黄颡鱼氨中毒机制研究及其外源牛磺酸调控

The previous studies showed that environmental ammonia has negative effect on the physiology and immunity in fish. The mechanism that ammonia poisoning leads the fish death is still not clear, it is necessary to find a nutritional method to eliminate or relieve ammonia effect. Metabolite fingerprint of yellow catfish brain (control group V.S. experimental group: intraperitoneal injection of ammonium acetate, LC50) will be obtained using the method of nuclear magnetic resonance (NMR) and gas chromatography mass spectrometry (GC-MS). Pattern recognition based on multivariate statistical analysis will be used to detect differential metabolites, the key enzyme and regulate factor can be identified, and thereby to find more negative metabolic pathways. The evaluation that inflammatory reaction and oxidative damage can lead to animal death will be created. This process includes enzyme activity detection, tissue section, molecular cloning, and fluorescent quantitative expression, etc. According to nutrition intervention experiment (in vitro and in vivo), we will further demonstrate the effect of exogenous taurine on ammonia poisoning of yellow catfish. We are expecting to put forward several kinds of nutritional strategies that will enable eliminate or relieve stress in yellow catfish farms. Our results of study will provide theoretical basis for developing an artificial compounding feeds.

前期研究表明，环境氨氮对鱼类的生理和免疫力具有不利影响。迄今，鱼类氨中毒致死机制尚未阐明，寻找消除或缓解氨中毒的营养学策略是一个重要的新课题。本项目拟采用核磁共振（NMR）和气质联用（GC-MS）相结合的分析方法，获取正常组和实验组（腹腔注射半致死浓度醋酸铵）黄颡鱼大脑中代谢产物的指纹图谱，运用模式识别技术筛选及指认差异代谢产物，推导造成黄颡鱼氨中毒的关键代谢酶及调控因子，全面评估其可能诱导的不良生理反应。并就鱼类氨中毒过程中最可能出现的不良生理反应，如炎性反应和氧化损伤机制进行重点讨论，采用酶活性检测、病理组织切片、分子克隆及荧光定量表达等技术，评估其导致动物死亡的可能性。在此基础上，结合体外、体内营养干预实验，进一步论证外源牛磺酸对黄颡鱼氨中毒的缓释效果。综合提出养殖生产中黄颡鱼氨中毒的营养学缓释策略，为鱼类人工配合饲料的研发提供理论依据。

本项目分析了不同食性鱼类氨中毒的差异；采用多组学联合分析，筛选正常组和实验组黄颡鱼大脑和肝脏差异基因、蛋白及代谢产物，推导造成黄颡鱼氨中毒的关键代谢酶及调控因子；采用酶活性检测、病理组织切片、分子克隆及荧光定量表达等技术，就黄颡鱼氨中毒过程中出现的炎性反应和氧化损伤进行重点讨论，发现氨中毒导致鱼类死亡的原因，可能与氧化损伤诱发的炎症反应和细胞凋亡有关；采用摄食生长实验，进一步论证投食频率、外源牛磺酸、丙谷二肽和诺丽果酵素对黄颡鱼氨中毒的缓释效果。综合提出养殖生产中黄颡鱼氨中毒的营养学缓释策略，为鱼类人工配合饲料的研发提供理论依据。