Surface disinfection of Atlantic halibut and turbot eggs with glutaraldehyde: evaluation of concentrations and contact times

To evaluate the effects of glutaraldehyde treatment at different disinfection temperatures, Atlantic halibut, Hippoglossus hippoglossus (L.), and turbot, Scophthalmus maximus (L.), eggs, incubated at 5 and 12°C, respectively, were disinfected with 400–1200 mg glutaraldehyde l-1 at three different contact times (2.5, 5 and 10 min). Egg batches of both poor and good quality were tested for halibut. Positive effects were more pronounced in poor than in good-quality batches at hatching. Egg disinfection had a highly positive effect on the viability of yolk-sac larvae in both types of batches. A level between 400 and 800 mg l-1 at a contact time of 5–10 min was optimal for halibut: at lower levels, the bactericidal effect was reduced, and at higher levels, there were indications of toxic effects. Halibut eggs disinfected with optimal doses of glutaraldehyde had furthermore a reduced hatching time and more synchronous hatching as compared with untreated eggs. Turbot was more sensitive to higher doses than halibut, and the best larval performance was obtained for 400–800 mg glutaraldehyde l-1 at a contact time of 2.5 min. A further evaluation should, however, be performed before recommendations are given for species incubated at temperatures higher than 5°C.