The Toxicity of Erythromycin, Minocycline, Malachite Green, and Formalin to Nauplii of the Shrimp Penaeus stylirostris

The toxicities of erythromycin, minocycline, malachite green, and formalin to nauplii of the shrimp Penaeus stylirostris were determined in a static bioassay. Toxicity was assessed on the basis of survival of nauplii after 12 and 24 hours of exposure to the compounds and metamorphosis of the nauplii to protozwa. The results suggested that metamorphosis to protozoea is more susceptible to toxic effects than is naupliar survival. Metamorphosis was either reduced or completely inhibited by lower concentrations of erythromycin, minocycline, and malachite green than was naupliar survival at 12 or 24 hours. Metamorphosis was either reduced or completely inhibited by erythromycin, minocycline, malachite green, and formalin concentrations of 80, 100, 0.08, and 27 mg/ L, respectively. Toxic effects were not observed at erythromycin, minocycline, malachite green, and formalin concentrations of 16, 62.5, 0.016, and 2.7 mg/L, respectively. The results suggest that formalin may be toxic at therapeutic levels frequently recommended for post larvae and older penaeids, but that erythromycin, minocycline and malachite green are not.     

Evaluation of the secondary stress response in healthy Nile tilapia (Oreochromis niloticus L.) after treatment with a mixture of formalin, malachite green and methylene blue

To determine the effects of exposure to a mixture of formalin, malachite green and methylene blue (FMC) on the secondary stress indices, changes in glucose, phosphorus, calcium, magnesium, sodium, potassium and haematocrit were monitored in healthy Nile tilapia, Oreochromis niloticus L. Fish were exposed separately to varying concentrations of a mixture of formalin, malachite green and methylene blue (0.1, 0.5 and 1 p.p.m.) for 1, 10 and 60 min. In general, treatment of fish with FMC elicited marked elevations of plasma glucose. Plasma phosphorus levels dropped after FMC treatment. In fish exposed to FMC, calcium levels in general were lower than those of the controls. Magnesium levels were not influenced by FMC treatment. Plasma sodium and potassium levels showed an unclear pattern for differing FMC concentrations and exposure times. Haematocrit values were affected by FMC treatment.     

The effects of malachite green upon proliferative kidney disease

Abstract. When rainbow trout infected with proliferative kidney disease (PKD) held in the laboratory were treated with malachite green and formalin to cure ichthyophthiriasis it was observed that subsequent development of PKD was delayed. Experiments are reported which indicate that this was due to the malachite green treatment. The possible use of malachite green in the treatment of PKD, tissue levels of malachite green achieved during treatments and the toxicity risks from multiple dose therapy with malachite green are discussed.     

Effect of temperature,pH, antibiotics,formalin and malachite green on the growth and survival of Saprolegnia and Achlya parastic on fish

Twenty-four strains of Saprolegnia and Achlya were isolated from different fish-rearing ecosystems and from diseased carp. Special test methods were developed to measure growth of the strains at different pH and temperature levels. Sensitivity and survival were determined for antibiotics and for 40 concentrations of formalin, malachite green and formalin-malachite green mixture.Out of the 33 antibiotics tested only nalidixic acid exerted a significant growth inhibiting effect. The minimum bathing treatment times necessary for 100% mortality (LT 100) at the different concentrations were determined, and then efficiency curves were constructed by means of computerized analysis of the data. A wide choice of concentrations and treatment times is suggested for practical use.     

In vitro effects of fungicides on Haliphthoros philippinensis*

Abstract. Pure cultures of the fungus Haliphthoros philippinensis isolated from infected Penaeus monodon larvae were exposed for 24 h to varying concentrations of the antifungal agents Benlate, calcium hypochlorite, clotrimazole, copper sulphate, Daconil, formalin, Fungitox, Furanace, griseofulvin, hydrogen peroxide, malachite green, Mysteclin C, phenol, potassium permanganate, Resiguard, Tide, tolnaftate and Treflan. The efficiency of each compound in inhibiting sporulation and mycelial growth of the fungus was measured. The results establish mycostatic and mycocidal levels for each fungicide.     

