One of the approaches to optimizing aquaculture practices involves the use of value-added byproducts from other industries. An area with significant potential is the recovery of byproducts for integrating feed with bioactive molecules, particularly in aquaculture. Olive oil extraction, for instance, produces a range of solid and liquid byproducts rich in polyphenols, bioactive molecules with numerous beneficial properties.
Various studies have reported that polyphenols possess antimicrobial, anti-inflammatory, antioxidant, and immunomodulatory properties. These bioactive molecules have the potential to improve growth performance and the overall health of farmed fish. In this study, researchers from the Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche “Togo Rosati”, the University of Perugia, and the Istituto Zooprofilattico Sperimentale delle Venezie investigated the effects of dietary supplementation with polyphenols derived from olive mill wastewater on growth performance and gene expression modulation in farmed gilthead seabream (Sparus aurata).
Methodology and Results
The study, published in the journal MDPI, involved a controlled experiment with two groups: a control group and a treated group. The treated group received feed supplemented with polyphenols derived from olive mill wastewater, while the control group was fed a regular diet.
The researchers employed a nutrigenomic approach to evaluate the effects of polyphenol molecules on the organism. The biomolecular workflow was based on RT-qPCR assays, which assessed the relative gene expression levels of several targets representative of metabolic pathways, immunological-inflammatory processes, and oxidative stress responses.
Key Findings
The results of this study revealed several key findings:
- Improved Growth Performance: Fish fed a diet supplemented with polyphenols derived from olive oil exhibited a significantly improved feed conversion ratio compared to the control group. This suggests that polyphenols can enhance nutrient utilization and promote growth in fish.
- Health Enhancement: The polyphenol-supplemented diet was associated with better fish health, as evidenced by various physiological parameters. These compounds may contribute to maintaining optimal immune function and reducing oxidative stress.
- Gene Expression Modulation: The polyphenol-supplemented diet caused significant changes in the expression of several genes involved in metabolic, immune, and oxidative stress pathways. Specifically, the expression of fatty acid-binding protein 2, superoxide dismutase 1, and interleukin-12 was upregulated in the treated fish. These genes play crucial roles in lipid metabolism, antioxidant defense, and immune response, respectively.
Potential Benefits of Polyphenol Supplementation
The findings of this study highlight the potential benefits of incorporating polyphenols from olive oil byproducts into fish diets:
- Enhanced Growth Performance: Polyphenols can stimulate growth and improve feed efficiency, leading to higher production and reduced feed costs.
- Improved Health and Wellbeing: These compounds can strengthen the immune system, reduce oxidative stress, and enhance the overall health of fish, minimizing disease outbreaks and mortality rates.
- Sustainable Aquaculture: By utilizing byproducts from the olive oil industry, polyphenol supplementation can contribute to more sustainable and environmentally friendly aquaculture practices.
Conclusion
This study underscores the potential of olive oil byproducts as a sustainable feed supplement for aquaculture. The use of polyphenol extracts improved growth parameters and reduced oxidative stress in gilthead seabream. The nutrigenomic approach employed in this study provides valuable insights into the effects of polyphenol molecules on the organism.
While this study offers valuable insights into the potential benefits of polyphenol supplementation in fish diets, further research is needed to fully understand the underlying mechanisms and optimize its application. Future studies could explore:
- Dose-response relationships: Determining the optimal dose of polyphenols to maximize benefits and minimize potential adverse effects.
- Combinatory effects: Investigating the synergistic effects of polyphenols with other dietary supplements or probiotics.
- Long-term impacts: Evaluating the long-term effects of polyphenol supplementation on fish health, growth, and reproductive performance.
This study was funded by the Italian Ministry of Health.
Reference (open access)
Torricelli, M., Felici, A., Branciari, R., Galarini, R., Biagetti, M., Manfrin, A., Boriani, L., Radicchi, E., Sebastiani, C., Ciullo, M., Ranucci, D., & Agnetti, F. (2024). Gene Expression Study in Gilthead Seabream (Sparus aurata): Effects of Dietary Supplementation with Olive Oil Polyphenols on Immunity, Metabolic, and Oxidative Stress Pathways. International Journal of Molecular Sciences, 25(22), 12185. https://doi.org/10.3390/ijms252212185
