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黄曲霉毒素B1在乳畜中的转化 总被引：1，自引：0，他引：1
黄曲霉毒素主要是由曲霉菌产生的一类具有高致癌性的次级代谢产物,我国饲料及饲料原料普遍受到黄曲霉毒素B1污染。乳畜摄入黄曲霉毒素B1后,代谢生成的羟基化产物黄曲霉毒素M1可通过乳汁污染乳及乳制品,并因这两种毒素都具有极强的毒性越来越受到人们的关注。黄曲霉毒素B1在乳畜的肝脏、瘤胃和乳腺等部位均可代谢转化,黄曲霉毒素M1向乳中的转移受到多种因素的影响。文章从黄曲霉毒素B1的代谢与转移排泄、影响黄曲霉毒素M1的转化因素以及黄曲霉毒素B1对乳腺上皮细胞和瘤胃微生物的影响进行论述。 相似文献
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黄曲霉毒素是由曲霉属中的黄曲霉和寄生曲霉所产生的有毒代谢产物.特曲霉也能产生黄曲霉毒素,但产量较少.目前已分离鉴定出的黄曲霉毒素20余种,主要是黄曲霉毒素B1、B2、G1、G2以及由B1和B2在体内经过羟化而衍生成的代谢产物M1、M2等[1].黄曲霉毒素的毒性极强,远远高于氰化物、砷化物和有机农药的毒性,其中以B1毒性最大[2].当摄入量大时,可发生急性中毒,出现急性肝炎、出血性坏死、肝细胞脂肪变性和胆管增生[3],对人和动物的健康甚至生命造成相当大的危害.近年来,犬只黄曲霉毒素中毒病例很多,研究黄曲霉毒素中毒对犬只肝脏组织的影响具有重要的临床意义. 相似文献
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1 黄曲霉毒素的特点
1．1 毒性强
黄曲霉毒素是黄曲霉菌、寄生曲霉菌、孔曲霉菌等某些菌株的代谢产物。黄曲霉菌素是一组结构类似的化合物，现已明确结构的有十几种，毒性较强的有B1、N1、G1、B2、M2、G2和P1等，其中以B1毒性最强，M1和G1次之，B2和M2等较弱，一般检测对象是B1和B2。 相似文献
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黄曲霉毒素是一类由曲霉属中的黄曲霉和寄生曲霉等产毒菌株的代谢产物,基本结构都有一个二呋喃环和双香豆素,又名氧杂萘邻酮,目前分离出的有B1、B2、G1、G2等18种,凡二呋喃环末端有双键者毒性较强。尤以B1最甚,其毒性是氰化钾的10倍,是砒霜的68倍,对人和动物危害极大,被国际癌症研究机构列为1A类致癌物质。饲料中的黄曲霉毒素多为B1、B2、G1、G2四种,动物摄取后,通过食物链进入人体。实验证明,当动物食入黄曲霉毒素B1后,经过代谢所产生的黄曲霉毒素M1从尿和乳汁排出,部分存留肌肉中。用含100μg/kg黄曲霉毒素B1的饲料喂牛,牛乳中含M1… 相似文献
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饲料中黄曲霉毒素的检测和脱毒研究现状 总被引：4，自引：0，他引：4
黄曲霉毒素 (Aflatoxin简称AFT)是寄生曲霉和黄曲霉产毒菌株的代谢产物 ,是一类结构相似含多环不饱和香豆素的化合物 ,双呋喃环与香豆素是黄曲霉毒素的基本结构 ,双呋喃结构为双键的毒性强。黄曲霉毒素在紫外线下都发荧光 ,黄曲霉毒素现已分离出 1 7种 ,分别命名为B1 、B2 、G1 、G2 、M1 、M2 、P1 等 ,其中AFTB1 毒性最大 ,所以一般饲料检测中主要检测AFTB1 。1 饲料中黄曲霉毒素的检测方法目前 ,黄曲霉毒素的检测方法主要有生物学测定法 ,化学分析法 (薄层层析法、仪器分析 )及酶联免疫吸附法 (ELISA)。国内外已有利用薄层层… 相似文献
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黄曲霉毒素中毒是家禽中常见的霉饲料中毒,黄曲霉毒素是黄曲霉菌代谢的产物,是结构相似的化合物的总称。黄曲霉毒素及其衍生物有20种,其中8种有致癌作用,以B1、B2、G1、G2毒素的毒力增强,尤其以B1毒素更为突出。所以,目前产生的黄曲霉毒素均指B1毒素。寄生曲霉也能产生黄曲霉毒素,由此霉素引起的中毒成为黄曲霉毒素中毒。 相似文献
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1 黄曲霉毒素的致病机理黄曲霉毒素是由黄曲霉和寄生曲霉等产生的有毒代谢物质,产生的黄曲霉毒素主要有B1、B2、G1、G2和M1、M2等类型,其中M1、M2是从牛奶中分离出来的,黄曲霉毒素B1的毒性最大。黄曲霉毒素在食品和饲料产品中是相当稳定的。黄曲霉毒素B1对所有动物肝脏都是原发性毒,可在肝脏、胆囊、胰腺、尿道以及胃中导致肿瘤、致癌,它可与细胞核和线粒体的DNA选择性结合,使活性增强。黄光琪等研究指出,黄曲霉毒素B1能跟tR NA结合成加成物,抑制tRNA与氨基酸的合成活性,从而在翻译水平上干扰了蛋白质的生物合成,影响细菌代谢。198… 相似文献
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奶牛摄入含有较高黄曲霉菌及毒素的饲料,奶牛代谢功能受到损害,抑制免疫机能,使得乳房炎增加,产奶量下降及奶牛体质下降。黄曲霉毒素B1在奶牛体内转换为黄曲霉毒素M1,并分布在牛奶中,人食用含有超标黄曲霉毒素Ml的牛奶后,能使人发生肝炎、肝癌[1]。作者从事奶牛科学养殖技术服务工作,为了预防和控制奶牛场黄曲霉毒素的危害,提供有关黄曲霉素危害、预防控制措施,有一定的利用性。 相似文献
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S D Holladay C F Brownie W T Corbett D D Talley 《American journal of veterinary research》1991,52(2):222-223
Enzyme-linked immunosorbent assay screening of antibody produced against aflatoxin was accomplished by a new and simple procedure. To demonstrate the new indirect ELISA technique used, antibody against aflatoxin M1 was produced in female BALB/CJ mice by immunization with an aflatoxin M1-bovine serum albumin conjugate. Instead of coating test-plate wells with purified antibody (direct ELISA) or synthesizing a second protein-aflatoxin conjugate (aflatoxin M1-poly-L-lysine) to coat test-plate wells, wells were coated with the readily available aflatoxin M1-bovine serum albumin and aflatoxin B1-bovine serum albumin. This method, applicable for any aflatoxin conjugated by the common cyclopentano-carboxymethoxyl-oxime technique, eliminates the more time-consuming and technically difficult portions of earlier direct and indirect ELISA. The new technique can be valuable in continued efforts toward development of new and improved immunoassays against aflatoxin metabolites. 相似文献
