The potential antimicrobial effects of dietary supplementation with Arak, Salvadora persica, on growth, health status, and pathogenic bacterial loads in Nile tilapia, Oreochromis niloticus fingerlings

Abstract

The main goal of this study was to investigate the potential antimicrobial effects and fish performance of dietary supplementation with Arak, Salvadora persica. The impacts of three levels of powdered Arak supplementation (0.25, 0.5 and 1%) compared with the control diet on growth, survival, feed utilization, whole-body composition, some blood parameters, pathogenic bacterial loads and cold-water stress tolerance were evaluated in Nile tilapia, Oreochromis niloticus fingerlings. Treatment with 0.25 and 0.5% powdered Arak had significant positive effects on growth and feed utilization, with the highest values obtained for 0.25% Arak. The results of some blood parameter analysis showed that the 0.25% Arak-supplemented group exhibited significantly higher levels of total protein and albumin and lower levels of A/G than the other groups. The Arak-supplemented diets significantly increased the recorded levels of glucose compared with the control diet. The final pathogenic bacterial loads recorded in water and intestine samples were lower for the Arak-supplemented diets than for the control diet. Arak-supplemented diets also enhanced the tolerance of tilapia to cold-water shock. In conclusion, Arak is a promising antibacterial feed additive. Addition of fine Arak powder to tilapia feeds at levels of 0.25–0.5% may be beneficial. However, further detailed studies are necessary to elucidate other advantages of potential uses of S. persica in the contexts of fish diets and health. Keywords: Tilapia, Arak-supplemented diets, Feed utilization, Pathogenic bacteria, Cold shock