T-2毒素毒性作用研究进展

<正>T-2毒素是由镰刀菌产生的一种单端孢霉烯类真菌毒素,通常存在于植物来源的各种食品中,可通过多种途径被迅速吸收,引起全身毒性。T-2毒素可随着食物链传递给人类,严重威胁人和动物的健康,因此关于其毒理学研究备受关注。T-2毒素是一种倍半萜烯类化合物,这种化合物含有的环氧键和双键被认为是其产生毒性的关键基团,其毒性作用主要机制是抑制蛋白质合成和对细胞产生氧化损伤,从而对消化、神经、免疫、生殖系统等产生不同程度的影响。本文将着重介绍T-2毒素的多种毒性作用。     

植物病原镰刀菌产生的毒素种类及其危害

镰刀菌(Fusarium spp.)是多种重要农作物的病原体,不仅可造成农作物产量和品质的严重损失还可在离体培养条件下或植物寄主体内产生一系列被称为镰刀菌毒素的次生代谢产物.这些毒素一方面作为致病因子与镰刀菌对宿主植物的致病力密切相关,另一方面可导致家畜生产性能下降和相关病症的出现,进而影响农业生态系统并对人类健康造成威胁.鉴于镰刀菌毒素对农作物生产的影响及其对家畜和人类的毒性作用,目前已有较多关于镰刀菌侵染粮食作物后产生毒素种类的研究,但关于镰刀菌侵染豆科牧草后产生的毒素种类以及毒素在镰刀菌对豆科牧草致病力方面作用的研究则较少.本文对引起主要粮食和饲料作物病害的常见镰刀菌物种产生的主要毒素,以及这些毒素对植物、家畜和人类的危害进行了综述,并对豆科牧草中镰刀菌毒素的研究前景及意义进行了展望.     

植物病原镰刀菌产生的毒素种类及其危害

镰刀菌(Fusarium spp.)是多种重要农作物的病原体，不仅可造成农作物产量和品质的严重损失还可在离体培养条件下或植物寄主体内产生一系列被称为镰刀菌毒素的次生代谢产物。这些毒素一方面作为致病因子与镰刀菌对宿主植物的致病力密切相关，另一方面可导致家畜生产性能下降和相关病症的出现，进而影响农业生态系统并对人类健康造成威胁。鉴于镰刀菌毒素对农作物生产的影响及其对家畜和人类的毒性作用，目前已有较多关于镰刀菌侵染粮食作物后产生毒素种类的研究，但关于镰刀菌侵染豆科牧草后产生的毒素种类以及毒素在镰刀菌对豆科牧草致病力方面作用的研究则较少。本文对引起主要粮食和饲料作物病害的常见镰刀菌物种产生的主要毒素，以及这些毒素对植物、家畜和人类的危害进行了综述，并对豆科牧草中镰刀菌毒素的研究前景及意义进行了展望。     

T-2毒素的理化特性及其对家禽的毒害作用

T-2毒素是A类单端孢霉稀族毒素中毒性最强的一种真菌毒素,是多种镰刀菌的次级代谢产物,并广泛存在于谷物和动物饲料当中,T-2毒素也成为当前研究的热门课题之一。禽类对T-2毒素比较敏感,摄入剂量和接触时间不同会产生不同的毒性效应。根据不同的接触时间,禽类会出现急、慢性毒性作用,另一方面,T-2毒素能够引起禽类不同系统的毒性,包括消化系统毒性、免疫系统毒性、生殖系统毒性、神经系统毒性等。本文着重论述了T-2毒素的相关信息以及其对禽类的毒性作用。     

饲料中霉菌毒素脱毒方法的研究进展

1主要产毒霉菌现在已明确能产生对人体毒害作用的霉菌有300多种,主要是曲霉菌属(aspergillus)、青霉菌属(pe nicilli-um)和镰刀菌属(fusarium)的霉菌产生。1.1曲霉菌属包括黄曲霉、杂色曲霉、构巢曲霉、棕曲毒、寄生曲霉、棒曲霉等。表面一般是绒毛状,开始为灰白色或白色,长出孢子后因菌种不同而呈现不同颜色。它们在生长繁殖过程中会产生黄曲霉毒素、赫曲霉毒素、杂色曲霉毒素等多种毒菌毒素。1.2镰刀菌属包括禾谷镰刀菌、三线镰刀菌、孢镰刀菌、梨孢镰刀菌、串珠镰刀菌、木贼镰刀菌、前病镰刀菌、粉红镰刀菌、尖孢镰刀菌等。一般呈白色绒…     

