Studies On The Development Of Digestive System And Enzyme Activity Of Chinese Sturgeon, Acipenser Sinensis

Chinese sturgeon (Acipenser sinensis Gray) is an endangered species under first rank protection in China, and its population has been decreased dramatically due to some natural and artificial reasons. At present, great progress had been made in the fields of morphology, reproductive biology and, especially, reproductive ecology and stock assessment of its spawning population. Yet, knowledge of the development of its digestive system and digestive enzyme remains rare. So we designed this experiment. The results are as following:1. The development of digestive system in Chinese sturgeonThe digestive organs of sturgeon from newly-hatched larvae to 120 day juvenile were observed. The mouth and anus of newly-hatched larvae were not opened yet. At the 4^th day after hatching, the differentiation of stomach and intestine was finished, and the functional gastric glands appeared. In the 9^th day, the number of spiral valve in valvula intestine increased, the rectum and anus appeared. During 10^th day to 11^th day after hatching, the liver has grown consummated and the pancreas differentiation completed, the spiral petal number is almost the same as the adults. Then the differentiation of digestive system completed. At the 40^th day after hatching, the digestive system developed perfectly.2. Morphological and histological studies on the digestive system of the Chinese sturgeonThe digestive system of the Chinese sturgeon contains oropharyngeal cavity, oesophagus, stomach, pyloric caeca, duodenum, valvula intestine, rectum, liver and pancreas. A few glands appear in oesophagus near cardiac region of the stomach. The pyloric division of stomach is muscular. There are about 17 cavities in horizontal section of pyloric caeca. Inside the pyloric caeca, the mucous folds are high enough to interlace into reticulation. The mucous folds in duodenum are also high and formed into numerous intestinal villus. There are about nine spiral valves in valvula intestine. The structure of rectum is same to that of normal intestine. Liver cell is irregular polygon and there are plenty of hepatin granules, which are addicted to eosin. Pancreas is a separate organ, with partial connection to liver. Both pyloric caeca, which belongs to teleostean, and valvula...