雏鸡黄曲霉毒素急性中毒

1986年某鸡场,分别饲养四批新汉雏鸡共3885只,4日龄发病,5日龄开始死亡,6、7、8日龄达死亡高峰,共死亡1281只,死亡率32.999。经剖检、组组学检查,饲料中黄曲霉毒素B_1的分析及饲养试验等,确诊为急性黄曲霉毒素中毒。病鸡肝稍肿大,淡黄色或灰白色,组织学病变为肝细胞急性坏死过程,胞浆内出现数个空泡,胞核稍增大,核质浓染,部分核溶解。饲料中黄曲霉毒素B_1含量为300ppb。本文尚对广西饲料中的黄曲霉毒素情况作了回顾与讨论。     

生猪黄曲霉毒素中毒的诊断与防治

猪黄曲霉毒素中毒是由于猪误食被黄曲霉或寄生曲霉污染的含有毒素的花生、玉米、麦类、豆类、油粕等而引起,误食后1～2周即可发病.黄曲霉毒素是黄曲霉菌的代谢产物,在高温多雨的季节或保存环境湿度大,24～30℃时在饲料中繁殖旺盛,产生大量毒素,目前发现有20多种,化学性质十分稳定、耐高温,以B1、B2、G1、G2的毒力为最强,对畜牧业生产危害极大.现就黔江区一生猪自繁自养规模养殖场的生猪不明原因陆续发病,随后出现中毒死亡,经临床检查、剖检诊断、病史调查、血液检查,诊断为黄曲霉毒素中毒.现将诊治情况简述如下.     

种鸭群黄曲霉毒素中毒病的诊断报告

本文报道了某鸭场的种鸭420只,因饲喂发霉饲料,引起严重的霉菌毒素中毒病。病鸭群逐渐消瘦,产蛋率由原来的40％下降至10％,并陆续死亡。从病鸭群中随机取样40个病鸭进行剖检,全部发现不同程度的肝癌病变,部份病例还有卵巢癌变。经组织学检查和真菌毒素分析等方法,诊断为鸭的黄曲霉毒素中毒病。该鸭场除饲养种鸭以外,还养有种鸡几百只,但在同样饲料喂养的条件下,鸡群却未见发病,明显可见鸭群对黄曲霉毒素是很为易感的。     

铝胁迫对决明属水土保持牧草幼苗根系的影响

耐铝能力对红、黄壤山区水土保持牧草的生长具有重要影响。AFT2 2 17(C .nictitans)、CPI3 472 1(C .rotundi folia)和CPI8613 4(C .rotundifolia)三个决明品系水土保持牧草耐铝能力均较强 ,但对Al3+ 敏感性有差异 ,按反应强弱排序为 :CPI8613 4>AFT2 2 17>CPI3 472 1;经 6个Al浓度梯度处理 ,从主根长、侧根数、根细胞质膜透性等指标分析 ,三个决明品系中CPI3 472 1的幼苗耐铝能力相对较强 ,AFT2 2 17、CPI8613 4耐铝能力稍弱 ,铝毒临界值前者为 60mg/L ,后两者为 40mg/L。同时试验表明决明品系水土保持牧草的根系需要适量铝的刺激 ,才能生长得更好     

山羊魏氏梭菌病的诊治

四川合江县某农户饲养了200多只山羊,圈养,饲喂农家饲料和青绿多汁饲草.羊群开始有个别羊突然发病,未见任何临床症状而很快死亡,继而发病羊逐渐增多,以腹胀为主要特征,发病20多只,死亡15只,发病率约10%,死亡率约7.8%.     

