Analysis of troponin I gene polymorphisms and meat quality in Mongcai pigs

Troponin I is one of myofibrillar proteins required for the calcium regulation of skeletal muscle contraction. The expression of both genes, TNNI1 and TNNI2, in troponin is muscle fibre specific and may affect meat quality traits. In this study, the PCR-RFLP method was applied to genotype 120 Mongcai pigs at three single-nucleotide polymorphisms (SNPs), namely T5174C, C8350A for TNNI1 (EU743939) and C1167T for TNNI2 (EU696779). The two SNPs, T5174C and C1167T, were significantly associated with drip loss48 (measured after 48 h) and compression force, while the second TNNI1 SNP (C8350A) did not show any association with meat quality traits. The results also revealed a relationship between the proportion of IIx muscle fibre and TNNI2. Additional analysis showed a significant association of the TNNI2 SNP (C1167T) with blood glucose. Animals carrying the CT genotype had the highest glucose concentration (93.7 mg/dL). The results demonstrate that TNNI1 and TNNI2 are likely to play a relatively important role in the development of pork quality in Mongcai pigs.Keywords: TNNI1, TNNI2, drip loss, meat colour, pork, indigenous Vietnamese pig