A biological method for the determination of mycotoxins--Tetrahymena pyriformis

The toxic action of selected mycotoxins on a biological subject was tested in the protozoan Tetrahymena pyriformis. The following toxins were tested: toxin T-2 at doses from 1.52 micrograms to 100.0 mg per litre of medium, ochratoxin A at doses from 12.21 micrograms to 800.0 mg per litre of medium, and rubratoxin B at doses from 12.21 micrograms to 800.0 mg per litre of medium. In toxin T-2 the LD100 was found to be about 390.63 micrograms and LD50 about 48.83 micrograms per litre of medium. In ochratoxin A the LD100 was about 25.0 mg and LD50 about 3.13 mg per litre of medium. In rubratoxin B the LD100 was about 200.0 mg and LD50 about 25.0 mg per litre of medium.     

Mechanisms of Mycotoxin-induced Dermal Toxicity and Tumorigenesis Through Oxidative Stress-related Pathways

Among the many mycotoxins, T-2 toxin, citrinin (CTN), patulin (PAT), aflatoxin B1 (AFB1) and ochratoxin A (OTA) are known to have the potential to induce dermal toxicity and/or tumorigenesis in rodent models. T-2 toxin, CTN, PAT and OTA induce apoptosis in mouse or rat skin. PAT, AFB1 and OTA have tumor initiating properties, and OTA is also a tumor promoter in mouse skin. This paper reviews the molecular mechanisms of dermal toxicity and tumorigenesis induced in rodent models by these mycotoxins especially from the viewpoint of oxidative stress-mediated pathways.     

16种植物性饲料原料中黄曲霉毒素B1、T-2毒素、赭曲霉毒素A、伏马毒素(B1+B2)污染调查检测及控制建议

为掌握黄曲霉毒素B1、T-2毒素、赭曲霉毒素A、伏马毒素(B1+B2)在植物性饲料原料中的污染状况,指导帮助饲料企业和养殖企业开展霉菌毒素防控,降低霉菌毒素对饲料产品质量及畜禽养殖产品危害,减少经济损失,2020年对16种60份植物性饲料原料进行调查采样,采用液相色谱—串联质谱法、免疫亲和柱净化—高效液相色谱法检测,依...     

Mycotoxin interactions in poultry and swine

Mycotoxins are toxic compounds produced by fungi. When one mycotoxin is detected, one should suspect that others also are present in a contaminated feed ingredient or finished feeds. The toxicity and clinical signs of observed in animals when more than one mycotoxin is present in feed are complex and diverse. Some mycotoxins, such as the combination of aflatoxin with either ochratoxin A or T-2 toxin, interact to produce synergistic toxicity in broiler chicks. The effects observed during multiple mycotoxin exposure can differ greatly from the effects observed in animals exposed to a single mycotoxin. For example, fatty livers in poultry are used for presumptive diagnostic identification of aflatoxicosis. However, simultaneous presence of ochratoxin A prevents fatty livers. Of the mycotoxin combinations that have been investigated in poultry and swine, the aflatoxin + ochratoxin A and aflatoxin + T-2 toxin interactions appear to be the most toxic.     

The significance of mycotoxin assimilation for meat animals

Mycotoxins may influence animal health and may be responsible for alterations in carcass composition and quality. Of major interest is the formation of residues in edible tissues, which had been demonstrated for the mycotoxins aflatoxin B1 and its metabolites, for ochratoxin A, zearalenone, as well as some trichothecenes. The amount of detectable residue depends on the initial feed contamination, duration of toxin exposure and persistence of the toxin within the animal the latter varying according to the species. Thus, residues of aflatoxins and ochratoxin A could be detected with a higher frequency than residues of trichothecenes which are rapidly metabolized and therefore only rarely contribute to a contamination of edible tissues. However, sufficient data for the evaluation of approximative carry over rates are not available for all mycotoxins. The majority of mycotoxins are heat tolerant and therefore a decomposition during cooking or processing is almost unlikely.     

