草鱼、鳡和翘嘴鲌消化道组织的早期发育

ONTOGENY OF THE DIGESTIVE TRACTS IN GRASS CARP (CTENOPHARYNGODON IDELLUS), YELLOWCHECK CARP(ELOPICHTHYS BAMBUSA) AND TOPMOUTH CULTER(CULTER ALBURNUS)

  • 摘要: 研究仔稚鱼消化机能的发育变化对于掌握鱼类早期发育阶段的消化特点、营养需要及提高仔稚鱼成活与生长等均有重要意义。采用HE、PAS等染色方法, 对草鱼(Ctenopharyngodon idellus)、鳡(Elopichthys bambusa)和翘嘴鲌(Culter alburnus)消化道组织的早期发育进行了研究, 结果表明: (1)初孵仔鱼卵黄囊的相对体积以鳡的最大; (2)均在孵后2d和3d分别出现肠管和口裂, 在孵后3d、4d和2d分别出现肠腔; (3)在孵后4d、7-9d和4d其肠腔内分别出现食物团, 表明此时草鱼、鳡和翘嘴鲌已分别开始外源性摄食; (4)在孵后5d、6d和6d其肠道内表面分别出现黏膜褶, 随后在稚鱼中其黏膜褶的高度和数量不同程度的发育; (5)草鱼和鳡的肠道分别在孵后14d和30d出现盘曲, 而在翘嘴鲌的切片图中未发现其肠道的盘曲; (6)草鱼、鳡和翘嘴鲌的肠道分别于孵后17-23d、30d和24-29d出现数量较多的黏液细胞, 此时标志着食性的转换和分化过程基本完善。

     

    Abstract: A thorough understanding of the temporal process of structure and function of larval and juvenile digestive systems has important values for investigating the digestive characteristics, nutritional needs of larva and juveniles, and enhancing their survival and growth. In inland aquaculture in China, grass carp Ctenopharyngodon idellus, yellowcheck carp Elopichthys bambusa and topmouth culter Culter alburnus are economically important freshwater species that belong to the family Cyprinidae, with entirely different nutritional needs. Using the methods of histology, a comparative study among the above species in early developmental stages was conducted in our study to examine the ontogeny of digestive tracts. The results of the three species in different days post hatching (dph) showed the following: (1) yellowcheck carp had the maximum relative bulk of yolk sac in newly hatched larva in the three species; (2) the intestinal tubes and oral fissures of the three species were differentiated apparently at 2 dph and 3 dph, and intestinal cavities of grass carp, yellowcheck carp and topmouth culter appeared at 3 dph, 4 dph, and 2 dph, respectively; (3) the food pulps were observed inside the intestines of grass carp, yellowcheck carp and topmouth culter in 4 dph, 7-9 dph, and 4 dph, respectively, indicating that these larval species had initiated exogenous feeding at different times post hatching; (4) mucosal folds of intestines in grass carp, yellowcheck carp and topmouth culter were initially differentiated at 5 dph, 6 dph and 6 dph, respectively, and subsequently the number and height of mucosal folds has been increased at different degrees with the development of larvae and juveniles, enabling the fishes to increase the total mucosal surface areas during development; (5) the intestinal coiling of grass carp and yellowcheck carp was initially observed from the transverse slices at 14 dph and 30 dph respectively, but no intestinal coiling appeared during the experiment at 30 dph in topmouth culter; (6) grass carp, yellowcheck carp and topmouth culter were observed to have numerous intestinal mucous cells at 17-23 dph, 30 dph and 24-29 dph, respectively, indicating that the conversion or the divergence of feeding habits within a specific species or between different species had been generally accomplished.

     

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