背角无齿蚌幼蚌食物中的藻类组成

The dietary algae at different juvenile stages of Anodonta woodiana

选取不同生长阶段(1.5月龄,2.5月龄,6月龄)的背角无齿蚌(Anodonta woodiana)幼蚌,通过生物学解剖对其消化道内容物中的藻类组成进行研究。结果显示,不同月龄幼蚌食物中藻类组成均以蓝藻、绿藻为主。随幼蚌个体发育,检出的藻种类数逐渐增多(1.5月龄仅11种,2.5月龄13种,6月龄37种)。在1.5月龄幼蚌食物中藻类主要优势种为微小色球藻(Chroococcus minutus)、小球藻(Chlorella vulgaris)和微小四角藻(Tetra?dron minimum);2.5月龄幼蚌食物中藻类主要优势种为小球藻、微小四角藻和银灰平裂藻(Merismopedia glauca);6月龄幼蚌食物中藻类主要优势种为银灰平裂藻、小球藻和直径较大的四尾栅藻(Scenedesmus quadricanda)。微小四角藻在6月龄幼蚌消化道前后端的出现频率差异显著(P<0.05),反映出较高的利用强度。上述结果可为突破饵料"瓶颈",建成标准化养殖背角无齿蚌实验动物种群提供科学依据,同时可为研究其他淡水经济蚌类的饵料藻类,以促进其人工繁育及资源恢复提供借鉴和参考。

The composition and variation of dietary algae were studied with swan mussels Anodonta woodiana at dif-ferent juvenile （1.5-month-old, 2.5-month-old and 6-month-old） stages. The results showed that Cyanophyta and Chlorophyta were the major components. The number of dietary algal species in the mussels tended to increase over the juvenile stages （i, e., 11 species at 1.5-month-old, 13 species at 2.5-month-old, and 37 species at 6-month-old）. The dominant algal species in 1.5-month-old juveniles were Chroococcus minutus, Chlorella vulgaris and Tetraedro mini-mum, while those in 2.5-month-old juveniles were C. vulgaris, T. minimum, and Merismopedia glauca. Besides C. vul-garis and M. glauca, some large algae （e.g., Scenedesmus quadricanda） could be found in the dominant algae species of 6-month-old juveniles. The quantity of T. minimum was significantly different between the fore-intestine and hind-intestine in 6-month-old juveniles （P〈0.05）, reflecting a possibly high bioavailability. The aforementioned results provide important scientific basis to break the dietary algae“bottleneck”for ongoing establishment of the standardized culture A. woodiana population, and also for the artificial culture and resource enhancement of other freshwater mussels.