盐碱胁迫对尼罗罗非鱼血清渗透压、离子浓度及离子转运酶基因表达的影响

Effects of salinity-alkalinity on serum osmolality,ion concentration and mRNA expression of ion transport enzymes of Oreochromis niloticus

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 change processes in adaptation to salinity and alkalinity water, Oreochromis niloticus were divided into four groups and directly transferred into four salinity-alkalinity treatments （ A ： salinity 10,1 g/L NaHCO3 ; B ： salinity 10,2 g/L NaHCO3 ; C ： salinity 15,1 g/L NaHCO3 ; D ： salinity 15,2 g/L NaHCO3 ） from freshwater, and the acute changes of serum osmolality, serum Na ^＋ , K^＋, C1^- concentration and mRNA expression of Na^ ＋ -K ^＋-ATPase （NKA）and carbonic anhydrase（CA） in gill of different treatments were observed at 0,6, 12,24,36,48,72 and 96 h post-transfer, respectively. Results showed that the changes of serum osmolality, serum Na ＋, K ＋ , C1 - concentration, and NKA, CA gene mRNA expression were relevant to the salinity-alkalinity stress levels. Meantime, these parameters shared a similar ＂up-peak-down＂ change trend. The serum osmolality in B,D treatments reached the peak at 24 h, while A, C treatments at 36 h. Serum Na^＋, K^＋ , C1^- concentration in all treatments reached the peak at 24 h. The highest NKA gene mRNA expression in B, D treatments was detected at 36 h, while 24 h in A and C treatments. The highest CA gene mRNA expression in B, C and D treatments was observed at 24 b. These results showed O. niloticus could adapt to salinity-alkalinity water to a certain degree, and NKA and CA were involved in ion transportations and osmolality balance under salinity-alkalinity stress.