Effect of oxolinic acid on fecal microflora of goldfish ( Carassius auratus)

Abstract

The present study was performed to investigate the effect of oxolinic acid (OA) on the intestinal microflora of goldfish ( Carassius auratus). OA was orally administrated to three goldfish at 20 mg/kg body weight for 7 days, and fecal microflora was successively determined. All three fish had Aeromonas hydrophila as a dominant component while pin-hole colony formers and Bacteroides type A were the dominant organisms in two out of three goldfish. Plesiomonas shigelloides and Pseudomonas spp. predominated in one fish. The pin-hole colony formers was suggested to be A. hydrophila which was sensitive to OA. The ability of fecal microflora to resist OA did not significantly change during the experimental period of 10 days. These results strongly suggested that the intestinal microflora of goldfish was not affected markedly by the oral administration of OA at the dosage of 20 mg OA/kg fish for 7 days.