ANAESTHETIC RESPONSE OF TOBACCO LEAF DUST ON GIFT TILAPIA

The present study aimed to evaluate the potential of tobacco (Nicotiana tabacum) leaf dust as a natural, inexpensive and eco-friendly sedative for GIFT tilapia. Most of the anaesthetics presently used in the aquaculture are synthetic and costly. Therefore, as an alternative, tobacco leaf dust was tested for its efficacy as natural anaesthetics to fish, GIFT tilapia. The experimental groups were divided into seven groups, among that one used as control (0 mg/L), followed by six treatment groups (25, 50, 75, 100, 125 and 150 mg/L) in triplicates. The fish size of 4.58±0.68 g at a stocking density of 10 fishes/ 20-liter tub was used for the study with a total duration of 24 hours. Results showed that an increase in the concentration of tobacco leaf dust decreased the induction time and delayed the recovery time in fish (p<0.05). At a lower dose (25 mg/L), induction time prolonged to 18.36+0.07 minutes and at a higher dose, the response was quicker (6.33+0.11 minutes). Conversely, the recovery time was shorter (1.36+0.07 minutes) in fish exposed to low dose (25 mg/L) and extended to 5.04+0.23 minutes at high dosage (150 mg/L). There was no mortality observed in control (without sedative) and up to the dosage of 25 to 100 mg/L, but thereafter mortality ensued from 6 to 16% in the groups exposed to 125 and 150 mg/L dosage, respectively (p<0.05). The results of this study are encouraging as it revealed in the present study that tobacco leaf dust has the potential to sedate the fish, in addition, to minimize the metabolic activity of fish at an appropriate level. Based on the outcome of this study, tobacco leaf dust at the levels of 25 to 100 mg/L can be recommended to the fish farmers for safe and successful transportation of GIFT tilapia without causing mortality.