The Differentiation And Structure Of Digestive System Of Triplophysa Bleekeri (Sauvage Et Dabry)

Anatomy,histological,histochemical and TEM methods were used to describe the structure and differentiation of the digestive system in Triplophysa bleekeri (Sauvage et Dabry) during December 2005 to December 2006. The results showed:The digestive system of Triplophysa bleekeri (Sauvage et Dabry) was composed of digestive tract and digestive gland. The digestive tract was divided into five parts : oropharyngeal cavity, esophagus, stomach, intestine and anus. Digestive gland include liver,pancreas,and so on. The oropharyngeal cavity of Triplophysa bleekeri was wide, the top wall and the end wall had mucosa, submucosa and muscle layer three-layer structure. The difference was that mucous cells and taste buds were more abundance in the top wall and the end wall had more baculiform cells.The histological structure in esophagus, stomach and intestinal were similar composed of mucosa, submucosa, muscle layer and adventitia.The stratified epithelium of esophageal mainly from squamous cells.There was short microvilli on the top of squamous cell. There were not many organelles except for mitochondria. Squamous cell inclusions among a large number of mucous cells.There were developed tublovesicular system in esophagus. A small reticular fiber and fibrocyte and large bundles of collagen fibers in basement membrane.No esophageal glands.Only one layer striated muscle around esophagus.The "V"-shaped stomach could be divided into three parts : cardiac, stomach and pylorus,those had typical simple columnar epithelium.The columnar epithelial cells contained a large number of secretory granules, that were strongly positive by the PAS reaction. Mitochondrial located in the lower part of cells, also advanced. Ther were no goblet cells in mucous layer. Advanced single tubular glands located in cardiac and body of stomach. The gastric glandular cells contained a large number of zymogen granule, mitochondria,rough surfaced endoplasmic reticulum and tublovesicular system. There was no gastric gland in pylorus. The inside muscular layer in gastric cardia and body of stomach was longitudinal muscle layer,and outer was circular muscle layer. The muscular layer of pylorus was in opposition to gastric cardia and body of stomach's.The intestine circled around the stomach like "φ",was provided with developed villus. the columnar epithelium had lots of microvilli.A large number of mucous cells which scattered among the epithelial cells ,were filled with homogeneous secretory granules. The amount of mucous cells had been declining from the former to backward volume in the entire colon. Mucosa cells had developed tublovesicular system.The structure of anus was semi-opened,which had stratified squamous epithelium.The dense connective tissue of submucosa layer was supported by thick striated muscle layer.Liver was irregular in shape,which had capsule outside. The lobules of liver could not distinguish clearly.The hepatocyte varied in shape. Kupffer cells could be seen occasionally. Vascular was very prosperous. Portal area was not obvious. Liver cells cytoplasm was enriched with organelle and cell contents, in which rough surfaced endoplasmic reticulum and mitochondria most common. The liver sinusoid was composed of endothelial cells and Kupffer cells. The hepatocytes microvilli could be seen in Disse's space and capillary bile duct.Pancreas was an independent thin strip, attached to the side of the liver and intestinal. Pancreas had exocrine and endocrine parts, where vascular tissue developed.The growth of Triplophysa bleekeri larvae is linear growth trends.Nutrition mostly came from the first end of the spoon-shaped egg yolk in endogenous nutrition phase.The mouth had already can be seen at the larvar hatching and linked to the outside world at 3dph. Oropharyngeal cavity completed basic development at 9dph. Esophagus completed development at 8dph. Newly hatched larvar, the digestive tract was a prototype, but no obvious differentiation gastrointestinal; At 64dph,the rudiment of gastric gland appeared in gastric pit,which showed the stomach started with the whole function.Intestine completed the basic development at 27dph.Liver cells begin to differentiate at 2dph;At 7dph, central vein and hepatic cord appeared. There was no obviously distinguish between larvar liver and adult's. The liver cells started to accumulate lipid vesicle at 27dph. Pancreas appeared at the side of the esophagus and stomach at 5dph. Pancreatic cavity with a large number of eosinophilic granular material. At 9dph, the appeared of pancreatic islet completed the development of pancreatic tissue. Digestive histological structure development completed in 64dph.Threr was no any bending only front enlargement in larval digestive tract at 64dph. At 85dph, stomach and esophagus was right angle after bending down, but no significant gastrointestinal boundaries. At 120dph, stomach bending to "Z" shape after straight down, no noticeable gastrointestinal boundaries; Liver of a whole, not divided. At one-year age, digestive anatomy was similar to adult's, except that liver lacking of the dexter liver and intestine lacking of a round ring bending.