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为了解鱼类适应盐碱水环境的生理变化机理,将尼罗罗非鱼从淡水直接转入4个不同盐碱混合梯度组(A组:盐度10,碱度1 g/LNaHCO3;B组:盐度10,碱度2 g/LNaHCO3;C组:盐度15,碱度1 g/LNaHCO3;D组:盐度15,碱度2 g/LNaHCO3)中进行为期96 h的急性胁迫实验,分别检测胁迫后0、6、12、24、36、48、72和96 h时尼罗罗非鱼的血清渗透压、血清Na+、K+、Cl-浓度以及鳃中Na+-K+-ATP酶(NKA)和碳酸酐酶(CA)基因相对表达量的变化过程。结果显示,血清渗透压、离子浓度以及鳃中NKA基因和CA基因mRNA表达量变化程度均与其盐碱胁迫浓度间呈正相关,变化过程随着实验时间推移均呈现为先升、后降,最后趋于平稳。B、D组血清渗透压峰值出现在24 h,A、C组出现在36 h。血清Na+、K+、Cl-浓度均在24 h达到峰值。B、D组NKA基因mRNA表达峰值出现在24 h,A、C组出现在36 h;除A组外,其余各组CA基因mRNA表达峰值时间出现在24 h。研究表明,尼罗罗非鱼具有一定的盐碱适应能力,盐碱胁迫下NKA、CA是参与离子转运、渗透压调节的重要转运酶。
To understand the physiological mechanism of fish adaptation to saline-alkali environment, Nile tilapia (Tilapia nilotica) were directly transferred from freshwater to four different salt-alkali mixed gradient groups (group A: salinity 10, alkalinity 1 g / L NaHCO 3; group B : Salinity 10, alkalinity 2 g / LNaHCO3; group C: salinity 15, alkalinity 1 g / LNaHCO3; group D: salinity 15, alkalinity 2 g / The serum osmolality, serum Na +, K + and Cl- concentrations at 0, 6, 12, 24, 36, 48, 72 and 96 h after stress were measured, and Na + -K + -ATPase ) And carbonic anhydrase (CA) gene relative expression level changes. The results showed that there was a positive correlation between serum osmotic pressure, ion concentration and the expression level of NKA and CA mRNAs in gill and its concentration of saline-alkali stress, and the change process increased first and then decreased with the increase of experimental time In a stable. Serum osmolality peak appeared in group B and group D at 24 h, group A and group C at 36 h. Serum Na +, K +, Cl- concentrations peaked at 24 h. In group B and group D, the expression of NKA gene mRNA appeared at 24 h, and in group A and C at 36 h. The peak time of CA mRNA expression appeared at 24 h in each group except A group. Studies have shown that Nile tilapia have some ability to adapt to salt and alkali. NKA and CA under salt and alkali stress are important transport enzymes involved in ion transport and osmotic regulation.