牛奶中霉菌毒素来源、转化及危害

霉菌毒素污染是牛奶质量安全的主要风险之一,其种类主要包括黄曲霉毒素(AFs)、赭曲霉毒素(OTs)、玉米赤霉烯酮(ZEA)、伏马毒素(FUM)、脱氧雪腐镰刀菌烯醇(DON)、T-2毒素(T-2)等。牛奶中的霉菌毒素主要来源于动物饲料,本文在国内外已有文献报道基础上,对牛奶中霉菌毒素来源、转化以及危害、限量进行综述。     

蒙脱石和凹凸棒石对霉菌毒素吸附性能的研究

试验将蒙脱石和凹凸棒石分别添加到含有黄曲霉毒素B₁(AFB₁)、玉米赤霉烯酮和T-2毒素的人工胃液或人工肠液中,探讨2种矿物对霉菌毒素的吸附作用。结果表明,蒙脱石和凹凸棒石对AFB₁、玉米赤霉烯酮、T-2毒素的吸附均在1 h达到平衡;钠基蒙脱石对AFB₁和T-2毒素的吸附率高于钙基蒙脱石和凹凸棒石,吸附率分别为96.8%、38%;蒙脱石和凹凸棒石对玉米赤霉烯酮的吸附率均小于10%。pH对蒙脱石和凹凸棒石吸附霉菌毒素影响显著(P<0.05),pH 5时钙基蒙脱石对AFB₁的吸附率显著高于pH 3、pH 7时(P<0.05),为90.1%;蒙脱石和凹凸棒石对玉米赤霉烯酮的吸附效果在pH 3时较佳,对T-2毒素的吸附效果在pH 7时显著高于pH 3、pH 5时(P<0.05)。蒙脱石和凹凸棒石对吸附的霉菌毒素均存在解吸现象,其中AFB₁和玉米赤霉烯酮解吸明显。蒙脱石和凹凸棒石对霉菌毒素的吸附作用使其成为重要的吸附剂,然而作为吸附剂的同时不能忽视霉菌毒素的解吸现象,综合考虑吸附与解吸2种现象以便在生产实践中更好的脱除霉菌毒素。     

Fusarium crookwellense-produced zearalenone in maize stubble in the field

Waste grain and vegetative material (stems and leaves) collected from a maize field several months after harvest was analysed by bi-dimensional thin layer chromatography for the presence of aflatoxins, deoxynivalenol, ochratoxin A, sterigmatocystin, T-2 toxin and zearalenone. Deoxinivalenol (0.7 mg/kg) and T-2 toxin (4.1 mg/kg) were found in the grain and zearalenone (3.0 mg/ kg) was found in the stem and leaf. No other toxins were detected. The stubble was examined for the presence of potentially toxigenic Fusarium species, and F. poae, F. moniliforme var. subglutinans and F. crookwellense were isolated and identified. When these isolates were cultured on cracked corn, only F. crookwellense was found to produce micotoxins and then only zearalenone was detected. As corn stubble is commonly grazed in Argentina and in other countries, these findings identify a further source of mycotoxins that may adversely affect animal health and productivity.     

Mycotoxins in fungal contaminated samples of animal feed from western Canada, 1982-1994.

Feed samples from 94 cases involving fungal contamination and suspected mycotoxicosis of farm animals in western Canada were examined during 1982-1994 to assess the incidence of mycotoxins. Samples were analyzed for aflatoxins, ochratoxin A, citrinin, sterigmatocystin, and the fungal estrogen zearalenone. Samples infected with Fusarium fungi were additionally assayed for nivalenol, deoxynivalenol, fusarenone-x, 15-acetyl-deoxynivalenol, diacetoxyscirpenol, HT-2 toxin, and T-2 toxin. Mycotoxins were found in 21 feed samples from 17 cases (18% of the reported cases), generally at levels far below those needed to induce symptoms under laboratory conditions. HT-2 toxin and other type-A trichothecenes were detected in 5 samples, deoxynivalenol and other type-B trichothecenes in 13, ochratoxin A in 5, and citrinin in 2. In 9 cases, symptoms observed in the animals were consistent with the known effects of the mycotoxin(s) found in the particular feed samples.     

