Effect of the proportion of Duroc genes in crosses with Large White and Landrace pigs on the characteristics of seasoned Parma ham

The aim of this study was to estimate the linear and quadratic effects of the proportion of Duroc genes on the characteristics of seasoned Parma hams by means of a covariance model. The study was carried out on 167 pigs (87 castrated males, 80 females) from different crosses among Duroc (D), Large White (LW) and Landrace (L) breeds, slaughtered at 300 d of age (live weight 170 kg). All pigs were raised under similar conditions. The curing period was 380 days. The proportion of Duroc genes was 0% (LWxL; n. 33), 25% [(LWx(DxL); n. 31 and Lx(DxLW); n. 35)] and 50% [Dx(LWx(LWxL)); n. 68]. The increase in the proportion of Duroc genes had a positive linear effect (P<0.01) and a negative quadratic effect (P=0.01) on the yield of deboned ham while ham fat thickness decreased linearly (P=0.07) and increased quadratically (P<0.01). A higher proportion of Duroc genes was also linearly associated with a lower lightness (P<0.01) and a less yellow color (P=0.09) of the biceps femoris muscle; positive quadratic coefficients have been shown for lightness (P<0.01), yellowness (P=0.01) and hue (P=0.03). The chemical composition of the semitendinosus muscle featured a linear increase in moisture (P<0.01) and decrease in fat (P=0.03) and non protein nitrogen (P=0.01) content, in addition to significant quadratic effects with an increase in the proportion of Duroc genes. In conclusion, crossbreeding with the Duroc breed (up to 50%) makes it possible to obtain positive quality characteristics of cured Parma ham.