Antibiotic treatment and dose-response of bacterial activity associated with flatfish eggs

Abstract

Newly stripped and fertilized eggs from Plaice (Pleuronectes platessa) and Atlantic Halibut (Hipppoglossus hippoglossus) were incubated in 34 ppt sea water. 150 eggs (Plaice), 30 eggs (Halibut) or 20 glass beads were incubated in 30 ml seawater in light at 5.5°C. The antibiotics Oxytetracycline (-HCl) and Flumiquil were added to end concentration ranges 0 - 105 ppm and 0 - 60 ppm, respectively. With a method modified from Somville and Billen (1983) it was possible to measure the activity both in the incubation water and on the chorion of the incubated eggs. The activity on egg surfaces was significant higher than the activity of a comparable surface aerea of the glass beads. The activity on the egg surfaces was greater than the activity in a water volume corresponding to the combined egg volume.