摘要
氮代谢是鱼类生理学领域研究的热点问题之一,当前对盐碱等特殊生境下鱼类氮废物的排泄机制仍不清晰。氨和尿素是鱼类氮排泄的主要形式,氮排泄主要受盐度、碱度、温度、摄食、运动等多种因素的影响。根据近年来国内外对鱼类氮排泄的研究进展,就鱼类氮代谢中氨和尿素排泄的一般规律、影响鱼类氮排泄的主要因素及盐碱水环境中鱼类独特氮代谢途径进行了归纳和总结,并提出了未来的研究重点。氮排泄机制的转变是鱼类适应盐碱环境的重要生理途径,我国拥有大量的盐碱水域和盐碱土著鱼类,开展盐碱土著鱼类氮排泄研究,揭示盐碱水环境中鱼类氮排泄机制,将为鱼类耐盐碱机制的揭示提供基础数据。
Nitrogen metabolism is one of the most sensitive physiological systems showing adaptive changes in response to environmental variations.Although nitrogen metabolism has been a subject of considerable research,it’s still unclear for fish nitrogen excretion mechanisms in saline-alkaline water.Ammonia and urea are the main products of protein and nucleotide metabolism and excreted as nitrogen wastes.Nitrogen excretion of fish is influenced by food composition,nitrogen intake,pH,salinity,temperature,and special behaviors.Most teleost fishes excrete ammonia as major nitrogenous end product in their aquatic habitat.However in circumstances such as high ambient alkalinity and pH,fishes can hardly excrete ammonia and toxic ammonia is concentrated in the blood and body tissues.Some fish take special nitrogen metabolism strategy when exposed to high saline-alkaline conditions.Such as,Tilapia graham survives in180mmol·L-1high alkaline water through excreting all nitrogenous waste as urea with high tolerance to plasma ammonia;Chalcalburnus tarichi excrete nitrogenous waste partly as urea and ammonia with high plasma ammonia tolerance;Oncorhynchus clarki henshawi could decrease ammonia excretion by low metabolism in high alkaline environment;Opsanus beta decreases nitrogen waste toxic by converting ammonia to free amino acid;while Gymnocypris przewalskii could excrete most of nitrogenous wastes as ammonia even in high saline-alkaline water by rebuilting ammonia gradient.The total saline-alkaline land area in China is about99.13million hectares,distributed throughout the northern China,coastal areas and areas along the north bank of the Yangtze River.About45.87million hectares of saline-alkaline water areas are distributed around these saline-alkaline lands,most of which are athalassic and characterized by a high pH value in excess of8.8associated with high carbonate alkalinity concentrations,and various types of ion imbalances.In such kinds of saline-alkaline water body survives many high saline-alkaline-tolerance species such as Gymnocypris przewalskii and Leuciscus waleckii Dybowski,which provides fantastic experimental fishes for nitrogen metabolism studies.This review summarizes the recent research progresses on ammonia and urea excretion,the effects of salinity and alkalinity on ammonia and urea excretion.It will provide ideas to better understand the nitrogen metabolism and future study advices on the response of the nitrogen metabolism in the saline-alkaline water environment.
作者
么宗利
衣晓飞
来琦芳
周凯
高鹏程
YAO Zong-li;YI Xiao-fei;LAI Qi-fang;ZHOU Kai;GAO Peng-cheng(Key Laboratory of East China Sea Fishery Resources Exploitation, Ministry of Agriculture and Rural Affairs, Engineering Research Center for Saline-alkaline Water Fisheries,East China SeaFisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai 200090, China)
出处
《海洋渔业》
CSCD
北大核心
2018年第6期740-751,共12页
Marine Fisheries
基金
中央级公益性科研院所基本科研业务费专项(中国水产科学研究院)(2016HY-ZD0601)
上海市科学技术委员会科研计划项目(14ZR1449800)
关键词
氮排泄
氨
尿素
盐碱
鱼类
nitrogen metabolism
ammonia
urea
saline-alkaline environment
fish
