Department of Anatomy and Embryology, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt.
Department of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, Assiut, Egypt.
Microsc Res Tech. 2022 Jan;85(1):56-70. doi: 10.1002/jemt.23884. Epub 2021 Jul 27.
The present study was implemented to provide comprehensive information on the developmental sequence of the proventriculus of Muscovy ducks by gross examination, macro-micrometric analysis and by using light microscope, scanning electron microscope (SEM) and transmission electron microscope (TEM). Samples from 55 healthy post-hatching Muscovy ducks of both sexes ranging from 1 to 60 days old. The proventriculus began cranially opposite to the cranial end of the liver at 1-15 days old, but in front this level at 30 and 60 days old. Morphometrically, the length of the proventriculus was increased by about four folds while weight by 19 folds at 60 days old when compared with those at one day old. Scanning electron microscopy of the proventricular lumen at one day old exhibited numerous small mostly rounded irregularly distributed openings of the glands, but uniformly distributed and surrounded by closely packed concentrically arranged mucosal folds resembling a rosette shape at the older ages. Histologically, in all studied stages, rounded, elongated oval or polymorphic shaped lobules of the proventricular glands were occupied within the muscularis mucosa. The tubuloalveolar secretory units lined with secretory (oxyntico-peptic) cells with variable shapes had secretory granules increased by the development. Numerous argyrophilic endocrine cells were demonstrated away from the glandular lumen at older ages. Transmission electron microscopy revealed that the cytoplasm of the secretory cells contained homogeneously electron-dense granules at a young age, but two types of these granules could be recognized at 60 days old. In conclusion, this study provides a wide difference in the morphometric and the structure of the proventriculus from one day to 60 days old. This difference between the examined age-stages may be related to the feeding strategy (behavior) and the functional adaptations from the young to the older ages.
本研究旨在通过大体检查、宏观-微观分析以及使用光学显微镜、扫描电子显微镜（SEM）和透射电子显微镜（TEM），提供有关麝香鸭前胃发育顺序的综合信息。研究对象为 55 只 1-60 日龄的雌雄健康孵化后麝香鸭。1-15 日龄时，前胃起始于肝脏头端的颅侧，但在 30 日龄和 60 日龄时，前胃位于此水平的前方。形态学上，前胃的长度增加了约四倍，而重量则增加了 19 倍，与 1 日龄时相比。1 日龄前胃腔的扫描电子显微镜显示，腺体内有许多小的、大多呈圆形、不规则分布的开口，但在较老的阶段，腺体内分布均匀，并被紧密排列的同心状黏膜皱襞环绕，形状类似于玫瑰花结。组织学上，在所有研究阶段，前胃腺的圆形、长椭圆形或多形小叶都位于黏膜肌层内。被分泌（氧合-消化）细胞排列的管状肺泡分泌单位，形状各异，分泌颗粒随着发育而增加。在较老的阶段，远离腺腔处显示出许多嗜银内分泌细胞。透射电子显微镜显示，分泌细胞的细胞质在年轻时含有均匀电子致密的颗粒，但在 60 日龄时可以识别出两种类型的颗粒。总之，这项研究表明，从 1 日龄到 60 日龄，前胃在形态计量学和结构上存在很大差异。这些不同的年龄阶段之间的差异可能与摄食策略（行为）和从幼年到老年的功能适应有关。
