Influences of breed, sex, and susceptibility to malignant hyperthermia on lipid composition of skeletal muscle and adipose tissue in swine

Objective - To determine influences of breed, sex, and susceptibility to malignant hyperthermia on composition of skeletal muscle and adipose tissue in swine. Animals - 35 male and female swine of German Landrace and Pietrain breeds and of 2 genotypes, nor mal (MHN) and susceptible to malignant hyperthermia (MHS). Procedure - Pigs were fed a standard diet ad libitum. After attaining body weight of approximately 100 kg, pigs were slaughtered and skeletal (longissimus thoracis and supraspinatus) muscle and adipose tissue (3 sites) specimens were removed. For each specimen, lipids were extracted by chloroform/methanol and fatty acid (FA) pattern, and cholesterol concentration was determined by gas chromatography. Results - The overall lipid contents differed significantly between breeds and genotypes; the MHS Pietrain pigs had the lowest lipid quantities. The relative amounts of saturated FA in all tissues were highest in Landrace pigs (P < 0,05), whereas the relative contents of monoenic FA were lower. In addition, for both breeds, the MHN pigs had significantly higher saturated and lower polyunsaturated FA values in all tissues, compared with MHS pigs. More specifically, MHS females of both breeds had the highest relative amounts of polyunsaturated FA. In general, relative cholesterol contents were found to vary little between identified groups. Conclusions - These data may indicate that, not only does mutation of the calcium release channel of the sarcoplasmatic reticulum, which occurs in MHS swine, influence secondary changes in lipid composition, but so do hormone concentrations and other genotypic factors. Observed differences in lipid content and FA composition could consequently influence specific membrane properties, such as fluidity and cell signaling.