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霉菌毒素在动物饲料、饲料原料和人类食品中广泛存在，它是由霉菌在农产品中产生的一系列具有广泛化学结构的有毒次级代谢产物。霉菌毒素污染不仅可造成畜牧业经济损失，部分霉菌毒素还具有致癌性或致畸胎性，且可在动物的肉、蛋、奶中残留，由食物链进入人体，对人类健康构成严重威胁。
我国霉菌毒素污染比较严重，动物采食被霉菌毒素污染的饲料可引起一些疾病。因此，饲料霉菌毒素感染已成为饲料工业和畜牧业不可忽视的问题，消除霉菌毒素，对保证动物健康，充分发挥动物的生产潜能降低经济损失有重大意义。而与其他家畜比较，猪的饲养管理最为粗放，因而猪的饲料中毒病，在各种家畜中发病概率最高，其造成的经济损失也最大。
1 霉菌毒素的产生与分类
对畜禽养殖业危害较大的霉菌毒素主要是由以下四种霉菌属所产生：曲霉菌属（主要分泌黄曲霉毒素AFT、赭曲霉毒素等），青霉菌属（主要分泌桔霉素），镰刀菌属（主要分泌T-2毒素、呕吐毒素DON、玉米赤霉烯酮、伏马毒素等），麦角菌属（主要分泌麦角毒素）。
迄今为止已经有超过300种霉菌毒素被分离和鉴定出来，上述的几种毒素即为现今普遍认识的8种主要毒素。
2 霉菌毒素的作用机理
霉菌毒素影响广泛，从动物的急性死亡，慢性死亡到生长缓慢和繁殖性能降低。摄入一定量的霉菌毒素可削弱其免疫力，降低动物对传染性疾病的抵抗力，可使动物脏器损伤（如肝脏、肾脏、胃肠道和繁殖器官等），繁殖性能下降，并且在动物性产品中残留，对人类健康造成危害。
霉菌毒素中毒主要是动物食入了被毒素污染的饲料，日粮中营养成分不足，缺乏蛋白质、硒和维生素也是引起霉菌毒素中毒的因素之一。由于大多数常见霉菌毒素的中间产物或终产物的毒性与霉菌毒素的毒性不同，因此减少或增加外源性的化合物、代谢的药物可影响机体对毒素的反应，这类药物对黄曲霉毒素和赭曲霉毒素的作用比较大，而对单端孢霉毒素相对比较小。
通常饲料中霉菌毒素不是单一存在而是两种或几种同时存在，当不同毒素同时存在时，霉菌毒素的毒性会可能出现加性效应、亚加性效应、协同效应、增效效应和颉颃效应。加性效应（Synergistic effects）是指2种霉菌毒素的组合作用等于二者单一作用的累积相加。亚加性效应（Less than additive effects）是指发生于2种霉菌毒素的组合作用低于二者单一作用的累积相加。协同效应（Synergistic effects）指2种霉菌毒素的组合作用高于二者单一作用的累积相加。增效效应（Potentiate effects）指一种霉菌毒素对某组织或器官不产生毒性作用，但摄人另一霉菌毒素后，前者使后者毒性增强。颉颃效应（Antagonistic effects）是指一种霉菌毒素干扰另一种霉菌毒素的毒性作用，这种情况较少见。
2.1 黄曲霉毒素
黄曲霉毒素（aflatoxin，简称为AF）在各霉菌毒素中，被认为毒性最强，危害最大的致癌物质，其耐热性强，超过80℃才能破坏，在紫外线照射下能产生荧光，是黄山霉菌和寄生曲霉菌的产物，几乎所有动物对AF都敏感，禽类最为敏感。AF对幼龄动物的毒性强，致死率高，而成年动物的耐受力较强。黄曲霉菌（AF）可分为黄曲霉菌B1、B2、G1、G2、M1、M2 ，其中危害最大，毒性最强的是黄曲霉菌B1 （简称为AFB1），对动物的主要影响是致肿瘤、免疫抑制、致突变和致畸，影响的主要靶器官是肝脏，是一种肝毒素，可引起肝脏出血、肝脏脂肪变性、胆管增生等，并可导致肝癌的发生（徐运杰等，2008；胡兰等，2001）。
黄曲霉毒素是养猪生产中危害最严重的毒素，对猪的危害主要有
（1）是最强的免疫抑制剂，当猪采食受其污染的饲料后，首先免疫系统受到干扰，对疫病易感性提高，药物治疗效果差。
（2）是凝血因子抑制剂，表现在伤处长时间流血不止及浆膜下层淤斑出血，小肠和结肠出血等。
