Use of antibiotics in fish ponds and its effects on environment

Abstract

Studies were conducted to investigate current status of antibiotics used in aquaculture and oxytetracycline’s effects on Sarpunti (Puntius sarana) muscle in Golapgonj and Jointapur upazilla of Sylhet. Additional investigations also were done to know microbial load and other water quality parameters of the same area. A questionnaire survey was conducted with various stakeholders engaged with aquaculture of study area from June to August, 2013. The study showed that fish farmers used various antibiotics mainly Renamycin, Aquamysine, Oxy-DoxF,

Oxytensin, Amoxyfish, Amoxivet, Tetravet, Orgamysin, Cottrim vet and their generic names were oxytetracycline, chlorotetracycline, amoxicillin, co-trimoxazole in aquaculture for fish health management and disease treatment. Oxytetracycline (OTC), the most widely used antibiotic, was fed to Sarpunti (Puntius sarana) at the rate of 4 g/kg through fish diet, and changes in water quality parameters and bacterial content were determined for a period of 21 days. Pond water, sediment and fish muscle were tested before antibiotic treatment and after oxytetracycline medicated feed. The initial oxytetracycline accumulation was 5070.0 ppb which reduced considerably to 1190.0 ppb after 5 days of stopping oxytetracycline treated diets and this antibiotic was not detected after 10 days. Physico-chemical parameters of pond water were determined. Before antibiotic treatment , temperature, dissolve oxygen (DO), pH and total hardness of sarpunti fish pond was 25.87 ± 0.015°C , 4.516 ± 0.25 mg/l and 7.413 ± 0.09 and total hardness of 822.33 ± 1.52 ppm, respectively which reached a value 27.33 ± 0.015°C, 5.27 ± 0.025 mg/l, 7.773 ± 0.04 and 769.66 ± 2.08 ppm, respectively indicating little change after 21 days. Before antibiotic treatment, bacterial load in sarpunti fish pond was 9.417 ± 0.035×10

cfu/g in fish gills, 8.52 3 cfu/ml in water, 7.31 ± 0.04×10 7 cfu/g in sediment, 6.51 ± 0.04 ×10 6 cfu/g in fish intestine, respectively which was significantly reduced to 5.28 ± 0.02×10

± 0.035 ×10 7 3 cfu/ml in water, 2.91 ± 0.02×10 7 in sediment, 2.21 ± 0.02×10 6 cfu/g in gills, 2.39 ± 0.02×10 7 cfu/g in intestine, respectively. During the field observation some problems were identified while using antibiotics which included poor understanding of farmers about the mode of action, real application of antibiotics, exact reason of disease, in adequate with drawl period and some adverse effects on fish and human health.