Effect of oxytetracycline on Thai silver barb (Barbonymus gonionotus) and on it’s culture environment

Abstract

Studies were conducted to investigate impacts of oxytetracycline on Barbonymus gonionotus muscle. Oxytetracycline the most widely used antibiotics, was fed to Barbonymus gonionotus with 4 g kg -1 rate through diet for 45 days. Growth rate was observed for different concentrations of oxytetracycline. Water quality parameters and bacterial quantification were observed for a period of 21 days. Pond water, sediment and fish muscle were tested before and after oxytetracycline medicated feeding. Before feeding of oxytetracycline medicated feed, there was no oxytetracycline in water, sediment and fish muscles. After 2 days of feeding the initial oxytetracycline accumulation was 5070.0 ppb, which reduced considerably to 1190.0 ppb after 20 days from end of medicated diet feeding and not detected after 42 days. Physico-chemical parameters of pond water were determined. Before treatment dissolve oxygen, pH and total hardness of fish pond was 4.516±0.25 mg L -1, 7.413±0.09 and 822.33±1.52 ppm, respectively. After 21 days of study period, reached to 5.27±0.025 mg L -1, 7.773±0.04 and 769.66±2.08 ppm. It indicates a little change after 21 days. Before oxytetracycline treatment, bacterial load in Barbonymus gonionotus pond was 9.417±0.035×103 CFU g -1 in water, 7.31±0.04×107 CFU g -1 in sediment, 6.51±0.04×06 CFU g -1 in fish gills and 8.52±0.035×107 CFU g -1 in fish intestine, which was significantly reduced to 5.28±0.02×103 CFU g -1 in water, 2.91±0.02×107 CFU g -1 in sediment, 2.21±0.02×106 CFU g -1 in gills and 2.39±0.02×107 CFU g -1 in intestine.