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.

No abstract

The physico-chemical characteristics of three different types of refined wheat flours (RWF-1, RWF-2 and RWF-3) were assessed to ascertain its suitability in shrimp feed along with three different types of whole (WWF-1, WWF-2 and WWF-3) and commercial (CWF-1, CWF-2 and CWF-3) wheat flours, and the essential amino acid index (EAAI) was determined based on the dietary requirement of three major penaeid shrimp species cultured in India viz., Penaeus vannamei, Penaeus indicus and Penaeus monodon. Results revealed that the fineness of WWF and RWF was 100% and alcoholic acidity exceeded an ideal level of 0.1% in WWF-2, CWF-3 and RWF-1. RWF had a low (p<0.05) water absorption (51.88-53.93%) and high bulk density (782.92-794.92 g l-1) compared to others. The moisture content was high (p<0.05) in RWF, whereas carbohydrate, protein, lipid and ash were found to be high in WWF. Of all the analysed samples, RWF had a higher (p<0.05) content of wet (28.56-31.82%) and dry (8.90-10.44%) glutens. Among the essential amino acids (EAA), arginine, lysine and methionine did not vary between the samples tested, while others showed significant (p<0.05) difference. EAAI was affected by the species (p=<0.001) but not by the flours (p = 0.173) and their interactions (p = 0.468). Both P. vannamei and P. indicus had a significantly higher EAAI (0.899 and 0.900, respectively) compared to P. monodon (0.862). Regression analysis showed a positive higher correlation between protein and EAA (r = 0.851) but EAA and its index were negatively correlated (r = 0.3464). Calories from carbohydrates were high in RWF (79.04-81.19%), but the reverse was true for protein and lipid in both WWF and CWF. Results conclude that RWF could be used for shrimp feed production, but ascertaining the processing effect on its utility by shrimps is essential.