单端孢霉烯族毒素抑制动物生长作用的研究进展

单端孢霉烯族毒素是主要的饲料污染物,包括T-2毒素、脱氧雪腐镰刀菌烯醇(DON)等,具有较强的毒性作用,能引起动物体多种病理变化。其毒性作用能改变真核翻译起始因子2α(EIF2α)、丝裂原激活的蛋白激酶(MAPK)、热休克蛋白90(Hsp90)、胰岛素样生长因子1(IGF-1)等细胞因子的活性,调节多种胺酰tRNA合成酶的活性,进而抑制蛋白质合成,阻滞动物生长。论文从单端孢霉烯族毒素对生长激素影响的角度,综述了该类毒素对动物生长的抑制作用,以期为阐明单端孢霉烯族毒素抑制动物生长的毒性作用机制奠定基础。     

T-2毒素的毒性作用及其诱导细胞凋亡机制概述

T-2毒素是一种毒性作用很强的霉菌毒素,是以镰刀菌属为主要产毒菌株所产生的一种A类单端孢霉烯族毒素,在多种谷物中的污染水平较高,通过食物摄入后在人类和动物机体内产生一系列毒性作用,严重威胁人类和动物的健康。论文从T-2毒素的理化性质、产毒菌株、毒性作用及对细胞凋亡的作用机制进行了简述,重点介绍了T-2毒素在免疫系统、消化系统和肝脏毒性、神经和皮肤毒性、血液毒性、生殖毒性方面的研究进展,以及T-2毒素通过线粒体信号通路介导细胞凋亡机制的研究进展,为T-2毒素的深入研究提供参考。     

镰刀菌毒素污染谷物和动物饲料的研究进展

谷物和相关的副产品构成了所有类型牲畜的重要能量和蛋白质来源。当谷物和动物饲料被霉菌定殖时,存在这些真菌的次生代谢产物污染的巨大风险。这些真菌化合物中的许多具有对动物和人类的毒性作用,并被赋予霉菌毒素的统称。镰刀菌、曲霉、青霉和链霉菌的许多种不仅是公认的植物病原体,而且还是动物和人类健康中关注的重要真菌毒素的来源。本文综述了镰刀菌毒素污染谷物和动物饲料的研究进展。     

呕吐毒素对动物免疫及繁殖性能的影响

脱氧雪腐镰刀菌烯醇(呕吐毒素)是分布最广泛的镰刀霉菌毒素之一。由于其广泛存在于谷物类饲料中,已经成为动物饲料中毒的重要原因之一。呕吐毒素对动物机体具有免疫毒性,在免疫水平上影响免疫细胞、细胞因子及免疫球蛋白的产生。另外,其通过作用于卵母细胞和通过胎盘直接影响胎儿2种方式来影响动物的繁殖性能。就国内外有关脱氧雪腐镰刀菌烯醇的免疫毒性及对动物繁殖性能影响的研究进行综述。     

饲料中镰刀菌毒素的危害和控制

饲料的生物性污染中以霉菌及霉菌毒素的危害最大,目前已明确能造成人和动物毒害的有300多种,主要有曲霉菌属,镰刀菌属和青霉菌属。镰刀菌可分泌多种毒素,包括单端孢霉烯族化合物、烟曲霉菌毒素、玉米赤霉烯酮等,其产生的毒素在全球危害最大。它们是谷类饲料和青贮料中最普遍存在的霉菌毒素。可以降低家畜的耗料量,导致生长下降,免疫抑制,繁殖障碍等。以拒食和繁殖障碍为标准,通常认为猪是对饲料中霉菌毒素最敏感的动物。镰刀菌在谷物上适宜繁殖的温度为16℃～24℃,相对湿度为85%;如在土壤中,则分别为12℃～24℃和40%～60%,故凡适合此菌生长…     

玉米赤霉烯酮和脱氧血腐镰刀菌烯醇对雌性动物的生殖毒性及作用机制

镰刀菌毒素玉米赤霉烯酮(ZEA)和脱氧血腐镰刀菌烯醇(DON)广泛存在于受污染的谷物和饲料中。体内和体外研究表明,ZEA和DON均可影响雌性动物的繁殖性能,引起生殖器官、胎儿形态,生殖细胞成熟率,性激素分泌的改变。本文综述了ZEA和DON对雌性动物繁殖性能的影响及潜在的作用机制。     

The Fusarium toxins deoxynivalenol (DON) and zearalenone (ZON) in animal feeding

The contamination of cereal grains with toxic secondary metabolites of fungi, mycotoxins, is a permanent challenge in animal nutrition as health and performance of the animals may be compromised as well as the quality of animal derived food. Therefore the present article reviews the issue of mycotoxins in animal nutrition. As the Fusarium toxins deoxynivalenol (DON) and zearalenone (ZON) are of particular importance under the production conditions in central Europe and Germany, with respect to their frequent occurrence in toxicologically relevant concentrations, special emphasis is layed on those mycotoxins. The effects of DON and ZON on susceptible animals as well as management strategies to cope with the contamination of grain with those toxins are reviewed.     

