Influence of microalgal diets in the mass production and nutrient enrichment of Apocyclops royi (Cyclopoida, Copepoda) - A potential live food for marine fish larvae

Abstract This study investigated the effects of three microalgal diets (Chloroidium saccharophilum, Chlorella vulgaris and Nannochloropsis oculata) on the population growth, nutritional composition of Apocyclops royi. The microalgal strains were taxonomically identified using 18S rRNA Technique. This copepod is mass cultured with C. saccharophilum diet is identified as potential live prey for marine finfish larval rearing. Under optimal water quality parameters and microalgal diet of C. saccharophilum, C. vulgaris and N. oculata at the concentration of 30,000 cells/mL, the A. royi showed high survival and ovisac production with the C. saccharophilum feeding regime. Mass culture of this copepod reached a density of (12700 ± 454 ind./L). on 21st day of culture period. The fatty acid profile showed enhanced content of saturated and PUFAs in A. royi (p < .05) with C. saccharophilum diet. The contents of EPA, DHA and ARA in A. royi are high with C. saccharophilum diet compared to other microalgal diets. Amino acid profile of A. royi fed C. saccharophilum showed significantly high content of Glycine, Alanine, Aspartic acid, Glutamic acid, Threonine and Histidine. The total essential amino acid content is significantly higher than the animals fed on C. vulgaris and N. oculata (p < .05). Our findings illustrate that the C. saccharophilum is the most suitable microalgal diet for mass culture of A. royi because it increases productivity and enhances the nutritional value of the copepods for use as fish larvae prey.