In the present work an attempt has been made to study energy value of metabolism (respiration or oxygen consumption) in a fresh water teleostean fish, Channa striatus (Bloch) at water temperature 29.5±1.00C. The energy value of total metabolism (R) ranged from 723.1-10390.3 Joule/day/fish within the weight range 9.3 to 103.0 gram fish. The percentage of total energy of food (C) used in the metabolism (R) ranged from 36.0-40.7% with a clear trend of decrease in R value with increasing body weight. The details have been discussed in this paper.
This study reports the curative effects of zinc and ascorbic acid on cadmium induced histopathological changes in kidney of the freshwater cat fish Heteropneustes fossilis. Exposure of the fish to 16.14 mg/L sub lethal concentration of cadmium for 30 days induced hypertrophy of glomeruli, dilation and rupture of Bowman’s capsule and glomerular tuft, degeneration of epithelial cells lining the renal tubules, haemorrhage between tubules, hyaline degeneration of tubules, indistinct lumen, cytoplasmic vacuolation, accumulation of lipid droplets and generalized necrosis in kidney. However, 16.14 mg/L cadmium + 0.5 mg/L zinc and 16.14 mg/L cadmium + 1.25 mg/L ascorbic acid exposed fish groups revealed signs of recovery which were more progressive with ascorbic acid as evident from considerable restoration of normal size of Bowman’s capsule, structure of tubular epithelial cells and almost normal structure of renal corpuscles. Our study concludes that zinc and ascorbic acid have protective influence on cadmium toxicity in fish but higher doses than the one selected in the present case are probably needed to overcome the effects of cadmium toxicity.