2种含砷兽药对蚯蚓的急性毒性试验

蚯蚓是土壤生态的重要指示生物。试验用3种方法研究了2种含砷兽药洛克沙胂(roxarsone)和阿散酸(arsanilic acid)对安德爱胜蚓(Eisenia andrei)的急性毒性。结果表明，人工土壤法、人造土壤法和自然土壤法测得的洛克沙胂和阿散酸对蚯蚓的LC50分别为每千克土壤3.23、2.99、3．56g和5．80、5．10、6．80g。2种舍砷兽药对蚯蚓的毒性都较低。     

美国马里兰州家禽饲料和废弃物中洛克沙胂对环境的影响

在肉鸡产业中洛克沙胂被广泛使用。本文就洛克沙胂对环境的影响进行了综述。总之,砷以洛克沙胂的形式添加到家禽饲料中,并最终被排到家禽废弃物中。新鲜废弃物主要含洛克沙胂,而老化废弃物主要含无机砷。长期使用家禽废弃物作为肥料可使土壤中砷浓度超过马里兰州(MD)的砷土壤背景修复标准。由于砷会在土壤中不断积累,所以人们认为使用含砷的家禽废弃物作为肥料是不可持续的。在土壤表层施加含洛克沙胂的家禽废弃物不会影响深层地下水中砷的浓度,但它在沉淀后可以无机砷的形式转运到受纳水体和浅层地下水。因而在一些以农业为主的受纳水体和沉积物中砷的水平超出了限量标准。砷在鱼和贝类中主要以有机砷形式存在。磷营养管理趋于限制一些区域(该区域相对于作物的需求已过度使用磷)家禽废弃物的使用,从而降低了砷的使用率和累积。尽管大部分地表土壤中的砷处于紧密结合状态,但随着地表土壤结合砷的含量增加,其向地表下层渗透的能力增强,然而,由于地表下层土壤中的粘土矿物质、铁和铝的氧化物都具有非常强的砷结合能力,在大部分土壤中这种渗透作用有限。2012年马里兰州通过了一项法律,禁止在家禽饲料中使用除硝苯胂酸以外的砷类添加剂。2013年美国食品和药物管理局(USFDA)撤销了洛克沙胂、卡巴胂和对氨基苯胂酸的使用许可,并正在审查硝苯胂酸。     

洛克沙砷、黄霉素及杆菌肽锌在畜禽日粮中的应用及研究

本文对洛克沙砷、黄霉素及杆菌肽锌的应用现状，作用机理及对畜禽营养作用的影响等方面进行了概念及分析，洛克沙砷具有经济、高效的促生长作用，但如果长期，大量使用会对畜禽造成不利的影响，而且对环境造成严重污染；黄霉素和杆菌肽锌对畜禽的促生长作用不及洛克沙砷，但这两种抗生素具有无毒、无害、无残留又无配伍禁忌的优点，所以利用它们各自的优点，通过饲养试验的手段，来寻找一种高效，经济又安全的一种抗生素预混料就成为     

有机砷对鸡的营养作用及应用前景

２０世纪初，Ｅｎｒｌｉｃｈ提出有机砷制剂可以与寄生虫体内的蛋白质的巯基结合，形成共价键以发挥药理作用。以后便有大量有关砷制剂的研究，并一度被认为是有效的促生长物质。早在５０年代美国、加拿大就已经应用砷制剂作为饲料添加剂来改善畜禽生产，我国１９９３年批准阿散酸使用于猪鸡，１９９６年批准洛克沙砷的使用。但最近又有报道，从生态及环保的角度讲，使用有机砷制剂不利于可持续发展。 一．有机砷制剂的种类 目前我国国内生产的有机砷产品主要为对－氨基苯砷酸及其钠盐（阿散酸）和３－硝基－４－羟基苯砷酸（洛克沙砷）。 …     

洛克沙胂在鲫鱼体内的残留及消除动力学研究

本文对洛克沙胂在鲫鱼体内的砷残留及消除动力学进行了研究，鲫鱼在室内水池洛克沙胂溶液10mg／L(以As计)中连续暴露15天进行富集残留试验后转入清水中进行消除试验。采用微波消解处理和氢化物一原子荧光光度法测定鱼鳃、肌肉、血清和内脏中总砷含量。结果表明，砷在鱼体内的表现为吸收和分布较快，肌肉和血清中总砷水平仅为0．3～0．4mg／kg，内脏中残留最高达30．25mg／kg。洛克沙胂在鲫鱼组织中消除符合一级速率动力学过程，消除半衰期(t1／2)为2．5～2．8h，鱼鳃中砷浓度在初始2h内下降快，此后消除较慢，t1／2为9．45h。     

