Chemoattractants: Their essentiality and efficacy in shrimp aquaculture

Aquaculture serves as a sustainable source of good quality wholesome food and major input is feed. In recent years, considerable quantities of plant sources have been attempted for inclusion in shrimp feed, due to high demand and high cost of fishmeal. Plant-based ingredients are in general poor in attractability and palatability to aquatic species compared to marine sources. It is desirable to develop an economical and nutritious feed that is attractive and palatable for ensuring reduction of feed wastage. Chemoattractants nowadays are unavoidable in commercial shrimp feeds and are included either individually or in combination. The present review revealed that the various marine sources, in particular krill meal would be more effective for aquatic species, compared to those derived from vegetable origin and chemical compounds. In addition to acting as a feed attractant, marine sources serve as a potential fishmeal substitute due to their rich nutritional composition. However, certain biogenic amines present in these marine-based ingredients need to be examined before their use, since these amines when present in high concentrations reduces feed intake by producing undesirable odour. Use of a combination of chemoattractants would give a better effect, rather than using them individually and compounds from plant origin have limited beneficial effects. The present review concludes that incorporation of chemoattractants would be beneficial in formulation of enriched and economical feeds with better attractability and palatability. The selection of suitable attractant and their supplementation at correct proportion is significantly more important to avoid undesirable effects in cultured shrimp. Further field-based research is needed to predict the actual effects of chemoattractants on farmed shrimp and to provide a sustainable base for the expansion of shrimp aquaculture sector, by reducing feed wastage.