Methionine Antagonizes Liver and Kidney Antioxidant Function Damage in Heat-Stressed Rex Rabbits

Area of Science:

• Animal Nutrition
• Oxidative Stress Research
• Comparative Physiology

Background:

• Heat stress induces systemic oxidative stress, disrupting physiological balance in animals.
• Understanding the impact of heat stress on hepatic and renal functions is crucial for animal welfare and productivity.
• Methionine, an essential amino acid, plays a role in antioxidant defense mechanisms.

Purpose of the Study:

• To investigate the effects of methionine supplementation on antioxidant capacity in the liver and kidneys of heat-stressed Rex rabbits.
• To evaluate methionine's influence on biochemical markers, oxidative stress indicators, and related gene expression under heat stress conditions.
• To determine the optimal methionine dosage for mitigating heat-induced oxidative damage in rabbits.

Main Methods:

• Rex rabbits were subjected to control conditions or heat stress (30-34 °C) with varying methionine supplementation (0.15%, 0.3%, 0.45%) for 21 days.
• Analysis included serum biochemistry, skin and tissue oxidative stress markers (malondialdehyde), enzyme activities (superoxide dismutase, catalase, glutathione peroxidase), and antioxidant gene expression.
• Histopathological examination of liver and kidney tissues was performed to assess cellular damage and fibrosis.

Main Results:

• Methionine supplementation (0.15-0.3%) improved methionine digestibility and reduced amino acid catabolism.
• Serum liver enzymes (ALT, AST) and skin malondialdehyde levels decreased with methionine supplementation.
• Optimal methionine (0.3%) enhanced hepatic antioxidant enzyme activities (SOD, CAT, GPx) and modulated Nrf2-mediated antioxidant gene expression.
• Histopathology revealed reduced hepatic congestion and renal vacuolization, indicating protection against organ damage.

Conclusions:

• Methionine supplementation effectively alleviates heat-induced oxidative stress and organ damage in Rex rabbits.
• A dosage of 0.3% methionine optimizes endogenous antioxidant defenses and redox signaling pathways.
• Dietary methionine represents a viable nutritional strategy to manage metabolic disorders associated with heat stress in rabbits.