THE USE OF BLOOD SERUM COMPONENTS IN THE IDENTIFICATION OF STRESS-SUSCEPTIBLE AND CARRIER PIGS

Abstract

A total of 284 pigs representing three genotypes were used to study the cause(s) of PSE musculature and possible means of detection of carriers of the halothane gene for stress susceptibility. The three genotypes included a homozygous halothane-sensitive line (H+), a homozygous halothane-negative line (H−) and a genetic carrier line (crossbreeds) from crosses between H+ and H− lines. A variety of blood components were determined in blood collected either from indwelling ear vein catheters on unrestrained pigs, from pigs during a halothane test or from conscious restrained pigs. Differences in levels of cortisol (P = 0.0003), creatinine (P = 0.0001), aspartate aminotransferase (AST, P = 0.0001) and lactate dehydrogenase (P = 0.0001) were highly significant between H+ and H− lines, with crossbreeds showing intermediate levels, except for AST where H− and crossbred animals had similar levels. In addition, red blood cell counts (P = 0.014) and serum protein levels (P = 0.008) were higher, and inorganic phosphorous (Pi) levels (P = 0.019) lower in H+ compared to H− and crossbred animals. Based on the results of this study, differences in the circulating levels of these metabolites, hormones or enzymes among genotypes would enable the discriminant identification of virtually all the halothane-positive pigs as well as up to 84% of the carrier animals. This approach theoretically could have a significant impact on the removal of pigs causing PSE pork.