Partial replacement of poly- with monounsaturated fatty acids and vitamin E supplementation in pig diets: effect on fatty acid composition of subcutaneous and intramuscular fat and on fat and lean firmness

Abstract

AbstractThe effect of partial replacement of poly- (PUFA) with monounsaturated (MUFA) fatty acids in pig diets on fatty acid composition of subcutaneous and intramuscular fat and on fat and lean firmness was studied. No effect of dietary fat was observed on total saturated fatty acid concentration in any of the backfat layers or intramuscular lipid fractions. No significant effect of dietary fat was observed for the MUFA concentration in the outer layer, but a marked effect was evident for the inner layer (P < 0·001). A linear effect of dietary MUFA was observed for MUFA (P < 0·001) and PUFA (P < 0·001) in polar lipids. No significant effect of dietary treatment was observed on total concentration of n-3 fatty acids in any lipid location but a marked effect was observed for total n-6 fatty acid concentration. The response of pig fatty acid n-6 concentration was different depending on the lipid location. The neutral lipid fraction showed significantly lower n-6/n-3 fatty acid ratio than the subcutaneous fat. Intramuscular polar lipids showed no significant response of n-6/n-3 ratio. A linear effect of dietary MUFA concentration was observed on the melting point on the inner backfat layer (MP = 34·4 (s.e. 2·51) + 0·15 (s.e. 0·07) ✕ dietary MUFA (g/kg dry matter) (R2 = 0·24, P < 0·05)), indicating that the partial substitution of dietary PUFA by MUFA produced a fat of higher consistency. No response of the melting point of the outer layer to dietary treatment was observed. A marked effect of dietary fat was shown for backfat hardness (P < 0·001), gumminess (P < 0·001) and chewiness (P < 0·001). No effect of dietary fat was observed on the rheological properties of longissimus lumborum muscle.