Natural-based solutions to mitigate dietary microplastics side effects in fish

Area of Science:

• Aquatic toxicology
• Fish physiology
• Environmental science

Background:

• Dietary microplastics (MPs) pose a threat to fish, translocating to organs and inducing oxidative stress.
• Effective mitigation strategies for MP-related issues in fish are urgently needed.
• Microencapsulated astaxanthin (ASX) is explored for its potential to reduce MP toxicity.

Purpose of the Study:

• To evaluate the efficacy of microencapsulated astaxanthin (ASX) in mitigating microplastic (MP)-induced oxidative stress and accumulation in zebrafish (Danio rerio).
• To assess the impact of different MP sizes and concentrations on zebrafish health.
• To determine if ASX can restore intestinal integrity and reduce MP translocation.

Main Methods:

• Zebrafish were fed diets with varying sizes (1-5 μm, 40-47 μm) and concentrations (50 or 500 mg/kg) of MPs for six months.
• Fish were subsequently fed diets with or without microencapsulated ASX (7 g/kg) for an additional month.
• Effects on intestinal epithelium, oxidative stress markers, and MP accumulation in organs were analyzed.

Main Results:

• Microencapsulated ASX counteracted negative effects of both small and large MPs.
• ASX restored intestinal epithelium damaged by larger MPs (40-47 μm).
• For smaller MPs (1-5 μm), ASX reduced oxidative stress and organ accumulation due to its antioxidant and coagulant properties.

Conclusions:

• Microencapsulated astaxanthin is a promising dietary supplement to mitigate microplastic pollution impacts on fish.
• Implementing microencapsulated ASX in aquafeeds can prevent MP-related health issues in fish.
• ASX demonstrates potential in restoring gut health and reducing MP bioaccumulation in aquatic organisms.