辉瑞生产药或致部分鸡肉含砒霜

<正>日前媒体披露,美国市场部分鸡肉可能含有少量砒霜。辉瑞公司一款在美国从20世纪40年代就在禽类中使用的药物洛克沙砷(Roxarsone),可能致使鸡体中含有致癌物质砷。洛克沙砷1996年在中国上市,目前有多个厂家生产。     

晶鸡伞替代抗生素饲喂黄羽仔鸡效果的试验

选用279只1日龄健康黄羽肉用仔鸡，随机分为3个组。在基础日粮的基础上，对照组添加金霉素540mg／kg 洛克沙砷75mg／kg；试验组分别添加100mg／kg、160mg／kg晶鸡伞。试验期为21天。试验结果表明晶鸡伞可以替代金霉素和洛克沙砷对肉仔鸡的抑茵和促生长作用。     

家禽服用洛克沙胂会引起致癌物残留

美国食品和药物管理局(简称药管局)6月8日宣布,检测显示,服用辉瑞公司生产的洛克沙胂的肉鸡体内会残留微量致癌物无机砷。洛克沙胂1944年在美国获准上市,是美国药管局批准上市的第一种含砷动物药。美国一些家禽饲养者使用洛克沙胂清除家禽体内的球虫。这种药也能使肉鸡增重,皮肤呈金黄色。     

洛克沙砷的作用、毒性及环境行为

砷作为动物体必需的一种微量元素 ,具有多种重要的生理功能 ,以及抗菌、抗寄生虫等多种药理作用。近年来砷制剂的使用越来越广泛。洛克沙砷 (Ｒｏｘａｒｓｏｎｅ ,ＲＯＸ ,也译作洛克沙生或洛克沙胂 )的化学名为 :3-硝基 - 4 -羟基 -苯胂酸 ,与阿散酸 (ｐ -ＡｒｓａｎｉｌｉｃＡｃｉｄ ,ＰＡＳＡ ,对氨基苯胂酸 )一起成为近年来在世界各国广泛使用的两种含砷饲料添加药物 ,而洛克沙砷比阿散酸应用更广。美国食品和药物管理局(ＦＤＡ)最早于 196 4年允许洛克沙砷用于鸡的饲料 ,1983年正式批准用作猪鸡的促生长剂。我国农业部 1996年批准了该…     

反相高效液相色谱法测定预混料中洛克沙脾的含量

洛克沙胂（Roxarsone，3-硝基-4-羟基苯胂酸）是我国目前使用量比较大的有机砷制剂之一．主要用于提高猪、鸡日增重和改进饲料利用率．改善皮肤营养，促进色素沉积等。在猪鸡饲料中允许添加量为50g／t，过量使用可引起畜禽中毒甚至死亡．其在畜禽产品中的残留以及向环境排出的大量砷元素会对食品卫生及环境造成不良影响。但由于有机砷制剂的用量不能直接测定而导致饲料中无机砷是否超标无法判断，因此准确定量预混料中洛克沙胂含量具有重要意义。     

Roxarsone (3-nitro-4-hydroxyphenylarsonic acid) poisoning in pigs

Young pigs, six to ten weeks of age, from two unrelated swine operations were fed a grower ration obtained from a common commercial supplier. Following ingestion of the feed for approximately two weeks, pigs in both groups developed neurological disturbances characterized by blindness, ataxia, incoordination, muscle tremors, posterior paralysis, and quadriplegia. Vocalization described as “screaming” was also observed in several animals. Necropsy findings and tissue arsenic concentrations were consistent with a diagnosis of phenylarsonic acid poisoning. The liver and kidney contained an average arsenic content of 2.9 and 1.8 mg/kg (wet weight), respectively. The feed contained 38 mg of arsenic/kg corresponding to 133 mg roxarsone (3-nitro-4-hydroxyphenylarsonic acid)/kg. This level of roxarsone is approximately three to five times higher than the levels recommended for swine rations. The feed company had placed roxarsone in the ration at levels recommended for the less toxic arsanilic acid. It was assumed that the two organic arsenicals could be added to the rations interchangeably at the same level of formulation. The present investigation indicated that roxarsone is more toxic than arsanilic acid and the margin of safety in swine rations is low.     

Reduction of liver copper concentration by the organic arsenical, 3-nitro-4-hydroxyphenylarsonic acid

