Objective Correlation between the polymorphisms of sirtuin 3-associated gene (SIRT3) in metabolically active tissues and the growth indicators of Guanling cattle was analyzed.

Methods Tissue samples from the heart, liver, spleen, lung, kidney, leg muscle, longissimus dorsi, and shoulder muscle were collected from three 18-month-old Guanling bulls. Expressions of SIRT3 in the organs and muscles were analyzed by qRT-PCR. A whole-genome resequencing was conducted on the population of 187 Guanling cattle to identify the single nucleotide polymorphism (SNP) loci in SIRT3. Association of the genetic variants with the cattle growth traits was evaluated using a mixed linear model.

Results The SIRT3 gene was ubiquitously expressed in the hindlimb muscle, longissimus dorsi muscle, spleen, lung, kidney, heart, shoulder hump, and liver of Guanling cattle. The longissimus dorsi muscle and shoulder hump had the highest level of expression, followed by the hindlimb muscle and relatively low in the heart, kidney, spleen, and lung. Two SNPs, i.e., g.8779 C＞T in Exon 6 and g.23000 C＞T in Exon 10, were identified. Significant correlations between the SNPs and the growth of Guanling cattle were observed at the g.8779 C＞T locus in the manner that the cattle of CC genotype exhibited significantly greater withers height than the TT genotype (P＜0.05) as well as significantly larger cannon bone circumference than the CT genotype (P＜0.05). And at the g.23000 C＞T locus, the TT genotype cattle had significantly greater withers height and ischial end width than the CC genotype (P＜0.05) and also wider chest than the CT counterparts (P＜0.05).

Conclusion The identified SNPs in SIRT3 significantly correlated with certain growth traits of Guanling cattle indicating a potential application of them as genetic markers for breeding purposes.