| Age and growth, embryonic development and digestive tract histology of the O. sinensis were studied in this paper. The results of this study are as follows:1. The major annual-ring feature of O. sinensis belonged to loose-close and cutting type. Fish aged0+～3+and1+～2years were dominant, accounting for62.45%of all samples. The body weight of the fish ranged from6.15-82.30g, and94.18%of them weighted from10.00to40.00g. Meanwhile,84.09%of the fish were from7cm to10cm in body length. The relationship between the standard length and diameters of scale was L=30.983R+10.904(r2=0.7895). The body length and body weight relationship was BW=0.0288L3.0266, r2=0.9219and the growth equations were L1=15.99(1-e-0.3904(t-0.1389)) and Wt=99.92(1-e-0.3904(t-0.1389))3.0266for body length and body weight respectively.2. The unfertilized mature eggs of O. sinensis, were oval, golden, sticky and2.1±0.5mm in diameter. The progress of embryonic developmental is composed of8stages: zygote period, cleavage period, blastula period, gastrula period, neural period, segmentation period, pharyngula period and hatching period. According to morphological features and other significant events, the embryonic developmental can be divided further into33periods. After432h, O. sinensis larvae were hatched with a total length of8.0±0.5mm at the water temperature of25±2℃, and the accumulative temperature could reach about11232℃·h. Around3-5d after hatching, the yolk sac of larva was absorbed completely. The fry were thickened up with bigger heads, thickened operculum, and protruding eyes. The second dorsal fin article was divided into two sections. The body type and color were similar to adult fish. The embryonic development time of O. sinensis is long, and organs have almost completed before hatching, which was obviously different from the early development process of other freshwater fish. This paper detailed the structure characteristics and temporal changes of O. sinensis, and recorded the time needed and effective accumulated temperature during embryonic development in different stages, which enrich the basic information of the development of early fish fry of O. sinensis.3. We used the anatomy and histology method to study the digestive tract of O. sinensis. The results showed that the digestive tract was consisted of buccopharyngeal cavity, esophagus, stomach, intestine (foregut, midgut and hindgut) and anus. The tissue of digestive tract was divided into mucosa, submucosa, muscularis and serosa. Comparing to the stomach and intestine, the esophagus had less mucosal fold. The stomach was U shape when expanded, with a large number of gastric glands distributed between the mucosal epithelium in the lamina propria in gastric cardia of the stomach and the stomach ontology. Helicobacter department organization structure was similar to foregut, with developed muscularis, rich goblet cells, but no gastric gland. The intestine had two obvious bendings in the body. The height of mucosal folds, thickness of submucosa and the number of goblet cells tapered before and after the bendings. This study first described the morphology and organization structure of digestive of the adult fish of O. sinensis, which can provide the basis data for its artificial breeding. |
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