花刺参幼参摄食和消化器官形态学和组织学研究

Morphology and histology of feeding and digestive organs in juvenile Stichopus monotuberculatus

花刺参(Stichopus monotuberculatus)是中国热带海参中具有较高经济价值的可食用海参之一。本文以花刺参幼参为实验对象,主要研究其摄食器官触手的形态特征与消化器官肠道不同区段的组织结构。结果显示,花刺参的口周围共有20个等长的触手,每个触手由柄部和楯状触手组成。楯状触手向外张开呈掌状,从掌心中央向外形成5~6个主要分支。主要分支上又形成了2~3级的分支,分支的腹面分布多个乳突,2~3个乳突多聚集在一起形成乳突簇。单个乳突的直径为69.99±20.97μm,每簇乳突的直径为104.99±24.15μm,适宜摄食细小的沉积物颗粒。花刺参的前肠和中肠黏膜层较厚,分别为127.42±102.09μm和114.10±35.47μm,均显著高于后肠(18.18±8.38μm)。后肠黏膜下层厚度则显著高于前肠和中肠。肌层和浆膜层厚度在肠道的三个不同区段无明显差异。前肠和中肠的绒毛长度和密度均显著高于后肠,而后肠的隐窝深度显著低于前肠和中肠。上述结果表明花刺参的消化吸收主要发生在前肠和中肠,后肠的消化吸收功能较弱但分泌能力较强。

Stichopus monotuberculatus is one of the edible tropical sea cucumbers with high economic value in China Seas.In this study,the morphological characteristics of the tentacles and the tissue structure of different parts of the intestine in juvenile S.monotuberculatus were examined.The results showed that the mouth is surrounded by 20 branched equal length tentacles,and each tentacle composed of a stalk and some peltate tentacles with five or six ramified processes.The main branches keep forming secondary and tertiary branches.On the ventral side of the branches,there are many mastoids,with 2-3 of them(each diameter:69.99±20.97μm)normally gathered together to form mastoid clusters(diameter:104.99±24.15μm)which is suitable for the uptake of fine sediment particles.Histological analysis showed that the thickness of mucosa in foregut(127.42±102.09μm)and midgut(114.10±35.47μm)are significantly higher than that in hindgut(18.18±8.38μm).The thickness of submucosa in hindgut aresignificantly higher than that in foregut and midgut.There is no significant difference in the muscular and serosal layer thickness among the three sections of the intestine.The villi length and density of the foregut and midgut aresignificantly higher than that of the hindgut,and the crypt depth of the hindgut issignificantly lower than that of the foregut and midgut.The results suggest that the digestion and absorption in S.monotuberculatus mainly occurred in foregut and midgut,and the secretion function of the hindgut is comparatively high.