 kg,p<0.01),fat coverage rate(50.38±20.46%,p<0.01),loin fat thickness(6.89±0.87 cm,p<0.05),whereas CC genotype showed greater length of hind leg(79.87±3.98 cm,p<0.01)and carcass(139.50±7.79 cm,p<0.05),greater weight of genital fat content(0.91±0.37 kg,p<0.01)and hind hooves(3.39±1.03 kg,p<0.01).Moreover,triglycerides content was significantly increased in bovine preadipocyte with ACSL5 overexpression(p<0.01),whereas triglycerides content was decreased in bovine preadipocyte with ACSL5 knockdown(P>0.05).Our study showed that 2 SNPs,g.33185918G>A and g.33186348C>T were significantly related to the beef traits and carcass traits in Chinese Simmental cattle.Additionally,the expression level of ACSL5 significantly influences the triglycerides content in bovine preadipocyte.This research could provide both theoretical and technical support in studying the gene function of ACSL5 and showed practical significant in molecular assisted cattle breeding system.