（3）侵害肝脏，致使肝功能下降，肝脏肿大，胆汁分泌减少，导致饲料中蛋白质和脂肪利用率下降（李梦云等，2005）。研究表明：生长育肥猪日粮中含黄曲霉毒素200-400μg／kg时，猪生长受阻和饲料报酬降低；含400-800μg／kg时，造成肝脏显微损伤，胆管炎、肝炎，有免疫抑制作用；含800-1200μg／kg时，生长受阻，采食量减少，被毛粗糙，黄疸，低蛋白血症；含1200-2000μg／kg时，表现为黄疸，凝血病，精神沉闷，厌食，部分死亡（闫甫等，2007）。
2.2 赭曲霉毒素
赭曲霉素（Ochratoxin，简称OCT）是由曲霉属及青霉属中的某些菌种产生的一类结构相似的有毒次生代谢产物，其中以赭曲霉毒素A（Ochratoxin A，简称OTA）的毒性最强。其毒性与黄曲霉毒素相当，肾是其主要的靶器官，是一种肾毒素，赭曲霉毒素A几乎对所有的动物都有肾毒性。尤其是人类，低摄入量时可造成生殖性能下降。研究表明，OTA对所有的单胃哺乳动物均有肾毒性，可引起动物肾萎缩或肿大、颜色变灰白、皮质表面不平及断面可见皮质纤维性变；
显微镜下可见肾小管萎缩、间质纤维化、肾小球透明变性和肾小管环死等，并伴有尿量减少、血中尿素氮升高、对氨基马尿酸清除降低、尿频、尿蛋白和尿糖增加等肾功能损害（李鹏等，2009）。试验表明给猪饲喂含赭曲霉毒素1mg/kg的饲料3个月，可引起腹泻、厌食和脱水，出现生长迟缓，饲料利用率低，剖检多见肾苍白、坚硬，即橡皮肾。除肾毒性外，OTA还有肝毒性、抑制免疫、致畸和致癌性。在生殖毒性方面，对于雄性动物而言，赭曲霉毒素A还可以使公猪精液品质下降（Biroeta1，2003）。
2.3 桔青霉素
桔青霉素（Citrinin）是青霉属和曲霉属的某些菌株产生的真菌毒，是一种肾毒素，它能引起猪、鸡、鸭和鸟类等几乎所有动物发生肾脏病变，但急性毒性在不同的品种之间有所差异。对鸭来说，半致死剂量是57mg／kg；鸡是95mg／kg；兔子是134mg／kg。桔青霉素与赭曲霉毒素A有协同作用，可抑制鼠科动物肾脏RNA的合成，小麦、燕麦、黑麦、大麦、玉米、稻谷等都可生长桔青霉素（刘仁荣等，2004）。
2.4 单端孢霉烯族毒素
单端孢霉烯毒素是由镰刀菌属产生的结构相似的一类化合物的总称，种类超过148种，其中主要代表有：T-2毒素（T-2 toxin）、二乙酰基镳草镰刀菌烯醇（DAS）和脱氧雪腐烯醇。主要损害动物的肝脏和肾脏，而且大多属于组织刺激因子和致炎物质。T-2毒素主要作用于细胞分裂旺盛的组织器官，如胸腺、骨髓、肝、脾、淋巴结、生殖腺及胃肠粘膜等，抑制这些器官细胞蛋白质和DNA合成，并造成神经机能损害。
T-2毒素或DAS会损伤禽类的消化道粘膜，引起口腔溃疡，一般临床症状表现为食欲减退或丧失，胃肠炎症，出血，呕吐，免疫机能降低等（Kubena等，1994）。猪对DON最敏感，主要导致猪食欲减退、拒食、呕吐和胃肠道损伤。许多研究显示：当日粮DON水平达3-5mg/kg时，猪的食欲大大减退，生长和生产性能下降。当生长育肥猪采食含有14mg/kg DON的饲料后，10~20min即会出现呕吐，不正常的焦虑和磨牙现象，DON对泌乳母猪的影响更严重，由于食欲不振导致母猪的泌乳量减少，从而导致仔猪生长速度缓慢。
另项研究表明：DON含量在0-14mg/kg的试验中，饲粮中每增加1mg/kg DON，生长肥育猪的采食量减少6％，含毒量超过10mg/kg时，即完全拒食（Trenholm等，1994）。饲料摄入量降低与饲料中DON浓度升高呈线性关系。其它的单端孢霉烯族毒素对反刍动物的健康或生产性能无影响（侯然然等，2007）。研究还表明T-2毒素对不同动物的毒性还有一定种属差异，新生或未成年动物比成年动物对毒素更敏感，雄性动物比雌性动物也要敏感（霍星华等，2008）。
2.5 玉米赤霉烯酮
玉米赤霉烯酮是镰刀霉菌通过聚酮途径合成的对哺乳动物具有雌激素样效应的一类次级代谢产物。适宜的条件下，所有的谷物类作物或饲料产品都可受到玉米赤霉烯酮的污染。猪对玉米赤霉烯酮最敏感，而受影响最大的部位是其生殖系统。由于玉米赤酶烯酮具有类雌激素作用，低于l mg／kg时导致动物表现出雌性化特征，公猪会表现睾丸萎缩，乳头增大的雌性特征。
