Evaluation of Mustard Seed (Brassica Nigra) Powder as Anaesthetic Agents in Different Life Stages of Black Jaw Tilapia (Sarotherodon Melanotheron)

Abstract

This study assessed the anesthetic effects of mustard seed (Brassica nigra) powder in different life stages of Black Jaw Tilapia (Sarotherodon melanotheron). A total of 540 fish comprising of 180 each of: fingerlings (mean length 5.54cm ± 1.08SD and mean weight 12.04g ± 2.09SD); juveniles (mean length 10.02cm ± 3.91SD and mean weight 30.91g ± 4.02SD) and adult (mean length 13.01cm ± 2.66SD and mean weight 70.82g ± 7.01SD) of S. melanotheron were used for the study. They were exposed to aqueous extracts of mustard seed (Brassica nigra) powder at different concentrations: 0.00-control; 10.00; 20.00; 30.00; 40.00 and 50.00 mg/L at the rate of 10 fish per tank in triplicates. The results obtained indicated a size related response of the fish to mustard seed extracts. The induction time decreased significantly (P < 0.05) as the concentrations of the mustard seed extracts increased. The recovery time in the three sizes of exposed fish, generally increased as the concentrations of the anaesthetics increased. The survival rate was 100.00% in adult sizes of the exposed fish in all concentrations. While in fingerlings and juveniles, 90-95% survival rates were recorded at higher concentrations of the anaesthetics. This study therefore revealed that mustard seed can effectively be used as anaesthetics agent in S. melanotheron at optimum dose of 30mg/L.