有机磷杀虫剂对产蛋鸡的作用

作者用50只产蛋鸡研究了地亚农、伏杀磷、和倍硫磷慢性毒性作用。将这些药品加进饲料喂鸡90天。伏杀磷的剂量为3。6和12mg/公斤饲料,地亚农的剂量为0.2、0.5和0.9mg/公斤饲料,倍硫磷剂量为4.8和16mg/公斤饲料。每个剂量试验用5只鸡。每月采皿进行血液学检查和胆硷脂酶、醣和蛋白含     

猪磷化锌中毒的病理解剖变化

由于不遵守磷化锌灭鼠药的使用规定,曾导致猪发生磷化锌中毒。三头7.5月龄、体重60—65公斤的猪是中毒死亡的,另一头则是因中毒严重而被迫宰杀的。对这四头猪的全身和胴体观察的结果是:营养良好,尸僵不明显,从口腔流出大量的透明的泡沫;上     

饮食保健新要点

豆腐比豆浆更有营养 100克豆腐含蛋白 质7.4克,脂肪、碳水化合物、钙、磷、铁、维生素 B1、B2含量都相当丰富;而100克新鲜豆浆中, 含蛋白质仅4.4克,其它营养物质比率亦低于 豆腐。 长期吃植物油不利健康 植物油中也含有 害物质,如花生油中混杂有致癌物质黄曲霉素, 棉籽油中有使人中毒的棉酚,菜籽油中的芥酸 能致高血压等病。植物油中太多的不饱和脂肪     

某些农药在绵羊饲料中的允许残留量

随着农药在农业中的广泛应用,显著地增加了兽医工作在预防动物中毒,以及在饲料中和畜产品中检测农药残留的重要性。用农药直接处理或者植物从土壤中吸收农药,都会使饲料植物受到污染。因此,在利用含有残留农药的饲料时,在各种情况下都必须考虑农药允许的残留量。作者用倍硫磷,二嗪农和伏杀磷作了长     

钾、硼和萘乙酸对烟株生长及钾吸收分配影响的研究

本文通过盆栽试验,研究了钾(K)、硼(B)和萘乙酸(NAA)对烟株生长和K吸收分配的影响。研究表明,在高K营养下,B、NAA及B NAA显著增加了烟株地上部干重和株高,但低K时影响不显著:B、NAA及B NAA明显提高了烟叶的光合强度、硝酸还原酶的活性及过氧化物酶的活性,这为提高烟叶产量和品质奠定了基础。B.NAA及B NAA各处理明显增加了中、上部烟叶的含K量。低K营养时,各处理烟叶的含K量上部>中部>下部;但在高K营养下,各处理烟叶上、中、下部含K量相近,以高K营养下B NAA处理的烟叶含K量最高。初步表明增施K肥时,喷施B和NAA可以提高烟叶的K含量。     

Gas chromatographic method for ethylene dibromide in grains and grain-based products: collaborative study

Nine laboratories analyzed samples of whole grain, intermediate, and ready-to-eat products for ethylene dibromide (EDB) residues. Supplied samples of wheat, rice, and flour contained both fortified and incurred EDB; corn bread mix, baby cereal, and bread contained only fortified EDB. The whole grains and intermediates were analyzed by the same basic procedural steps as in the official method for multifumigants: They were extracted by soaking in acetone-water (5 + 1). The baby cereal and bread were analyzed by a modification of the Rains and Holder hexane co-distillation procedure. EDB was determined by electron capture gas chromatography operated with an SP-1000 column. All products contained 3 different levels of EDB and were analyzed as blind duplicates. Overall mean recoveries ranged from 85.2% for 69.6 ppb to 105.0% for 4.35 ppb, both in baby cereal. Interlaboratory relative standard deviations ranged from 5.7% for 869 ppb in wheat to 20.2% for 69.6 ppb in baby cereal, both fortified. Mean levels of incurred EDB in wheat, rice, and flour were 926.7, 982.0, and 49.9 ppb, respectively; corresponding relative standard deviations were 9.9, 7.7, and 13.1%. The method was adopted official first action.     

