小心饲料中的黄曲霉毒素

饲料应该不含霉菌毒素,对由生长在谷物中的真菌所产生的黄曲霉毒素隐患应给予特别的警告。忽视该危害可能会导致家禽生产性能的巨大损失,甚至会致其死亡。     

猪胃肠道食糜中黄曲霉毒素B_1和玉米赤霉烯酮检测方法的改进及其在霉菌毒素吸附剂吸附效果评价中的应用

本试验旨在建立测定猪胃和小肠食糜上清液中黄曲霉毒素B1和玉米赤霉烯酮含量的高效液相色谱(HPLC)法,并利用该方法评价霉菌毒素吸附剂分别在不同介质中对黄曲霉毒素B1和玉米赤霉烯酮的吸附效果。为消除食糜上清液中复杂组分对目标毒素检测的干扰,本试验对毒素提取方法、液相色谱的检测波长设置和流动相组成进行了优化。利用单浓度体外吸附试验评价了4种霉菌毒素吸附剂分别在水、猪胃和小肠食糜上清液介质中对黄曲霉毒素B1和玉米赤霉烯酮的吸附效果。结果表明:1)反应上清液经过1次正己烷和3次二氯甲烷提取,荧光激发波长和发射波长在0~9 min和9~14 min分别设定为360、440 nm和235、418 nm,乙腈/水流动相中乙腈比例控制在40%~60%时,本试验采用的HPLC仪对1.00~10 000.00 ng/m L黄曲霉毒素B1和20.00~5 000.00 ng/m L玉米赤霉烯酮具有良好的分离定量效果,线性相关系数分别为1.000和0.999;检出限分别为0.16和2.00 ng/m L;黄曲霉毒素B1和玉米赤霉烯酮日内精密度相对标准差分别为2.37%、4.50%;日间精密度相对标准差分别为2.74%、8.84%。黄曲霉毒素B1和玉米赤霉烯酮标准添加回收率分别为89.1%~110.3%、98.7%~104.1%。2)自制霉菌毒素吸附剂样品P3、M3和市场采购的霉菌毒素吸附剂产品Y1、Y2在猪胃食糜上清液介质中对黄曲霉毒素B1的吸附率依次为72.10%、84.18%、83.17%和66.01%;在猪小肠食糜上清液介质中的吸附率依次为78.15%、88.08%、88.12%和67.34%。4种吸附剂在胃食糜上清液介质中对玉米赤霉烯酮的吸附率依次为85.35%、18.41%、16.20%和12.98%;在猪小肠食糜上清液介质中的吸附率分别为39.75%、25.15%、21.40%和24.85%。综上,本试验建立的HPLC法可同时测定猪胃和小肠食糜上清液中的黄曲霉毒素B1和玉米赤霉烯酮,检测限和检测范围满足我国《猪饲料卫生标准》的要求。该方法可用于评价霉菌毒素吸附剂猪生理体液条件下对黄曲霉毒素B1和玉米赤霉烯酮的吸附效果。     

饲料霉变处理方法

<正>营养解毒法。一是添加抗氧化物质。如添加V A、V C、V E、硒等都会缓解霉菌毒素对细胞的作用;二是添加蛋氨酸。肝脏解毒的基础是谷胱甘肽,蛋氨酸是谷胱甘肽的主要成分。营养解毒法可起到一定的解毒效果,但能造成营养的不均衡。吸附法。一是用葡聚甘露聚糖法,但效果一般,费用较高;二是用活性炭法和硅酸盐法。只对黄曲霉毒素有效,对其他毒素无效。且在吸附霉菌毒素的同时也吸附了大量的维生素和氨基酸,目前应用效果较差。添加活力酶法。活力酶不同于霉菌毒素吸附剂或处理剂,更不同于一般防霉剂。防霉剂只能抑制··········     