船体网箱饲养的鲤鱼水霉病发病条件及防治药物筛选

本文研究了水霉病的发病条件，病原分离和防治药物，结果表明：水霉病主要发生在１￣４月份，水温和机械损伤是水霉病发生的主要条件，孔雀石绿对水霉菌抑菌，杀菌效果最佳，其安全浓度为０．１３ｐｐｍ。生产中与甲醛，敌百虫和食盐结合使用，效果更佳。     

Two in vitro methods for screening potential parasiticides against Ichthyophthirius multifiliis using Tetrahymena thermophila

Ichthyophthirius multifiliis (Ich) is a ciliate parasite that infects many species of freshwater fishes worldwide and causes heavy economic losses in aquaculture. Currently, parasiticides for controlling this parasite are limited, and few pond‐practical chemical therapies exist. Hence, the search for new parasiticides is urgently needed. One challenge confronting the screening of potential parasiticides is the difficulty in raising enough parasite for efficacy testing as Ich is an obligate parasite. This study used species of Tetrahymena, Ich‐related and cultivable ciliate protozoa, to evaluate two in vitro methods to test parasiticides. Plate counting and MTS assays (CellTiter 96^® AQ_ueous Non‐Radioactive Cell Proliferation Assay) were used to compare lethal concentrations or median lethal concentrations (LC₅₀) of copper sulphate, formalin and malachite green between T. thermophila and Ich theronts or between T. thermophila and Ich tomonts. The parasiticides that killed T. thermophila have been demonstrated to kill theronts or tomonts. These in vitro methods using T. thermophila can be used to screen novel parasiticides against Ich.     

中华绒螯蟹蟹栖拟阿脑虫病的研究

在室内越冬的中华绒螯蟹亲蟹上检出一种嗜腐性纤毛虫,经鉴定为蟹栖拟阿脑虫Paranophrgs carci-ni。在感染初期,多寄生于新蟹残肢等伤口组织处;在感染后期,侵蚀到蟹体,进入血淋巴,甚至可分布全身,致使器官组织受到严重损害,造成亲蟹死亡。对越冬亲蟹危害严重,短期内使亲蟹死亡率达40％左右。用15～30ppm的福尔马林或0.1～0.5ppm的孔雀石绿短期药治无效,改用25ppm的福尔马林或0.3～0.5ppm的孔雀石绿每天药浴8h,连续10～15d,病情基本得到控制。     

Heavy infection of Ichthyophthirius multifiliis in striped catfish (Pangasianodon hypophthalmus,Sauvage 1878) and its treatment trial by different therapeutic agents in a control environment

ABSTRACT

Striped catfish (Pangasianodon hypophthalmus) fingerlings were stocked (60 fishes/m³) in cemented square tanks for ornamental fishery purposes at the College Fish Farm in Mangalore. A total of 400 fishes with a mean weight (g) ranging from 3.24 ± 1.21 to 6.70 ± 1.13 and a mean length (cm) of 7.50 ± 0.94 to 9.50 ± 1.10 were examined. A severe outbreak of salt-like granule white spots was found on the body surface. Ichthyophthirius multifiliis, a ciliate pathogen, was identified as the causative agent by clinical signs, wet mount, and histopathological observations. Infected fishes were transferred and equally distributed to the 0.45 m³ glass aquaria and treated with three treatments: (T1) methylene blue + salt; (T2) raising temperature with salt; and (T3) formalin + malachite green. The best fingerling survival (55 ± 9.36%) was obtained by elevated water temperature with salt in T2.     