Simultaneous detection of multiple mycotoxins in broiler feeds using a liquid chromatography tandem-mass spectrometry

Mycotoxins are secondary fungal metabolites that are typically present in grain and feed ingredients used for animal feeds. An analytical method using LC-ESI-MS/MS was developed to quantify nine mycotoxins, consisting of aflatoxin B₁ (AFB₁), AFB₂, AFG₁, AFG₂, T-2 toxin, deoxynivalenol (DON), nivalenol (NIV), zearalenone (ZEA) and ochratoxin A (OTA) in broiler feeds. In total, 100 samples of broiler feeds were collected from poultry farms in Central Thailand. The survey found that AFB₁ and ZEA were the most prevalent mycotoxins in the feed samples at percentages of 93% and 63%, respectively. The limit of detections (LODs) of investigated mycotoxins was 0.20–0.78 ng/g. AFB₂, DON, AFG₁, NIV and T-2 toxin were also detectable at low contamination levels with percentages of 20%, 9%, 7%, 5% and 1%, respectively, whereas OTA and AFG₂ were not detected in any of the feed samples. These results suggest that there is a very low level of risk of the exposure to mycotoxins in feeds obtained from broiler farms in Central Thailand.     

Fusarium crookwellense-produced zearalenone in maize stubble in the field

Waste grain and vegetative material (stems and leaves) collected from a maize field several months after harvest was analysed by bi-dimensional thin layer chromatography for the presence of aflatoxins, deoxynivalenol, ochratoxin A, sterigmatocystin, T-2 toxin and zearalenone. Deoxinivalenol (0.7 mg/kg) and T-2 toxin (4.1 mg/kg) were found in the grain and zearalenone (3.0 mg/ kg) was found in the stem and leaf. No other toxins were detected. The stubble was examined for the presence of potentially toxigenic Fusarium species, and F. poae, F. moniliforme var. subglutinans and F. crookwellense were isolated and identified. When these isolates were cultured on cracked corn, only F. crookwellense was found to produce micotoxins and then only zearalenone was detected. As corn stubble is commonly grazed in Argentina and in other countries, these findings identify a further source of mycotoxins that may adversely affect animal health and productivity.     

Mycotoxins in foods and feeds in the United States.

Mycotoxins are considered unavoidable contaminants in foods and feeds because agronomic technology has not yet advanced to the stage at which preharvest infection of susceptible crops by fungi can be eliminated. The aflatoxins have received greater attention than any of the other mycotoxins because of their demonstrated carcinogenic effects in susceptible animals and their acute toxic effects in humans. Since 1965, the U.S. Food and Drug Administration (FDA) has enforced regulatory limits on the concentrations of these toxins in foods and feeds involved in interstate commerce. The FDA routinely monitors the food and feed industries through compliance programs to ensure that the levels of exposure to these toxins are kept as low as practical. This report summarizes data generated from compliance programs on aflatoxins for the fiscal years 1989, 1990, and the first half of 1991. Commodities sampled included peanuts and peanut products, tree nuts, corn and corn products, cottonseed, and milk. Higher than usual levels of contamination were found in corn examined from all areas of the United States in 1989 as a result of the severe drought that affected the 1988 corn crop. The drought in parts of the South and Southeast in 1990 resulted in increased contamination in corn and peanuts from those areas. A review of the surveillance data obtained on deoxynivalenol, zearalenone, ochratoxin A, sterigmatocystin, penicillic acid, and patulin over the years along with available toxicological data for these mycotoxins indicated that no regulatory actions were warranted. The lack of sufficient surveillance data on other mycotoxins that occur in the United States can be attributed in part to the unavailability of reliable analytical methodology.     