对于母猪而言，含量过高可以引起排卵、假怀孕、胎儿发育等，临床特征也表现为外阴充血、水肿、乳房肿大和乳头肥大、严重时可造成阴道和直肠脱（郭成志等，2010）。玉米赤酶烯酮能与类固醇合成相关酶反应，影响类固醇的形成，干扰内分泌系统，它长期的效应和对后代的毒性效应有待进一步研究。
2.6 伏马毒素
伏马菌素是由镰刀菌属产生的水溶性代谢产物，是一类由不同的多氢醇和丙三羧酸组成的结构类似的双酯化合物。其中FB1毒性最强，是近年来发现的能损伤免疫系统、肝肾，降低动物生产力甚至引起动物死亡的一种霉菌毒素。伏马菌素与猪肺水肿病（PPE）有关，导致猪肺毛细血管上皮细胞的变化，呼吸障碍，心脏机能损伤（Diaz等，1994），而对马来说，伏马菌素可引起脑白质液化性坏死（ELEM）、大脑皮层损伤、共济失调、局部麻痹、神情冷漠、运动功能削弱等，还会引起羊肝肾病变（王少康，2003
），另外小剂量的呕吐毒素和伏马毒素可以激活许多免疫反应，如细胞因子表达增加。
结合上述霉菌毒素的毒性机制，可以得出霉菌毒素中毒主要表现在对动物免疫系统、胃肠道、肝脏、肾脏及生殖系统等的影响。表3给出不同霉菌毒素对猪机体的毒性水平。由表可以看出霉菌毒素对猪的免疫机能、繁殖能力、采食量和肝脏肾脏都有影响，并且每一种毒素对各机能的影响程度不同。
3 霉菌毒素对全国饲料的污染情况
根据联合国粮农组织（FAO）资料，全世界每年约有25％的谷物不同程度地受到霉菌毒素的影响，约2%的农作物因污染严重而失去营养价值和经济价值。对中国28个省市自治区194份饲料及原料玉米、麦麸的调查结果显示，DON、T-2毒素和ZEN的污染率分别为50.0%、18.1%和26%（计成等，2007）。动物性原料鱼粉同时被多种霉菌毒素污染的情况也很普遍，霉变的饲料被动物采食后，毒素及其代谢产物可残留在畜产品及其加工制品中，通过食物链进入人体，这些具有极强致病及致癌作用的毒素严重威胁人类的健康。
敖志刚等（2008）发现副产品原料，特别是玉米副产品如干燥酒糟（DDGS）和玉米蛋白粉中霉菌毒素的污染非常严重，并且饲料原料和全价饲料中多种霉菌毒素往往同时存在，由于不同毒素间具有协同作用，将加剧毒素的毒性作用和中毒症状的严重程度。张丞等（2009）对2009年上半年中国饲料和原料抽样调查的结果显示，在90份样品中，完全没有检测出霉菌毒素的样品仅8份，占样品总数的8.9％；只检测到1种霉菌毒素的样品数为7份，占样品总数的7.8％；同时检测到含4种以上霉菌毒素的样品数占67.8％。黄广明等（2010）分析了我国2008年、2009年和2010年从多个省市的饲料厂及养殖场客户采集饲料原料及配合饲料样品，结果发现，在我国大部分地区，玉米赤霉烯酮和呕吐毒素的污染情况较严重，尤其是2009年和2010年。
4 猪霉菌毒素中毒的预防
饲料中各种霉菌毒素之间有协同作用，几种霉菌毒素协同作用对动物健康和生产性能的影响比任何一种霉菌毒素单独作用都要大。使猪群中毒时临床症状更为复杂，特别是当有细菌性和病毒性因素存在的情况下尤为突出。因而，在临床上多种霉菌毒素和细菌、病毒混合感染引起猪群中毒的诊断变得更为困难。猪霉菌毒素中毒诊断比较困难，中毒后的治疗效果不理想，猪场应提前采取有效措施加以预防。
4.1 饲料防霉措施
饲料的防霉要从源头做起，增强抗霉菌植物的培育、选用抗霉菌品系、加强田间管理。对于无法避免的污染，在收获和储藏的过程中应选择合适的收获时间、储藏在温度和湿度合适的场所。需要严格控制饲料原料的水份含量。水分是决定饲料中霉菌能否生长的一个最主要因素。
理想的物料中含水量应不超过12％，含水量>l5％时可致霉菌生长和大量繁殖，饲料含水l7％~ 18％为真菌繁殖产毒的最适条件。保持设备清洁，不仅控制病原菌，而且要控制和减少霉菌和霉菌毒素在饲料生产设备内生长。必要时添加防霉剂，这即经济又可大量获得的防霉剂主要为短链脂肪酸，如甲酸、乙酸和丙酸，目前最常用的防霉剂是丙酸盐，包括丙酸钠、丙酸钙、丙酸铵和二丙酸铵。