Evaluation of a testing program for aflatoxin in corn

A computer model that accounts for sampling and analytical variability was developed to simulate the aflatoxin testing program administered by the North Carolina Department of Agriculture (NCDA) to regulate aflatoxin in corn meal. Monte Carlo solution techniques were employed to account for conditional probabilities that rise from multiple samples being used in the testing program. The NCDA testing program was then evaluated by applying the computer model to a hypothetical group of 1000 corn meal lots with the same distribution of aflatoxin concentrations as was observed among aflatoxin assays made by NCDA on commercial lots of corn meal from 1977 to 1980. The average of the 1000 lots assayed was 17.7 parts per billion (ppb). The model predicted that 79.5% of the lots would be accepted and 20.5% of the lots would be rejected by the NCDA testing program. The accepted and rejected lots contained an average of 5.7 and 64.2 ppb aflatoxin, respectively. The testing program accepted 7.3% of the lots with more than 20 ppb aflatoxin (consumers' risk) and rejected 1.0% of the lots with 20 ppb or less (processors' risk). A correct decision was made 94% of the time.     

An analytical survey of aflatoxins in tissues from swine grown in regions reporting 1988 aflatoxin-contaminated corn.

A joint project was undertaken by the Food Safety and Inspection Service (FSIS) and the Agriculture Research Service branches of the U.S. Department of Agriculture to determine the presence of aflatoxins in the U.S. meat supply during a drought year. In 1988, high incidences of aflatoxins occurred in corn grown in regions of the Midwest, Southeast, and South. Six states were identified as having serious aflatoxin contamination in their corn crop: Virginia, North and South Carolina, Texas, Iowa, and Illinois. Swine liver and pillars of diaphragm (muscle) tissues were sampled by federal FSIS Inspectors in plants located in these states. A worstcase sampling plan was conducted. Samples were taken in January 1989 from hogs fed corn soon after harvest and in April 1989 from hogs fed corn originally stored and then fed in the spring. A modification of the official AOAC method for the thin-layer chromatography (TLC) determination of aflatoxins in animal tissue was used to permit quantitation by LC with fluorescence detection. The official AOAC TLC confirmation of identity method was used to confirm all positive samples with B1 concentrations greater than 0.04 ppb and M1 concentrations greater than 0.1 ppb. Sixty samples in the January group and 100 samples in the April group were assayed. Concentrations of aflatoxins B1 and M1 in the first group of pig livers ranged from 0.04 to 0.06 ppb. The identity of aflatoxin B1 was confirmed in all positive samples. Aflatoxin M1 could not be confirmed in any of the positive liver samples because the method was insufficiently sensitive for this aflatoxin.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mycoflora and multimycotoxin detection in corn silage: experimental study

Agricultural activities involve the use of crop preservation such as "trench-type" silo, which can sometimes be contaminated by fungi. To investigate the exposure of livestock and farm workers to fungal spores and mycotoxins, a multimycotoxin analysis method has been developed. Six mycotoxins (aflatoxin B1, citrinin, deoxynivalenol, gliotoxin, ochratoxin A, and zearalenone) were quantified by high-performance liquid chromatography coupled to mass spectrometry after solid-phase extraction. An experimental study of fungal species and mycotoxins was conducted in corn silage (Normandy, France) during 9 months of monitoring. The results indicated the recurrence of around 20 different species, with some of them being potentially toxigenic fungi such as Aspergillus fumigatus, Aspergillus parasiticus, Fusarium verticillioides, and Monascus ruber, and the detection of aflatoxin B1 (4-34 ppb), citrinin (4-25 ppb), zearalenone (23-41 ppb), and deoxynivalenol (100-213 ppb). This suggested a possible chronic exposure to low levels of mycotoxins.     

