Plastic pollution is an increasing environmental threat, especially in our oceans. It breaks down into microplastics (MP) and even smaller nanoplastics (NP), posing a significant risk to marine life, including the aquaculture industry.
Microplastics and nanoplastics can harm farmed fish and shrimp, affecting their growth and health. A study by scientists from the Fishery Machinery and Instrument Research Institute (China) and East China Normal University (China) sheds light on a possible solution: dietary manipulation.
The research focused on the Pacific white shrimp (Litopenaeus vannamei), a commercially important species. The scientists explored how dietary supplementation with different levels of lipids affected lipid metabolism in L. vannamei exposed to different concentrations of nanoplastics.
The Growing Threat of Nanoplastics
Plastic consumption is skyrocketing, leading to an increase in plastic waste entering our oceans. Nanoplastics, particularly concerning due to their small size and large surface area, are easily absorbed by aquatic organisms like shrimp. Research suggests that nanoplastic particles can disrupt several vital processes in shrimp, including:
- Growth: Shrimp may grow more slowly when exposed to NP.
- Immune system: NP can weaken a shrimp’s ability to fight off diseases.
- Nutrient metabolism: NP can interfere with how shrimp store and use fats for energy.
- Oxidative stress: NP can create an imbalance of harmful molecules in shrimp cells.
These disruptions raise concerns about the overall health of shrimp populations and the sustainability of the shrimp farming industry.
NP and Lipid Metabolism: A Hidden Danger
While the effects of NP on energy metabolism are documented, their impact on lipid metabolism in aquatic organisms remains less explored. Recent studies reveal that NP can:
- Induce hyperglycemia
- Cause oxidative stress
- Alter amino acid metabolism pathways
- Inhibit lipid metabolism genes and enzymes
These findings highlight the urgent need for more research on how NP affect the critical process of lipid metabolism in shrimp.
The Power of Lipids to Combat Microplastics
The study investigated how different dietary fat levels affected shrimp exposed to various NP concentrations. The scientists raised shrimp on diets with three different fat levels (3%, 6%, and 9%) and exposed them to different microplastic concentrations (0 mg/L, 1 mg/L, and 3 mg/L) for two months. Here’s what they found:
- Shrimp thrived with more lipids: As dietary fat content increased, shrimp grew better, with improved survival rates, body weight gain, and more efficient feed utilization. Their bodies also contained higher levels of proteins and healthy fats.
- Lipids mitigate microplastic damage: The harmful effects of the highest microplastic concentration (3 mg/L) were more severe in shrimp fed the low-fat diet (3%).
- Fat boosts metabolism: Shrimp fed high-fat diets showed increased activity of enzymes involved in lipid metabolism, suggesting more efficient fat processing. Additionally, genes associated with this process were also more expressed.
Paving the Way for Sustainable Shrimp Farming
The research is the first to demonstrate that dietary manipulation can be a powerful tool to combat the harmful effects of microplastics on shrimp. By strategically increasing dietary fat content, shrimp producers can potentially:
- Improve shrimp growth and health: Better growth rates and feed utilization translate into higher yields and economic benefits.
- Reduce microplastic impact: Dietary fat seems to act as a buffer, mitigating the damage caused by microplastic ingestion.
Conclusion
“Lipids provided in animal feed can help promote growth, improve disordered body lipid metabolism, and alleviate NP toxicity. Our research findings suggested that increased dietary lipid intake promoted shrimp growth, protected hepatopancreas structure, and enhanced lipid metabolism enzyme activities and gene expression,” the scientists concluded.
By optimizing shrimp nutrition, we can not only boost production but also create healthier, more resilient shrimp populations, better equipped to face the challenges of a microplastic-contaminated environment.
The study was funded by the Young Elite Scientists Sponsorship Program of CAST and the National Freshwater Genetic Resource Center.
Contact
Yunlong Zhao
Fishery Machinery and Instrument Research Institute, Chinese Academy of Fisheries Sciences
63 Chifeng Rd., Shanghai 200092, China.
Email: ylzhao426@163.com
Xuan Che
School of Life Science, East China Normal University
500 Dongchuan Road, Shanghai, China.
Email: chexuan@fmiri.ac.cn
Reference
Li, Y., Ye, Y., Yuan, H., Li, S., Rihan, N., Liu, X., Zhao, Y., & Che, X. (2024). Dietary lipid supplementation alleviated the impacts of polystyrene nanoplastic exposure in Litopenaeus vannamei. Aquatic Toxicology, 272, 106974. https://doi.org/10.1016/j.aquatox.2024.106974
