The use of ozone in trout
hatchery to reduce saprolegniasis incidence
G. Forneris, S. Bellardi, G. B. Palmegiano, M.
Saroglia, B. Sicuro, L. Gasco, I. Zoccarato-2003
Aquaculture, 221(1-4): 157-166
Abstract:
At present, the prophylactic measures in trout
hatchery are based on the use of formaldehyde. The purpose of this work is
to set up an alternative system of prevention of saprolegniasis, using
ozone. The experiment was carried out in two successive cycles. The first
experiment lasted 46 days and five different treatments were applied on
every second day on the same number of lots of 250 eggs each, of which three
were treated with ozone (O3) in concentrations of 0.01, 0.03 and
0.2 ppm (10 min), one reference treatment with formaldehyde (1–2 ml/l, 15
min) and one as control, without any disinfectants. The second experiment,
which lasted 60 days, consisted also of five levels of treatment on the same
number of lots of 100 eggs each, to which 0.01 ppm O3 (10 min)
was applied on every second day, while 0.01, 0.1 and 0.3 ppm O3
(10 min) were applied daily. The formaldehyde treatment was performed in the
same way as the experiment 1 (exp. 1). From the results, it has emerged that
the treatment with ozone is effective and the hatching eggs range from 42.6%
to 49.1% dose of ozone from 0.01 to 0.2 ppm. As observed in experiment 2
(exp. 2), the dose of 0.3 ppm applied every second day seems to be over the
threshold of toxicity.