title: Ammonia toxicity induces glutamine accumulation, oxidative stress and immunosuppression in juvenile yellow catfish Pelteobagrus fulvidraco.
abstract: A study was carried to test the response of yellow catfish for 28 days under two ammonia concentrations. Weight gain of fish exposure to high and low ammonia abruptly increased at day 3. There were no significant changes in fish physiological indexes and immune responses at different times during 28-day exposure to low ammonia. Fish physiological indexes and immune responses in the treatment of high ammonia were lower than those of fish in the treatment of low ammonia. When fish were exposed to high ammonia, the ammonia concentration in the brain increased by 19-fold on day 1. By comparison, liver ammonia concentration reached its highest level much earlier at hour 12. In spite of a significant increase in brain and liver glutamine concentration, there was no significant change in glutamate level throughout the 28-day period. The total superoxide dismutase (SOD), glutathione peroxidase (GPX) and glutathione reductase (GR) activities in the brain gradually decreased from hour 0 to day 28. Liver SOD, GPX and GR activities reached the highest levels at hour 12, and then gradually decreased. Thiobarbituric acid reactive substance brain and liver content gradually increased throughout the 28-day period. Lysozyme, acid phosphatase and alkaline phosphatase activities in the liver reached exceptionally low levels after day 14. This study indicated that glutamine accumulation in the brain was not the major cause of ammonia poisoning, the toxic reactive oxygen species is not fully counter acted by the antioxidant enzymes and immunosuppression is a process of gradual accumulation of immunosuppressive factors.
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo 315211, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo 315211, China.
authors.forename: Shiyan
authors.initials: S
authors.lastname: Gong
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo 315211, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Li
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo 315211, China.
authors.forename: Lixia
authors.initials: L
authors.lastname: Yuan
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo 315211, China.
authors.forename: Fanxing
authors.initials: F
authors.lastname: Meng
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo 315211, China. Electronic address: wrx_zjou@163.com.
authors.forename: Rixin
authors.initials: R
authors.lastname: Wang
mesh_terms: D000641:Ammonia / Q000008:administration & dosage / Q000378:metabolism / Q000506:poisoning*; D000643:Ammonium Chloride / Q000008:administration & dosage; D000818:Animals; D017756:Aquaculture; D001921:Brain / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D002397:Catfishes / Q000254:growth & development / Q000276:immunology / Q000502:physiology*; D002681:China; D004305:Dose-Response Relationship, Drug; D029941:Fish Proteins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism; D005973:Glutamine / Q000819:agonists / Q000378:metabolism*; D007113:Immunity, Innate / Q000187:drug effects; D015227:Lipid Peroxidation / Q000187:drug effects; D008099:Liver / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D018384:Oxidative Stress; D010088:Oxidoreductases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D011897:Random Allocation; D014018:Tissue Distribution; D066007:Toxicokinetics; D014874:Water Pollutants, Chemical / Q000008:administration & dosage / Q000378:metabolism / Q000506:poisoning*; D015430:Weight Gain / Q000187:drug effects
chemical_list: D029941:Fish Proteins; D014874:Water Pollutants, Chemical; D000643:Ammonium Chloride; D005973:Glutamine; D000641:Ammonia; D010088:Oxidoreductases
keywords: Ammonia; Glutamine; Immunosuppression; Oxidative stress; Yellow catfish