丙酸盐具有对饲料设备无腐蚀、稳定和在饲料中长期起防霉作用的优点。需要指出的是，防霉剂可以抑制霉菌的生长，而对饲料或饲料原料中已经存在的霉菌毒素不起任何作用。
4.2 霉变饲料的脱毒处理
化学方法
碱处理、臭氧处理、氨处理法以及一甲胺和氢氧化钙处理可能有一定的效果。臭氧是一种对双键物质有优先作用效果的强氧化剂。臭氧可在体外通过化学反应降解AFB1、AFGl、AFB2和AFG2，这一点已经通过试验证实。
何祖平等用碳酸氢钠、次氯酸钠、氢氧化钠和氯化钠对青霉酸进行脱毒，碳酸氢钠、次氯酸钠和氢氧化钠具有一定的脱毒效果。重亚硫酸钠与AF反应生成水溶性产物，从而解除AF的毒性。应当注意的是这种方法只对某种毒素有效，并不是全都能降解，另外这些化学品在饲料中的残留问题无法有效和经济的解决，因此不太实用，且存在危险。
吸附剂的使用
用来控制饲料或食品中霉菌毒素最常用的方法是使用霉菌毒素吸附剂。大多数霉菌毒素吸附剂通过降低霉菌毒素质量浓度而减少其进入血液和靶细胞的机会，从而起到有效防止霉菌毒素产生毒害的作用。主要包括无机盐类吸附剂及有机霉菌毒素吸附剂两大类。
然而，各种吸附物质对不同种毒素的吸附能力和吸附的效果都各不相同，而同时使用多种吸附剂复合使用是否能达到预期的那种吸附效果叠加的效应应该做试验加以论证。因此，在实际生产中，饲料、原料霉变中毒的情况依旧严重。且吸附剂不仅吸附霉菌毒素，也吸附饲料中的小分子物质，如生物素，从而引发母猪肢蹄病。
5 猪霉菌毒素中毒的修复
猪霉菌毒素中毒后，由于侵害的是肝脏、肾脏等功能性器官与免疫系统的抑制，几乎没有很好的方法进行治愈，这与人类患脂肪肝、肝硬化的治疗是同一个道理，核心在于减轻脏器负担和尽量修复其功能。
我们以肝脏修复为例：
肝脏是动物体内最为复杂的器官之一，承担着蛋白质、糖类及脂类的合成、分解与储存，尤其是脂质代谢，肝脏合成脂蛋白，有利于脂质运输，也是脂肪酸氧化和酮体形成的主要场所。正常时肝含脂质量不多，约为4％，其中主要是磷脂。若肝脏不能及时将脂肪运出，脂肪在肝细胞中堆积，即形成脂肪肝。在肝脏堆积的脂肪，可影响肝细胞功能，破坏肝细胞，使结缔组织增生，造成肝硬变。
而各种营养物质的合成代谢都需要依靠相应的酶、维生素、活性物质等活性因子来完成，而这些活性因子大部分也是有肝脏自身合成，如活性磷脂、胆汁酸、脂蛋白等等，才能顺利完成脂质代谢。因此，补充肝脏所需的活性因子是修复肝脏疾病的良好药物，这也是大部分的肝病辅助药物都是酶类、维生素类、氨基酸类等，饮食也是清淡蔬菜为主。
6 总结
霉菌毒素污染范围广泛，危害程度严重，是饲料工业和畜牧养殖业的重大问题，如何有效防控和降解饲料和食品中的霉菌毒素将是畜牧业和食品工业亟待解决的科学难题。
The English version
 
Mycotoxins in animal feed, feed raw materials and widely exist in the human food, which is produced by mould in agricultural products series of toxic secondary metabolites with a broad range of chemical structure. Mycotoxin contamination animal husbandry economy loss, not only can cause fetal part have carcinogenic mycotoxin or birth defects, and can be in the animal residues in meat, eggs, milk, from the food chain enter human body, a serious threat to human health.
