Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: November 29, 2011
Publication Date: January 14, 2012
Citation: Nonneman, D., Brown Brandl, T., Jones, S.A., Wiedmann, R.T., Rohrer, G.A. 2012. Genome-wide association of a novel porcine stress-syndrome to dystrophin [abstract]. Plant and Animal Genome XX Conference Proceedings. Abstract #W696. Technical Abstract: Losses of slaughter-weight pigs due to transport stress are both a welfare and an economic concern to pork producers. We identified two sibling barrows in the USMARC swine herd that died from apparent symptoms of a stress syndrome after transport at 12 weeks of age. The symptoms included open-mouth breathing, skin discoloration, vocalization and loss of mobility. The original mating was repeated, along with sire-daughter matings to produce additional offspring. At 8 weeks of age, pigs were challenged with isoflurane anesthesia and electrocardiographs (ECG) were monitored during anesthesia. Most affected animals died after one minute of anesthesia and had elevated plasma creatine phosphokinase levels and cardiac arrhythmias. Additional animals were identified during regular processing and weighing as having a stress response, sometimes resulting in death. A pedigree containing 250 pigs, including 49 affected animals, was genotyped with the Illumina Porcine 60K SNP Beadchip and one region, SSCX at 25.1-27.7 Mb over the dystrophin gene, was significantly associated with the syndrome. An arginine to tryptophan (R1958W) polymorphism in exon 41 of dystrophin was the most significant marker associated with stress susceptibility. Immunoblots of heart and skeletal muscle showed a dramatic reduction of dystrophin protein in affected animals and histopathology indicated muscle fiber degeneration. The causative genetic factor for this novel stress syndrome most likely resides within the dystrophin gene and results in cardiac abnormalities that can lead to death under stressful situations. The identification of the mutation will allow us to determine the prevalence of this disease in commercial swine populations. USDA is an equal opportunity provider and employer.