|Effects of diet transition regimen on survival, growth and lipid composition of intensively reared Atlantic cod, Gadus morhua, larvae|
Shields, R.J.; Irwin, S.; Smith, P.L.; McEvoy, L-A. (2003). Effects of diet transition regimen on survival, growth and lipid composition of intensively reared Atlantic cod, Gadus morhua, larvae. Aquacult. Int. 11(1-2): 119-130
In: Aquaculture International. Springer: London. ISSN 0967-6120, more
Growth; Intensive culture; Larvae; Lipids; Marine fish; Survival; Artemia Leach, 1819 [WoRMS]; Gadus morhua Linnaeus, 1758 [WoRMS]; British Isles, Scotland [Marine Regions]; Marine
|Authors|| || Top |
- Shields, R.J., correspondent
- Irwin, S.
- Smith, P.L.
- McEvoy, L-A.
Replicated groups of Atlantic cod were reared for up to 40 days in 100 l tanks stocked at a density of 75 eggs l-1. Larvae were transferred from rotifers, Brachionus plicatilis, to either fresh-hatched or enriched Artemia nauplii on each of days 5, 15 and 25 post-hatch (ph). Rotifers were progressively withdrawn over a 5 day period. The type of Artemia offered (fresh-hatched, enriched) did not affect survival or growth rates at any of the 3 transfer ages. Larvae transferred to Artemia from day 5 ph suffered a high incidence of swimbladder over-inflation and high mortality during metamorphosis (< 1% survival to day 36 ph). Cod in the day 15 and day 25 transfer groups did not differ significantly in weight-specific growth rate or size on day 40 ph (mean standard length 13.8 mm, dry weight 3.8 mg). Highest mean survival rates to day 40 ph (18.1%) and lowest mortality following transfer to nursery tanks were also observed in the day 25 transfer groups. Fish that received Artemia from day 5 ph contained circa twice as much total lipid per unit body weight and had a 30% higher triacylglycerol (TAG) content compared to all other groups. Ratios of the essential fatty acids docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and arachidonic acid (ARA) also differed according to age-at-transition. DHA:EPA ratio exceeded 1 only in cod transferred to Artemia on day 25 ph. Based on these findings, it is recommended that intensively reared Atlantic cod should continue to receive rotifers until completion of metamorphosis.