2种新型消毒剂在虹鳟幼鱼养殖中的应用效果研究

为研究2种新型消毒剂在虹鳟养殖中的应用效果,进行了这2种消毒剂对常见病原菌的抑菌效果、对虹鳟幼鱼的急性毒性以及对养殖水质影响的试验。通过体外抑菌试验发现,这2种新型消毒剂对爱德华氏菌(Edwardsiella)、哈维氏弧菌(Vibrio harveyi)、杀鲑气单胞菌(Aeromonas salraonicida)、金黄色葡萄球菌(Staphylococcus aureus)等致病菌具有明显的杀灭、抑制作用,其中消毒剂2(主要成分是有机季铵盐、碘和碘化物)的作用更明显。采用48 h半静水法分别分析这2种消毒剂对体质量为(8. 0±0. 3) g的虹鳟幼鱼产生的急性毒性效应,当消毒剂1(主要成分是有机季铵盐和有效碘)的质量浓度≤1. 65 mg/L、消毒剂2的质量浓度≤1. 28 mg/L时,对虹鳟幼鱼无毒性伤害作用。使用这2种消毒剂后,水体中总氮、挥发性酚、硫化物、总悬浮物等的含量均保持在合理范围内,对养殖动物的健康及环境均未产生负担。通过高通量测序分析,2种消毒剂进入环境后会对细菌菌群结构产生不同影响,且存在剂量-效应关系。结果表明,这2种新型消毒剂均可在虹鳟等水产动物养殖中使用。     

海水人工湿地脱氮效果与系统内基质酶、微生物分析

利用人工湿地系统探讨了海水养殖外排水中不同形态氮的去除效果,分析了系统内部微生物空间分布、基质酶活性对氮去除效率的影响,深入研究了系统内部各微生物间相互作用、基质酶活性与微生物空间分布关系。选择互花米草为人工湿地植物,种植密度为64株/m2;基质填料选择细纱、高炉矿渣和珊瑚石。在3种不同工况条件下,研究人工湿地系统中氮的去除效果、微生物数量和基质酶活性。结果显示,系统对 TN、NH4-N 平均去除率分别为(25.02±12.69)%、(82.91±17.51)%;系统中不同基质层次的微生物数量和脲酶、脱氢酶活性不同,基质中、上层好氧微生物数量和脲酶、脱氢酶活性显著大于下层,系统下行池中、上层硝化细菌、亚硝化细菌显著高于下层,中、上层反硝化细菌数量明显低于下层;细菌总数与 TN(R2=0.50)和 NH4-N(R2=0.61)去除率存在一定正相关性,基质脲酶与 TN 去除率存在显著正相关性(R2=0.86)。研究结果将有助于理解海水人工湿地处理系统中氮的迁移转化机制。     

丙酮酸钠对硝化细菌制剂活性的影响

分别研究丙酮酸钠对淡水型和海水型硝化细菌制剂中氨氧化细菌(AOB)和亚硝酸盐氧化细菌(NOB)活性的影响。结果表明,丙酮酸钠能明显提高AOB活性,缩短其对环境的适应时间。在丙酮酸钠浓度为7mmol/L时,12h海水型硝化细菌和淡水型硝化细菌对氨氮去除率分别为54.7%和63.4%,是对照组的8.82倍和2.98倍。丙酮酸钠对NOB活性影响与AOB存在不同,其中,丙酮酸钠对海水型硝化细菌NOB有抑制作用,并随其浓度升高而增大,但对淡水型硝化细菌NOB活性影响较小。     

硝化菌剂对多刺裸腹溞的急性毒性试验研究

硝化细菌是一种在水产养殖中应用较为普遍的微生态制剂,对于养殖水体水质净化至关重要。同时各种微生物制剂的应用对自然环境所造成的安全性影响也十分值得研究和关注。本研究选择多刺裸腹溞作为受试物,研究不同浓度硝化细菌菌剂对受试物24 h、48 h急性毒性。结果表明,24 h LC50为1.15×1025mg/L、48 h LC50为1.00×1022mg/L,说明硝化细菌菌剂对水溞的急性毒性影响较小。     

