Effects of dietary tamarind (Tamarindus indica L.) leaves extract on growth performance, nutrient utilization, gut physiology, and susceptibility to Aeromonas hydrophila infection in Nile tilapia (Oreochromis niloticus L.)

The rise in global concern on the adverse effects of uncontrolled utilization of synthetic antibiotics in the production of food fish necessitates search for alternative natural products in aquaculture. Tamarind (Tamarindus indica) leaf has great medicinal potentials but with scanty documentation of its utilization in fish production. Therefore, this study investigated the effect of tamarind leaves extract (TLE) on the growth performance, apparent nutrient digestibility, gut physiology, and resistance against Aeromonas hydrophila infection in Nile tilapia (Oreochromis niloticus) fingerlings. The fish were fed experimental diets enriched with 0.0 (control), 5, 10, 15 or 20 g TLE/kg diet at 3% body weight daily for 12 weeks. Thereafter, a 4-week challenge test with A. hydrophila infection was done. The results showed that dietary TLE significantly (P < 0.05) enhanced fish growth, nutrient digestibility, and utilization, villi height and absorption area at 1.0-1.5% inclusion levels, compared to the control diet. Regression analysis showed 1.12% as the level of TLE for optimum weight gain. Post-challenge fish fed TLE-enriched diets showed higher survival rate, relatively to fish fed the control diet. The results from the present study demonstrated that dietary TLE promoted growth, nutrient digestibility and protection against A. hydrophila infection in Nile tilapia and its inclusion at 1.0% was therefore recommended for aquaculture use.