Toxicity of four commonly used chemotherapeutic compounds to fry of the African catfish, Clarias gariepinus (Burchell)

Acute toxicity tests were carried out for four compounds commonly used against various fish pathogens to determine their 24-h LC₅₀ values to fry of the African catfish, Clarias gariepinus (Burchell). Compounds tested and their calculated 24-h LC₅₀ values (mg l^?1) were as follows: praziquantel (13.4); malachite green oxalate (0.14); acriflavin neutral (10.0); and mebendazole (315). The results show that dosage levels of malachite green oxalate, praziquantel and acriflavin neutral recommended in the literature for the control of most fish ectoparasitoses caused substantial mortalities and cannot be applied to Clarias gariepinus fry.     

不同冷冻贮藏时间对三种鱼类肌肉中孔雀石绿残留量的影响

研究鲤鱼、鳗鲡、鳜鱼在加入不同浓度的孔雀石绿标准样品且在不同冷冻贮藏时间下对孔雀石绿残留量的影响。三种基质中,鳗鲡组织中添加有无色孔雀石绿降解速率最慢、鳜鱼次之、鲤鱼较快。三种基质中添加10μg/kg、50μg/kg、100μg/kg有色孔雀石绿平均降解率分别为57.9%、48.0%、23.0%;无色孔雀石绿平均降解率分别为46.6%、43.4%、19.8%,有色孔雀石绿较无色孔雀石绿降解快,低浓度较高浓度降解快。在三种基质鲤鱼、鳗鲡、鳜鱼组织中有色和无色孔雀石绿降解反应均符合准一级反应动力学。分析可能由于鳗鲡组织脂肪较多,其结合方式影响了有色无色孔雀石绿的降解。     

Larval rearing of an Asian catfish Pangasius hypophthalmus (Siluroidei,Pangasiidae): Analysis of precocious mortality and proposition of appropriate treatments

Both in Indonesia and Vietnam, larval rearing of Pangasius hypophthalmus remains problematic due to the variable and generally low survival rates obtained. The first week represents the most critical period for these larvae and up to now, cannibalistic behaviour was considered as the main cause of mortality. In the present study, two experiments were carried out in order to better understand the evolution and causes of mortality of P. hypophthalmus larvae from hatching up to 8 d of age and to find measures to improve survival rates. The first experiment was designed to evaluate the importance of cannibalism and differences in mortality when larvae from two different females were reared either in groups of 30 individuals or in isolated condition (30 larvae reared separately). In both cases, the culture was carried out either with or without antibiotic. The aim of the second experiment was to test oxytetracycline and different disinfectants (chloramine-T, formalin and ‘formalin + malachite green oxalate’) at different dosages in order to prevent bacterial outbreaks in the culture. The results indicated that the survival rates of P. hypophthalmus larvae was dependent on the initial quality of larvae or eggs and that larval mortality was more a consequence of pathogenic infection than a direct effect of cannibalism. The present study demonstrated that the survival rates of larvae were systematically improved when rearing was carried out in water containing antibiotic (oxytetracycline at a dose of 5 to 20 mg·L¹). Survival rate and final mean body weight of larvae as high as those obtained using antibiotic were also reached with applications of disinfectants such as chloramine-T and formalin. The use of these disinfectants is recommended for commercial P. hypophthalmus hatcheries.     

Acclimation of the brown trout, Salmo trutta L., to the stress of daily exposure to malachite green

Exposure of brown trout to a single dose of malachite green (2.27 ppm) caused a significant elevation of blood cortisol levels within 1 h. After 4 weeks of daily exposure to malachite green, however, this stress response was totally abolished. Daily treatment had no long-term effects on basal plasma cortisol levels, or on the numbers of circulating erythrocytes, thrombocytes and lymphocytes. Blood neutrophil numbers were significantly reduced in malachite green-treated fish, an effect thought to be due to a decreased ectoparasitic load.     

