Broodstock
nutrition research on marine finfish in Japan
T. Watanabe, R. Vassallo-Agius
Aquaculture, 227(1-4): 35-61
Abstract:
Broodstock diet formulations are essential for the
development of marine fish breeding and propagation. Japanese research has
mainly focused on red sea bream (Pagrus major), yellowtail (Seriola
quinqueradiata), the Japanese flounder (Paralichthys olivaceus)
and striped jack (Pseudocaranx dentex), and indicated that the
required quantities of essential dietary components may vary according to
species. The more recent work carried out on yellowtail and striped jack
consolidated the trends already observed in red sea bream. In yellowtail,
soft-dry pellets were used and astaxanthin was found to be the determining
factor for good egg quality, when supplemented at around 30 mg/kg. Paprika
powder supplementation that provided about 30 mg/kg paprika esters further
improved the spawning performance of yellowtail in terms of egg production,
egg quality and larval survival whereas squid meal inclusion also showed
potential as an effective ingredient. Work on the development of dry pellets
for striped jack broodstock revealed that egg production and quality were
affected by separate nutrients. Even though striped jack eggs do not contain
carotenoids, dietary astaxanthin, added at 10 mg/kg to the diet, increased
fecundity whereas egg quality was improved through the replacement of half
the fish meal with squid meal. The combination of these two ingredients in
dry pellets produced a spawning performance that matched the widely used raw
fish mix. Fatty acids, especially n-3 highly unsaturated fatty acid
(HUFA) in fertilized eggs, were derived from dietary lipids in all the
species studied.
From the present information, it is evident that
optimal levels of astaxanthin or paprika esters that have high oxygen
quenching abilities, squid meal and n-3 HUFA play an important role
in gonadal development of different marine fish. These dietary components
should be utilised for the development of wholesome dry pellets for marine
broodstock.
(Department of Aquatic Biosciences, Tokyo University
of Fisheries, Minato, Tokyo 108-8477, Japan, e-mail of R. Vassallo-Agius: robert.j.vassallo@gov.mt)