铁离子对固定化和游离态硝化细菌活性的影响

采用聚乙二醇—海藻酸钠—氯化钙方法包埋淡水型和海水型硝化细菌,比较分析铁离子对固定化和游离态硝化细菌中氨氧化菌和亚硝酸盐氧化菌活性的影响。结果表明,Fe~(3+)对游离态硝化细菌的影响大于固定化硝化细菌,当Fe~(3+)浓度为1mg·L~(-1)时固定化淡水硝化细菌氨氧化活性最高,游离态淡水型氨氧化活性受Fe~(3+)影响较大,120h后明显降低,但对亚硝酸盐氧化活性影响均较小。在不同Fe~(3+)浓度条件下,固定化海水硝化细菌氨氧化活性和亚硝酸盐氧化活性与不加Fe~(3+)组基本相同,而游离态海水型氨氧化和亚硝酸盐氧化活性均随Fe~(3+)浓度增大而略有降低。     

硝化细菌浓度及滤料对养殖水中氨氮处理效果的影响

分别研究了不同硝化细菌浓度(0、20、60、120 mL/100 L)和不同微生物滤料(珊瑚石、锅炉煤渣、牡蛎壳)对养殖水中氨氮处理效果的影响。结果显示,添加硝化细菌后,水体中的氨氮浓度呈现下降趋势,在8～12 h出现极低值后,开始上升,但上升速度较慢;随着水体中硝化细菌添加量的增加,水体中的氨氮浓度下降速度加快;水体中亚硝酸氮浓度呈现先上升后下降的趋势,并在4～6 h出现极高值,然后迅速下降,且硝化细菌添加量越高,下降速度越快。硝化细菌对以珊瑚石和锅炉煤渣为滤料的养殖水体中氨氮和亚硝酸氮的处理效果显著优于牡蛎壳,但珊瑚石和锅炉煤渣之间无显著差异。综合试验结果,应急水质处理时,硝化细菌菌剂的添加量以一次60 mL/100 L(或以活菌计数为1.2×109个/100 L)、间隔24 h添加1次为宜;经过脱硫筛选之后的锅炉煤渣可以作为循环水养殖用滤料。     

关于对虾育苗的技术之一PVP-Ⅰ消毒剂在对虾育苗和养成生产中的应用

本文通过PVP-Ⅰ养殖高效水体消毒剂(聚乙烯吡咯烷酮碘,含有效碘5%)与常规福尔马林、抗生素在对虾育苗和养成中对比试验,证明了PVP-Ⅰ在不同品种育苗和养虾过程中对病毒、弧菌、真菌等有较强的杀灭及抑制作用.     

养殖水循环净化系统中4种载体对硝化反应效果的影响

<正>在循环净化系统中,生物净化是不可或缺的组成部分,通过硝化细菌完成的两个短程硝化反应,将养殖水中主要有害物质氨,先转化为亚硝酸盐,再转化为对水生动物毒害作用微弱的硝酸盐,是生物净化的工作机理。由于硝化细菌是固定菌,需要固着于固态的载体上,不同的载体由于形态及理化性质不同,对硝化细菌的固着和繁衍产生影响,从而影响净化系统的工作效果,本实验旨在通过对采用4种不同载体材     

冰冻对硝化细菌制剂活性的影响

在实验室模拟条件下,研究冰冻对淡水型硝化细菌和海水型硝化细菌制剂中氨氧化细菌和亚硝酸盐氧化细菌活性的影响。结果表明,冰冻对淡水型硝化细菌和海水型硝化细菌制剂活性均有较为明显的抑制作用,且10d处理组的抑制作用高于5d处理组,对淡水型硝化细菌制剂活性的抑制作用大于海水型硝化细菌制剂。液体硝化细菌制剂在冬季运输和保存过程中要采取保温措施,以避免由于冰冻导致的菌剂活性降低。     