Mycotoxin contamination is serious in our country, feed animals feed of mycotoxin contamination can cause some diseases. Therefore, feed mycotoxins infection has become a feed industry and animal husbandry, the lack of eliminate mycotoxin, to guarantee the animal health, give full play to the animal production potential has great significance to reduce economic loss. Compared with other domestic animals, and the most extensive pig breeding management, thus the pig feed poisoning disease, the highest in all kinds of livestock disease probability, its biggest economic losses caused by.
1 mycotoxin produced and classification
For livestock and poultry breeding harm larger mycotoxin is mainly produced by the following four moulds belong to: aspergillus species (mainly secreted aflatoxin AFT, ochre and aspergillus toxin, etc.), penicillium (mainly secreted citrinin), sickle bacteria genera (mainly secrete toxins DON T 2 toxin, vomiting, corn gibberellic ketene, fu ma toxin, etc.), claviceps (mainly secreted ergot toxin).
So far there have been more than 300 kinds of mycotoxin were separated and identified, and the above several toxin is the current understanding of eight kinds of main toxins.
The mechanism of the 2 mycotoxins
Mycotoxin, from animal acute death, chronic death to slow growth and reproductive performance. Consume a certain amount of mycotoxin can weaken the immune system, reduce the animal's ability to fight infectious diseases, can make the animal viscera damage (such as liver, kidney, gastrointestinal tract, and reproductive organs, etc.), reproductive performance, and residues in animal products, cause a harm to human health.
Mycotoxin poisoning mainly animal feed into the feed contaminated by toxins, lack of nutrients in the diet, lack of protein, selenium and vitamins is one of the factors that cause the mycotoxin poisoning. Mycotoxins because most of the intermediate or end product toxicity and toxicity of mycotoxin, therefore to reduce or increase the exogenous compounds, metabolism of drugs affect the body's reaction to the toxin, such drugs for aflatoxin and ochre and aspergillus toxin effect is larger, and the single spore mold toxin is relatively small.
Usually mycotoxins in feed there is not a single but two or several exist, when different toxins exist at the same time, the mold toxin toxicity will likely additive effect, the additive effect, synergies, synergistic effect and the effect of the rivalry. Additive effect (Synergistic effects) refers to the combination between two kinds of mycotoxin is equal to the cumulative sum of action. The additive effect (Less than additive effects) refers to occur from a combination of two kinds of mycotoxin below the accumulation of both single function together. Synergistic effect (Synergistic effects) refers to two kinds of mycotoxin combination is higher than the accumulation of both single function together. Synergistic effect (Potentiate the effects) refers to a kind of mycotoxin on a tissue or organ does not produce toxic effects, but taken one after another mycotoxin, toxicity of the former to the latter. Rivalry effect (Antagonistic effects) is a mycotoxin interfere with another mycotoxin toxic effect, this kind of situation is rare.
2.1 aflatoxin
Aflatoxin (aflatoxin, referred to as AF) in the mycotoxin, considered most, the most harmful carcinogens, its heat resistance is strong, more than 80 ℃ to destroy, would produce fluorescence under ultraviolet light, is the product of huangshan mold and parasitic aspergillus, almost all of the animals is sensitive to AF, birds are the most sensitive. AF strong toxicity to young animals and fatality rate is high, and with a strong tolerance of adult animals. Yellow aspergillus (AF) can be divided into the aflatoxin B1, B2, G1, G2, M1, M2, of which the most damage, most toxic aflatoxin B1 (AFB1) is, for all the animals are the main influence tumor, immunosuppression, mutagenic and teratogenic effects of main target organ is the liver, is a hepatotoxin, can cause bleeding, hepatic steatosis, liver bile duct hyperplasia, etc., and can lead to the occurrence of cancer of the liver (yun-jie xu, etc., 2008; hu LAN, etc., 2001).
Yellow aspergillus toxin is the most serious harm in pig production of toxins, the harm of pigs are mainly
(1) is the most powerful immunosuppressant, when, after feed pigs feed contaminated with its first disturbance of immune system, increased predisposition to disease, drug treatment effect is poor.
(2) is clotting factor inhibitor, in injury time of bleeding and serous lower blotchy areas of hemorrhage, bleeding from the small intestine and colon, etc.
