Triphala involved in reducing the susceptibility of Nile tilapia (Oreochromis niloticus) fingerlings to Saprolegnia ferax infection by boosting immune and antioxidant responses, improving growth performance, histological improvement, and gene expression indicators

This study investigated the effects of different dietary levels of Triphala fruit powder on the growth performance, histology, serum parameters, gene expression indicators, and survival of Nile tilapia (Oreochromis niloticus) fingerlings against Saprolegnia ferax infection. The fish were fed with either a control diet (without Triphala fruit powder addition) or three experimental diets including 1, 2, and 3% of TFP over a 60-day period. Two hundred and forty healthy fish (28.0 ± 0.2 g) were stocked in 12 tanks, 20 fish per tank. Dietary TFP supplementation significantly improved growth performance and feed efficiency to the un-treated group (P < 0.05). All Triphala fruit powder dietary groups had a significant higher amylase activity and lower levels of ALT, AST, and cholesterol than the control group (P < 0.05). The Triphala fruit powder treatment (3%) resulted in a significant increase in packed cell volume, red blood cell count, haemoglobin, and monocyte values compared to other groups (P < 0.05). The study reported significant (P < 0.05) improvements in immune response and increased levels of haemoglobin, white and red blood cells, albumin, globulin, and total protein for the Triphala dietary groups. In all Triphala dietary groups, the mRNA expression levels of the growth-related (growth hormone (GH) and insulin-like growth factor 1 (IGF-1)) and immune-related genes (cc-chemokine, intereluekin-1β (IL-1β), and intereluekin-8 (IL-8)) were significantly (P < 0.05) upregulated compared to the control groups. After exposure to Saprolegnia ferax infection, the control group exhibited a higher mortality rate (up to 75%) than the Triphala-treated groups. In conclusion, this study demonstrated that dietary inclusion of Triphala at an optimal level of 3% improved the growth performance and immune response of Nile tilapia (Oreochromis niloticus) fingerlings.