Abstract
Copepods are the natural food source for fish larvae and ideal as live feed in aquaculture. They have an ideal size range and are grown on algae, providing a sustainable alternative to existing aquafeeds of Artemia and rotifers, which are nutritionally deficient and can require artificial enhancement with fish meal. The use of copepods is currently limited as they can host fish pathogens and culturing requires a lot of labour and expertise. We tested culturing of the pelagic copepod Acartia tonsa with pre- and probiotics and explored potential benefits for commercial production. This is in line with a growing trend in aquaculture towards microbial management. Prebiotics can stimulate a beneficial microbiome and can be converted to short chain fatty acids (pyrivate, acetate, butyrate) with beneficial intestinal effects. Probiotics directly add beneficial microbes and can steer the microbiome in a controlled manner.
Tests were performed in a semi-industrial set-up to test the effect of prebiotic short chain fructo-oligosaccharides, probiotic Bacillus sp. and the combined synbiotic treatment. A beneficial effect was observed on hatching success with the prebiotic short chain fructo-oligosaccharides. These fibers are commercially available and cheap, and ideally suited for further exploration. Probiotics were likely administered in a too high dose, and high amounts of dead cell mass were linked to lower hatching success. Treatments with prebiotic fibers (prebiotic and symbiotic treatment) showed a significant change in fatty acid composition and possible de novo lipogenesis under prebiotic exposure.
Acknowledgment
The research is a results of a research stay funded by AQAUSERV and a collaboration between Ghent University (Belgium), NTNU Sealab (Norway) and a commercial partner C-FEED (Norway).