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The effects of Kurasan antioxidant (min. 78% ethoxyquin) were studied on toxin formation of the fungus Aspergillus flavus (strain AF 1982/M1). Aflatoxins mostly of type B1, G1, M1 are produced by the mentioned fungal strain. The strain was cultivated for seven days at high relative humidity on a substrate mostly of cereals (Karlovarské suchary--Carlsbad rusks). Application of 25 mg Kurasan per 1 kg substrate reduced type G1 aflatoxin formation by 90%. The total production of aflatoxins decreased expressively (by 50-60% after addition of 100-200 mg Kurasan per 1 kg substrate). It was only at high amounts of Kurasan that B1 and M1 aflatoxin formation was inhibited and it was correlated. Positive effects of Kurasan antioxidant applied to feed mixtures were demonstrated--aflatoxin formation by toxicogenic fungi is inhibited. 相似文献
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Kuilman ME Maas RF Woutersen-van Nijnanten FM Fink-Gremmels J 《The Veterinary quarterly》2000,22(1):30-35
It is well known that cattle ingesting aflatoxin B1 contaminated feed commodities excrete aflatoxin M1 into their milk. As aflatoxin M1 originates from hepatic metabolism, measures to prevent aflatoxin M1 formation need to be directed to either the immobilization of aflatoxin B1 in the gastrointestinal tract or the modification of hepatic metabolism of aflatoxin B1. Here we studied the influence of oltipraz and a second dithiolthione, (1,2) dithiolo (4,3-c)-1,2-dithiole-3,6 dithione (DDD) on bovine hepatic aflatoxin B1 biotransformation. Oltipraz inhibited aflatoxin B1 metabolism as no aflatoxin M1 and no aflatoxin B1-dihydrodiol, the second metabolite found in bovine hepatocytes, was formed. DDD did not significantly inhibit aflatoxin B1 metabolism. It could be demonstrated that the inhibition of aflatoxin B1 metabolism was due to the inhibition of several cytochrome P450 enzyme activities by oltipraz. In contrast, DDD inhibited only ethoxyresorufin O-deethylation activity. These findings suggest a high efficacy of oltipraz in inhibiting aflatoxin M1 contamination of milk from dairy cows exposed to aflatoxin B1 contaminated feeds. 相似文献
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The two possible pathways contaminating milk and milk products with mycotoxins are either the secretory or post-secretory route. The latter is of only little importance due to cooling conditions in production and storage. A secretory contamination can only occur with such mycotoxins, which undergo no complete degradation through their passage into the milk. From the mycotoxins, present in cow's feed; virtually only aflatoxin B1 yields a milkborne metabolite, the aflatoxin M1. The carry over rate is low (2 +/- 1%), but can be enhanced by polyhalogenated biphenyls, also present in the forage. Under normal conditions, however, this enhancement will not be measurable due to low equimolar concentrations of both reactants. The aflatoxin M1 content in herd's bulk milk depends exclusively on the content of the precursor aflatoxin B1 in the ration of the cow and is with less than 10 ng/kg fairly low at present in the Federal Republic of Germany. A careful supervision of the imported feed ingredients for mixed feed, however, will ensure to keep those batches out of dairy cow feeding which exceed a certain level of aflatoxin. The legal threshold is 10 micrograms/kg, being even too high to ensure a milk containing less than 10 ng/kg under high energy feeding conditions. The discussed thresholds for aflatoxin M1 in milk are 50 and 10 ng/kg resp., the latter value is scheduled for milk used in infant nutrition. To keep this low concentration the intake of aflatoxin B1 must be less than 2 micrograms/kg of the daily ration. 相似文献
