Temperature plays important role in the culture of aquatic organisms. The exposure of fish at low temperature especially during winter season affected the aquaculture production. The murrel Channa punctatus (58.93±1.72 g) were acclimated at 25°C and were fed with three experimental diets containing amino acids, arginine (2.0 g/100 g), leucine (2.0 g/100 g) and tryptophan (2.0 g/100 g) and one control diet without amino acid. After 45 days of feeding, fish were exposed at temperature 15°C. Experimental temperature was achieved at a rate of change of 1°C/12 h starting from acclimation temperature 25°C. Various tissue and blood samples were collected after the 12 h and 7 days of reaching the assigned temperature.
Significantly (P < 0.05) lower serum cholesterol level was found in tryptophan-enriched diet fed fish in both days of sampling. Serum triglyceride level was significantly (P < 0.05) higher in fish fed with arginine supplemented diet compared to others. The triglyceride level was minimum in the control diet fed fish. The glucose level was significantly (P < 0.05) higher in fish fed with leucine and tryptophan supplemented diets compared to others after 12 h of exposure. After 7 days, the maximum glucose level was found in leucine supplemented diet fed fish compared to others. The cortisol level was significantly (P < 0.05) lower in tryptophan supplemented diet fed fish compared to others diets fed fish in both days. The reduced glutathione (GSH) level was significantly (P < 0.05) higher in the liver of leucine and tryptophan enriched diets fed fish compared to others after 12 h of exposure. The heat shock protein 70 (Hsp 70) and heat shock protein 90 (Hsp 90) levels were (P < 0.05) higher in the liver of control diet fed fish compared to others. The Hsp 70 and Hsp 90 levels were minimum in tryptophan-enrihed diet fed fish.