FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

1Tungkang Biotechnology Research Center, Fisheries Research InstituteIn this study, the condensed Nannochloropsis oculata which has been cultured outdoor, concentrated by the centrifuge and stored in the refrigerator was used as food for rotifer. Rotifer cultured in the test tube and fed with either the condensed or fresh Nannochloropsis. The reproductive characters of rotifers included final individuals, population growth rate and percentage of rotifers carrying eggs. Each single factor, such as, storage period, preservative, algae type, light, and rotifer strain, and their interactions on the reproductive characters of rotifer were compared. The results showed no significant difference between the fresh and 120-day-stored condensed algae as food for Thailand strain SS rotifer Brachionus rotundiformis. Vitamin C addition as preservative also showed no significant improvement. However, a higher rotifer density, 3000 individuals/ml was observed when high condensed algae was given. At the same algal density, reproduction of Fiji strain SS rotifer and A strain S rotifer Brachionus ibericus fed with the condensed algae was better than that of fed with the fresh algae. However, C strain S rotifer showed a reversed result. No significant difference has been observed in other rotifers tested. It is also observed that S rotifer reproduced better under light than dark, while SS rotifer showed no significant difference between light & dark treatments. Among the S rotifers, C strain had the best reproduction, while the tested 3 SS rotifer strains showed no difference in reproduction. The best combination for the reproduction performance of Taiwan strain SS rotifer was feeding the condensed algae under dark, while it was feeding concentrated algae under light for C strain S rotifer. In conclusion, there was no significant difference between feeding the fresh and condensed Nannochloropsis in both SS and S rotifer, but the reproduction of rotifer varied with according to their status of carrying eggs, strains and species.