Porcine stress syndrome

Porcine Stress Syndrome (PSS) is a genetic disorder in pigs, characterized by hyperthermia triggered by stress, and can lead to sudden death. It is also known as Malignant Hyperthermia (MH). The syndrome is caused by a mutation in the ryanodine receptor gene (RYR1).

Causes

PSS is caused by a mutation in the RYR1 gene. This gene provides instructions for making a protein that plays a key role in muscles used for movement (skeletal muscles). In response to certain signals, the RYR1 protein opens to allow positively charged calcium ions to flow out of storage compartments within muscle cells, a critical step in muscle contraction. The mutation that causes PSS changes a single protein building block (amino acid) in the RYR1 protein, which makes the channel more likely to open. This leads to an excessive release of calcium ions within muscle cells, resulting in a continuous contraction of the muscles (rigidity) and an increase in body temperature.

Symptoms

The symptoms of PSS include:

• Rapid heart rate
• High body temperature
• Muscle rigidity
• Metabolic acidosis
• Rapid breathing
• Dark, firm, dry meat (DFD)

Diagnosis

Diagnosis of PSS is based on the clinical signs and genetic testing. The genetic test identifies the mutation in the RYR1 gene.

Treatment

There is no cure for PSS. Treatment is supportive and includes measures to reduce body temperature and control symptoms. In severe cases, the pig may die suddenly.

Prevention

Prevention of PSS involves genetic testing and selective breeding to avoid the propagation of the mutated gene.

See Also

• Genetic disorders in pigs
• Malignant Hyperthermia
• RYR1

Porcine stress syndrome Resources
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