Moina macrocopa, a potential natural feed for fish larvae, contains high levels of protein, fat, and carbohydrates, making it suitable for larval feeding due to its size (500–1000 µm), matching the larvae’s mouth opening. The ephippia of M. macrocopa, dormant egg cells, can be stored for long periods and hatched as needed, similar to Artemia cysts, optimizing M. macrocopa availability as natural feed for aquaculture.
The quality and quantity of ephippia produced can be influenced by the quality and quantity of their diet. The quality is determined by the number of ephippia containing two fertilized eggs, while the quantity is determined by the total ephippia produced by M. macrocopa. Diets containing EPA and DHA can enhance ephippia quality and quantity, as the eggs in the ephippia require higher concentrations of EPA and DHA than those produced by parthenogenesis.
Cultivating M. macrocopa with rice bran suspension results in ephippia with relatively low quality and quantity due to the low content of omega-3 fatty acids like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in rice bran. Therefore, the addition of EPA and DHA is necessary to improve ephippia quality and quantity.
Lemuru fish oil, containing 34.9% omega-3 fatty acids, including 9.6% EPA and 10.09% DHA, can enhance the fatty acid content, particularly EPA and DHA, in rice bran suspension, potentially increasing the quality and quantity of M. macrocopa ephippia production.
The study included various treatments, including a control without lemuru fish oil addition and rice bran suspension with different amounts of lemuru fish oil. The optimal concentration of lemuru fish oil in rice bran suspension that increased ephippia quantity was found to be 6 mL/100 g of rice bran, resulting in an average ephippia production of 425.8 pieces/L, with 98% containing fertilized eggs.
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