Comparison of microstructural traits of Musculus longissimus lumborum in wild boars, domestic pigs and wild boar/domestic pig hybrids

Abstract. The aim of the present study was to compare the histological structure of muscles in wild boars, pigs and wild boar/domestic pig hybrids by determining the percentage of different muscle fibre types and diameters and the intramuscular fatty tissue content of the Musculus longissimus lumborum (LL). The study involved 24 males representing three groups: wild boars (6 animals), pigs (12 animals: 6 of Polish Landrace and 6 of Duroc breeds) and wild boar/domestic pig hybrids (6 animals). Wild boar/domestic pig hybrids were obtained by crossing DU pigs with wild boars. Samples of the LL were frozen in liquid nitrogen. Frozen muscle samples were cut into 10- μm sections. These were later placed on a glass slide and stained using different histochemical reactions: NADH-TR and myofibrillar ATP-ase activity to distinguish muscle fibre types and Oil Red staining to determine the intramusuclar fatty tissue content. The highest proportion of slow twitch oxidative fibres and fast twitch oxidative fibres, being indicative of high meat value, was characteristic of wild boar muscles. The lowest diameters of all three muscle fibre types, associated with the largest number of fibres in the analysed area, suggest that the meat had the most delicate structure. Compared to wild boars, wild boar/domestic pig hybrids showed a decrease in the percentage of oxidative fibres and an increase in the percentage of glycolytic fibres. The diameters of all muscle fibre types in this group of animals were similar to those obtained in pigs.