Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 6/15/2010
Publication Date: 7/1/2010
Citation: Nonneman, D.J., Brown Brandl, T.M., Jones, S., Rohrer, G.A. 2010. Genome-wide association of a novel porcine stress-syndrome and isoflurane sensitivity to dystrophin. Journal of Animal Science. 88(ESuppl. 2):II Abstract #LB5. Interpretive Summary:
Technical Abstract: Losses of slaughter-weight pigs due to transport stress are an economic concern to pork producers. Historically, the HAL-1843 mutation in the ryanodine receptor 1 gene was considered responsible for most of the losses; however, DNA testing has effectively eliminated this mutation from commercial herds. We identified two sibling barrows in the USMARC swine herd that died after transport to a research location at 8 weeks of age. The original mating was repeated along with sire-daughter matings to produce additional offspring. Pigs were challenged with isoflurane anesthesia (3% for 3 min) at 8 weeks. Heart rate and ECG were monitored during anesthesia and blood was collected one week before challenge and immediately after isoflurane administration. Four males from the original sire-dam mating and two males from a sire-daughter mating died after one minute of anesthesia. Animals from six other litters were identified as having a stress response, sometimes resulting in death, during regular processing and weighing. Their littermates were also challenged with isoflurane. Affected animals tended to have elevated plasma creatine phosphokinase (CPK) levels and cardiac arrhythmias, as determined by ECG. Pedigrees containing fifty-eight pigs including 14 affected animals were genotyped with the Illumina Porcine 60K SNP Beadchip and two chromosomal regions were significantly associated with the syndrome at the genome-wide level. One is on SSC14 at position 82.7-88.9 megabases, and the other is on SSCX at 25.1-27.7 megabases over the dystrophin gene. In addition to muscular dystrophies, mutations in human dystrophin can cause dilated cardiomyopathy, rhabdomylosis and a malignant hyperthermia-like reaction in response to inhaled anesthesia, which supports this locus as a cause for the observed phenotypes in pigs. The identification of the causative mutation in these families will allow investigation of the prevalence of this disease in commercial populations.