SummaryIn the present study, the morphological development of the Brycon amazonicus digestive tract is described to provide basic knowledge for nutritional studies and, therefore, increase the survival of this species during larviculture. Samples were collected from hatching up to 25 days of age, measured, processed and observed under a stereomicroscope and light microscopy. Newly hatched larvae presented their digestive tract as a straight tube, dorsal to the yolk sac, lined with a single layer of undifferentiated cells. At 24 h post-hatching (hPH), the buccopharyngeal cavity was open, but the posterior region of the digestive tube remained closed. At 25 hPH, the digestive tube was completely open and could be divided into buccopharyngeal cavity, oesophagus and intestine. At 35 hPH, the intestine presented a dilatation in the proximal region, which had the function of storing food. Differentiation of the stomach started at 83 hPH, and mucous cells were observed in the epithelium. These cells are important in the production of mucus, whose function is to protect the organ against acidity, although the gastric glands began developing only from 171 hPH, when three stomach regions were observed: cardiac, fundic and pyloric. The gastric glands were observed in the cardiac region, indicating that this organ already had digestive functionality. From 243 hPH, the absorption and assimilation of nutrients were already possible but, only from 412 hPH, the digestive tract was completely developed and functional.

中文翻译：

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Brycon amazonicus (Teleostei, Bryconidae) 在培养条件下消化道的个体发育：从孵化到幼年

摘要在本研究中，野马铃薯消化道被描述为为营养研究提供基本知识，因此在幼体养殖过程中增加了该物种的存活率。从孵化到 25 日龄收集样品，在立体显微镜和光学显微镜下进行测量、处理和观察。新孵化的幼虫的消化道呈直管状，位于卵黄囊背侧，内衬单层未分化细胞。孵化后 24 小时 (hPH)，颊咽腔开放，但消化管后部区域保持闭合。25 hPH时，消化管完全开放，可分为颊咽腔、食道和肠道。在 35 hPH 时，肠道在近端区域出现扩张，具有储存食物的功能。胃的分化在 83 hPH 开始，在上皮中观察到粘液细胞。这些细胞在粘液的产生中很重要，粘液的功能是保护器官免受酸性影响，尽管胃腺仅从 171 hPH 开始发育，当时观察到三个胃区域：心脏、胃底和幽门。在心脏区域观察到胃腺，表明该器官已经具有消化功能。从 243 hPH 起，营养物质的吸收和同化已经成为可能，但只有从 412 hPH 起，消化道才完全发育并发挥作用。当观察到三个胃区域时：心脏、胃底和幽门。在心脏区域观察到胃腺，表明该器官已经具有消化功能。从 243 hPH 起，营养物质的吸收和同化已经成为可能，但只有从 412 hPH 起，消化道才完全发育并发挥作用。当观察到三个胃区域时：心脏、胃底和幽门。在心脏区域观察到胃腺，表明该器官已经具有消化功能。从 243 hPH 起，营养物质的吸收和同化已经成为可能，但只有从 412 hPH 起，消化道才完全发育并发挥作用。