The occurrence of mycotoxins in cereals and animal feed-stuffs

During the period 1976–1979, just over 4000 samples of animal feedstuffs comprising cereals, compound feeds, hay and silage were examined for moulds and mycotoxins. Examination was carried out in the course of routine advisory and investigational work undertaken by the Agricultural Development and Advisory Service (Ministry of Agriculture, Fisheries and Food) Microbiology Laboratories in England and Wales in connection with livestock health and production problems and defects in grain storage. Mouldy cereals, mostly invaded byPenicillium andAspergillus species, were often found contaminated with ochratoxin A (12.8% positive) and also with citrinin, sterigmatocystin and zearalenone to a lesser extent. Aflatoxin B1 was detected in barley which had been inadequately treated with propionic acid in 3 instances.Commerically-produced compound feedstuffs and protein concentrates were found to contain aflatoxin B1 at levels ranging from less than 10 to 750 g/kg due to the inclusion of contaminated constituents such as ground-nut, palm kernels, cottonseed and copra. There was no evidence that any significant spoilage byAspergillus flavus in compound feedstuffs after manufacture had led to the formation of aflatoxin.Mould spoilage of hay, as indicated by mould counts exceeding 100,000 per g, was common withAspergillus glaucus andPenicillium spp. frequently present, though mycotoxins were not detected, with the exception of sterigmatocystin in just one sample. Silage which had been exposed to air was frequently colonised byPaecilomyces species, giving rise to the formation of patulin in several samples. Despite the frequent detection of mycotoxins in animal feedingstuffs, there was rarely any conclusive evidence implicating them in causing impaired performance or disease in animals.     

Effects of some clinically significant mycotoxins on the incorporation of DNA, RNA and protein precursors in cultured mammalian cells

The effects of zearalenone (F-2), ochratoxin A and T-2 toxins on the synthesis of DNA, RNA and proteins in mouse L cells were studied. F-2 toxin inhibited protein synthesis to a lesser extent than DNA and RNA synthesis, whereas ochratoxin A inhibited the synthesis of each equally. Exposure to the toxins for 24 hours relatively reduced the synthetic ability of the cells. T-2 toxin inhibited protein and DNA synthesis in parallel but RNA synthesis to a lesser extent. Enhanced incorporation of tritiated thymidine was found when L cells were exposed to 0.4 to 0.016 ng of T-2 toxin ml-1 for 24 hours.     

电化学生物传感器在真菌毒素检测中的研究进展

真菌毒素是真菌在食品或饲料中生长所产生的代谢产物,这些低分子质量化合物既是天然存在的,同时也是无法避免的。真菌通过两种途径进入食物链,一方面可以直接从受真菌毒素污染的植物性食品成分进入食物链;另一方面也可以通过食物中产毒真菌生长的间接污染进入食物链。真菌毒素广泛存在于成熟的玉米、谷物、大豆、高粱、花生和饲料作物中。食用受真菌毒素污染的食物或饲料会对人和动物造成急性或慢性毒性。真菌毒素除了有直接食用受霉菌毒素污染的食物和饲料造成的不良影响外,还有因为摄入动物源性食品,如肉类、牛奶或鸡蛋,含有真菌毒素的残留物或代谢物而引起的公众健康问题。目前虽然已经鉴定出超过400种真菌毒素,但食物中广泛存在的6种毒素：黄曲霉毒素、赭曲霉毒素、玉米赤霉烯酮、伏马菌素、呕吐毒素及T-2毒素,已在世界范围内引发了持续的食品安全问题。该论文总结了6种真菌毒素的毒性,重点分析了近年来电化学生物传感器在这几种真菌毒素检测中的研究进展,旨在通过一系列的总结分析去展望其在真菌毒素检测方面的发展前景。     

青贮饲料中霉菌毒素的产生、毒性作用及脱毒研究进展

青贮饲料是反刍动物日粮中重要的组成部分,但青贮饲料在收获前、发酵期间及青贮完成后都会受到多种霉菌毒素污染。反刍动物摄入霉菌毒素后会对其健康和生产性能产生不利影响,并对食品安全及人类健康构成威胁。青贮饲料中优势霉菌包括镰刀菌属(Fusarium)、曲霉属(Aspergillus)、青霉属(Penicillium)和链格孢属(Alternaria)真菌,所产生的主要霉菌毒素包括单端孢霉烯族毒素、伏马菌素、玉米赤霉烯酮、黄曲霉毒素、赭曲霉毒素、蓝酪霉菌毒素、霉酚酸和麦角生物碱等。本文将对上述毒素在青贮饲料中的产生、影响、预防和脱毒的方法进行简要综述,以期为生产优质青贮饲料提供理论支持。     

