Immunity changes in confined animals: a route to disease?

Area of Science:

• Immunology
• Animal Physiology
• Stress Research

Background:

• Exogenous factors can regulate the immune system.
• Environmental stimuli affect cell-mediated immunity in mice.
• Restraint-induced immunosuppression in mice is linked to corticosterone.

Purpose of the Study:

• To investigate the effects of short-term restraint stress on the immune system of pigs.
• To determine if restraint stress impacts cortisol levels and immune parameters in pigs.

Main Methods:

• Pigs (5-8 weeks old) were restrained for 2 hours daily for 3 consecutive days.
• Serum cortisol levels were measured.
• Thymus gland weight and in vivo phytohemagglutinin-stimulated cell-mediated reactions were assessed.
• In vitro effects of cortisol on mitogenesis of porcine lymphocytes were examined.

Main Results:

• Restraint significantly increased serum cortisol levels.
• Restraint significantly reduced thymus gland size (0.14% to 0.10% of body weight).
• Restraint significantly reduced in vivo cell-mediated reactions by 25%.
• In vitro cortisol addition suppressed mitogenesis of porcine lymphocytes.

Conclusions:

• Short-term restraint stress negatively impacts the pig immune system.
• Increased cortisol levels during restraint may mediate immunosuppression.
• These findings highlight the link between environmental stress and immune function in pigs.