河蟹盖虫病的防治研究

对成蟹养殖期,附着于成蟹体表的盖虫进行了形态学观察及其分类学鉴定,并做了不同药物的防治实验,其结果表明,７．５ｍｇ／ＬＺｎＳｏ４、６ｍｇ／Ｌ－１２ｍｇ／Ｌ蟹安、０．３ｍｇ／Ｌ孔雀石及３０ｍｇ／Ｌ福尔马林对盖虫有较强的杀伤效果。     

肉桂活性成分肉桂醛杀灭离体多子小瓜虫效果

研究从肉桂中分离纯化出具有抑杀多子小瓜虫活性的化合物。以乙醇为提取剂,用索氏超声提取法从肉桂中提取浸膏,再用石油醚、乙酸乙酯、甲醇为萃取剂,萃取不同有效组分,以不同浓度分别进行杀灭离体多子小瓜虫实验,发现石油醚萃取物的杀虫效果最优。然后对石油醚萃取物采用硅胶层析柱和制备型高效液相色谱进行分离纯化,利用质谱和核磁波谱分析,最终鉴定其杀虫活性成分为肉桂醛;将肉桂醛溶于二甲基亚砜并用二倍梯度稀释法配成不同浓度的药液测试其对离体小瓜虫的杀灭活性。结果表明,100%杀灭滋养体和感染性幼虫的剂量分别为50和8 mg/L,半数有效浓度分别为13.9和1.8 mg/L;使用剂量在50 mg/L可完全抑制小瓜虫包囊孵化。     

Sensitivity of juvenile lobsters, Homarus americanus L., to different concentrations of malachite green during various states of the intermoult cycle

Abstract. Survival of the early stages (egg, larva and juvenile) of the American lobster, Homarus americanus L., reared under controlled conditions has often been threatened by a variety of fungi and microbial epibionts. A preliminary study was conducted for the purpose of defining toxicity levels of malachite green for 5th stage juveniles during each of the following intermoult (or fused intermoult) states: A-B, C₄, D₀ and D₂-D₃ Irrespective of exposure time or concentration, all the lobsters treated during intermoult state A-B died. This contrasts with seemingly good survival of lobsters in intermoult states C₄, D₀ and D₂- D₃ treated at concentrations of 900 mg/1 malachite green for exposure periods of 10 min. The findings suggest that an effective treatment combination for lobsters immersed in malachite green may be one which is employed during intermoult state C₄, for about 6min and at concentrations of about 700–800 mg/l.     

上海市售鳜渔药残留现状的调查研究

为了解上海市场销售鳜(Siniperca chuatsi)渔药残留现状,于2018年4月-2019年3月,对上海市批发市场销售的72份鳜肌肉样,采用高效液相色谱法,分别测定孔雀石绿(MG)、硝基呋喃(NFs)、喹诺酮(4-Qs)以及亚甲基蓝(MB)四大类共10种药物。结果显示:孔雀石绿、隐色孔雀石绿以及呋喃唑酮、呋喃它酮无检出,呋喃西林、呋喃妥因检出样占样本量的50%,喹诺酮类占76.39%,亚甲基蓝占15.3%;呋喃西林的检出浓度为(0.49±0.03)μg/kg、呋喃妥因(3.51±2.27)μg/kg,诺氟沙星(25.52±10.36)μg/kg、环丙沙星(20.98±6.85)μg/kg、恩诺沙星(27.95±4.17)μg/kg、亚甲基蓝(120±14)μg/kg;呋喃唑酮类主要集中在10月份到次年4月份之间,喹诺酮类与亚甲基蓝则主要集中在4月份到10月份之间,环丙沙星全年可检出。结果表明:市售鳜肌肉中仍有部分禁用药物和限用渔药的残留,且不同药物残留表现出一定的季节性差异。     

水产品中孔雀石绿检测方法研究进展

水产品的安全问题日益成为社会关注的焦点,近年来,我国出口的鳗鲡以及国内市场上的水产品都发现了孔雀石绿残留.国内各有关检测机构相继开展了水产品中孔雀石绿残留量的检测.本文对现有的各种检测方法的优点和局限性作一概述,以便研究者能在此基础上进一步改进和发展.     

