Growth and lipid composition of Atlantic cod (Gadus morhua) larvae in response to differently enriched Artemia franciscana

Abstract

Considerable progress has been achieved in the intensive culture of Atlantic cod (Gadus morhua). However, there is little information concerning optimum live-feed enrichments for cod larvae, since many of the techniques used during the larviculture have been borrowed from other fish species and adapted for the production of Atlantic cod. The present study compared four different protocols for the enrichment of Artemia to be used as live feed for cod larvae. The protocols tested were: (1) AlgaMac 2000, (2) AquaGrow Advantage, (3) Pavlova sp. + AlgaMac 2000, and (4) DC DHA Selco + AlgaMac 2000. Larvae were fed differently enriched Artemia between 37 and 59 days post hatch. At the end of the experiment, larvae from treatment 1 [specific growth rate (SGR) = 10.4 +/- 0.4% day(-1)] grew faster than larvae from treatments 3 (SGR = 6.9 +/- 0.2% day(-1)) and 4 (SGR = 4.9 +/- 0.4% day(-1), P < 0.0001). However, treatments 3 and 4 resulted in better larval survival at the end of the experimental period, estimated to be 3 on a scale from 1 to 5, whereas the survival estimates for the two other groups were 2. The treatments affected the fatty-acid composition of Artemia and of cod larvae. Larvae from treatment 1 had a higher percentage of AA (20:4omega6, P < 0.0001) and omega6DPA (22:5omega6, P < 0.0001) than the other larvae. Levels of DHA (22:6omega3) were similar in larvae from treatments 1 and 4, and higher than in the other larvae (P < 0.0001). Our results suggest that Artemia containing a DHA/EPA/AA ratio of 7/2/1 result in good larval performance.

The influence of first‐feeding diet on the Atlantic cod Gadus morhua phenotype: survival, development and long‐term consequences for growth

“…Given the fact that the larvae increased in body mass up to six times during this specific period, it was expected that optimal prey size would increase accordingly (Ward & Coburn, 2008), which would then have led to increased growth in the zooplankton group, which was not observed until later. Differences in live prey species can lead to early differentiation of larval growth (Grageda et al , 2008), which can be due to purely nutritional factors (Garcia et al , 2008 a , b , c ). The present findings show a lack of growth differences between the first‐feeding groups until 29 dph.…”

“…Two different enriched Artemia sp. diets with similar DHA contents fed to G. morhua larvae (37–59 dph) resulted in significantly different mean g (10·4 or 6·9% day −1 ) (Garcia et al , 2008 a ). A similar result was reported for different rotifer enrichment methods where a diet containing the highest DHA content did not result in the highest g in G. morhua larvae (Garcia et al , 2008 b ).…”

“…At high density, survival at 50 dph was low in both feeding groups, which may be related to unsuccessful weaning rather than high density, because 41·6% survival up to 44 dph has previously been reported at high densities (300 larvae l −1 ) (Baskerville‐Bridges & Kling, 2000 c ). Survival was positively correlated with DHA levels in larval feed (Cutts et al , 2006) or omega 6DPA in the larval diet (Garcia et al , 2008 a ), which could have influenced the results in the present study too.…”

The copepod Acartia tonsa as live feed for fat snook (Centropomus parallelus) larvae from notochord flexion to advanced metamorphosis

“…The larvae in the Diet RC had higher amounts of DHA, with the highest DHA/EPA ratio (3.2), similar to values found in other marine fish larvae (Izquierdo et al, 2000). The amount of ARA obtained was also within the standards described in the literature (Garcia et al, 2008b), indicating that Diet RC had a good balance between the essential fatty acids. When comparing these final contents with the initial larvae (15 days-old), it was found that in this treatment larvae assimilated dietary DHA, probably from the copepods, which have high DHA content.…”

Vibrio spp. Control at Brine Shrimp, Artemia, Hatching and Enrichment

“…In addition, Artemia can modify the fatty acid composition of the enrichment product as well as its lipid classes. The lipid conversion during the Artemia enrichment process is responsible for an extensive incorporation of eicosapentaenoic fatty acid, important to larval development (Navarro et al ; Garcia et al ). The enrichment technique exploits the fact that Artemia is a non‐selective filter feeder organism in its second stage of development (instar II or metanauplius), which occurs 8 h after hatching (Campbell et al ; Dixon et al ; Sorgeloos et al ).…”