一种通过在饲料中添加葡甘露聚糖来消除肉鸡和雏鸭黄曲霉毒素中毒症的生物学方法

进行了两个肉鸡试验,一个雏鸭试验,来评估在饲料中添加葡甘露聚糖对于消除黄曲霉毒素毒性的功效。第一个实验涉及了3个水平的葡甘露聚糖(0,0.1%,0.2%酵母1026,奥特奇公司)添加到含有500及1000ppb黄曲霉毒素的肉鸡日粮中。日粮加入黄曲霉毒素后,家禽的体重、饲料转化率、血清总蛋白、白蛋白以及新城疫血球凝集抑制效价都显著下降而死亡率显著提高了。在含有黄曲霉毒素的日粮中添加葡甘露聚糖后这种情况有了改变。用更大数日的鸡进行了第二个实验来证实第一个实验得到的结果。3个实验组包括对照组(无黄曲霉毒素,无葡甘露聚糖),500ppb黄曲霉毒素和500ppb黄曲霉毒素加0.1%葡甘露聚糖。在添加黄曲霉毒素的组体重和饲料转化率都受到抑制(P<0.05),死亡率增加,肝的相对重量和半胱氨酸转移酶的活性增大了,法氏囊的相对重量降低了。添加葡甘露聚糖后缓解了黄曲霉毒素的毒性。第三个实验涉及了160只公雏鸭,分成5个组:对照组,100ppb或200ppb黄曲霉毒素不添加或添加0或0.1%葡甘露聚糖。黄曲霉毒素的中毒特点是体重、法氏囊相对重量、血清白蛋白和总蛋白浓度、血红细胞数、血色素比重%和红细胞压积的显著下降,以及死亡率、肝组织中黄曲霉毒素浓度、肝的相对重量、半胱氨酸转移酶活性和谷丙转氨酶活性的显著上升。加入0.1%葡甘露聚糖能显著缓解这些霉菌毒素中毒症状。     

饲料中黄曲霉毒素的HACCP控制

黄曲霉毒素属剧毒物质,是迄今发现的最强的化学致癌物,并且具有强烈的致畸、致突变作用。动物饲料中玉米、花生饼、棉籽饼等黄曲霉毒素的含量常常超过国家《饲料卫生标准》中的最高限量。因此,在饲料生产过程中对黄曲霉毒素的含量及其毒性进行有效的系统控制显得尤为重要。 HACCP(Hazard analysis and critical control points)即危害分析与关键控制点管理体系是一种以食品和饲料安全为基础的预防性控制体系。它     

Occurrence of aflatoxins in pig feed]

Sixty-seven pig feed samples were examined for the presence of aflatoxins by the method after Velasco, with simultaneous qualitative determination by the thin-layer chromatographic method. All samples were collected at about the same time (June 1977) from central stores, feed preparing plants, storage containers and feeding lines on farms. On the whole, the feeds formed a representative sample of the conditions of pig feed storage and treatment. The presence of aflatoxins was proved in 18 samples (26.8%). One sample (1.4%) showed just traces of aflatoxin, six samples (8.4%) contained 0.014 to 0.45 mg aflatoxins, eight samples (11.2%) contained 0.10 to 0.30 mg aflatoxins, and three samples (4.2%) had 2.7 to 3.5 mg aflatoxins per 1 kg of feed. The samples with the highest aflatoxin concentrations came from metallic storage containers for complete feed mixtures in front of the pigsties.     

Selection of screening methods for the detection of aflatoxins in animal feed]

Five different screening methods of the detection of aflatoxin B1 are compared as to their usability in ten feeds, feed concentrates, and complete feed mixtures. Method II, i. e. the author's modification of the method of Pons et al. (1973) was found to be the best for the highest number of different feeds. Aflatoxin B1-positive findings were obtained in samples of groundnut cake and protein concentrates a) for laying hens and b) for breeding pigs. No aflatoxins were detected in other feed samples: soya, sunflower, maize, fish meal, complete feed mixtures--table trout trout feed, carp stock feed, table carp feed, duckling fattening mixture.     

The occurrence of aflatoxins in some components and complete feed mixtures for pigs]

The feed components and complete feed mixtures used in pig breeding and fattening in June 1978 were examined qualitatively by the silica-gel thin-layer chromatographic method, and quantitatively by the method after Velasco. The object of the examination was the occurrence of aflatoxins. On the whole, 104 feed samples were taken and subjected to the laboratory examination; this total number included 77 samples (74.0%) coming from 24 farms and 27 samples (26.0%) from eight feed plants in the South Moravian region. The presence of aflatoxins was detected in 14 samples of the examined feeds, i. e. 13.4%. The highest content -- 1920 micrograms kg-1 -- was found in groundnut from India. As to the complete feed mixtures, aflatoxin was found in mixtures for pig fattening (A1 and SOL), in mixtures for pregnant sows (KPB), for lactating sows (KPK), and in the complete feed mixtunts ranged between 50 and 350 micrograms kg-1 of feed. The organoleptically altered feed samples, taken from metallic containers standing in front of the stables on the farms, contained aflatoxin almost in all cases. It will be necessary, on the basis of these findings, to take preventive measures during the harvesting, post-harvest treatment, and storage of grain and feed components, in order to avert the multiplication of the mould and deterioration of the feeds.     

