White worms are a good feed for juvenile fish, and as composters, they are easy to culture and fast growing. They are also nutritious and a good source of n-3 LC-PUFA.

Alexis Bergman from Southern Illinois University Carbondale, has been feeding white worms on five different feeds: algae, stale bread, spent coffee grounds, leafy produce and brewery grains, and measuring the proximate and fatty acid composition in the feeds and subsequently in the worms. She presented her findings at Aquaculture 2016, in Las Vegas, USA.

The highest protein levels were found in the leafy produce and brewery grains, and the lowest in coffee, whereas the highest lipid levels in the worms came from those fed on coffee. These worms also had the highest saturated fatty acids - n-3 and n-6 MC-PUFA. LC-PUFA was also detected.

Worms fed the algae diets were highest for ARA and EPA but coffee was the only feed to produce DHA in the worms, which was surprising as initially the coffee did not contain any DHA.

Worms fed the algae feed had the highest protein, ARA and EPA levels but lower lipids and worms fed coffee had the highest lipid levels and some DHA but lower protein.

Ms Bergman suggested that feed choices could be based on which is of most importance - fatty acid, protein or lipids in the worms.

Another researcher, Michelle Walsh from Florida Keys Community College, focused her research on whether macroalgae is some measure replace baker’s yeast as a feed as it contains beneficial PUFA\'s plus DHA and EPA.

Caulerpa algae was fed as a sole diet or as part of the diet alongside baker’s yeast. The results showed that worms did not grow well on the purely algae diet, but on the 50-50 diet of yeast and algae, they fared better. However, they performed best on a 75 per cent yeast and 25 per cent algae diet.

Isiforme algae offered even better results. Future research will now look at fatty acid and nutritional analysis.

Source: Lucy Towers, TheFishSite. Read the full article here.