一株中度嗜盐反硝化细菌的分离鉴定及其代谢特性研究

从某海产养殖企业的水质净化单元中分离获取反硝化细菌,探明其对硝酸盐的代谢特性,旨在为高盐度养殖废水的脱氮处理提供耐盐型菌种。采用添加海水的反硝化细菌培养基,利用系列稀释法和平板划线法分离获取反硝化细菌,通过其形态特征和分子生物学特征进行鉴定,并在不同环境条件和营养条件下测定其反硝化活性。试验结果表明,分离筛选得到的反硝化菌株DN20为革兰氏阴性杆菌。该反硝化细菌为Halomonas属,其最佳代谢条件为温度30℃,盐度100,p H 7.5~8.5,C/N(质量比)4∶1。菌株DN20对NO_3~--N的半饱和常数(K_s)为94.09 mg/L,最大比反硝化速率(q_(max))为3.90 mg/(g·h)。     

四种消毒剂对摇蚊幼虫杀菌效果研究

为筛选四种鱼用消毒剂对摇蚊幼虫(Chironomid larvae)最适消毒条件,在单因素试验基础上,以消毒剂对摇蚊幼虫携带细菌相对灭菌率为考察指标进行正交试验;以消毒后摇蚊幼虫相对存活率、稀有鮈鲫(Gobiocypris rarus)对摇蚊幼虫平均摄食时间、消毒后未杀灭细菌种类为指标,综合评价消毒虫体质量。结果显示:浓度因子对聚维酮碘、新洁尔灭、高锰酸钾的相对灭菌率有极显著影响;时间因子对聚维酮碘的相对灭菌率影响极显著;温度因子对聚维酮碘的相对灭菌率影响极显著,对新洁尔灭影响显著;浓度、时间和温度因子均对戊二醛的相对灭菌率无显著影响;在实验室条件下,根据消毒剂对相对灭菌率的各影响因子主次顺序得到了四种消毒剂消毒摇蚊幼虫的最佳因子参数,其中高锰酸钾:消毒剂浓度60 mg/L,消毒温度28℃,消毒时间1.5 h;聚维酮碘:消毒温度24℃,消毒剂浓度150 mg/L,消毒时间1 h;新洁尔灭:消毒剂浓度3 200 mg/L,消毒温度24℃,消毒时间1 h;戊二醛:消毒温度28℃,消毒时间1.5 h,消毒剂浓度20 000 mg/L。四种消毒剂最佳消毒条件对摇蚊幼虫相对存活率及对稀有鮈鲫摄食效果影响不大;消毒后从不同来源的四份虫体样品共分离出未杀灭的细菌16种,主要隶属于气单胞菌属和不动杆菌属。     

Toxicity of Four Chemotherapeutic Agents to Rabbitfish Siganus rivulatus

As aquaculture evolves from extensive pond culture to intensive tank and cage systems, chemical dips and baths are increasingly being used to treat a concomitant increase in ectoparasitic and bacterial infestations. Some of the main disease‐causing agents are ectoparasites on the skin and gills of fish. Consequently, application of chemotherapeutics is increasing in aquaculture industries in order to control outbreaks of parasitic infestations. However, the toxic effect of commonly used chemotherapeutic agents on specific aquacultured fish species is often unknown. The present work was performed to test the effect of four commonly used chemical treatments on rabbitfish, Siganus rivulatus. The lethal concentrations for 50% of population (LC₅₀) of formalin, copper sulfate, potassium permanganate, and hydrogen peroxide for S. rivulatus juveniles treated for 1 h were assessed. Formalin and potassium permanganate tolerance values were determined by calculating 72‐h LC₅₀ values through probit analysis. The 72‐h LC₅₀ values for the formalin toxicity tests were 551.0 and 1.68 mg/L, respectively. LC₅₀ of copper sulfate and hydrogen peroxide could not be determined from the concentrations tested but were found to be >3 and >700 mg/L, respectively. Accordingly, treatment concentrations of formalin and potassium permanganate used for other fish species could be lethal to S. rivulatus, but the species appears to be quite tolerant to copper sulfate and hydrogen peroxide.     