(3) infringe on the liver, cause liver function drops, hepatomegaly, bile secretion decline, resulting in a decline in feed utilization rate of protein and fat in (meng-yun li, etc., 2005). Research shows that the growth in pig diet containing aflatoxin mu 200-400 g/kg, pig growth and feed remuneration; Containing 400-800 mu g/kg, microscopic liver damage, cholangitis, hepatitis, immune inhibition; Containing 800-1200 mu g/kg, the growth, feed intake reduced, rough coat, jaundice, hypoalbuminemia. Containing 1200-2000 mu g/kg, characterized by jaundice, coagulopathy, spirit dull, anorexia, part of death (闫甫 etc., 2007).
2.2 ochre and aspergillus toxin
Ochratoxin (Ochratoxin, OCT) by certain strains of aspergillus and penicillium genus of A structure similar to that of toxic, secondary metabolites with Ochratoxin A (Ochratoxin A, OTA) toxicity strongest. Its toxic aflatoxin and kidney is the main target organ, is A kind of renal toxins, ochratoxin A for almost all animals have renal toxicity. Mankind, in particular, when low intake can cause reproductive performance. Studies have shown that the OTA single stomach to all mammals have renal toxicity, can cause renal atrophy or swelling, colors, animals going grey, cortical surface uneven, and the section visible cortical fibrous degeneration;
Microscopically visible renal tubular atrophy and interstitial fibrosis with renal glomerular hyaline degeneration, and small pipe ring die, etc., accompanied by reduced the volume of urine, blood urea nitrogen increased, cleared to amino hippuric acid reduced, frequent urination, urine protein and urine sugar increased renal impairment (li, 2009). To pig feeding with ochre and aspergillus toxin tests showed that the 1 mg/kg of feed for 3 months, can cause diarrhea, anorexia and dehydration, growth retardation, feed utilization rate is low, autopsy rare renal pale, hard, namely rubber kidney. In addition to the renal toxicity, OTA and liver toxicity, suppress the immune, teratogenic and carcinogenic. In terms of reproductive toxicity, for males, ochratoxin A can also make boar semen quality drops (Biroeta1, 2003).
2.3 the orange of penicillin
Orange penicillin (Citrinin) is penicillium and aspergillus certain strains of fungal poison, is a kind of renal toxins, it can lead to pigs, chickens, ducks and birds occurred almost all animals such as kidney disease, but the differences between acute toxicity in different varieties. For duck, half lethal dose is 57 mg/kg; Chicken is 95 mg/kg; The rabbit is 134 mg/kg. Orange penicillin has synergism with ochratoxin A, inhibits murine animal kidney RNA synthesis, wheat, oats, rye, or barley, corn, rice etc all orange penicillin (ren-rong liu, 2004).
2.4 single spore alkene toxins
Single-ended spore alkene toxins are produced by sickle species structure is the floorboard of the similar kind of compounds, species more than 148 species, including main representative: T - 2 toxin (T 2 toxin), two acetyl bodyguards grass sickle germ enol (DAS) and deoxidization snow enol. Major damage animal liver and kidney, and mostly belongs to the organization stimulating factor and inflammatory substances. T 2 toxin a major role in cell division of tissues and organs, such as thymus and bone marrow, liver, spleen, lymph nodes, gonads, and gastrointestinal mucosa, inhibit these organs protein and DNA synthesis, cell and nerve function damage.
T - 2 toxins or DAS can damage the digestive tract mucous membrane in the poultry, oral ulcer, general clinical symptoms of anorexia or loss, gastrointestinal inflammation, bleeding, vomiting, decreased immune function (Kubena, etc., 1994). Pigs to DON the most sensitive, the main cause pig anorexia, refus feeds, nausea and gastrointestinal injury. Many research shows that: the grain DON level up to 3 to 5 mg/kg, pigs greatly decreased appetite, and growth and production performance. When growing pig feed feed containing 14 mg/kg DON after 10 ~ 20 min can appear namely vomiting, abnormal phenomenon of anxiety and molar, DON to secrete nurse pig is more serious, the influence of amount of lactation sows decrease due to loss of appetite, leading to piglet growth speed is slow.
Another study showed that the content of DON in the 0 to 14 mg/kg trial, fodder in every increase 1 mg/kg DON, growth of fattening pigs feed intake by 6%, the poison content is more than 10 mg/kg, namely completely (Trenholm, etc., 1994). Feed intake reduce DON concentration increases linearly with the feed, the relationship. Single-ended spore alkene families of the other toxins or had no effect on production performance for ruminant animal health (Hou Ran however, etc., 2007). Study also shows that T - 2 toxin toxicity of different animals, we still have some differences between species, new or young animals than adult animals more sensitive to toxins, males than females are sensitive (huo seika, etc., 2008).
