High-M alginate
immunostimulation of Atlantic halibut (Hippoglossus hippoglossus L.)
larvae using Artemia for delivery, increases resistance against
vibriosis
J. Skjermo, Ø. Bergh-2004
Aquaculture, 238: 107-113
Abstract:
A strategy for microbial management in marine
juvenile production should include nonspecific immunostimulation to reduce
losses caused by infectious diseases. Halibut (Hippoglossus hippoglossus
L.) larvae (250 day degrees) were distributed into first-feeding tanks of 10
000 l, at a Norwegian halibut juvenile farm. Immunomodulatory high-M
alginate was bioencapsulated in Artemia by use of alginate microbeads
(2–30 µm), and administered to halibut larvae at three stages during the
first feeding period (days 7–9, 20–22 and 41–43). A fourth treatment
was run after weaning, 5–3 days prior to a challenge test with two
different doses of Vibrio anguillarum O2 that was started at day 90
after first feeding. After 15 days, the mortality at the highest dose was 45±1%
in the control and 28±8% in the stimulated group, corresponding to 38%
reduction in mortality, whereas no significant differences were measured at
the low dose. It is concluded that feeding immunostimulants to halibut
larvae for four short periods during 3 months enhanced resistance against
vibriosis, and that high-M alginates are suitable as immunostimulants for
marine larvae during first feeding and weaning.
(Department of Bioresources, SINTEF Fisheries and
Aquaculture, N-7465, Trondheim, Norway, e-mail: Jorunn.Skjermo@sintef.no)