水体Cu2+对罗氏沼虾溞状幼体生长发育、存活及抗氧化功能的影响

Effects of waterborne Cu2+ on the growth, development, survival, and antioxidant function of Macrobrachium rosenbergii zoea larvae

  • 摘要: 【目的】 探究水体中Cu2+对罗氏沼虾溞状幼体生长发育、存活及抗氧化功能的影响,为罗氏沼虾健康养殖过程中的水质安全管理提供理论依据。【方法】 以罗氏沼虾健康Ⅰ期溞状幼体为试验对象,设对照组(Cu2+≤0.001 mg/L)和6个Cu2+浓度梯度处理组(0.0025、0.0100、0.0500、0.1000、0.1500和0.2000 mg/L),养殖25 d。每5 d于显微镜下观察溞状幼体所处的发育阶段,测量体长并统计存活率。采用试剂盒检测铜锌超氧化物歧化酶(Cu/Zn-SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GPx)活性及丙二醛(MDA)含量。提取总RNA并检测抗氧化基因Cu/Zn-SOD、CATGPx的相对表达量。【结果】 随着Cu2+浓度升高,罗氏沼虾溞状幼体体长日增长值和出苗率呈先升高后降低的变化趋势,0.1000 mg/L组溞状幼体体长日增长值和出苗率最高,且0.1000 mg/L组溞状幼体在各取样时间的存活率高于0.1500 mg/L和0.2000 mg/L组。0.0500 mg/L和0.1000 mg/L组溞状幼体蜕壳和变态发育较快,0.1500 mg/L和0.2000 mg/L组溞状幼体发育受阻,且0.2000 mg/L组溞状幼体无法完全变态发育为仔虾。对照、0.0025 mg/L、0.0100 mg/L、0.0500 mg/L和0.1000 mg/L组MDA含量随Cu2+处理时间延长整体上呈先升高后降低的变化趋势,相同Cu2+处理时间下各组无显著差异(P>0.05)。相同Cu2+处理时间下,Cu/Zn-SODCATGPx基因相对表达量随Cu2+浓度升高整体上呈先升高后降低的变化趋势,第5 d、第10 d和第15 d,0.1000 mg/L组Cu/Zn-SODCATGPx基因相对表达量均高于其他组,第20 d和第25 d,0.1500 mg/L和0.2000 mg/L组Cu/Zn-SODCATGPx基因相对表达量显著低于其他组(P<0.05)。【结论】 罗氏沼虾溞状幼体的生长发育、存活及抗氧化功能对Cu2+浓度具有明显的浓度依赖性效应。Cu2+≤0.1000 mg/L时,能通过诱导机体产生适度的抗氧化应激反应,促进罗氏沼虾溞状幼体生长发育并提高其存活率;Cu2+≥0.1500 mg/L时,Cu2+的促氧化作用占据主导,导致ROS大量积累,超出机体清除能力,引发严重的氧化损伤,最终抑制罗氏沼虾溞状幼体生长并导致其发育停滞。

     

    Abstract: 【Objective】 This study aimed to investigate effects of waterborne Cu2+ on the growth, development, survival, and antioxidant function of zoea larvae of Macrobrachium rosenbergii, so as to provide a theoretical reference for water quality safety management in the process of Macrobrachium rosenbergii aquaculture.【Method】 Using healthy Macrobrachium rosenbergii zoea larvae at stage I as tested subjects, the experiment set a control group (Cu2+≤0.001 mg/L) and six Cu2+ concentration gradient treatment groups (0.0025, 0.0100, 0.0500, 0.1000, 0.1500, and 0.2000 mg/L), with the culture period of 25 d. The developmental stages of zoea larvae in each group was observed every 5 d using a microscope, and their body length and survival rate were recorded. The activities of copper-zinc superoxide dismutase (Cu/Zn-SOD), catalase (CAT), glutathione peroxidase (GPx), and malondialdehyde (MDA) content were detected using kits. Total RNA was extracted, and the relative expressions of the antioxidant genes Cu/Zn-SOD CAT, and GPx were detected.【Result】 As Cu2+ concentration increased, the daily body length growth rate and emergence rate of zoea larvae of Macrobrachium rosenbergii showed a trend of first increasing and then decreasing. In the 0.1000 mg/L group, the zoea larvae exhibited the highest daily body length growth rate and emergence rate, and their survival rate was higher than that in the 0.1500 mg/L and 0.2000 mg/L groups at all sampling time. Zoea larvae in the 0.0500 mg/L and 0.1000 mg/L groups underwent faster molting and metamorphosis; in the 0.1500 mg/L and 0.2000 mg/L groups, zoea larvae experienced inhibited development; in the 0.2000 mg/L group, zoea larvae could not fully metamorphose into shrimp larvae. The MDA contents in the control group, 0.0025 mg/L, 0.0100 mg/L, 0.0500 mg/L, and 0.1000 mg/L groups generally showed a trend of first increasing and then decreasing, with no significant differences among the groups treated with Cu2+ for the same time (P>0.05). At the same Cu2+ treatment time, the relative expressions of Cu/Zn-SODCAT, and GPx genes generally showed a trend of first increasing and then decreasing as the Cu2+ concentration increased: on 5 d, 10 d, and 15 d, the relative expressions of Cu/Zn-SODCAT, and GPx genes in the 0.1000 mg/L group were higher than those in other groups; on 20 d and 25 d, the relative expressions of Cu/Zn-SODCAT, and GPx genes in the 0.1500 mg/L and 0.2000 mg/L groups were significantly lower than those in other groups (P<0.05).【Conclusion】 The growth, development, survival, and antioxidant function of zoea larvae of Macrobrachium rosenbergii exhibit an obvious concentration-dependent effect on Cu2+concentration. When Cu2+≤0.1000 mg/L, it can induce a moderate antioxidant stress response, thus promoting the growth and development of zoea larvae of Macrobrachium rosenbergii and improving their survival rate. When Cu2+≥0.1500 mg/L, the domination of Cu2+ pro-oxidative effect of leads to a large (reactive oxygen species) ROS accumulation that exceeds the body’s clearance capacity, causing severe oxidative damage, thereby ultimately causing growth inhibition and causing developmental stagnation of zoea larvae of Macrobrachium rosenbergii.

     

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