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J L Richard A C Pier R D Stubblefield O L Shotwell R L Lyon R C Cutlip 《American journal of veterinary research》1983,44(7):1294-1299
Two of 3 groups of Holstein-Friesian steers (groups II and III; n = 5 each) were fed a ration containing corn naturally contaminated with 800 ng of aflatoxin/g. The other group of steers (group I; n = 5) was fed a ration containing noncontaminated corn. The respective rations were fed for 17.5 weeks, except the ration given to group III; the latter's first diet (contaminated with aflatoxin) was changed to a noncontaminated diet after 15 weeks, continuing for the remaining 2.5 weeks. All steers were killed and tissues and fluids were obtained for aflatoxin analysis. Although aflatoxin B1 and M1 could be detected in blood and urine at several sampling times during the experimental period in groups II and III steers (given the diets containing aflatoxin), there appeared to be no effects on body weight gains and immune phenomena, such as lymphoblastogenesis and antibody production, but there was a waning of the delayed cutaneous hypersensitivity in steers given aflatoxin-contaminated diets. In group III animals (diet was changed to noncontaminated ration at 15 weeks), aflatoxin B1 and M1 disappeared from urine before they were slaughtered. All tissues and fluids, except the rumen contents from these group III steers, were void of detectable aflatoxins B1 and M1 at necropsy. The concentrations of aflatoxin B1 in the rumen content of the latter steers were low. All tissues collected at necropsy from the group II steers fed the aflatoxin diet throughout the 17.5 weeks had detectable aflatoxins B1 or M1 present. 相似文献
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大豆肽是由大豆蛋白经水解所得到的由5～6个氮基酸残基组成的低分子肽混合物，分子量以低于1000Da的为主。以豆粕为原料，采用黑曲霉、米曲霉混合菌种固态发酵法生产大豆肤，制得的大豆肽具有较好的理化特性和生理活性，克服了酶解法产品苦味大和口感差等缺点，在很多领域得到了广泛应用。 相似文献
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This research compared the toxic effects of aflatoxin B1 and monocrotaline, the active principle of Crotalaria spectabilis, and the additive effect between aflatoxin B1 and monocrotaline in turkey poults. It was of interest whether selenium fed at dosage levels of 0.1, 5, or 10 micrograms/g of feed would protect against the toxic effect of aflatoxin and/or monocrotaline, and whether the toxicants would result in detectable residues in poult tissues. A total of 180 healthy 1-day-old male turkey poults was assigned at random to 12 treatment groups (15 birds/group). Body and liver weight losses, and low serum concentrations in total protein (TP), albumin (A), alpha-globulin (alpha G), and beta-globulin (beta G), as well as high values in gamma-globulin (gamma G), were produced in the groups fed crotalaria. Pathologic changes were induced by monocrotaline with no protection afforded by the added selenium. Low values in TP, A, alpha G, and beta G and in body and liver weights were observed in groups given the combination of aflatoxin plus crotalaria. Gross lesions were associated with an additive toxic effect and a lack of protective effect of selenium against this combination. However, higher values in TP, A, alpha G, and beta G, and liver weights in groups fed aflatoxin B1 plus selenium indicated that selenium had a protective effect against aflatoxin toxicity. Residues of aflatoxin B1 and aflatoxin M1 were found in the kidneys of poults fed aflatoxin B1; also, dehydroretronecine (the metabolite of monocrotaline) was detected in livers of poults fed Crotalaria spectabilis seeds. 相似文献