A comparison of carcass, meat quality and histochemical characteristics of Iberian (Guadyerbas line) and Landrace pigs

Abstract

Carcass, meat quality and histochemical traits were studied in 20 Landrace (LR) pigs from a maternal line and 12 Iberian pigs (IB) from the Guadyerbas line, including boars and gilts. The animals were reared under commercial intensive management and fed ad libitum from 27 kg liveweight (12 weeks of age) to 100 kg for LR, while IB pigs were 6 weeks older in order to reach the tentative 100 kg slaughter weight at the same time. Actual LR and IB slaughter weights were 105±10 and 118±11 kg, respectively. Iberian pigs had higher killing out percentage (78.6 vs. 72.4, P<0.001) and backfat depth (48.1 vs. 20.7 mm, P<0.001) than LR pigs. Higher pH 24 h post-mortem were observed in m. longissimus lumborum and m. semimembranosus muscles of IB than of LR breeds. Also, IB breed had higher haem pigment contents than LR. Iberian pigs showed higher intramuscular fat percentage (3.91 vs. 0.66 in longissimus, P<0.001), more saturated and monounsaturated backfat and lower concentrations of C18:2 and C18:3 than LR pigs. Muscle showed a more oxidative metabolism in IB than in LR pigs. The proportion of type I fibres was higher (12.09 vs. 9.09%, P<0.001) and their diameter was larger (44.37 vs. 40.83 μm, P<0.05) in IB than in LR pigs, whereas the opposite occurred for type 2B fibres proportion and diameter. The percentage of intramuscular fat in IB pigs was positively correlated ( P<0.05) with the proportion of type I fibres.