Abstract

Transferrins (Tfs) are a class of related metal-binding transport glycoproteins with high specificities for iron. Testicular Tf was found to be synthesized by sertoli cells and involved in the net transport of ferric ions to germ cells. In the present study, the polymerase chain reaction-restriction fragment length polymorphism method was applied to detect the g.−1748G>A (5′ flanking region), g.13942T>C (exon8), and g.14037A>G (intron 8) polymorphisms of the Tf gene in 327 Chinese Holstein bulls. The associations of these polymorphisms with sperm quality traits were analyzed. Statistical analyses revealed a significant association between g.13942T>C and sperm abnormality traits. Six haplotypes were constructed from 14 genotype combinations. Association analyses of these haplotypes showed that bulls with the combined haplotypes GAT/GAT had the highest ejaculate volumes, and that bulls with the combined haplotypes AAT/AAT had the highest fresh sperm motility. The quantitative data indicated that the Tf mRNA level was significantly higher in liver tissue than in the heart, spleen, lung, kidney, and testis tissues.The Tf mRNA level was higher in testis tissue than in spleen, lung, and kidney tissues, but there was no significant difference among them. Therefore, GAT/GAT and AAT/AAT can be possible candidates for marker-assisted selections in bull breeding programs.

Key words: Chinese Holstein bull, genotypic combination, semen quality traits, SNPs, transferrin