Machado Marina, Arenas Francisco, Svendsen Jon C, Azeredo Rita, Pfeifer Louis J, Wilson Jonathan M, Costas Benjamín
Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Matosinhos, Portugal.
Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal.
Front Physiol. 2020 Jan 31;11:26. doi: 10.3389/fphys.2020.00026. eCollection 2020.
Increasing water CO, aquatic hypercapnia, leads to higher physiological pCO levels in fish, resulting in an acidosis and compensatory acid-base regulatory response. Senegalese sole is currently farmed in super-intensive recirculating water systems where significant accumulation of CO in the water may occur. Moreover, anthropogenic releases of CO into the atmosphere are linked to ocean acidification. The present study was designed to assess the effects of acute (4 and 24 h) and prolonged exposure (4 weeks) to CO driven acidification (i.e., pH 7.9, 7.6, and 7.3) from normocapnic seawater (pH 8.1) on the innate immune status, gill acid-base ion transporter expression and metabolic rate of juvenile Senegalese sole. The acute exposure to severe hypercapnia clearly affected gill physiology as observed by an increase of NHE3b positive ionocytes and a decrease of cell shape factor. Nonetheless only small physiological adjustments were observed at the systemic level with (1) a modulation of both plasma and skin humoral parameters and (2) an increased expression of HIF-1 expression pointing to an adjustment to the acidic environment even after a short period (i.e., hours). On the other hand, upon prolonged exposure, the expression of several pro-inflammatory and stress related genes was amplified and gill cell shape factor was aggravated with the continued increase of NHE3b positive ionocytes, ultimately impacting fish growth. While these findings indicate limited effects on energy use, deteriorating immune system conditions suggest that Senegalese sole is vulnerable to changes in CO and may be affected in aquaculture where a pH drop is more prominent. Further studies are required to investigate how larval and adult Senegalese sole are affected by changes in CO.
水中二氧化碳增加，即水生高碳酸血症，会导致鱼类生理上的pCO水平升高，从而引发酸中毒和代偿性酸碱调节反应。塞内加尔鳎目前在超密集循环水系统中养殖，水中可能会大量积累二氧化碳。此外，人为向大气中排放二氧化碳与海洋酸化有关。本研究旨在评估从正常碳酸海水（pH 8.1）急性（4小时和24小时）和长期暴露（4周）于由二氧化碳驱动的酸化（即pH 7.9、7.6和7.3）对幼年塞内加尔鳎的先天免疫状态、鳃酸碱离子转运体表达和代谢率的影响。急性暴露于严重高碳酸血症明显影响鳃的生理功能，表现为NHE3b阳性离子细胞增加和细胞形态因子降低。尽管如此，在系统水平上仅观察到微小的生理调节，包括（1）血浆和皮肤体液参数的调节，以及（2）HIF-1表达增加，表明即使在短时间（即数小时）后也能适应酸性环境。另一方面，长期暴露后，几种促炎和应激相关基因的表达增强，鳃细胞形态因子随着NHE3b阳性离子细胞的持续增加而加重，最终影响鱼类生长。虽然这些发现表明对能量利用的影响有限，但免疫系统状况恶化表明塞内加尔鳎易受二氧化碳变化的影响，并且在pH下降更为明显的水产养殖中可能会受到影响。需要进一步研究来调查幼体和成体塞内加尔鳎如何受到二氧化碳变化的影响。
