EFFECT OF OXYTETRACYCLINE ON MORPHOMETRY AND METABOLIC ACTIVITIES OF POLY-CULTURED TILAPIA AND ROHU

Oxytetracycline, an antimicrobial agent has been playing a potent role in aquaculture to control the bacterial diseases, but it’s over dose may pose an undesirable effect. However, the purpose of the experiment was to evaluate the impacts of dietary oxytetracycline on the primary productivity, growth performance, biochemical activity, as well as immunity performance of tilapia (Oreochromis niloticus) and rohu (Labeo rohita) in a polyculture system. Oxytetracycline was mixed with feed at 100 mg/kg and fed with no antibiotic was denoted as the control. A total of 480 fish were cultured for 70 days, comprising 240 tilapia (with a length of 14.63 cm and weight of 59.85 g in an average) and 240 rohu (with a length of 11.43 cm and weigh of 24.6 g in an average). The findings indicated that there was not any significant (p >0.05) change in the growth of treated fishes in comparison with the control one. Amylase activity increased significantly (p <0.05), while superoxide dismutase activity increased but in a non-significant (p >0.05) way in the both of fish species. Protease and catalase activities were found to decline significantly (p <0.05) in both species. There was no significant increase in plankton abundance in the treatment ponds. Spectrometry study of chlorophyll-a revealed in control and treatment ponds where, there found no significant (p> 0.05) variation among each week. These results suggested that oxytetracycline dosing rate at 100 mg/kg having no significant impact on the growth and enzymatic activity of poly-cultured tilapia and rohu as well as primary productivity of the pond. A therapeutic dose (100 mg/kg) of oxytetracycline is subjected to be safe, polyculture.