Introduction
The growing demand for sustainable aquaculture has led to increased interest in natural feed additives. Terminalia catappa is a promising plant with bioactive compounds like flavonoids and tannins that can enhance fish health and growth (Abdel-Tawwab et al, 2018; 2019; Ajani et al., 2020). However, extraction methods significantly influence the quality of the extract (Bae et al., 2012). This study aims to evaluate the impact of different T. catappa extracts on the growth, health, and disease resistance of Heterobranchus longifilis. Five experimental diets were formulated with varying concentrations of ethanol and aqueous extracts of Terminalia catappa. Diets were fed to triplicate groups of Heterobranchus longifilis for 70 days. Growth parameters, feed utilization, and hematological indices were measured. Liver samples were analyzed for antioxidant enzyme activity (SOD, GST, GPx) and lipid peroxidation (MDA). Fish were challenged with Pseudomonas aeruginosa to assess their disease resistance. Data were analyzed using one-way ANOVA and Duncan’s Multiple Range Test to determine significant differences among treatments.
The study compared the efficacy of ethanol and aqueous extracts of Terminalia catappa on Heterobranchus longifilis. Ethanol extracts were found to have higher concentrations of bioactive compounds, but negatively impacted feed intake and growth performance. In contrast, aqueous extracts improved growth, feed utilization, and survival rates. This can be attributed to the varying polarity in the solvents. According to Archundia et al, (2019), the polarity in ethanol be described as medium while it is high in water. This suggests that aqueous extracts of T. catappa may be a more suitable dietary supplement for enhancing fish growth and health. Antioxidant indicators like GST and SOD were higher in aqueous extract diets, showing oxidative stress protection, which is required in fish during the normal feeding cycle. Fish fed T. catappa extracts showed increased resistance to P. aeruginosa, improving survival rates.