Document Type : Original Article
ICAR-Central Inland Fisheries Research Institute, Barrackpore, Kolkata-700120, India
ICAR-Central Institute of Fisheries Education, Mumbai-400061, India
In the present study, solvent extracts were used at 10, 20, 30, 40, and 50 mg/L, at 1, 2, 3, 4 and 5 hours and 12, 24, 36,48 and 60 hours under in-vitro and in-vivo conditions, respectively 25-30, (A. bengalensis/fish) Labeo rohita (30±1.5 g). The 5 % dimethyl sulphoxide was used as negative control (DMSO). The LC50 values of solvent extracts for L. rohita were 67.67±12.59, 78.13±14.17, 79.12±17.68, 156.47±12.67 and 256.43±8.93 mg/L for Terminalia arjuna ethanolic bark extract, Terminalia arjuna methanolic bark extract and Terminalia arjuna acetone bark extract, respectively, at 60 hours interval. Under in-vitro condition, 100 % anti-parasitic efficacy (AE) and minimum therapeutic index (TI) value (1.2) was ascertained by Terminalia arjuna ethanolic bark extract at 50 mg/L in 2 hour, and minimum LC50 was reported by Terminalia arjuna ethanolic bark extract under in-vitro condition (13.14 ±3.79 mg/L) and maximum by Terminalia arjuna acetone bark extract under in-vitro condition (75.8±12.69 mg/L) at 5 hour interval. While, under in-vivo conditions, minimum LC50 for immersion and bath treatments was observed with Terminalia arjuna ethanolic bark extract (27.92±9.56 mg/L) and TAEBIM (33.6±7.58 mg/L), correspondingly, at 60 hours. The minimum TI was reported in bath treatment of Terminalia arjuna ethanolic bark extract (1.1). The 100% anti-parasitic activity was observed in bath treatment of Terminalia arjuna ethanolic bark extract at 24 hours. The PCA bi-plot explains 79.34 % and 14.32 % variations for component 1 & 2, respectively. The efficacy of solvent extracts varied significantly in response to concentrations of the extracts and exposure times and toxicity of the extracts (Exposure time*extract *treatment: F=16.12, P=0.04). The study provides, the evidences for safe and effective application of prospective solvent extracts of T. arjuna against A. bengalensis in L. rohita juveniles, and yield first-hand information on acute toxicity of solvent extract in L. rohita.