Enrichment of the nematode Panagrolaimus sp., a potential live food for marine aquaculture,with essential n-3 fatty acids

The nematode Panagrolaimus sp. (strain NFS-24-5) may have potential as a live food organism for larvae of several marine species. It can be mass-produced in liquid culture and is desiccation tolerant enabling long-term storage and transportation. Nematodes lack the essential fatty acid docosahexaenoic acid (DHA), so this investigation examined an enrichment procedure by incubating nematodes in S.presso^® (INVE Aquaculture, Belgium), a commercial enrichment product. Mass-produced nematodes from liquid cultures on yeast cells were cleaned and then exposed to concentrations of 0.1–3 % S.presso^® for 24 h at 200,000 nematodes ml^?1. Nematode viability was >90 % after the treatment. Following enrichment percentage, total lipid ranged from 23.6 to 33.3 % of nematode dry matter, and nematodes incubated in 3 % S.presso^® had a significantly higher lipid percentage than untreated controls. Enrichment was successful in increasing the percentage of DHA, and a maximum value of 5.8 % of total fatty acids was achieved. The results of enrichment of Panagrolaimus sp. (strain NFS-24-5) following treatment with 3 % S.presso^® should promote the carrying out of feeding trials to test the efficacy of the nematodes as a live food for larval marine fish and crustaceans.