Estimation of genetic parameters for fatty acid composition in M. longissimus thoracis of Japanese Black cattle

The objective of this study was to estimate the genetic parameters of fatty acid composition in the rib eye of Japanese Black cattle. Genetic relationships between fatty acids and image analysis traits of marbling were also investigated to clarify the response to the improvement of fatty acids composition on the marbling characteristics. Carcass data were obtained from Japanese Black cattle (n = 4,615) shipped to a meat processing plant in Hokkaido, Japan. Fat tissues were sampled from the rib eye of each carcass, and the fatty acid composition was analyzed using gas chromatography. Image analysis traits such as marbling percent (MP), coarseness index of marbling (CIM) and fineness index of marbling (FIM) in the rib eye were calculated. Using single/multiple traits animal models, genetic analyses were conducted to estimate heritabilities of all the traits and genetic correlations of the major fatty acids percentages with the image analysis traits. The estimated heritabilities of the fatty acids ranged from 0.67 to 0.82. The genetic correlation coefficients of Oleic acid (C18 : 1) with BMS and MP were positive (0.24 and 0.16, respectively) showing a favorable relationship in which the increased MP resulted in the improvement of C18 : 1 percent. On the other hand, undesirable correlation coefficients of C18 : 1 with CIM and FIM were estimated (0.32 and —0.35, respectively) and results suggested that the improvement of C18 : 1 percent increases the coarseness of marbling flecks in the rib eye.