Epoxide hydrolase 1 (EPHX1) plays an important role in both the activation and detoxification of exogenous chemicals. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed that the highest level of EPHX1 expression occurred in Berkshire liver, which is an organ that plays a key role in detoxification. We examined EPHX1 SNPs to analyze effect on increased expression of EPHX1 gene in Berkshire liver by total of 192 pigs of a pure Berkshire line (males = 97; females = 95). As a result, two nonsynonymous SNPs (nsSNPs) of EPHX1 were found from c.685T>G and c.776C > T, and located in 5th and 6th exons, respectively, which constitute the A/b hydrolase 1 domain of epoxide hydrolase. The nsSNP c.685T > G was significant differences in meat color, protein content, collagen content, and pH24 hr. Especially, T and G alleles of the nsSNP c.685T > G were significantly associated with CIE a*/CIE b* and protein content/pH24 hr, respectively. The nsSNP c.776C > T was significant differences in drip loss and protein content. Among meat quality traits to associate with SNPs, the protein content was only significantly associated with sex. Therefore, it is suggested that nsSNP c.685T> G in EPHX1 gene is a potential to apply as appropriate DNA markers for improvement of porcine economic traits.

We investigated glycogen synthase and upstream regulatory proteins determining meat quality in porcine longissimus dorsi at 24 h post-mortem. The general meat quality traits of 300 muscle samples were estimated. Muscle samples were classified into two groups based on ultimate pH of meat 24 h post-mortem (pH_24h). Muscle glycogen synthase belonging to the low pH_24h group showed remarkably higher expression than that in the high pH_24h group. AMP activated protein kinase (AMPK) and glycogen synthase kinase 3 (GSK-3) as negative regulators of glycogen synthase deactivated the suppression of glycogen synthase by phosphorylating Ser485 of AMPK and Ser9 of GSK-3B. These inhibitory kinases lead to high glycogen synthase expression. These results suggest that the accumulation of glycogen by up-regulating glycogen synthase and inhibiting AMPKa and GSK-3B was rapidly converted to lactate resulting in acidic meat. This molecular clue representing acidic meat based on post-mortem muscular pH can be used to estimate meat quality via Akt-AMPK?/GSK-3?-mediated up-regulation of glycogen synthase

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