Sustainable Growth of Shrimp Aquaculture and Protection of Natural Fisheries Through Biofloc Production as Alternative to Fishmeal in Shrimp Feeds

Abstract

As capture fisheries are now fully exploited in Egypt, aquaculture is considered the only source for meeting the demand of seafood for rapidly growing populations in Egypt. To meet these demands for seafood, aquaculture has to grow fast and to be more intensive. This expected growth in aquaculture require utilization of inputs mainly, sources for high quality seeds and fishmeal for production of feeds for cultured fish and crustacean. Fishmeal sources from cap-ture fisheries are fully exploited and thus become costly ingredient in fish and crustacean feeds formulation. There is a need to develop technology that will increase economic and environ-mental sustainability. The present study evaluated biofloc technology as a sustainable alterna-tive to fishmeal in the shrimp feeds. It based on using cheap carbon source for stimulation of the growth of the microbial biofloc in addition to reduce protein content of the feeds and in-crease carbohydrate content. This lower feed price without affecting shrimp growth. Also, shrimp are not efficient in the digestion of the carbohydrates, which will be released in the wa-ter in shrimp faeces and in turn stimulate biofloc production. The shrimp were fed diets with low fishmeal content had a slightly better growth and FCR. The biochemical composition of the biofloc treatments didn’t vary significantly. Bioflocs grown on 25.20 % CP + rice bran have a high protein content 20 ± 7 DW. Regarding the composition of the PUFAs in the bio-flocs, the bio-flocs with 25.20 % CP + Rice bran treatment contained significantly more LNA (18:3(n-3)) than that with 30.10 % CP+ Rice bran treatment and the opposite for LA (18:2(n-6)). In particular bio-flocs with 25.20 % CP + Rice bran treatment had a total n-6 PUFAs. The biofloc proofed to be a possible good additional nutritious aquaculture feed and accepted by the shrimp which play a crucial role in the use of bioflocs technology in aquaculture.