Abstract
BackgroundThe zebrafish intestine is a simple tapered tube that is folded into three sections. However, whether the intestine is functionally similar along its length remains unknown. Thus, a systematic structural and functional characterization of the zebrafish intestine is desirable for future studies of the digestive tract and the intestinal biology and development.ResultsTo characterize the structure and function of the adult zebrafish intestine, we divided the intestine into seven roughly equal-length segments, S1-S7, and systematically examined the morphology of the mucosal lining, histology of the epithelium, and molecular signatures from transcriptome analysis. Prominent morphological features are circumferentially-oriented villar ridges in segments S1-S6 and the absence of crypts. Molecular characterization of the transcriptome from each segment shows that segments S1-S5 are very similar while S6 and S7 unique. Gene ontology analyses reveal that S1-S5 express genes whose functions involve metabolism of carbohydrates, transport of lipids and energy generation, while the last two segments display relatively limited function. Based on comparative Gene Set Enrichment Analysis, the first five segments share strong similarity with human and mouse small intestine while S6 shows similarity with human cecum and rectum, and S7 with human rectum. The intestinal tract does not display the anatomical, morphological, and molecular signatures of a stomach and thus we conclude that this organ is absent from the zebrafish digestive system.ConclusionsOur genome-wide gene expression data indicate that, despite the lack of crypts, the rostral, mid, and caudal portions of the zebrafish intestine have distinct functions analogous to the mammalian small and large intestine, respectively. Organization of ridge structures represents a unique feature of zebrafish intestine, though they produce similar cross sections to mammalian intestines. Evolutionary lack of stomach, crypts, Paneth cells and submucosal glands has shaped the zebrafish intestine into a simpler but unique organ in vertebrate intestinal biology.
Highlights
The zebrafish intestine is a simple tapered tube that is folded into three sections
Morphological development of zebrafish intestine has been relatively well characterized in embryos and larvae [7,8,9,10,11], the organization and physiology of digestive tract has not been documented for adult zebrafish several books are available for description of general fish intestine anatomy [12,13,14]
It is not known whether these regions are functionally distinct or whether their functions correspond to the mammalian stomach, small intestine or large intestine
Summary
The zebrafish intestine is a simple tapered tube that is folded into three sections. whether the intestine is functionally similar along its length remains unknown. The surface of the intestine epithelium is the site where nutrients are absorbed into the body This absorption function is aided by expanding the surface area of the gut into villi at the tissue level and microvilli at the cellular level. Previous studies have described the zebrafish intestine as a tapered tube that begins at the esophageal junction and is folded into three sections, the large diameter rostral intestinal bulb, the mid-intestine, and the small diameter caudal intestine [9]. It is not known whether these regions are functionally distinct or whether their functions correspond to the mammalian stomach, small intestine or large intestine. By comparing the morphological and molecular characteristics, we identified structurally and functionally distinct areas that correspond to the small intestine and large intestine but not stomach
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