Residues of [14C]-malachite green in eggs and fry of rainbow trout, Oncorhynchus mykiss (Walbaum), after treatment of eggs

Abstract. Rainbow trout, Oncorhynchus mykiss (Walbaum), eggs were exposed to [methane-¹⁴C] malachite green chloride on day 0 and on every third day thereafter through day 24, with a final treatment administered to fry on day 31. Eggs or fry were sampled before each treatment, and at selected times from day 31 to day 59. Malachite green equivalence in eggs and fry was determined by sample oxidation and liquid scintillation counting. Total malachite green residues increased throughout the exposure period to 0.271 ± 0.042 μg g⁻¹ (± SD) on day 31. Residues declined to 0.055 ± 0.011 μg g⁻¹ on day 59. The depuration phase declined monoexponentially with a half-life of 13.3 days for the absolute amount (μg sample⁻¹) and a half-life of 9.7 days for the concentration of malachite green residues (μg g⁻¹). Growth dilution accounted for the 25% increase in the elimination (9.7 days) of malachite green residues. Extracts from treated eggs and fry were analysed by reversed-phase liquid chromatography. Three peaks were resolved in treated eggs: chromatic malachite green, leuco malachite green and an unknown polar metabolite. Only two peaks were resolved in the fry: leuco malachite green and the unknown polar metabolite. The most prominent residue in all samples was leuco malachite green.     

Use of formalin and copper to control ichthyophthiriosis in the Australian freshwater fish silver perch (Bidyanus bidyanus Mitchell)

Infestations of the protozoan parasite, Ichthyophthirius multifiliis, cause the serious disease ichthyophthiriosis in freshwater fish throughout the world. Formalin is a recommended treatment for ichthyophthiriosis in the Australian fish silver perch (Bidyanus bidyanus Mitchell), but the disease is difficult to control in ponds, particularly at low water temperatures. Experiments were carried out to develop an improved treatment regime for formalin and to evaluate copper as a therapeutant. Silver perch fingerlings infested with I. multifiliis were stocked into 55 L aquaria at temperatures of 14.8–17.6 °C and alkalinities of 70–110 mg L^?1. Formalin (34–38% formaldehyde) or copper (24.5% copper sulphate) were added to the aquaria and then monitored and readjusted to nominal concentrations daily. A concentration of 30 mg L^?1 formalin controlled ichthyophthiriosis, but fish treated with 20 mg L^?1 remained infested with theronts and trophonts on day 17; survival at both concentrations was 100%. A concentration of 10 mg L^?1 formalin did not control ichthyophthiriosis and all fish were dead from the infestation by day 17. Fish treated with 0.1 or 0.2 mg L^?1 copper were free of theronts and trophonts by days 17 and 14, respectively, and survival was 100%. Survival at 0.05 mg L^?1 copper was 100%, but fish remained infested. At 0.25 mg L^?1 copper, survival was 82.5% and there were no theronts or trophonts on gill and skin tissues of fingerlings by day 14. There was total mortality of fish treated with 0.5 or 1.0 mg L^?1 copper suggesting these concentrations are toxic to silver perch. All fish in infested‐control treatments died. In earthen ponds containing silver perch, 0.2 mg L^?1 copper was depleted to below 0.1 mg L^?1 within 24 h, and concentrations of 25–38 mg L^?1 formalin were depleted to below 15 mg L^?1 within 48 h. Treatment regimes involving daily applications of formalin or copper controlled ichthyophthiriosis in silver perch in earthen ponds at costs of $US466.37 and $US65.58 hectare^?1 day^?1 respectively. This study has developed a new formalin‐treatment regime for the control of ichthyophthiriosis, and demonstrated that copper sulphate is a potential therapeutant for this serious disease of silver perch.