The interaction between 3-nitro-4-hydroxyphenylarsonic acid (roxarsone) and Cu was studied in a series of experiments with crossbred, broiler-type chicks. A fully fortified corn-soybean meal diet was fed in all assays. While roxarsone caused a marked reduction in liver Cu concentration, arsanilic acid (4-aminophenylarsonic acid), As2O3 and As2O5 were without effect. When structural analogs of roxarsone were studied, it was found that o-nitrophenol and 3-nitro-4-hydroxybenzoic acid also had no effect on liver Cu concentration in birds fed a high level of Cu. However, liver Co concentration was reduced by the addition of either o-nitrophenol or roxarsone to the diets of birds fed a high level of Co. It was concluded that arsenic per se had no effect on liver Cu accumulation or depletion, but that a chelate was probably formed between Cu or Co and the nitroso and hydroxyl groups of the ring portion of roxarsone. In addition to the reduction in liver Cu deposition, concentrations of Cu in the bile, brain, heart and pancreas of chicks were reduced by the addition of roxarsone to a high-Cu diet. Neither dietary nor intraperitoneally (ip) injected roxarsone had an effect on liver Cu concentration when Cu was injected ip. Therefore, both roxarsone and Cu had to be present in the diet for the liver Cu-lowering effect of roxarsone to be exerted. A further experiment was conducted with growing rats to determine the effect of roxarsone on Cu balance. Feeding roxarsone elevated Cu excretion in the urine but had no effect on Cu excretion in the feces.     

Amelioration of selenium toxicity by arsenicals and cysteine

Young chicks exhibited a 61% reduction in weight gain when a corn-soybean meal diet was supplemented with 15 mg/kg Se provided as Na selenite. The same level of Se provided as selenomethionine depressed weight gain by 32%. Supplementing the high selenite diet with isoarsenous (14 mg/kg As) additions of As2O5, As2O3, phenylarsonic acid, phenylarsine oxide and roxarsone ameliorated the Se-induced growth depression: As2O5 almost totally restored growth rate; As2O3, phenylarsonic acid and phenylarsine oxide gave intermediate responses; and roxarsone gave only a small ameliorative growth response. Arsanilic acid was without effect in stimulating growth rate of selenite-intoxicated chicks. Dietary addition of .4% L-cysteine produced a growth response in selenite intoxicated chicks that was somewhat greater than that obtained with roxarsone; administering both roxarsone and cysteine corrected growth better than either compound given singly. Both roxarsone and As2O5 also effectively ameliorated the Se-toxicity growth depression caused by selenomethionine (15 mg Se/kg) supplementation, but cysteine showed no efficacy against morbidity caused by this form of Se. Liver Se concentration was elevated 10-fold by selenite and 25-fold by selenomethionine supplementation. The arsenic compounds had varying effects on liver Se, whereas cysteine tended to increase Se concentration. These findings suggest that both inorganic and organic arsenicals as well as cysteine ameliorate selenium toxicity by different mechanisms.     

Absence of obvious short-term impact of the nematode-trapping fungus Duddingtonia flagrans on survival and growth of the earthworm Aporrectodea longa

The nematode-trapping fungus Duddingtonia flagrans may be used in biological control of parasitic nematode larvae in faeces of domestic host animals after feeding the hosts with fungal chlamydospores. In this experiment a possible undesirable fungal impact on earthworms, of the species Aporrectodea longa, was investigated. As earthworms eat animal faeces, D. flagrans may come into contact with earthworms both in their alimentary tract and on their body surface. However during the experimental period of 20 days, when earthworms were living in soil and eating cattle faeces that were heavily infested with viable chlamydospores of D. flagrans there were no indications of internal or external mycosis among the earthworms.     

猪场周围环境中砷的分布及迁移规律研究

为了解猪场周围环境中砷含量及迁移规律,对广东省5个典型猪场周围的土壤、植物、水和鱼的砷进行了检测。结果表明,土壤砷均未超标,但含量有升高趋势;植物中的蔬菜砷超标率为100%,其中67%为重污染;水中的砷超标率为66%,为轻污染;鱼肉中砷的检出率为100%,其中超标率为67%。说明猪场周围环境中砷污染严重,且从环境向生物体富集。     

猪粪中洛克沙胂的HPLC检测及排泄规律

在建立猪粪中洛克沙胂HPLC检测方法基础上,选用24头育肥猪,分别混饲给予0、25、50、100 mg/kg洛克沙胂,混饲给药后不同时间采集粪样,以高效液相色谱法测定其中洛克沙胂质量浓度,了解洛克沙胂混饲给药后在猪体内的排泄情况,然后从江苏和山东省15个使用洛克沙胂的集约化猪场采集150头猪的粪样,调查猪粪样中的洛克沙胂含量。结果表明,所建立的猪粪中洛克沙胂HPLC检测方法的平均回收率为82.09%~84.03%,变异系数为2.92%~5.45%,检测限为0.05 mg/kg,定量限为0.1 mg/kg;以不同剂量混饲给药后,洛克沙胂在粪中排泄量在36~48 h达峰,峰质量浓度分别为12.31、22.52、34.78 mg/kg,猪粪中检测不到洛克沙胂的时间分别为72、108、132 h;所调查150个粪样中洛克沙胂平均质量浓度为23.13 mg/kg。     