Acute columnaris infection in channel catfish, Ictalurus punctatus (Rafinesque): efficacy of practical treatments for warmwater aquaculture ponds

Columnaris disease was induced in channel catfish, Ictalurus punctatus (Rafinesque), by bath exposure to four highly virulent isolates of Flavobacterium columnare. In untreated controls, mortality began 20 h after exposure and reached 100% by 48 h. Mortality in channel catfish given antibiotic treatments with oxytetracycline or a combination of sulphadimethoxine and ormetoprim in feed prior to bacterial challenge was zero with all four strains of F. columnare. Diquat (Zeneca Agricultural Products, Wilmington, DE, USA) was the most effective bath treatment; mortality with all four strains was zero. With potassium permanganate, chloramine-T, hydrogen peroxide and copper sulphate, bath treatment efficacy varied significantly among strains (P = 0.0346) and among treatments (P = 0.0033). Bath treatments with chloramine-T and potassium permanganate significantly reduced (P < 0.05) mortality from 100 to 75 and 69%, respectively, but copper sulphate and hydrogen peroxide treatments were not effective. Based on our results, oral antibiotics prevented columnaris disease but, of the bath treatments, only Diquat produced a dramatic reduction in the mortality of acutely infected fish. Diquat is labelled for aquatic use as an herbicide in the USA but in large ponds it is prohibitively expensive.     

A Preliminary Study on the Effects on Growth,Condition, and Feeding Indexes in Channel Catfish,Ictalurus punctatus,after the Prophylactic Use of Potassium Permanganate and Oxytetracycline

The prophylactic use of potassium permanganate (KMnO₄) and oxytetracycline and its effects on catfish growth were assessed. For eleven weeks, healthy channel catfish, Ictalurus punctatus, juveniles were exposed to KMnO₄ and oxytetracycline. KMnO₄‐treated fish were exposed to 1 ppm twice a week for 1 h, while oxytetracycline‐treated fish received a 50 mg/kg dose in the feed (35 fish per tank, two tanks per treatment). Assessed parameters included body weight and length, specific growth rate (SGR), feed intake (FI), condition, and feed conversion index (FCI). Potassium permanganate did not have a suppressive effect on growth, while oxytetracycline significantly enhanced growth on channel catfish (weight and length), as they were heavier (12.5%) than KMnO₄‐treated fish and controls at the end of the trial. SGR (%/d), FI, and FCI were not significantly different (P > 0.05) among the three groups of fish. Condition index (K) was significantly higher (ANOVA, P < 0.05) in the oxytetracycline‐treated fish. The present study suggests that, at concentrations commonly used in aquaculture, exposure of healthy channel catfish to oxytetracycline enhanced growth, while KMnO₄ does not induce growth suppression.     

硝化细菌对海参养殖系统水质的净化效果

氨和亚硝酸盐对海洋生物有强烈的毒害作用,是海水养殖系统的主要污染物。本文研究硝化细菌制剂对海参养殖系统水质的净化效果。结果表明:硝化细菌对养殖系统水质有明显的净化效果。投加菌剂的实验组氨氮和亚硝酸盐氮出现峰值的时间和对照组相比明显缩短,表明投加硝化细菌制剂后,养殖系统内的氨氧化细菌、亚硝酸盐氧化细菌可在短时间内形成优势,促进了氨和亚硝酸盐的进一步转化。对照组氨氧化细菌和亚硝酸盐氧化细菌需要较长的时间才形成优势,从而导致氨氮和亚硝酸盐氮的积累。观察实验过程中海参的生长情况发现,实验组海参生长状况良好,而对照组中海参在19d时全部死亡。     

Efficacy of Common Aquaculture Compounds for Disinfection of Flavobacterium columnare and F. psychrophilum

Flavobacterium columnare and F. psychrophilum are important pathogens of the aquaculture industry, and thus disinfection of aquaculture systems and equipment is essential for disease control. This study examined commercially available compounds in vitro for their ability to eliminate these two species of Flavobacterium from the water. The compounds evaluated included Clorox, ethanol, Roccal, Lysol, iodine, formalin, Chloramine-T, glutaraldehyde, potassium permanganate, sodium chloride, and Virkon Aquatic. In this study, 70% ethanol, 50% ethanol, Clorox, Roccal, Lysol, iodine, glutaraldehyde, Chloramine-T, and Virkon Aquatic reduced the number of bacteria of both species to zero within one minute of contact time. Formalin and 30% ethanol also killed both species of bacteria, but required a longer contact time. Potassium permanganate killed F. columnare within one minute, but did not reduce the numbers of F. psychrophilum even after one hour of contact time. Sodium chloride was not effective.     