2.5 gibberellic ketene corn
Corn gibberellic ketene, polyketone synthesis by sickle mold of mammals have estrogen-like effect of a class of secondary metabolites. Appropriate conditions, all of the grain crops or feed products can be polluted by corn gibberellic ketene. Pig's most sensitive to corn gibberellic ketene, and most affected area is the reproductive system. Because corn red enzyme ketene have class estrogen effect, lower than l mg/kg in animal show the female character, boar will show testicular atrophy, nipple increase female characteristics.
For sows, the content is too high can cause ovulation, false pregnancy, fetal development, clinical characteristics and performance for vulva hyperemia, edema, breast swelling and nipple hypertrophy, serious when can cause the vagina and rectum (cheng-zhi guo, 2010). Corn ketene red enzyme can be associated with steroid synthesis enzyme reaction, affect the formation of steroids, interfere with the endocrine system, its long-term effect and toxicity of offspring effect needs further research.
2.6 v horse toxins
Fu ma cephalosporins is water-soluble metabolites produced by sickle species, is a kind of different and more hydrogen by 3 c structure similar to the double ester compounds composed of carboxylic acid. The strongest FB1 toxicity, it is found in recent years can damage the immune system, liver and kidney, reducing the mortality of animals productivity and even cause a mycotoxin. V horse rhzomorph associated with swine edema disease (PPE), lead to the change of pig lung epithelial cells of the blood capillary, respiratory disorder, heart function damage (Diaz, etc., 1994), and for the horse, fu ma rhzomorph liquefactive necrosis (ELEM) can cause brain white matter, brain cortex injury, ataxia, partial paralysis, listless and movement function weaken, sheep can also cause liver and kidney lesions (shao-kang wang, 2003
), and small doses of vomiting toxins and v horse toxins can activate many immune response, such as cytokines.
Combined with the toxicity mechanism of mycotoxin, can draw the mold toxin poisoning of animals mainly manifested in the immune system, gastrointestinal tract, liver, kidneys and reproductive system, etc. Table 3 shows different mycotoxin to the pig body levels of toxicity. Can be seen from the table mycotoxin on the immune function, reproductive capacity, pig feed intake and liver kidney has influence, and each kind of poison to the influence degree of each function is different.
3 mold toxin pollution for the feed
According to the United Nations food and agriculture organization (FAO), the world each year, about 25% of the grain under the influence of mycotoxins in different degrees, about 2% of the crops because of serious pollution and loss of nutritional value and economic value. Of Chinese 28 provinces and autonomous regions, 194 feed and raw material of corn, wheat bran, survey, DON, T 2 toxin and ZEN pollution rate are 50.0%, 18.1% and 50.0% respectively (meter into etc., 2007). Animal raw fish meal at the same time, a variety of mycotoxin contamination are also very common, mildew was feed in animal feed, toxin and its metabolites can be residues in animal products and its processing products, enters the body through the food chain, these highly pathogenic and carcinogenic toxin a serious threat to human health.
AoZhiGang (2008) found that a by-product of the material, especially corn by-products such as dry lees (DDGS) and corn protein powder of mycotoxin contamination is very serious, and a variety of feed ingredients and full price feed mycotoxins often exist at the same time, due to different toxins have synergy between, will add to the toxic effects of toxin and the severity of the poisoning symptoms. Zhang Cheng etc. (2009) for the first half of 2009 China feed and raw material sampling survey results show that in 90 samples, did not detect the sample only 8 of mycotoxin, accounting for 8.9% of the total number of samples; Only detect one kind of mycotoxin sample number is 7, 7.8% of the total number of samples; While detecting the number of samples containing more than 4 kinds of mycotoxin accounted for 67.8%. Huang Guangming etc. (2010) in 2008, 2009 and 2008 in China was analyzed from various provinces and cities in feed mills and farms feeds for customer acquisition of feed raw materials and samples, the results found that in most parts of our country, corn gibberellic ketene and vomiting toxins pollution situation is more serious, especially in 2009 and 2010.
4 pig mycotoxin poisoning prevention
There are synergies between various mycotoxins in feed, several kinds of mycotoxin synergy effect on animal health and production performance than any kind of mycotoxin separate function. Creates a more complex when pigs poisoning symptoms, especially when there is the presence of bacterial and viral factors are most important. Therefore, the variety of mycotoxin bacteria, viruses and mixed infection caused by swine poisoning diagnosis become more difficult. Pig mycotoxin poisoning diagnosis is difficult, after the poisoning of the treatment effect is not ideal, the pig should take effective measures to prevent in advance.
