Increased awareness of freshwater consumption for microalgal cultivation and excessive investment for aquaculture feeds has driven studies towards building a recycling system. Thereby, mariculture wastewaters (MW) modified with monosodium glutamate residue (MSGR) or NaNO3 & K2HPO4 were used to culture microalgae, and then whether generated microalgae could meet nutritional standards for aquatic animals was evaluated. The results showed that MW + MSGR was the optimum medium for microalgae as aquaculture feeds: microalgae could accumulate plentiful high-quality protein with essential amino acid indices exceeding 0.90; and 13.49% of the fatty acids in microalgae were highly unsaturated, attributed to the organic carbon and some dehydrogenase present in MSGR. Furthermore, microalgae could provide desirable carotenoids, which have been proposed as an important defensive line to scavenge the excess oxidants under salinity stress. Additionally, elemental composition satisfied standard limits for safe consumption. In combination, aquaculture achieved self-reliance by virtue of microalgae with desirable biochemical composition.
Keywords: Carotenoids; Highly unsaturated fatty acids; Mariculture wastewater; Microalgae; Protein.
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