C. Lanteigne, J. Castell, T. Blair
Abstract:
The total lipid, fatty acid, ash and total organic dry matter of the trochophores of three different molluscan species (mussel Mytilus edulis, hard shell clam Mercenaria mercenaria and surf clam Spisula solidissima) were determined. There was not a significant difference among species in total trochophore lipid content which averaged about 15-17% of dry matter, or in ash which ranged from 23 to 28% of dry matter. Mussel larvae were shown to have higher levels of the n-3 HUFA (20:5n-3, 15-22% and 22:6n-3, 11-16%) than trochophores of Mercenaria mercenaria or Spisula solidissima. Mercenaria mercenaria throchophores did have significantly higher levels of 20:4n-6, 2.5-4%, compared with 0.7-1.2% in mussel trochophores and 0.6-0.9% in Spisula solidissima. Laboratory feeding of mussel broodstock with n-3 rich algae was shown to further enrich the essential n-3 HUFA in larvae compared with those produced by mussels collected from the field. Studies included evaluations of the effects of culture temperature on the nutritional composition of mussel larvae from both cultured (laboratory fed) and wild mussel broodstock. For example, when mussel trochophores were held for 24 h at 4 C the content of HUFA, including 22:6n-3 was further enhanced. Of the three molluscan species investigated, mussel trochophores appear to hold the best promise as potential live feed in larval fish culture.
(Department of Fisheries and Aquaculture, Centre Marine, Shippagan, NB E0B 2P0, Canada)