Effect Of Myoglobin Gene Expression On Meat Color And Polymorphism Of Meat Color Candidate Genes In Pig

1 The effect of breed and sex on developmental patterns of meat color related candidate gene expressionIn present study, Large White boars, Erhualian boars and Erhualian gilts were employed to investigate the developmental patterns of meat color related candidate genes expression in Longissimus Dorsi (LD ) muscle.Four candidate genes, Myoglobin, MEF2, Calcineurin and NFATcl mRNA expression in LD muscle were determined with semi-quantitative RT-PCR as to Erhualian and Large White pigs. The results indicated that Myoglobin, MEF2, NFATcl and Calcineurin mRNA expression were all up-regulated (P<0.05) during early postnatal development. Myoglobin, MEF2, and Calcineurin mRNA levels were significantly higher in Erhualian than Large White pigs which may indicate that these three genes are all related to transcriptional activation of slow fiber gene expression program because myoglobin was thought to be one typical slow muscle-specific fiber gene. Besides, some similar patterns of myoglobin and MEF2 mRNA expression were found in both sexes and breeds. There was no significant gender difference in Calcineurin mRNA expression. However, NFATcl was different from other genes, across the period of investigation, NFATcl mRNA level was significantly higher in Large White than Erhualian pigs which may imply that NFATcl was contributed to fiber hypertrophy. Besides, NFATcl mRNA showed a first rise subsequently fall trend through the whole developmental course, but there was no significant gender difference at each age.2 Mechanism of individual differences effect on meat color in Sutai pigs100 Sutai pigs of marketing body weight were employed to study the mechanism of individual difference in meat color. LD muscles were sampled for measuring various parameters related to meat color. Hal genotype was determined by PCR-RFLP, and the results indicated that all Sutai pigs were all NN. Meat color was evaluated both bycolorimeter and subjective color scoring, and Semi-quantitative RT-PCR was applied to determine mRNA level of candidate genes including myoglobin, MEF2, Calcineurin and NFATcl. Photometric method was used to measure myoglobin concentration. Correlation analysis was performed to investigate relationships between parameters. It was found that a*-value was correlated with b*-value(r=0.745, P=0.001); subjective color scoring was correlated with a*-values(r=0.459, P=0.002) and Hunter L*-values (r=-0.235, P=0.018); Myoglobin concentration was correlated with subjective color scoring (n=0.407, P=0.0002), a*-values(r=0.406, P=0.0002), and myoglobin mRNA level (r=0.364, P=0.008). Myoglobin mRNA level was correlated with subjective color scoring (r=0.426, P=0.002) and a*-values (r=0.379, P=0.006). pH24 was correlated with myoglobin concentration(r=0.282, P=0.002) and mRNA level(r=0.383 P=0.002); On the contrary, water loss rate (r=-0.244, P=0.002) (r=0.-0.504, P=0.002) was negatively correlated with these two traits.MEF2, calcineurin and NFATcl mRNA were all correlated with myoglobin mRNA, and among these four candidate genes, only two of them, say myoglobin mRNA and NFATcl mRNA were widely and significantly correlated with subjective color scoring, colorimeter parameters and myoglobin concentration.3 cDNA Polymorphism of color related candidate geneIn this study, there was no polymorphic site on NFATcl gene detected by RT-PCR-SSCP, and there were polymorphic sites on myoglobin gene, but no significant differences were identified among these three genotypes.