Biochemical responses of two Erythrinidae fish to environmental ammonia

Brazilian Journal of Biology

G. Moraes²  V. L. P. Polez²  G. K. Iwama¹ 

[1] ,Universidade Federal de São Carlos Departamento de Genética e Evolução São Carlos SP ,Brazil

关键词: Hoplias malabaricus;    Hoplerythrinus unitaeniatus;    ammonia;    biochemical adaptation;    fish;    Ornithine-urea cycle enzymes;    Hoplias malabaricus;    Hoplerythrinus unitaeniatus;    amônia;    adaptação bioquímica;    peixe;    enzimas do ciclo Ornitina-urea;   

DOI  :  10.1590/S1519-69842004000100011

来源: SciELO

【 摘 要 】

The non-ionized form of ammonia is very toxic to many aquatic species. It is especially important in several aspects of fish biology. A large range of organismal strategies for coping with environmental stressors is usually observed in living organisms. Among those, the responses for managing chemical stressors are well studied. The present work compares biochemical responses of two evolutionarily close species, Hoplias malabaricus and Hoplerythrinus unitaeniatus, exposed to environmental ammonia. Adult fish were submitted to 1.0 mg/L of ammonium chloride for 24 hours, and plasma ammonia and urea levels were determined. The activities of OUC enzymes OCT and ARG, and the accessory enzyme GS, were quantified in liver extract and are expressed below in mumol/min/mg of wet tissue. Increases in OUC enzymes (GS from 1.14 to 2.43, OCT from 0.81 to 1.72, and ARG from 3.15 to 4.23), plasma ammonia (from 0.95 to 1.42 mmol/L), and plasma urea (from 0.82 to 1.53 mmol/L) were observed (p < 0.05) in H. malabaricus exposed to 1 mg/L of ammonia chloride. The GS in H. unitaeniatus increased from 1.43 to 1.84, however the OCT, ARG, and plasma urea from H. unitaeniatus did not change. These data indicate that each species responds differently to the same environmental stressor.

【 授权许可】

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