Marquardt R R, Frohlich A A
Department of Animal Science, University of Manitoba, Winnipeg, Canada.
J Anim Sci. 1992 Dec;70(12):3968-88. doi: 10.2527/1992.70123968x.
Ochratoxin A (OA) is a toxin that contains an isocoumarin moiety linked by a peptide bond to phenylalanine. It is produced by certain Penicillium (mainly P. verrucosum) and Aspergillus (mainly A. alutaceus) species of storage fungi. Total amounts of OA and other related toxins produced by these fungi are influenced by many factors. Several forms of OA have been discovered, some of which are highly toxic, whereas others have lower toxicity. Ochratoxin A has been detected in foods, feeds, animal tissues, and human blood in both Europe and North America. It has been implicated in the fatal human disease Balkan endemic nephropathy, has been shown to be a powerful carcinogen in rodents, and produces many other adverse effects in animals. It is absorbed passively throughout the gastrointestinal tract and in an active manner in the kidney. It is subjected to intestinal secretion and reabsorption via enterohepatic recycling. Binding of OA in the blood to the albumin fraction and recycling in the bile and kidney contributes to its long half-life in animals. Ochratoxin A is hydrolyzed to its nontoxic alpha form (O alpha) by microorganisms in the rumen, cecum, and large intestine. The toxin is excreted primarily in the urine as O alpha and to a lesser degree as OA; smaller amounts of OA and O alpha are generally excreted in the feces. Three distinct mechanisms of OA toxicity have been proposed; other toxic effects of OA seem to be secondary in nature. Several different strategies can be employed for controlling or neutralizing the effect of OA, including the use of proper storage conditions, the use of specific adsorbents to reduce absorption of OA, and the feeding OA-contaminated feedstuffs to ruminants. Antioxidants such as ascorbic acid have been shown to reduce the toxic effects of OA in laying hens. In summary, OA contamination of cereal food and feed may occur, given appropriate conditions. Implementation of suitable procedures may eliminate or minimize this potentially serious problem.
赭曲霉毒素A（OA）是一种毒素，它含有一个通过肽键与苯丙氨酸相连的异香豆素部分。它由某些贮藏真菌青霉菌（主要是疣孢青霉）和曲霉菌（主要是黄曲霉）产生。这些真菌产生的OA及其他相关毒素的总量受许多因素影响。已发现OA的几种形式，其中一些毒性很高，而其他形式毒性较低。在欧洲和北美，食品、饲料、动物组织和人体血液中均检测到了赭曲霉毒素A。它与致命的人类疾病巴尔干地方性肾病有关，已被证明是啮齿动物中的一种强力致癌物，并在动物中产生许多其他不良影响。它在整个胃肠道被动吸收，在肾脏中以主动方式吸收。它通过肠肝循环进行肠道分泌和重吸收。血液中的OA与白蛋白部分结合以及在胆汁和肾脏中的循环导致其在动物体内的半衰期较长。赭曲霉毒素A在瘤胃、盲肠和大肠中被微生物水解为无毒的α形式（Oα）。该毒素主要以Oα形式随尿液排出，以OA形式排出的程度较小；通常少量的OA和Oα随粪便排出。已提出OA毒性的三种不同机制；OA的其他毒性作用似乎本质上是继发性的。可以采用几种不同的策略来控制或中和OA的作用，包括使用适当的储存条件、使用特定吸附剂以减少OA的吸收，以及将受OA污染的饲料喂给反刍动物。已证明抗氧化剂如抗坏血酸可降低蛋鸡中OA的毒性作用。总之，在适当条件下，谷物食品和饲料可能会受到OA污染。实施适当的程序可以消除或最小化这个潜在的严重问题。
