Functional feeds to tackle meagre (Argyrosomus regius) stress: physiological responses under chronic and acute stressful conditions
Under intensive rearing conditions fish are often exposed to husbandry-related stressors such as acute water temperature changes, crowding, handling, transportation, or confinement. In fish, stress response is initiated by the endocrine system, which regulates the secondary stress response factors that alter the distribution of resources, such as energy sources and oxygen, to vital areas of the body, and may compromise hydro mineral imbalance and the immune system. These events render fish more susceptible to disease and reduce production yield. To mitigate such effects, fish antioxidant response to stressors can be modulated nutritionally, since nutritional factors were reported to differently affect fish oxidative status.
The need to diversify Mediterranean aquaculture species has recently arisen to face market saturation by gilthead seabream and European seabass. Meagre appears as potential candidate to Mediterranean aquaculture diversification, with high growth rates, good processing yield, nutritional value, and market acceptability. Meagre is, however, very sensitive to stress.
Having this in mind, this project aims at developing aquafeeds that allow fish to cope with husbandry-related stressful conditions, thus improving fish growth, health and welfare. For that, algae extracts pre-selected in our lab for their antioxidant potential (Chlorella sp., Nannochloropsis gaditana, Fucus vesiculosus, and Ulva rigida) will be incorporated in balanced dietary formulations for meagre with the major goal of contributing to reduce physiological imbalances resulting from sustained (temperature fluctuation) and acute (grading/manipulation) stressors. To achieve such goals, effects of diets including algae extracts on stress biomarkers and antioxidant enzymes activities, mobilization of energy reserves (carbohydrate and glycogen metabolism) and immune response will be analyzed.
- Soja de Portugal, SGPS, SA; FAD , IJUP