The study of the effect of natural contamination of feed with mycotoxins on the occurrence of diseases in farm animals.

(1) 2000-2004年对泰国饲料及其原料中黄曲霉毒素B1 （AFB1）、玉米赤霉烯酸（ZEA）和脱氧雪腐菌烯醇污染情况进行了调查。其中，木薯受真菌毒素污染最严重。(2)污染霉菌分析发现黄曲霉、黑曲霉、黑曲霉。育成饲料中的青霉、玉米中的黄曲霉和黑曲霉、木薯中的青霉和拟青霉、米糠中的根霉为优势霉菌。(3)采集木薯样品进行霉菌毒素和霉菌污染分析。部分样品检出黄曲霉、镰刀菌等曲霉，大部分样品检出真菌毒素，其中AFB1、AFB2、AFG1、AFG2和ZEA的最高浓度分别为31.3ppb、18.2ppb、53.4ppb、48.5ppb和188.4 ppb。(4)猪的黄曲霉毒素代谢研究表明，猪的高易感性反映了猪的肝脏谷胱甘肽s转移酶活性较其他动物低，还原酶活性与黄曲霉毒素毒性的物种差异无关。(5)给猪饲喂含有香豆素或茶提取物的饲料一个月，然后研究单次口服AFB1对猪的毒性作用。香豆素对AFB1的毒性和组织残留有轻微的抑制作用，而茶提取物对AFB1的毒性和组织残留没有抑制作用。

(1) In 2000-2004, aflatoxin B1 (AFB1), zearalenon (ZEA) and deoxynivalenol contamination in feed and its materials were surveyed in Thailand. Among them, cassava was most heavily contaminated with mycotoxins. (2) Analysis of contaminated molds revealed Aspergillus flavus、 A.nigar、. and Penicillium in completed feeds, Aspergillus flavus and A.nigar in corn, Penicillium and Paecilomyces in cassava and Rhizopu in rice bran, as dominant molds. (3) Cassava samples were collected and analyzed for mycotoxin and mold contamination. Aspergillus sp including A.flavus and Fusarium sp were found in a part of the samples, but mycotoxins were detected in most of them, the maximum concentrations of AFB1,AFB2,AFG1,AFG2 and ZEA being 31.3ppb、 18.2ppb、 53.4ppb、 48.5ppb and 189.4ppb, respectively. (4) The study of aflatoxin metabolism in pigs demonstrated that high susceptibility of pigs reflects lower hepatic glutathion S-transferase activity compared with the other animal species, and that the reductase activity is not involved in the species difference of aflatoxin toxicity. (5) Pigs were given the feed containing coumarin- or tea extract for one month, and then toxic effects of a single oral administration of AFB1 in them were studied. Inhibitory effects of the treatment on toxicity and tissue residue of AFB1 were noted slightly in coumarin, but not in tea extract.