Author/Editor		Fazarinc, G; Uršič, M; Bavdek, SV
Title		Histochemical profile of the longissimus dorsi muscle of the pig breeds with different porcine stress syndrome (PSS) susceptibility
Type		članek
Source		In: Cestnik V, Pogačnik A, editors. Referati 6. Zavrnikovega spominskega sestanka; 1995 nov 9-11; Lipica. Ljubljana: Veterinarska fakulteta,
Publication year		1997
Volume		str. 107-12
Language		eng
Abstract		The histochemical properties of the longissimus dorsi muscle in pig breeds with different incidence of the RYR 1 gene mutation have been described. Fortytwo seven months old boars of four breeds (Duroc, Large White, German Landrace, Swedish Landrace) were analyzed. Duroc boars had bigger proportions of slow twitch oxidative (STO=13.9% ) and fast twitch oxidative fibres (FTO=14.3%), a lower proportion of fast twitch glycolitic fibres (FTG=7l.8%) and a higher pHl of the muscle than other breeds (pHl=6.20). All Duroc boars were RYR 1 gene nonmutated. The incidence of the mutated RYR 1 gene was highest in the German Landrace boars (over 70% of dimutant and heterozygous pigs). The pHl of the muscle was in German Landrace boars lower than in other breeds (pHl=5.59). The histochemical muscle fibre type composition, pHl of the muscle and the incidence of the RYR 1 gene mutation in Swedish Landrace and Large White boars were similar. There were no significant differences in the muscle fibre type composition of the longissimus dorsi muscle between German Landrace boars with different RYR 1 gene genotype. The longissimus dorsi muscle of all pigs with the mutated RYR 1 gene showed pale, soft, exudative (PSE) changes. There were no differences in the pHl of the longissimus dorsi muscle between homozygous (dimutant) or heterozygous boars. Low pHl (lower than 5.8) and less intensive PSE changes were observed also in three German Landrace boars with wild RYR 1 gene. We conclude that the appearance of the PSE muscles is not strictly linked to the RYR 1 gene mutation but is in some animals conditioned also by the histochemical composition of the muscles in which FTG fibres dominate.
Descriptors		MUSCLE FIBERS, SLOW-TWITCH MUSCLE FIBERS, FAST-TWITCH RYANODINE SWINE