Fungal nephrotoxins

The nature, occurrence and effects of nephrotoxic mycotoxins are considered at their different levels of involvement in animal renal disease. The four associated with field outbreaks of nephrotoxicosis, viz. ochratoxin A, citrinin, aflatoxin and oxalic acid are mainly produced by Aspergilli and Penicillia in grain and other crops, e.g. peanuts. Ten nephrotoxins detected by experimentation including cyclopiazonic acid, penicillic acid and viridicatumtoxin, may also eventually be found to play a role in these diseases. Thirteen fungi frequently isolated from foodstuffs have produced renal (mostly tubular) lesions on the feeding of cultures to animals, in the absence of known nephrotoxins. The pathological changes reported have been predominantly in the proximal tubules with profound cytoplasmic and nuclear effects. The relationship of porcine nephropathy (due to ochratoxin A) to Balkan Nephropathy and the associated urinary tract tumours in man is discussed and the close parallel to the carcinogenic hepatoxicity of the aflatoxins indicated.     

基于体外细胞模型的霉菌毒素毒性评价

霉菌毒素是由多种真菌产生的次级代谢产物,广泛存在于食品和饲料中。霉菌毒素污染的粮食和饲料会给畜牧业生产和畜产品质量安全带来极大隐患。研究霉菌毒素致毒机理,为今后研究其对动物及人的影响开展更深入更全面的研究提供理论依据。细胞模型作为一种常用的体外试验方法广泛用于毒理学研究中。本文简述了黄曲霉毒素B_1(AFB_1)、赭曲霉毒素A(OTA)、脱氧雪腐镰刀菌烯醇(DON)、玉米赤霉烯酮(ZEA)和展青霉素(PAT)的一般特性,并综述了利用细胞模型进行AFB_1、OTA、DON、ZEA和PAT毒性、联合毒性及致毒机理研究的进展。     

奶牛养殖中霉菌毒素的危害和脱毒技术

霉菌毒素是真菌产生的有毒的二级代谢产物,经常在奶牛饲料及其原料中发现。最常见的霉菌毒素是黄曲霉毒素（AF）、伏马菌素（FB）、玉米赤霉烯酮（ZEN）、脱氧雪腐镰刀菌烯醇（DON）、T-2毒素和赭曲霉毒素A（OTA）。当饲料中霉菌毒素的浓度超过一定水平时,会导致奶牛发生免疫抑制、肝肾毒性、繁殖障碍等诸多健康问题。奶牛饲料原料在生长、收获、加工和储藏过程中不可避免受到霉菌毒素的污染,应用脱毒方法是预防霉菌毒素危害奶牛健康的关键控制点。物理、化学和生物脱毒是实现霉菌毒素脱毒的常见技术措施。其中,物理吸附和生物降解脱毒具有安全、绿色、去除率高、不破坏饲料营养物质等诸多优势,是国内外研究的重点和方向。本文主要介绍了奶牛饲料中常见霉菌毒素的生物特性、致病机理及其对奶牛的危害和物理、化学、生物脱毒方法,为防控霉菌毒素污染,实现健康养殖提供参考。     

霉菌毒素的研究进展

霉菌毒素是霉菌在生长繁殖过程中产生的有毒次级代谢产物,在饲料中广泛存在,主要包括黄曲霉毒素、赭曲霉毒素、烟曲霉毒素、玉米赤霉烯酮、单端孢霉菌素等。目前,关于单一霉菌毒素的毒性研究报道较多,而对多种霉菌毒素的联合毒性进行探索将是今后霉菌毒素研究的热点。