Effect of natural bioactive compounds on growth and welfare in Octopus vulgaris paralarvae

The aquaculture of Octopus vulgaris is gaining interest due to its high demand, rapid growth, and nutritional value. However, significant challenges remain, particularly in rearing paralarvae to juveniles, mainly due to their specific nutritional needs. This study evaluates the impact of two bioactive compounds— Hytolive ® syrup (natural olive fruit extract rich in hydroxytyrosol) and black cumin seed oil (rich in thymoquinone)— using Artemia as a vector, on growth performance, fatty acid profiles, antioxidant responses and lipid peroxidation in O. vulgaris paralarvae from 0 to 30 days post-hatch (dph). Paralarvae were fed one of three diets: control diet ( Artemia metanauplii enriched with marine lecithin, CON), control diet supplemented with 10% of Hytolive ® syrup (HYT), or control diet supplemented with 30% black cumin seed oil (BCO), with three replicates per treatment. While no significant differences were observed in specific growth rates (SGR) or survival, the HYT and BCO groups exhibited reduced lipid peroxidation at 30 dph, indicating enhanced antioxidant defenses. Additionally, bioactive supplementations altered fatty acid profiles, increasing polyunsaturated fatty acids compared to the control. Although enzymatic antioxidant responses such as catalase (CAT) and superoxide dismutase (SOD) were unaffected, glutathione S-transferase (GST) activity significantly decreased in the BCO group, suggesting a reduced need for detoxification due to lower oxidative stress. This study is the first to demonstrate the transfer of hydroxytyrosol and thymoquinone metabolites from Artemia to O. vulgaris paralarvae and their potential to mitigate oxidative stress. These findings highlight the potential benefits of bioactive-enriched diets in octopus aquaculture and their protective effects during early development. Future research should explore optimal dosages and synergies between bioactive compounds to enhance the immune system and overall health of this species.