EFFECTS OF FEEDS AND TEMPORAL CYCLES ON WHITE WORM Enchytraeus albidus PRODUCTION

White worms show great promise as a feed (either live, frozen, or an ingredient in processed feeds) for a diverse set of cultured organisms, including freshwater and marine fishes (including ornamentals), as well as some crustaceans, amphibians, reptiles, and birds. White worms are robust and grow in terrestrial systems to 2-4 cm in length. As a live feed, they are euryhaline and will survive in both fresh and full saline water for several hours, wiggle and attract predators, and do not impair water quality. In addition, they are retained longer in aquaculture systems as they are bottom-dwelling and are not easily flushed out like other traditional live feeds. White worms are easy and inexpensive to rear on a small scale. Research organism suppliers grow the worms for biological and toxicological studies as worm tissue is sensitive to chemical composition, and aquarium hobbyists cultivate them as a live feed for ornamental fishes. However, these worms are overlooked throughout the world as a potential large-scale feed in the aquaculture industry.

Despite their potential, scant information is available regarding large-scale and optimal protocols for white worm production. Using waste by-products as feed in aquaculture operations is attractive, in terms of sustainability, reducing industry disposal costs, and for cost-effective production. The diet flexibility white worms exhibit is one of the main advantages of worm production. Many industries generate waste which white worms will eat, however, it is not known if any of these wastes is optimal for worm growth and production. To address this question, we evaluated worms fed spent coffee grounds, sugar kelp, mixed expired produce (e.g., various leafy greens), stale bread, or spent brewery grains over three different production cycles (6, 9, or 12 wks) during the winter of 2014-15 using two way analysis of variance. The type of feed and duration of the production cycle had a significant effect on worm population growth (worm density) and reproductive potential (cocoon density). No effects were apparent at 6 weeks, but generally, worm production was greatest when worms were fed stale bread or spent brewery grains for 9 weeks or longer. Of the feeds tested, spent coffee grounds was the least time intensive feed, followed by spent brewery grains and stales, then produce, and lastly sugar kelp.

Evaluating feeding and harvesting protocols, as well as the effects of these feeds on the nutritional profile of the worms, are paramount to developing large-scale, cost-effective white worm production. More research is warranted to guarantee a desirable feed for the aquaculture industry.