Date Full Report Received04/02/2009
Date Abstract Report Received04/02/2009
Funded ByIowa Pork Producers Association
Long-term selection for increased lean has come at the expense of meat quality traits, namely IMF percentage, objective loin color, and eating quality traits such as flavor and off-flavor. Results obtained in the current study suggest that the fatty acid composition of longissimus dorsi muscle IMF is correlated genetically with production and meat quality traits. It has been suggested that the fatty acid composition of intramuscular fat is greatly influenced by dietary feed content, and to a lesser extent, the effect of genetics (Cameron et al., 2000). Heritability estimates in the current study are moderate to high for the major fatty acids found in the intramuscular fat of the longissimus dorsi muscle. The greatest heritability estimates were found for lauric acid (C12:0), palmitoleic acid (C16:1n7), stearic acid (C18:0), linoleic acid (C18:2n6), and α-Linolenic acid (C18:3n3) which were 0.73, 0.40, 0.36, 0.33, and 0.26, respectively. Genetic correlations between IMF content and C16:0, C18:0, and C18:1 did not differ from zero. However, negative genetic correlations between IMF and C17:0, and between IMF and C18:2 were found (-0.61 and -0.80, respectively). Loin muscle area was positively correlated with C18:2 concentration (0.75) and tenth-rib backfat was negatively correlated (-0.62) with C18:2. Monounsaturated fat concentrations from IMF were negatively correlated with LMA (-0.70), but positively correlated with BF10 (0.77). No significant genetic correlations were found in the current study between sensory panel scores (flavor and off-flavor) and the respective fatty acids. The change in fatty acid composition of IMF is a correlated response to selection for increased quantity of IMF. Therefore, when selection for IMF is executed, we must understand the possible changes that may occur in fatty acid composition of the various adipose tissues. Understanding the response in fatty acid composition to selection for IMF is more important than directly selecting for individual fatty acids.