The environmental safety of eprinomectin to earthworms

A study was conducted to assess the environmental safety of the endectocide eprinomectin to the earthworm Lumbricus terrestris under conditions mimicking typical product use on pasture. The LC50 value of eprinomectin in artificial soil after 28 days of exposure is higher than the levels expected in feces from dosed cattle or in soil fertilized with manure from dosed cattle, which indicates a wide margin of safety for this compound to earthworms. However, the no-observed-effect concentration has not been established. Therefore, the current study was conducted to determine whether there would be any effects on earthworms from feces from cattle treated with the commercial formulation of eprinomectin. Feces were collected rectally from grazing cattle on Day 0 before treatment and on Days 2, 4, 7 and 14 after treatment with EPRINEX (eprinomectin) Pour-On for Beef and Dairy Cattle (Merial Limited) at 0.5 mg eprinomectin per kg bodyweight. Assays of eprinomectin B1a (the major component of eprinomectin) were 0, 0.427, 0.152, 0.0512 and 0.00185 mg kg-1 wet weight of feces (equivalent to 0, 3.34, 1.19, 0.40 and 0.010 mg kg-1 on a dry weight basis, respectively). No significant differences (p>0.05) were observed at any day post-treatment in the survival or behavioral effects of any worms fed post-dose feces relative to the worms fed control feces. All post-dose comparisons of weight changes of living earthworms to the control group were not significantly different (p>0.05), indicating that treatment of cattle with EPRINEX (eprinomectin) Pour-On for Beef and Dairy Cattle did not affect feeding or weight gain of the earthworms. The LC50 value and the results of this study establish the wide margin of safety afforded to earthworms by eprinomectin under typical usage conditions.     

Toxic effects of supplemental copper and roxarsone when fed alone or in combination to young pigs

Three experiments were conducted to investigate the roxarsone (3-nitro-4-hydroxyphenylarsonic acid) X copper (Cu) interaction in weanling pigs. Supplemental roxarsone at 400 mg/kg diet decreased rate and efficiency of weight gain and caused visible neurological signs of toxicosis. Copper addition (CuSO4 X 5H2O) at a level of 650 mg Cu/kg diet likewise decreased weight gain and feed efficiency, and it also increased hepatic Cu deposition. The combination of these growth-depressing dosages of roxarsone and Cu resulted in a far greater reduction in gain and efficiency of feed utilization than was the case when either compound was fed alone. A growth-promoting dosage of Cu (250 mg/kg) increased weight gain by 32% in one experiment but showed no efficacy in alleviating the growth-depression resulting from feeding 400 mg/kg roxarsone. A roxarsone dosage of 100 mg/kg increased gain and feed efficiency. Surprisingly, the decreased weight gain in pigs fed 650 mg/kg Cu was ameliorated by feeding 100 mg/kg roxarsone concomitantly. This level of roxarsone also reduced liver Cu concentration substantially. It thus appears that the nature of the roxarsone X Cu interaction is dependent on the dose of each compound administered. Moreover, low-dose roxarsone administration appears to ameliorate Cu toxicity, but low-dose Cu feeding does not show efficacy against roxarsone toxicity.     

猪舍氨气防控措施研究进展

养猪生产中产生的氨气严重影响生猪健康,降低猪只免疫力,从而诱发疾病,降低了养猪生产效益。此外,氨气排放会对大气环境造成污染、引起土壤和水体的酸化。如何减少和控制猪舍氨气排放成为近年来的研究热点。本文将从饲料源头、生产过程和末端控制3个阶段减少猪舍氨气排放的研究现状做一综述,以期为规模化养猪生产提供参考。     

Abundance of earthworms in Nigerian ecological zones: implications for sustaining fertilizer-free soil fertility

The abundance of earthworms in the ecological zones in Nigeria has been determined and the possibility of earthworm functions replacing both mechanized land preparation and organic fertilizers discussed. The most abundant earthworms, comprising 62 % of the population, were the advantageous solid-wormcast makers. Mixed Leguminous Wooded Savanna had the highest earthworm density (1.50 million worms/ha), while Wooded Savanna had the lowest (0.23 million worms/ha). Coastal Forest and Mangrove (0.51 t/ha) had the highest earthworm biomass and Afziela Savanna/Semi-Deciduous Forest (0.03 t/ha) had the least. A new soil impact index (SIINDEX) is introduced, which simultaneously incorporates both earthworm biomass and density. The highest SIINDEX was from Mixed Leguminous Wooded Savanna (0.72) and the lowest from Afziella Savanna/Semi-Deciduous Forest (0.11). Forests with SIINDEX less than 0.2 should be regarded as endangered, because their earthworm functions are too low to accomplish significant leaf-litter breakdown and recycling. We suggest that if the illegal annual bush burning is prevented, the soil surface will be naturally mulched, earthworms protected, and by their function in the soil, the need for soil mechanization and fertilization could be replaced by earthworms to produce natural foods.