Membrane lipid oxidation and proteolytic activity in thigh muscles from broilers fed different diets

Area of Science:

• Animal Science
• Food Science
• Biochemistry

Background:

• Lipid oxidation in meat affects quality and shelf-life.
• Dietary factors, including fatty acid unsaturation and antioxidants, influence meat oxidation.
• Understanding these effects is crucial for broiler meat production.

Purpose of the Study:

• To investigate how diets varying in unsaturation, antioxidants, and prooxidants affect lipid oxidation in broiler thigh meat.
• To assess the impact of these diets on enzymatic proteolysis via lysosomal cysteine proteinase activity.

Main Methods:

• Microsomal membranes from broiler thigh muscles were analyzed for lipid oxidation.
• Enzymatic, nonenzymatic, and sarcoplasmic protein oxidation were measured.
• Lysosomal cysteine proteinase activities were determined.

Main Results:

• Unsaturated diets, particularly with sunflower oil, led to the highest meat oxidation.
• Alpha-tocopherol (vitamin E) supplementation significantly reduced oxidation levels.
• Prooxidant diets with iron or copper deficiency showed unexpectedly higher oxidation.
• Cysteine proteinase activity was enhanced by vitamin E and copper absence.

Conclusions:

• Dietary fat unsaturation is a key driver of broiler meat oxidation.
• Antioxidant supplementation, especially alpha-tocopherol, effectively mitigates meat oxidation.
• Mineral deficiencies (iron, copper) can paradoxically increase oxidation, warranting further investigation.