The objective of this research was to find a nematode species that could replace the use of Artemia and rotifers as a fish and shrimp feed in aquaculture hatcheries. Panagrellus redivivus is shown to be the most promising nematode of all the species tested. An inexpensive medium containing bovril, yeast extract and com oil/fish oil was developed for the culture of this species. It is demonstrated that P. redivivus can be mass produced using conventional fermentation technology and formulated into a carrier matrix such as sodium alginate gel.
Present research demonstrates that the fatty acid profile of the nematode can be manipulated by the addition of fish oil rich in highly unsaturated fatty acids (HUFAs) to the growth medium of the nematode. This produces an increase in the essential fatty acids (EFAs) such as eicosapentaenoic acid (20:5ω-3) and docosahexaenoic acid (22:6ω-3). It is also shown that P. redivivus can be pigmented with astaxanthin by the addition of carophyll pink to the growth medium. The overall nutritional profile of P. redivivus was modified to be similar to that of Artemia.
Fish and shrimp trials undertaken using P. redivivus alone revealed that it could not support the growth and development of Scopthalmus maximus, Pleuronectes platessa, Ctenolabrus rupestris and Clupea harengus. However nematodes pigmented with astaxanthin and enriched with HUFAs support good growth and survival of Penaeus indicus larvae.