Histological characteristics of longissimus dorsi muscle and their correlation with restriction fragment polymorphisms of calpastatin gene in F2 Jinghua × Piétrain crossbred pigs

Abstract

In order to evaluate the genotype of the calpastatin (CAST) gene and its relationship to muscle histology and other post mortem traits in the Jinhua 3 Pié train F 2 pig family, 158 barrows and gilts were electrically stunned and exsanguinated. Both blood and muscle samples were collected, and both post mortem traits and meat qualities were recorded. Restriction fragment length polymorphism (RFLP) analysis, the periodic acid Schiff reaction (PAS) and myosin heavy-chain immunohistochemistry were employed to explore the relationship between genotype and muscle histology. Based on PAS reactivity, muscle fibres can be classified into three types: PAS (2), PAS (1) and PAS (11). Myosin heavy-chain immunohistochemistry can differentiate muscle fibres into either slow or fast fibres; the proportion of slow and fast fibres were 6% and 94%, respectively. When the amplification products of the CAST gene were digested with MspI, HinfI and RsaI, two different cleavage patterns could be discriminated from the endonuclease map detected using each enzyme. The results showed that the polymorphisms detected using these three endonucleases are identical. Only three genotypes (AA/CC/EE, AB/CD/EF and BB/DD/FF) were distinguished. Their frequencies were 0.1835, 0.5823 and 0.2342, respectively. Different genotypes had significant association with area and pH 45m value of loin muscle, while showing no significant association with the water-holding capacity and conductivity of loin muscle. The results also revealed that the genotypes had a significant correlation with diameter, area, circularity and the aspect ratio of muscle fibres. It was also presented that the genotypes significantly correlated with the percentage of intramuscular connective tissue.

The Differential Expressions of PPARγ and CAST mRNA in Muscle Tissues of Jinhua and Landrace Pigs

“…These results indicated that the IMF and carcass lean content is not significantly affected by CAST gene expression. Wu et al (2007) found that CAST was significantly correlated with diameter, area, circularity, and the aspect ratio of muscle fiber, but not with carcass lean and IMF content of pigs. Although the association between CAST mRNA expression and meat quality has been reported on cattle and pigs (Chung et al, 2001;Koćwin-Podsiadla et al, 2003), how CAST affects meat quality in other animals and its molecular mechanism need to be further studied.…”

Effects of calpastain (CAST) polymorphisms on carcass and meat quality traits in Mongcai pigs

“…However, Klosowska et al (2005) concluded on significant associations between CAST_RsaI, another locus in intron 6 of the gene with diameters of fibers and the proportion of fast-twitch fibers in a bundle. Additionally, in F2 Jinhua x Pietrain crossbred pigs, different genotype patterns of CAST polymorphisms (MspI, HinfI and RsaI) are statistically related to loin muscle area (Wu et al, 2007), of which BB/DD/FF pigs provided higher muscle area than those of AB/CD/EF individuals. This difference is probably from the discrepancy between the IIb fiber content of the two animal groups as mentioned by Wimmers et al (2008).…”

“…This was further supported by Krzęcio et al (2005), who demonstrated the effect of CAST_MspI on drip loss and nutritional value of the meat, that is, protein content. In the Jinhua x Pietrain F2 population, the three genotypes at these loci were proven to associate with loin area and pH 45 min value as well as the percentage of intramuscular connective tissue (Wu et al, 2007). Moreover, the association of CAST_HinfI locus with pork quality traits including pH, drip loss and meat color was reported in a cross of commercial Pietrainbased breed.…”