Production and nutritional composition of white worms Enchytraeus albidus fed different low-cost feeds

The marine oligochaete, white worm, Enchytraeus albidus (Henle, 1837), was evaluated as a potential live feed by exploring its production capacity and nutritional composition fed coffee grounds, spent brewing grains, stale bread, mixed produce, or sugar kelp over the course of 6-, 9-, or 12-week production cycles. Feed type and production cycle duration affected white worm biomass, reproductive potential, and proximate and fatty acid composition. In general, white worm cultures fed coffee grounds, stale bread, and spent brewing grains had higher production yields than cultures fed mixed produce or sugar kelp. Dependent on feeds and production cycle duration, white worms were high in protein (49-69%) and lipids (10-27%) and low in ash (5-8%), indicating that they would meet the dietary needs of species requiring a high protein, relatively high lipid, low ash diet. Compared to fatty acid profiles reported for standard live feeds like rotifers, Artemia, and copepods, white worms provided less n-3 long-chain polyunsaturated fatty acid content (DHA 0-0.5%, EPA 2-18%, total LC-PUFAs 4-25%), with the highest levels in worms fed mixed produce or sugar kelp. White worms exhibit many attractive characteristics as feeds, but commercialization will require improved culture techniques to produce greater worm biomass while reducing production costs. Depending on the target species, white worms may need enrichment to increase n-3 LC-PUFA levels.