Effect of different dietary microalgae combinations on growth and survival of black-lip pearl oyster (Pinctada margaritifera) larvae and the feasibility of replacing microalgae with a dietary lipid emulsion

Abstract

A 10-day experiment was performed to examine different mono, binary and ternary dietary combinations on survival and growth of D-shaped and umbone black-lip pearl oyster, Pinctada margaritifera, larvae. The three tropical microalgae species were the flagellate Isochrysis galbana clone T. Iso (CS-177) and diatoms Chaetoceros calcitrans (CS-178) and Chaetoceros muelleri (CS-176) which were fed to D-shaped and umbone larvae at a density of 7000 and 14 000 cells mL−1, respectively. A second experiment was performed to investigate the feasibility of replacing T. Iso with a lipid emulsion for both D-shaped and umbone larvae for 10 and 12 days, respectively. The treatments included only T. Iso, unfed and lipid emulsion to substitute T. Iso at levels of 10% (LIP10), 30% (LIP30) and 100% (LIP100). In the first experiment, results showed that a monospecific diet of T. Iso led to significantly higher (P 0.05) from the unfed treatment. For D-shaped larvae, no significant growth difference was detected (P > 0.05) between the T. Iso and LIP10 fed treatments while for umbone larvae, the T. Iso, LIP10 and LIP30 were not significantly different (P > 005). These results indicate that microalgae combinations appear more necessary for later staged P. margaritifera larvae. In addition, the use of a lipid emulsion appeared to provide some nutrition to the larvae, although more research should be conducted to improve the use of such replacements.