Fusarial toxins and their role in animal diseases

Fusarial toxins are toxic metabolites produced mostly by toxigenic micromycetes of genus Fusarium. Dominant mycotoxins of this group include trichothecenes, moniliformin, zearalenone, and fumonisins. Recently, special attention has been paid to these toxins because of their harmful effects on both animals and humans. On the basis of the available literature, we review here the characteristics of major fusarial mycotoxins with an emphasis on their toxic effects on animals. The most important fusarial mycotoxins, their sources, and their pathology including clinical signs, necropsy findings, as well as changes in haematological, biochemical, and immunological indices, are addressed.     

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。     

牛奶中霉菌毒素共污染及联合毒理效应

霉菌毒素是由镰刀菌、曲霉和青霉等丝状真菌产生的低分子质量次级代谢产物。食品和饲料中霉菌毒素的共污染现象广泛存在,深受各国相关从业者和研究人员的重视,但直到今天,有关霉菌毒素的联合毒理效应研究仍然有所欠缺,如低毒性长期暴露的体内试验如今仍然很少。目前,世界范围内相关标准和法规的建立普遍只关注于单独霉菌毒素的毒理效应。牛奶作为居民日常消费的主要产品,同时更是婴幼儿前期成长过程中重要的食物来源,其安全性尤为重要。本文综述了牛奶中霉菌毒素共污染及联合毒理效应的研究进展,可以为牛奶和奶制品中霉菌毒素共污染风险评估及相关标准的建立和完善提供参考。     

Mycotoxins and mycoflora in animal feedstuffs in western Canada.

Feed samples associated with 51 cases of suspected or potential mycotoxicoses of farm animals in western Canada were examined during a three year study. Ochratoxin A was detected in four cases, T-2 toxin and diacetoxyscirpenol in one, and sterigmatocystin in one. Samples examined for microflora associated with production of these mycotoxins contained Penicillium spp., Aspergillus ochraceus, Fusarium spp. and fungi of the Aspergillus glaucus group. Samples were analyzed for T-2 toxin and diacetoxyscirpenol only if Fusarium spp. were present. The first known incidence of suspected sterigmatocystin poisoning of poultry through feed ingestion has been encountered.     

Effects of feeding a blend of grains naturally contaminated with Fusarium mycotoxins on swine performance,brain regional neurochemistry,and serum chemistry and the efficacy of a polymeric glucomannan mycotoxin adsorbent

The co-occurrence of Fusarium mycotoxins in contaminated swine diets has been shown to result in synergistic toxicity beyond that observed for individual toxins. An experiment was conducted, therefore, to investigate the effects of feeding a blend of grains naturally contaminated with Fusarium mycotoxins on growth, brain regional neurochemistry, serum immunoglobulin (Ig) concentrations, serum chemistry, hematology, and organ weights of starter pigs. Three levels of glucomannan polymer (GM polymer, extract of yeast cell wall, Alltech Inc.) were also tested for its efficacy to overcome Fusarium mycotoxicoses. A total of 175 starter pigs (initial weight of 10 +/- 1.1 kg) were fed five diets (seven pens of five pigs per diet) for 21 d. Diets included (1) control, (2) blend of contaminated grains, (3) contaminated grains + 0.05% GM polymer (4) contaminated grains + 0.10% GM polymer and (5) contaminated grains + 0.20% GM polymer. Diets containing contaminated grains averaged 5.5 ppm deoxynivalenol, 0.5 ppm 15-acetyldeoxynivalenol, 26.8 ppm fuuric acid, and 0.4 ppm zearalenone. Feed intake and weight gain of all pigs fed contaminated grains was significantly reduced compared to controls throughout the experiment. The weights of liver and kidney, expressed as a percentage of body weight, were lower in pigs fed the contaminated diet than in those fed the control diet. The feeding of contaminated grains significantly reduced concentrations of dopamine in the hypothalamus and pons and concentrations of dihydroxyphenylacetic acid and norepinephrine in the pons. The ratios of 5-hydroxyindoleacetic acid to serotonin, however, were elevated in the hypothalamus and pons. The feeding of contaminated grains increased serum IgM and IgA concentrations, while serum IgG concentrations were not altered. The supplementation of GM polymer prevented some of the mycotoxin-induced alterations in brain neurotransmitter and serum Ig concentrations. In summary, the feeding of grains naturally contaminated with Fusarium mycotoxins reduced growth, altered brain neurochemistry, increased serum Ig concentrations, and decreased organ weights in starter pigs. Some of the Fusarium mycotoxin-induced changes in neurochemistry and serum Ig concentrations can be prevented by the feeding of yeast cell wall polymer at appropriate concentrations, although this was not reflected in increased growth rate under these experimental conditions.     

