Cannabidiol (CBD) reduced physiological stress and was associated with improved survival in juvenile sea bass, according to a study examining CBD as a potential tool for improving the welfare of farmed fish. The study was published in Frontiers in Marine Science, and conducted by researchers from Universidad de Las Palmas de Gran Canaria, Institut de Recerca i Tecnologia Agroalimentaries La Rapita and the University of Stirling Institute of Aquaculture.
For the study, researchers evaluated whether adding CBD to fish feed, modifying aeration through environmental enrichment, or combining the two could improve health and stress resilience in European sea bass.
Fish received dietary CBD at a concentration of 0.001%, environmental enrichment using a microbubble curtain, both treatments together or standard conditions for five weeks. The fish were then subjected to a confinement stress challenge. Researchers examined survival, stress and immune markers, lipid mediators and the expression of genes involved in stress responses and appetite regulation across several regions of the brain.
CBD-treated fish showed reduced plasma cortisol during both acute and adaptive phases of the stress response, indicating a diminished physiological reaction to confinement. CBD also increased baseline serum lysozyme activity, an indicator of innate immune function, and was associated with faster stabilization following stress.
Importantly, CBD supplementation did not negatively affect growth performance.
Survival was significantly higher among all three groups receiving CBD, environmental enrichment or both compared with fish kept under standard conditions. Environmental enrichment on its own also improved production-related measures and increased dissolved oxygen levels.
The strongest overall effects were observed when CBD and environmental enrichment were used together. Researchers found evidence that the combination affected lipid mediators involved in inflammatory responses while moderating the expression of stress-related genes. The findings also pointed to possible effects on appetite regulation and energy balance.
“These results highlight the potential of microbubble curtain enrichment and CBD for improving welfare of juvenile sea bass, enhancing growth, stress resilience, and physiological regulation, with the combined treatment showing the strongest and most effective improvements”, concludes the study.
