Search

Litter size is an important trait in the pig industry. Therefore, a lot of effort has been put into improving this trait. DNA methylation is an essential epigenetic modification present in unique DNA sequences. Alterations in methylation can affect transcription and phenotypic variation. The purpose of this study was to investigate the effect of DNA methylation on litter size. Methylation-specific restriction enzymes are simple and useful tools for detecting DNA methylation status. We used a pair of methylation-sensitive isoschizomers, which have the same recognition site, HpaII and MspI. Insulin-like growth factor binding protein 4 (IGFBP4) is a key regulator of ovarian follicular development and fetal growth in eutherian mammals. In this study, we discovered that IGFBP4 was hyper-methylated in the uterus tissue of a larger litter size group using bisulfite sequencing, and validated the positive relationship between the methylation status of IGFBP4 and the total number born of pigs using the porcine methylation-specific restriction enzyme polymerase chain reaction (PMP) assay. We suggest that the IGFPB4 gene can be used as a prognostic biomarker for hyperprolific sows and that the PMP assay is a useful tool for methylation status screening.

Corticosteroid-binding globulin (CBG) is a plasma transport protein that has glucocorticoid-binding activity. In the present study, we identified CBG gene expression in several tissues of four pig breeds: Berkshire, Duroc, Landrace, and Yorkshire. Expression of CBG mRNA was detected in the liver of all four breeds, and was the highest in Berkshire pigs. We also found single nucleotide polymorphisms (SNPs) in the CBG gene from Berkshire pigs, including SNP c.919G>A, which corresponds to 307G>R. We analyzed the relationships between this CBG variant and various meat-quality traits. The SNP was significantly associated with backfat thickness, post-mortem pH24h, meat color [CIE a* (redness), CIE b* (yellowness)], water-holding capacity, fat content, moisture content, protein content, cooking loss, and shear force. However, the effects differed by gender: the values were significantly associated with almost all traits in gilts, whereas only cooking loss and shear force were shown significantly in barrows. The variant G allele was associated with decreases in backfat thickness, post-mortem pH24h, CIE a*, fat content, and cooking loss, but with increases in CIE b*, water-holding capacity, moisture content, protein content, and shear force. Because the general correlation between meat-quality traits were not validated in the present study, we suggest that certain SNP might be used in the restrictive application to distinguish meat-quality traits.