臭氧对条石鲷幼鱼鳃组织结构和抗氧化系统的影响

臭氧(O₃)在工厂化养殖水处理中有较高的应用价值,为了解臭氧对条石鲷幼鱼的影响,采用自制的臭氧毒性试验装置(授权利号:ZL 200920122441.3),对条石鲷幼鱼进行了不同质量浓度(0、0.08、0.13、0.17、0.22、0.28和0.32 mg/L)和不同时间(0.5、1、6、12、18和24 h)的急性胁迫试验,并分析了臭氧对条石鲷幼鱼的行为响应、半致死浓度、幼鱼鳃的组织形态学、酶活性等的影响。结果表明,随着臭氧胁迫浓度的升高,条石鲷幼鱼在水层中的分布位置逐渐上移,呼吸频率逐渐加快,受惊反应逐渐迟缓;条石鲷幼鱼的开始死亡时间与臭氧浓度负相关,12 h的半致死方程为Y=16.815 8+20.340 5X(r=0.998 7),半致死浓度为0.262 5 mg/L。24 h的半致死方程为Y=17.614 1+17.898 3X(r=0.950 0),半致死浓度为0.197 4 mg/L;条石鲷幼鱼鳃SOD和GPX活性与臭氧胁迫时间和胁迫浓度负相关,并都在胁迫24 h、质量浓度0.32 mg/L时降至谷值;MDA含量与臭氧胁迫时间和胁迫浓度正相关,并在胁迫24 h、质量浓度0.32 mg/L时达到峰值;在臭氧胁迫下,条石鲷幼鱼的鳃小片细胞排列不规则并萎缩,鳃小片上皮细胞脱落或粘滞于鳃小片间,鳃小片末端膨大,鳃丝血管固缩无腔或变空腔,管壁粗糙、干缩,血细胞固缩、坏死,零散分布或紧贴血管壁。

Effects of ozone on the histological structure and the antioxidant systems in gills of juvenile Oplegnathus fasciatus

Ozone(O₃)was frequently used in water treatment for industrial aquiculture.Therefore,in order to understand the impacts to ozone on aquiculture species Oplegnathus fasciatus,acute exposure of ozone on juvenile was conducted using self-designed ozone toxicity experimental set-up(authorized Patent Number:ZL 200920122441.3)with various exposure doses(0,0.08,0.13,0.17,0.22,0.28 and 0.32 mg/L)and durations(0.5,1,6,12,18 and 24 h).The impacts of ozone on behavioral responses,mortality,gill histomorphology,and antioxidant enzyme activities were investigated in present study.The results showed the distribution of juvenile O.fasciatus tends to move up to upper layer with increasing ozone exposure doses,in the meanwhile,the respiration rate was sped up and the startle response was slowed down.Moreover,evident dose-response relationship was found between mortality and ozone concentration.The regression equations between mortality and ozone dose at 12 and 24 hours were Y=16.815 8+20.340 5X(r=0.998 7)and Y=17.614 1+17.898 3X(r=0.950 0),respectively.The half lethal concentration(LD₅₀)at 12 and 24 hours were 0.262 5 and 0.197 4 mg/L,respectively.Compared to control,with the increase of ozone exposure dose and duration,the activities of superoxide dismutase(SOD)and glutathione peroxdase(GPX)in gills of juvenile O.fasciatus were downgraded,while the quantity of malonaldehyde(MDA)was upgraded in experimental trials.Under ozone exposure stress,the gill lamella of juvenile O.fasciatus was shown to be in irregular array and some necrosis phenomenon was detected.Shedding epithelial cells from gill lamella were also observed.The vessel of gill filaments was pycnosis or even became cavum.The vessel wall was found to be rough and shrunk,with pyknotic and necrotic blood cells attached.