Frequency of the malignant hyperthermia gene in the South African pig industry

Abstract

Porcine stress syndrome (PSS) is a genetic disorder caused by a recessive mutation in the halothane (HAL) gene and results in sudden death of pigs when placed under stress during transport and preslaughtering conditions. Animals that are affected by this mutation tend to develop pale, soft and exudative (PSE) meat, which results in an economic loss. In South Africa, the frequency of the number of carriers (Nn) and recessive (nn) pigs has increased by 21% to 30% from 2000 to 2003. This study aims to determine the prevalence of the malignant hyperthermia (MH) gene in breeding boars at nucleus or seed-stock level, and the prevalence at commercial abattoirs across the South African pig industry. Results indicate a low number of carriers (Nn = 17) and recessive (nn = 1) pigs at seed-stock level. For commercial abattoirs, 96.4% of the pigs tested did not carry the mutation. The low incidence of the MH mutation from breeding stock should eliminate a contributory factor to PSE meat in South Africa. Transport over long distances to abattoirs may ultimately have an effect on pork obtained even from non-carriers of the MH mutation. ______________________________________________________________________________________

Wild pigs (Sus scrofa) population as reservoirs for deleterious mutations in the RYR1 gene associated with Porcine Stress Syndrome

“…Given the economic losses caused by this syndrome, porcine breeding companies tried to eradicate it, promoting the use of other breeds like the Large White, which has similar meat quality and composition characteristics, but does not express PSS ( Ghio & Lucero de la Sota, 2014 ). Nonetheless, up to date there are still domestic and wild pigs worldwide carrying this detrimental allele ( Borman et al., 2016 ; Feng et al., 2012 ; Figueroa, 2020 ; Hernández et al., 2008 ; Marini et al., 2012 ; Rui & Shuiming, 2020 ; Sánchez et al., 2006 ; Soma, van Marle-Köster & Frylinck, 2014 ).…”

Exercise-induced hyperthermia syndrome (canine stress syndrome) in four related male English springer spaniels

“…Most people with MH susceptibility have few or no symptoms or signs unless they are exposed to a triggering agent, and the same is true of the equivalent disease in pigs. 1 , 12 The most common triggering agents are volatile anesthetic gases or depolarizing muscle relaxants. In rare cases, the biological stresses of physical exercise or heat may act as the trigger.…”

“…In rare cases, the biological stresses of physical exercise or heat may act as the trigger. 1 , 2 , 13 …”

“…Malignant hyperthermia (MH) is a clinical syndrome that has been reported in a variety of species, most notably humans, pigs, and dogs. 1 , 2 When fully developed, it is charac-terized by muscle rigidity, hyperthermia (often rapid in onset), tachypnea, metabolic acidosis, hypercarbia, and cardiac arrhythmias. 3 More subtle or abortive presentations of canine MH have also been reported.…”