Pyroligneous Extract as Dietary Additive for Nile Tilapia Health: In Vitro and In Vivo Assessments.

Studies on plant extracts as growth promoters and immunostimulants have shown promising results. However, their effects on fish health and growth remain unclear. This study evaluated the in vitro and in vivo effects of pyroligneous extract (PE) on Nile tilapia. In vitro, minimal inhibitory and bactericidal concentration (MIC and MBC) and antibiogram analyses showed that PE could eliminate key bacterial strains affecting fish and human health, but only if its volatile components were preserved. In vivo, juveniles were fed diets containing 0.5% and 1% PE. We assessed fish hematology, phagocytosis, survival against , and growth parameters. Fish fed 1% PE had lower erythrocyte and lymphocyte counts but higher neutrophil levels than controls. Their phagocytic capacity was significantly enhanced compared to both the control and 0.5% groups. However, the 0.5% PE group had a higher phagocytic index than both the control and 1% groups. No protection against or significant effects on growth were observed. In conclusion, distilled PE shows potential as an immunostimulant for fish. However, further studies are needed to preserve its volatile compounds and optimize its use in aquaculture.