Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China.
Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China.
Ecotoxicol Environ Saf. 2018 Mar;149:203-210. doi: 10.1016/j.ecoenv.2017.11.052. Epub 2017 Dec 19.
pH variation could cause a stress response in euryhaline penaeids, we evaluated the mortality, growth performance, osmoregulation gene expression, digestive enzyme activity, histology, and resistance against Vibrio parahemolyticus of white shrimp Litopenaeus vannamei reared under conditions of gradual changes to a low-pH environment (gradual-low pH, 6.65-8.20) or a high-pH environment (gradual-high pH, 8.20-9.81) versus a normal pH environment (8.14-8.31) during a 28-d experiment. Consequently, under gradual-high pH, the cumulative mortality rate (CMR) rose with time until 39.9% on days 28; the weight gain percentage (WGP) and length gain percentage (LGP) decreased continuously. However, under gradual-low pH, the CMR of shrimp stabilized at 6.67% during 7-28 d; the WGP and LGP decreased first and then returned to normal. These results indicated that L. vannamei displayed a moderate tolerance to gradual-low pH, compared with gradual-high pH. Under gradual-low pH, the Na/K-ATPase, cytoplasmic carbonic anydrase (CAc), and glycosyl-phosphatidylinositol-linked carbonic anhydrase (CAg) transcripts of shrimp increased continuously or then back to normal; the amylase, lipase, and trypsin activities decreased first and then returned to normal or increased; the hepatopancreases and midguts showed histopathological lesions first and then got remission. Thus, the major adaptation mechanism of shrimp to gradual-low pH might be its high osmoregulation ability, which made shrimp achieve a new, balanced steady-state, then promoted longer intestinal villi and recuperative hepatopancreases of shrimp with enhanced digestive enzyme activities to increase nutrient absorption after long-term exposure. Meanwhile, the enhanced resistance against V. parahemolyticus under gradual-low pH would probably inhibit disease outbreak in the shrimp farming.
pH 值的变化可能会引起广盐性对虾产生应激反应，我们评估了凡纳滨对虾在逐渐变化到低 pH 值环境（逐渐低 pH 值，6.65-8.20）或高 pH 值环境（逐渐高 pH 值，8.20-9.81）下的死亡率、生长性能、渗透调节基因表达、消化酶活性、组织学和对副溶血弧菌的抗性，与正常 pH 值环境（8.14-8.31）相比，在 28 天的实验期间。结果表明，在逐渐高 pH 值条件下，累积死亡率（CMR）随时间增加，直到第 28 天达到 39.9%；体重增加率（WGP）和体长增加率（LGP）持续下降。然而，在逐渐低 pH 值条件下，虾的 CMR 在第 7-28 天稳定在 6.67%；WGP 和 LGP 先下降然后恢复正常。这些结果表明，与逐渐高 pH 值相比，凡纳滨对虾对逐渐低 pH 值表现出中等耐受能力。在逐渐低 pH 值下，虾的 Na+/K+-ATP 酶、细胞质碳酸酐酶（CAc）和糖基磷脂酰肌醇连接的碳酸酐酶（CAg）转录物持续增加或恢复正常；淀粉酶、脂肪酶和胰蛋白酶活性先下降然后恢复正常或增加；肝胰腺和中肠首先出现组织病理学病变，然后缓解。因此，虾适应逐渐低 pH 值的主要机制可能是其高渗透压调节能力，这使虾达到了一个新的、平衡的稳定状态，然后促进了虾的长期暴露后，更长的肠绒毛和恢复性的肝胰腺，提高了消化酶的活性，增加了营养物质的吸收。同时，在逐渐低 pH 值下，虾对副溶血弧菌的抵抗力增强可能会抑制虾养殖中的疾病爆发。