不同免疫亲和柱对饲料中黄曲霉毒素检测结果的影响研究

免疫亲和柱是饲料中黄曲霉毒素检测常用的净化产品,试验选取两家公司的黄曲霉毒素免疫亲和柱,研究其对检测结果的影响。结果表明,免疫亲和柱的不同对阳性添加样品和阳性检出样品的检测结果均有较大影响,故建议饲料检测机构务必考察免疫亲和柱的各种性能后再决定是否购买使用,保证检测结果的科学公正。     

A screening method for simultaneous immunochemical detection of aflatoxins and ochratoxin A in cereals and feed]

An immunochemical method was proposed for simultaneous determination of aflatoxin and ochratoxin A with the use of mixed solutions of the following reagents: standards of both mycotoxins, antiserums against the mycotoxins, and radioligands of 125I-aflatoxin B1 and 125I-ochratoxin A. The result of the analytical procedure is the value of concentration of the aflatoxin + ochratoxin A sum in the sample. The procedure needs half the amount of reagents as separate determination of each of the two mycotoxin, and is far less laborious. The proposed simultaneous immunoanalysis is suitable for large-are inspection of grain and feed safety from the viewpoint of aflatoxin and ochratoxin A levels.     

用纳米粘土吸附霉菌毒素

世界上很多地方都有粘土。大量科研结果证明,某些粘土可与霉菌毒素相结合。所以,在动物饲料中应用粘土,尤其是应用"蒙脱土"(Montmorillonite,这是一种膨润土型的粘土),多年来就已经成为常用的做法了。然而,粘土颗粒和有机分子(霉菌毒素)的结合,是个非常复杂的过程。有些类型的粘土能够吸收     

Effects of aflatoxins in young ponies

Sixteen clinically normal, healthy ponies were randomly assigned to 4 groups and given aflatoxin B1 in doses of 0.045, 0.030, 0.015, and 0 (control) mg/kg of body weight per day for 21 days (or total doses of 0.945, 0.630, 0.315, and 0 mg/kg). The animals were allowed to recover for 3 months and then were reassigned to 4 treatment groups such that each group during the 2nd trial included a pony from each of the groups of the 1st trial. The animals in the new groups were intubated and were given aflatoxin in doses of 0.4, 0.2, 0.1, and 0 (control) mg/kg/day for 5 days ( or total doses of 2.0, 1.0, 0.5, and 0 mg/kg). Venous blood samples were drawn every other day to monitor for toxicosis; examinations were made for RBC and WBC counts, hemoglobin concentration, PCV, serum urea nitrogen, prothrombin time, and serum concentrations of aspartate aminotransferase, iditol dehydrogenase, alkaline phosphatase, albumin, gamma-glutamyl transferase, and arginase. There were no significant differences between treatment groups and controls (given no aflatoxin) in the toxicologic values examined for during the 1st trial. During the 2nd experiment, 2 of the ponies in the large-dose treatment gorup (2.0 mg/kg) demonstrated increased serum enzyme activities. These animals had been in the large-dose (0.945 mg/kg) and median-dose (0.63 mg/kg) groups during the 1st trial. Arginase, iditol dehydrogenase, and gamma-glutamyl transpeptidase activities became increased on the 4th day of treatment and continued to increase until the 6th day of the experiment (1 day after treatment was terminated). These enzymes approached control group values at 10 days after cessation of treatment. These increases were indicative of hepatocellular toxicity. It was concluded that the possibility of equine aflatoxicosis exists although ponies given high quality rations appear to be less susceptible than some other species. Prior exposure to aflatoxins may predispose to clinical toxicity on subsequent exposure, despite lack of expression of clinical signs.