A 60‐day feeding trial was conducted to examine the effects of replacing fish meal protein with poultry by‐product meal (PBM) and bioprocessed poultry by‐product meal (BPBM) on growth performance, nutrient utilization, whole‐body chemical and amino acid composition and haemato‐biochemical responses in GIFT tilapia reared in floating cages. Seven isonitrogenous (320 g/kg crude protein), isolipidic (50 g/kg crude lipid) and isoenergetic (17 MJ/kg) experimental diets were formulated by replacing 0%, 33.33%, 66.67% and 100% of fish meal protein with PBM and BPBM respectively and referred as Control, PBM 33.33, PBM 66.67, PBM 100, BPBM 33.33, BPBM 66.67 and BPBM 100. Triplicate groups of 30 GIFT tilapia juveniles with an average initial weight of 11.28 ± 0.14 g were fed with experimental diets daily thrice until apparent satiation (08:00, 12:00 and 16:00 h). Among PBM and BPBM dietary groups, significantly (p < 0.05) higher growth performance and nutrient utilization were observed in fish fed BPBM 66.67 group compared to other treatment diets including control diet. No significant difference (p > 0.05) was observed in survival rate of GIFT tilapia fed different levels of PBM and BPBM‐incorporated diets. Moreover, dietary inclusion of PBM and BPBM did not (p > 0.05) affect the whole‐body chemical and amino acid composition and haemato‐biochemical responses in GIFT tilapia. It is concluded that PBM and BPBM can completely replace dietary fish meal protein in GIFT tilapia diets without any negative impact on growth performances, nutrient utilization and blood haemato‐biochemical responses. However, significantly higher growth performances and nutrient utilization were obtained in fish fed BPBM 66.67 diet.

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The present study evaluated the anaesthetic activity of tobacco (Nicotiana tabacum) leaf dust in fish. GIFT tilapia was used as an experimental animal with the total study duration of 24 hours. The fish size of 4.58±0.68 g was randomly distributed into the 20-liter plastic tub at a stocking density of 10 fishes per container. Anaesthetics were added into experimental tubs of seven different groups viz. one control (0 mg/L), followed by six treatment groups (25, 50, 75, 100, 125 and 150 mg/L) in triplicates. Results showed that an increase in the concentration of tobacco leaf dust shortened the induction time, but delayed the recovery time in fish (p<0.05). There was no mortality observed in control (without sedative) and up to the dosage of 25 to 100 mg/L, but after that mortality ensued from 6 to 16% in the groups exposed to a high dose of more than 100 mg/L (p<0.05). The temperature in the tanks showed no difference among all groups, while DO, pH, and C02 were affected by anaesthetics given (p<0.05). The results of this study are encouraging that tobacco leaf dust has the potential to sedate the fish, and it minimizes the water quality concerns at a correct level. Based on the result 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 the mortality.