We offer a “PSS Test” for the autosomal recessive genetic disorder in pigs, Porcine Stress Syndrome (PSS), also known as Malignant Hypothermia-Susceptibility.
The DNA test for PSS is a superior alternative to the Halothane Challenge test, which in 2005 ceased to be recommended by the Australian Veterinary Association (AVA) due to potentially negative consequences with respect to animal welfare. Not only is our DNA Solutions’ PSS test able to be performed without stress to the animal, it determines whether the animal has two, one or no copies of the defective gene; that is, whether an animal has the disorder, is a carrier, or is free of the defective gene.
As a recessive disorder, PSS only occurs in animals which have two copies of the defective form of the gene. Animals with only one copy of the defective gene are carriers of the disorder, and do not themselves exhibit the full-blown syndrome; however, they do exhibit some traits that fall between the PSS condition and that of normal, healthy pigs.
The PSS disorder is a consideration for pig farmers and breeders, as it may result in the following: sudden death during transportation; pale, soft and exudative (PSE) meat which is rejected at the abattoir; and, halothane sensitivity (hyperthermia on exposure to this anaesthetic). On the other hand, some breeders like to maintain carrier animals due to perceived superiority in growth and carcass quality characteristics. Managing stock in which the defective gene is present benefits from knowledge about the genetic status of the animals.
The affected gene in the case of PSS expresses a skeletal muscle form of the Ryanodine Receptor. The defective and normal forms of this gene differ by a single base-pair mutation that alters the amino acid sequence of the Ryanodine Receptor. This single base-pair difference also alters the recognition sequence of a restriction enzyme, permitting the digestion of the defective gene form, but not the wildtype by that enzyme.
The PSS Test may be performed on any number of biological materials that can be acquired by minimally invasive means, and yield a sufficient quantity of DNA; the recommended sample is 6-10 pulled-out hairs (hairs that have fallen out by themselves do not provide sufficient DNA), although oral swabs, blood and tissue samples are also reliable sample types.