Valorising plant-based residues for shrimp production through biofloc technology

Summary

Biofloc is a heterogenous aggregate consisting of a mixture of microorganisms (e.g., bacteria, archaea, algae, protists, zooplankton and fungi) and detritus suspended in the water column. Microbiota in biofloc maintain the water quality and enhance shrimp production. However, biofloc uses organic carbon as energy source. Therefore, conventional biofloc systems consume a high amount of carbon resulting in up to a fivefold higher carbon loss compared to non-biofloc systems.

This thesis explored an alternative biofloc management approach by adding carbohydrates in the diet, such as wheat bran, which shrimp cannot digest but microorganisms in the biofloc can. To do so a dual-purpose feed which nourishes both the shrimp and the biofloc was formulated. With this feed, the biofloc system could be maintained operational without requiring a higher carbon input than a conventional feed applied to a non-biofloc system. The effects of this approach on shrimp production, water quality, biofloc quantity and quality, and biofloc microbial composition were investigated. The goals are to enhance feed efficiency and circularity in shrimp farming.