|关键词: 叶硝水母 盐度 消化酶 螅状体 水母体
|Influences of Three Salinities on the Growth Performance and Digestive Enzyme Activities at Different Stages of Phyllorhiza chinensis
YANG Cui-hua, ZHANG An-qi, JIANG Yu-li, QI Ji-guang
Qingdao Marine Science and Technology Museum
|This study aimed to evaluate that culture salinity levels affected on the growth and digestive enzyme activities of Phyllorhiza chinensis. Three salinity levels (12‰, 22‰ and 32 ‰) were used in cultured jellyfish at three stages of scyphula, juvenile and adult. Results suggested that salinity had changed jellyfish physiological performance about growth and digestion. The scyphula was capable of growth and asexual reproduction in three salinity levels. All digestive enzyme activities (pepsin, cellulase, lipase and amylase) of scyphula were significantly higher than those of juvenile and adult (P＜0.01). Appropriate salinity levels had improved growth, survival and digestive enzyme expression in artificial conditions. Salinity 12 was beneficial to the developed body and adult breeding and further desalting, and it could be used as the preservation salinity of scyphula for inland aquarium and home ornamental jellyfish. In salinity 22 jellyfish showed a good state of asexual reproduction, growth performance and vitality, and the activities of four digestive enzymes were the highest, which could be used as a suitable salinity for artificial breeding. The content of pepsin was the highest among the four digestive enzymes due to the high protein in artemia nauplii and the high protein demands. P.chinensis had a stronger ability to degrade protein than cellulose, dietary fats and starches. It was suggested to appropriately increase the ratio of protein in daily bait to reduce the feeding cost. The analyses of results revealed the scyphula showed strong adaptability to external salinity changes, and its cell osmotic regulation ability was stronger than the developed body and adult. Further desalination could be used in inland aquariums and home viewing jellyfish. Artificial domestication of freshwater was possible to improve the economic benefits in the future. Scyphula could asexual reproduce to permanently maintain its characteristic of feeding in fresh water and had strobilated in a certain condition to produce medusa which could be fed in fresh water. And this study provided a theoretical basis for the adjustment of bait, the activation and adaptation mechanism of P.chinensis to environment and its commercial cultivation and development. This test detected a certain cellulase in the digestive cavity. However, further study was required that jellyfish had a complete cellulase system which could produce endogenous cellulose or had symbiotic fungus and bacterial, as zooxanthellae, which could produce exogenous cellulose.
|Key words: Phyllorhiza chinensis salinity digestive enzyme scyphistoma medusa