A
formulated diet for Atlantic halibut (Hippoglossus hippoglossus, L.)
larvae
A diet for Atlantic halibut-larvae was formulated
taking into account the fact that marine fish larvae have a limited ability
to assimilate protein and lipid. Dietary protein consisted of a free
amino-acid premix (7.2% of crude protein), predigested-squid mantle (7.2%),
squid mantle (8.6%) and cod-muscle mince (77.0%). Lipid sources were soybean
lecithin (33% of crude lipids), crude phospholipids extracted from cod roe
(10%) and sardine oil (57%). Larvae were weaned onto the experimental diet
at wet-body weights of 0.07, 0.10 or 0.16 g, respectively. The
experimental diet was fed for 31, 25 or 17 days, respectively, and the
experiment was terminated on the same calendar day for all groups. A control
group was fed with Artemia nauplii enriched with DHA Selco™ from
0.07 g. Survivals ranged from 78% in larvae transferred at 0.10 g
to 96% in those transferred at 0.16 g and in the control group. Daily
specific-growth rates (SGR) were 3.1 ± 0.07, 3.3 ± 0.11
and 2.2 ± 0.01% day-1 in larvae transferred at
0.07, 0.10 and 0.16 g, respectively, while growth in the control group
was 5.1% day-1. It was concluded that weaning of
Atlantic-halibut larvae is feasible from 0.7 g (approximately 20 days
post first-feeding) when the formulated diet contains predigested protein
and ample amounts of phospholipids.
(Institute of Nutrition, Directorate of Fisheries,
P.O. Box 185, Sentrum, N-5804 Bergen, Norway; e-mail: kristin.hamre@nutr.fiskeridir.no)