常用化学消毒剂对罗氏沼虾的急性致毒试验

选用１１种常用的化学消毒剂对罗氏沼虾仔蚜和幼虾进行急性致毒试验。结果显示,罗氏沼虾虾苗对农药类的兴棉宝,敌百虫最敏感。对硫酸铜次之。对之最不敏感的药物为甲醛,其次为次氯酸钠和生石灰。不同的个体大小对药物的耐受能力朱同,大个体能忍受较高的药物浓度。根据２４ｈ半致死浓度ＴＬｍ２４的大小来判定药物对罗氏沼虾虾苗的毒性大小,可将其由高至低排列如下：兴棉宝〉敌百虫〉硫酸铜〉二氯异氰尿酸钠〉孔雀绿〉商锰酸钾》     

The in‐vitro antibacterial effects of organic salts,chemical disinfectants and antibiotics against pathogens of black disease in fairy shrimp of Thailand

The antibacterial effects of organic salts, chemical disinfectants and antibiotics were evaluated on cultures of Aeromonas hydrophila C03, Aeromonas sobria C26, A. sobria C29, Aeromonas caviae C24 and Acinetobacter sp. SH‐94B, the pathogens that cause black disease found in fairy shrimps (Streptocephalus sirindhornae Sanoamuang et al. (2000) and Branchinella thailandensis Sanoamuang, Saengphan & Murugan) of Thailand. The minimal inhibitory concentrations (MICs) of organic salts (sodium chloride and potassium chloride) and antibiotics (oxytetracycline dihydrate, streptomycin sulphate, kanamycin monosulphate, chloramphenicol and ampicillin) were determined using the agar‐dilution method. The effect of chemical disinfectants (sodium hypochlorite and chlorine dioxide) was evaluated by exposing bacteria to different concentrations of these chemicals for different periods of time. Interestingly, all strains were intrinsically resistant to 0.25–3% sodium chloride and potassium chloride. The effect of sodium hypochlorite was greater than that of chlorine dioxide, and 5–20 μg mL^?1 of sodium hypochlorite was sufficient to inhibit the growth of these bacteria, but the exposure time varied, depending on the bacterial species. Of the antibiotics tested, chloramphenicol and oxytetracycline dihydrate completely inhibited the selected strains. Chloramphenicol showed the highest antibacterial effect against all pathogenic species – the MIC and minimal bactericidal concentration (MBC) ranged from 0.8 to 3.1 μg mL^?1 from 3.1 to 6.25 μg mL^?1, respectively. To achieve control of black disease during cultivation of fairy shrimp, data derived from this study can be used as a basis for further toxicity tests in vivo.     

Effect of particulate organic carbon on heterotrophic bacterial populations and nitrification efficiency in biological filters

Competition between heterotrophic and nitrifying bacteria is of major practical importance in aquaculture biofilter design and operation. This competition must be understood to minimize the negative impact of heterotrophic bacteria on an aquaculture system. On the other hand, the heterotrophic population is suspected of having a positive effect against pathogenic bacteria. Little information is available on the bacterial communities present within aquaculture systems, except for nitrifying bacteria, but a combination of traditional aquacultural engineering research methods and novel microbiological techniques offers new opportunities for the study of these communities.

The heterotrophic bacterial population activity and the nitrification efficiency of a submerged biological filter were studied for an influent TAN concentration of 2 mg/l and varying C/N ratios. The TAN removal rate was found to be 30% lower at a C/N ratio of 0.5 than at a C/N ratio of 0. For higher C/N ratios the reduction in nitrification efficiency was 50% while the attached bacterial abundance was doubled. Moreover, results confirm that abundance of sheared and attached bacteria are correlated. It is not known to what extent biofilter configuration might influence the relationship between heterotrophic and nitrifying bacteria, and further work will be carried out with moving bed and fluidized filters. A better understanding of the role of the heterotrophic bacteria in RAS will help to optimize any positive “biocontrol” effect and to minimize the microbial degradation of rearing water and the reduction of nitrification rates.