Dietary Tithonia diversifolia improves hematology, antioxidant capacity, liver health, and disease resistance in hybrid of Oreochromis mossambicus × Oreochromis niloticus

Herbal medicines have been used for centuries for the treatment of various ailments and there has been a recent resurgence of interest in the use of natural products. This investigation was carried out to evaluate the role of Tithonia diversifolia (TD) on haematology, antioxidant and transaminases enzymes, liver histology and disease resistance in juvenile tilapia hybrids (Oreochromis mossambicus × Oreochromis niloticus). TD powder (0, 40, 80, 120 and 160 g kg-1 diet) was fed to cultured fish at a density of 15 fish/aquarium (n = 3 aquaria per treatment) for eight weeks (pre-challenge period). At the end of the feeding trial, 18 fish from each group were given intraperitoneal injections with a pathogenic strain of Aeromonas hydrophila to test the protective efficacy of TD against bacterial infection for seven days (post-challenge period). The results after eight weeks revealed significant differences (P < 0.05), with an increase in haematological variables and antioxidant activity, low levels of transaminases and an adequate hepatic histological response in the TD-fed fish. In the experimental challenge, the control group experienced higher mortality rates than the other groups after the IP injection with A. hydrophila at a dose of 0.25 ml for fish (1×106 CFU ml-1) and the relative level of protection (RLP = 78.33%) was significantly higher (P < 0.05) with the treatment containing 160 g.kg-1 of dietary TD. A correlation and principal component analysis (PCA) confirmed the results. In conclusion, these findings suggest that TD up to levels of 160 g.kg-1, could serve as a natural phytobiotic to enhance tilapia health and disease resistance, potentially reducing reliance on synthetic products in aquaculture.