不同饵料对双刺纺锤水蚤繁殖的影响研究

Effects of diatom diets on the reproduction of Acartia bifilosa

在食物浓度为1.0μg C/ml的条件下,研究了硅藻对双刺纺锤水蚤Acartia bifilosa繁殖的影响。实验设6个食物处理:三角褐指藻Pt,中肋骨条藻Sc,混和硅藻D-mix,亚心型扁藻Ts,眼点拟球藻No和4种微藻混合DG-mix。16d的室内实验结果显示,与初始产卵率相比,硅藻中,中肋骨条藻处理产卵率高于三角褐指藻处理,而所有混合食物处理中产卵率均可保持较高水平。这一结果表明,单种硅藻对产卵率的抑制作用可以通过对其他食物的摄食补充而被减弱甚至消除。实验中卵在过滤海水中的孵化率与在藻液中无显著差异,表明硅藻并未释放阻碍卵孵化的代谢物质;各处理间孵化率的差异则证明在该浓度下,藻类对双刺纺锤水蚤孵化率的影响是通过内源(食物)而非外源(胞外分泌物)因素所产生的。

Four microalgal diets were fed to Acartia bifilosa separately or in mixture, at a concentration of 1.0 g C/ml for 16d, and the potential influence on its reproduction was investigated. The microalgal diets included： diatoms Skeletonema costatum （Sc） and Phaeodactylum tricornutum （Pt）, and their mixture （D-mix） ; green microalgae Terraselmis subordiformis （Ts）, Nannochloropsis oculata （No） ; and a mixture of the four microalgal species （DG-mix）. Compared with the initial value, egg production of A. bifilosa reduced when fed on diatom diet Pt, but kept normal level when fed on Sc. Furthermore, all mixed diets supported higher egg production, indicating that the negative effect of single diatom on egg production can be diminished and/or removed by ingesting mixed food. Irrespective of the treatments, there was no significant difference on hatching success between eggs kept in filtered seawater or algal suspen sion, indicating that diatom did not produce any toxic agents under this feeding regime. However, either in filtered seawater or algal suspension, the differences among all treatments showed that the influence of diatom on hatching of Acartia bifilosa was caused by internal （feed） reasons rather than external （cell secretion） ones.