Effects of replacing microalgae with an artificial diet on pearl production traits and mineralization-related gene expression in pearl oyster Pinctada fucata martensii

Abstract

The effects of replacing dietary microalgae with artificial diet on pearl production traits and biomineralization-related gene expression were investigated in pearl oyster (Pinctada fucata martensii). Three experiment groups (EG1, EG2 and EG3) were set. EG1 and EG3 were separately fed Platymonas subcordiformis and artificial diet (D4), respectively, and EG2 was fed with mixed P. subcordiformis and D4. A control group (CG) was cultured in natural sea. All groups were continuously fed for 150 days. The results showed that the survival rates of EG1, EG2 and EG3 were significantly higher than that of CG. No significant differences in retention rate and pearl thickness were observed among the four groups, but CG had the lowest values of both parameters. The relative expression levels of EGFR and FGF18 mRNA did not significantly differ among EG1, EG2 and EG3. Moreover, the relative expression levels of GHITM and TβR I mRNA significantly varied among the groups and EG3, and EG1 had the highest and lowest relative expression levels of GHITM and TβR I mRNA respectively. The relative expression levels of nacrein and chitin-binding mRNA significantly differed among the groups, and EG1 had the lowest expression levels of nacrein and chitin-binding mRNA. No significant differences in the relative expression levels of MSI60 and TIMP mRNA were observed among the groups. The results suggested that D4 can replace part of microalgae, which is helpful for further studies on developing artificial diet of pearl oyster.