织锦巴非蛤幼虫对不同种类单胞藻的摄食和消化效果

【目的】明确织锦巴非蛤幼虫在不同发育时期饲喂单胞藻饵料的合适种类，为织锦巴非蛤的苗种规模化人工繁育提供饵料投喂策略及参考依据。【方法】以从广西北海市铁山港区自然海域捕捞的织锦巴非蛤2龄贝为亲本，人工培育D形幼虫，在幼虫培育期间分别投喂小球藻、微绿球藻、杜氏盐藻、亚心形扁藻、湛江等鞭金藻、球等鞭金藻、绿色巴夫藻、牟氏角毛藻和三角褐指藻，显微镜下观察幼虫在不同时期对不同种类单胞藻的摄食情况和消化效果。【结果】织锦巴非蛤初孵幼虫（D形幼虫）大小（壳长×壳高）为（82.49±3.02）μm×（63.98±2.16）μm，于4 dph（孵化后第4 d）发育至壳顶前期（115.89±3.86）μm×（101.62±3.80）μm，13 dph进入变态期（205.61±15.84）μm×（182.61±13.53）μm，于15 dph变态至稚贝（225.63±8.99）μm×（198.65±8.25）μm。织锦巴非蛤幼虫在运动过程中也伴随着摄食，通过纤毛的摆动形成水流，单胞藻则随着水流方向进入幼虫口沟，在口沟纤毛摆动下进入胃内，胃内的单胞藻在微绒毛摆动下快速旋转并消化。织锦巴非蛤幼虫在1 dph时能摄食小球藻、微绿球藻、绿色巴夫藻、湛江等鞭金藻和球等鞭金藻，在4 dph时有少量幼虫开始摄食杜氏盐藻，至10 dph时幼虫开始摄食亚心形扁藻和牟氏角毛藻，整个浮游幼虫期均不摄食三角褐指藻。在9种单胞藻饵料中，小球藻和微绿球藻较其他种类更难消化。【结论】在织锦巴非蛤幼虫培育过程中，幼虫开口饵料宜选择湛江等鞭金藻、球等鞭金藻和绿色巴夫藻，在10 dph时适宜投喂杜氏盐藻，至13 dph时可投喂牟氏角毛藻和亚心形扁藻；在其他易被摄食和消化单胞藻种类充足的情况下，一般不选取小球藻和微绿球藻作为幼虫培育的首选饵料。

Effects of Paphia textzle larvae on ingestion and digestion of different microalgae species

【Objective】To clarify the suitable species of microalgae bait for Paphia textzle larvae at different developmental stages，so as to provide seeding strategy and references for large-scale artificial breeding of seedlings.【Method】 Two-year old P. textzle caught from the natural waters of Tieshangang District，Beihai City，Guangxi Province were cultivated as parents. When cultivating D-shaped larvae were，species of microalgae，Chlorella vulgaris，Nannochloropsis oculata，Dunaliella salina，Platymonas subcordiformis，Pavlova viridis，Dicrateria zhanjianggensis，Isochrysis galbana， Chaetoceros muelleri，and Phaeodactylum tricornutum were fed to P. textzle larvae every 3 days at larval stage. The ingestion and digestion effects of larvae feeding by different species of microalgae were observed at different stages.【Result】 The size of the newly hatched larvae（D-shaped larvae）（shell length×shell height）of the P.textzle was（82.49±3.02）μm×（63.98±2.16）μm. They developed to the early umboveliger at 4 dph（days post hatch）with a size of（115.89±3.86）μ m×（101.62±3.80）μ m. Then they entered metamorphosis stage with a size of（205.61±15.84）μ m×（182.61±13.53）μm at 13 dph. They became byssus at 15 dph with a size of（225.63±8.99）μm×（198.65±8.25）μm. The P. textzle larvae also ingested during the movement process，forming a water flow through the swing of cilia，and the microalgae entered the groove of the larva with the direction of the water flow，and entered the stomach under the swing of the groove cilia，and the microalgae in the stomach quickly spined and digested under microvilli wiggles. Larvae could ingest C. vulgaris，N. oculata，P. viridis，D. zhanjianggensis，and I. galbana at 1 days post hatch（dph）and very few larvae could ingest D. salina small individual at 4 dph. The larvae began to ingest P. subcordiformis and C. muelleri small individual at 10 dph. P. tricornutum could not be ingested by larvae during the planktonic period. It found that C. vulgaris and N. oculata was more difficult to digest than others of nine microalgae.【Conclusion】During the breed of P. textzle larvae，the spherical shape with small particle size of P. viridis，D. zhanjianggensis and I. galbana that is easier to digest would be used as bait at first，and followed by D. salina，P. subcordiformis and C. muelleri.