Interactions between genotype, dietary fat saturation and vitamin A concentration on intramuscular fat content and fatty acid composition in pigs.

The effect of dietary fat saturation (dFat) and dietary vitamin A (dVitA) level (0 IU vs. 100,000 IU) on performance, carcass characteristics and fatty acid composition in the offspring of two terminal sires: Duroc (DU) and Landrace×Large White (LD×LW) was studied. In the inner backfat layer, the DU-sired pigs had higher C16:0 proportion (P<0.05) and tended (P<0.07) to have higher total saturated fatty acids (SFA) and lower C18:1 n-9 proportions than LD×LW-sired pigs. An interaction sire line×dVitA was observed for intramuscular fat (IMF) content (P<0.005). The effect of supplementation with the high dVitA level in DU-sired pigs was associated with a 20% increase in IMF while no effect was observed in LD×LW pigs. Fatty acid pattern was affected by dFat and sire line. In the inner backfat layer, LD×LW-sired pigs receiving the low dVitA level increased C18:0 proportions by 8% in comparison to animals receiving the high dVitA, whereas in DU-sired pigs the effect of vitamin A was opposite. It is concluded that the effect of dFat and dVitA concentration on IMF content and fatty acid profile of subcutaneous backfat and IMF is variable according to pig genotype.