4.1 feed mildew proof measures
Feed mildew to start from the source, enhance the resistance to mold plant cultivation, choose mold resistant strains, strengthen field management. For the inevitable pollution, in the process of harvesting and storing should choose the right time to harvest, stored in temperature and humidity appropriate places. Need to strictly control the water content of feed ingredients. Water is decided to feed mildew can grow in one of the most main factor.
The ideal material should be no more than 12% of water content, water content > l5 % can cause mould to grow and multiply, feed water about % ~ 18% fungi reproduction for toxin-producing optimum conditions. Keep the equipment clean, not only control the pathogenic bacteria, and to control and reduce the growth of mold and the mold toxin in feed production equipment. When it is necessary to add fungicide, the economy and can get mould inhibitor to a large number of short chain fatty acids, such as formic acid, acetic acid and propionic acid, is currently the most commonly used mould inhibitor propionate, sodium propionate, calcium propionate, ammonium propionate and two ammonium propionate.
Propionic acid salt with the feed equipment, stability and corrosion in the advantages of long-term feed mildew role. Need to point out is, mould inhibitor can inhibit the growth of mold, and the existing mycotoxins in feed or feed raw materials.
4.2 mildew seedling of feed processing
Chemical methods
Alkali treatment, ozone treatment, ammonia treatment method and the methylamine and calcium hydroxide treatment may have certain effect. Ozone is a substance of double bond has preferential effect of strong oxidizer. Ozone can through chemical reaction in vitro degradation of AFB1, not much, AFB2 and AFG2, this has been confirmed by experiment.
He Zu equality with sodium bicarbonate, sodium hypochlorite, sodium hydroxide and sodium chloride to detoxification of penicillium acid, sodium bicarbonate, sodium hypochlorite and sodium hydroxide seedling has certain effect. Sodium sulfite and AF reaction of water-soluble products, so as to relieve toxicity of AF. Should pay attention to is this kind of method applies only to some sort of toxin, and not all can degrade, and residues of these chemicals in the feed problem cannot solve effectively and economically, so it's not very practical, and there is a danger.
The use of the adsorbent
Used to control mycotoxins in feed or food the most commonly used method is the use of mycotoxins adsorbent. Most mycotoxins adsorbent by lowering the mycotoxin mass concentration and reduce its an opportunity to enter the blood and target cells, thereby effectively prevent mycotoxins produce harm. Mainly includes the adsorbent inorganic and organic mycotoxins adsorbent two kinds big.
Various adsorption material, however, adsorption capacity and adsorption of different kind of toxin effects are each are not identical, while the use of a variety of adsorbent composite use whether can achieve the desired test the effect of the adsorption effect overlay should do to argue. Therefore, in actual production, feed, raw material of mildew poisoning situation is still severe. And adsorbent adsorption mycotoxin not only, also the adsorption of feed of small molecules, such as biotin, triggering the sow limb hoof disease.
Five pigs mycotoxin restoration of poisoning
Pig mycotoxin after poisoning, due to the violation is liver, kidney and other organs and suppression of the immune system, there is almost no good way to cure, the treatment of fatty liver disease and cirrhosis of the liver with humans is the same principle, the core is to reduce the financial burden on viscera and try to repair the function.
We in the liver repair, for example:
The liver is one of the most complex organ for animals, bear the protein, carbohydrate and lipid synthesis, decomposition and storage, especially in lipid metabolism, the liver synthetic lipoproteins, promotes lipid transport, also form the main fatty acid oxidation and ketone body place. Quality of normal liver fat, about 4%, mainly phospholipids. If the liver is not to fat out in time, fat accumulation in liver cells, namely the formation of fatty liver. Fat accumulated in the liver, can affect the liver cell function and damage of liver cells, the connective tissue hyperplasia, cause liver cirrhosis.
And various nutrients we need to rely on anabolic corresponding enzymes, vitamin, active substances, such as active factor to complete, and the most active factor is the liver has its synthesis, such as active phospholipids, bile acid, lipoprotein and so on, can smoothly complete the lipid metabolism. Supply active factor is required for the liver repair, therefore, good drug of liver disease, which is most of the auxiliary liver disease drug enzymes, vitamins, amino acids, food is bland vegetables give priority to.
6 summarizes
The wide range of mycotoxin contamination, damage is serious, is a major problem of feed industry and animal husbandry and aquaculture, how to effectively control and degradation of mycotoxins in feed and food will be scientific problem urgently to be solved in animal husbandry and food industry.
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