Some fungi, zearalenone and other mycotoxins in chicken rations, stock feedstuffs, lucerne and pasture grasses in the communal farming area of Rhenosterkop in South Africa

Mycotoxins may be present in feeds without any visible signs of mould contamination. There is a need for rapid and accurate measurement of mycotoxins for purposes of continual monitoring and identification of high risk commodities. Samples from commercial chicken feed (maize kernels), cattle feed (lucerne, grass and hay) and milk were analysed for the presence of certain mycotoxins and cultured for fungi. Results of fungal profiles showed that most samples were contaminated by moulds belonging to the genera, Alternaria, Aspergillus, Fusarium, Penicillium, Mucor, Phoma and Rhizopus. All the chicken feed samples tested contained mycotoxins either below the recommended safe levels for poultry or below the detection limits of the ELISA tests. However, samples of grass contained levels of zearalenone greater than the allowable concentration for dairy and beef cattle (250 ppm), which may be linked to the presence of Fusarium scirpi identified in the fungal profiles. The levels of AFMI were below the detection limits of the ELISA tests, which may be attributed to the low levels of aflatoxins found in the feed (grass) samples. The presence of the fungus in samples analysed is not evidence for the presence of mycotoxins.     

镰孢霉菌的侵染规律、单端孢霉烯族毒素形成及调控机制

镰孢霉菌是一类数量大、种类繁多的真菌。它是农作物的重要病原体,可引起多种农作物腐烂和枯萎病,其中以小麦头痂病和玉米穗腐病最为普遍。镰孢霉菌代谢所产生的霉菌毒素也会污染农产品,其中单端孢霉烯族毒素污染粮食和饲料的问题非常普遍,是食品安全的重大威胁。单端孢霉烯族毒素对谷物特别是玉米和小麦的污染已成为一个全球性的问题,每年对种植业和养殖业造成巨大的经济损失。镰孢霉菌污染农作物以及霉菌毒素的产生是一个具有连续效应的过程,对镰孢霉菌的生长条件,侵染机制及毒素生成规律的研究有助于找到解决这一问题的对策。文章对镰孢霉菌侵染植物的规律,霉菌毒素形成过程以及调控技术加以综述。     

Effects of feeding grains naturally contaminated with Fusarium mycotoxins with and without a polymeric glucomannan mycotoxin adsorbent on reproductive performance and serum chemistry of pregnant gilts

Contamination of animal feedstuffs with Fusarium mycotoxins can cause reduced feed intake and hyperaminoacidemia resulting from reduced hepatic protein synthesis. The current study investigated the effects of feeding grains naturally contaminated with Fusarium mycotoxins on reproductive performance, serum chemistry, ADFI, and ADG of gilts, and tested the ability of a polymeric glucomannan mycotoxin adsorbent (GMA) to reduce or eliminate the effects of the contaminated feeds. Thirty-six Yorkshire gilts were fed 3 diets (n = 12 gilts/diet) from 91 +/- 3 d of gestation until farrowing. Diets included 1) control, 2) contaminated grains, and 3) contaminated grains + 0.2% GMA. Diets contaminated with Fusarium mycotoxins did not affect ADFI (P = 0.24), but ADG (P = 0.029) and G:F (P = 0.047) were reduced. Serum concentrations of beta-hydroxybutyrate, haptoglobin, protein, albumin, globulin, urea, glucose, cholesterol, Ca, Na, Mg, P, K, and Cl, and hepatic enzyme activities were not affected by diet. The frequency of stillborn piglets was greater (P = 0.03) for gilts fed contaminated grains compared with that of gilts fed contaminated grains + GMA. The feeding of contaminated grains + GMA also increased (P = 0.026) the percentage of pigs born alive compared with gilts fed the contaminated diets. In conclusion, feeding gilts diets that are naturally contaminated with Fusarium mycotoxins can increase the incidence of stillborn piglets and this effect can be reduced by dietary supplementation with GMA.