Appraising waste from fed aquaculture animals as a food source for sea cucumbers

Nutrient-rich solid waste and effluent water from aquaculture remain a major problem for aquaculture in terms of environmental impact. Integrated multitrophic aquaculture (IMTA), where lower trophic level species consume the waste of fed animals, has been proposed as an alternative for sustainable aquaculture. The use of deposit-feeding sea cucumbers as extractive species in IMTA has attracted research and commercial interest in recent times, due to their low trophic level, high commercial value as food for humans, and ability to ingest sediment containing organic matter, bacteria, protozoa, diatoms, and detritus. Still, the suitability of using faecal waste from fed aquaculture animals as a potential feed requires further studies to ensure not only palatability but also nutritional value, health, and immune responses of the cultured organism. This review discusses various performance indices, such as palatability, ingestion rate, assimilation rate, faecal production rate, feed conversion ratio, growth, and survival of sea cucumber species fed various faecal wastes from different aquaculture animal sources. It further discusses various IMTA applications of sea cucumbers with selected animals. The compatibility, viability and efficacy of sea cucumbers and some aquatic animals in IMTA are summarised.