Structural and functional relations of the white sturgeon alimentary canal (Acipenser transmontanus).

The anatomy and histology of the white sturgeon digestive system is described for the adult stage and the first 36 days of posthatch development. Although the adult gut is only 87% of standard length, absorptive surface area is effectively increased by the thick mucosa of the postgastric gut and by lengthening of the gut due to the presence of the spiral valve and the pyloric caecum. Modifications of the gut of this species, relative to that of other chondrosteans, are consistent with its durophagous feeding habits. The arrangement of the intestinal epithelium differs from that of most fish and is organized so that absorptive activities occur in deeper regions, whereas goblet cells dominate the lumenally exposed epithelium. The gut develops from an intraembryonic yolk endoderm. At conclusion of the endogenous nutrition phase the alimentary canal is similar to the adult form and a functional gastric region is present. The anatomical characteristics coincide with physiological data collected throughout the life history of this species.