Comparative evaluation of commercially available aflatoxin test methods

Five qualitative methods and 1 quantitative aflatoxin analytical method were compared with the Holaday-Velasco (HV) minicolumn and thin-layer chromatography (TLC) methods for corn in an evaluation involving 4 U.S. Department of Agriculture Federal Grain Inspection Service (USDA-FGIS) laboratories, 1 laboratory at the University of Georgia, and 1 laboratory at the University of Arizona. Samples analyzed included 1 set of artificially contaminated corn containing both aflatoxin B1 and B2 (ratio of B1:B2 of 92:8), 1 set of artificially contaminated corn containing only aflatoxin B1, and 1 set of naturally contaminated corn. Levels of total aflatoxin tested were 0, 10, 15, 20, 25, 30, and 40 ppb. Results of analysis of these samples with each method evaluated are reported. Chi-square analyses indicated that performance of the Afla-20-Cup, Aflatest, EZ-Screen, OXOID, and SAM-A methods was not statistically different from that of the HV minicolumn. Agri-Screen results were not statistically different from those obtained with TLC.     

A gas chromatography-flame ionization detection method for detection of fusaproliferin in corn

A sensitive and accurate detection method is of great importance in monitoring fusaproliferin levels in foods and animal feeds and evaluating its potential hazard to human and animal health. Several methods have been developed to detect fusaproliferin in cereals and cereal-related products, including thin-layer chromatography, high-performance liquid chromatography, enzyme-linked immunosorbent assay, liquid chromatography-mass spectrometry (MS), gas chromatography (GC), and GC-MS. However, these detection methods either suffer from low sensitivity, need expensive instruments, or are susceptible to interfering substances in the sample matrix. The GC-flame ionization detector method developed herein is sensitive, reliable, and easy to use for detecting fusaproliferin in corn and corn-based samples. Its detection limits were 0.04 ng for standard trimethylsilyl-fusaproliferin and about 5 ppb for fusaproliferin in corn samples. The limits of quantitation of this method were 0.15 ng fusaproliferin/injection and 20 ppb of fusaproliferin in corn samples. The recovery rates of fusaproliferin from corn samples spiked with 200, 1000, and 5000 ppb standard fusaproliferin were 109, 85.7, and 98.9% on average. The repeatability of the method was acceptable when evaluated by the Horwitz equation. Of the tested corn samples, three out of five sweet corn and the three yellow corn samples were found to have low levels of fusaproliferin (9.4-45.3 ppb). A moldy corn sample had a fusaproliferin content of 297 ppb.     

Rapid thin layer chromatographic method for determining aflatoxin B1, ochratoxin A, and zearalenone in corn

A multimycotoxin thin layer chromatographic method is described for the analysis of corn. Aflatoxins are extracted from the samples with acetonitrile-water, and sodium bicarbonate is added to separate the acidic ochratoxin from zearalenone and aflatoxin B1. After chloroform extraction, 1N NaOH is added to separate zearalenone and aflatoxin B1. The separated mycotoxins are spotted on TLC plates, which are then examined under ultraviolet light. The following recoveries (%) were obtained for corn samples: aflatoxin B1 71, ochratoxin A 87, and zearalenone 85. The limits of detection for the respective mycotoxins were 2, 40, and 200 ppb.     

A convenient thin layer chromatographic cleanup procedure for screening several mycotoxins in oils.

A thin layer chromatographic cleanup development with benzene-hexane (3+1) effectively removed lipids and some contaminants from mixtures of mycotoxins in corn oil, olive oil, peanut oil, soybean oil, and seed extracts. A second development in the same direction as the first, using toluene-ethyl acetate-formic acid (6+3+1) or benzene-acetic acid (9+1), separated the mycotoxins. Satisfactory separation was achieved for commercial oils spiked with sterigmatocystin, zearalenone, ochratoxins A, B, and C, and aflatoxins B1, B2, G1, and G2. This technique permits detection of 5 ppb aflatoxin B1 in corn.     

Improved enzyme-linked immunosorbent assay for aflatoxin B1 in agricultural commodities

An improved enzyme-linked immunosorbent assay (ELISA) for aflatoxin B1 in cornmeal and peanut butter was developed. Aflatoxin B1 in cornmeal and peanut butter samples was extracted with 70% methanol in water containing 1% dimethylformamide diluted with assay buffer to a final concentration of 7.0% methanol, and directly subjected to an ELISA procedure that took less than 1 h for quantitative analysis and less than 30 min for screening tests. Analytical recoveries for 5-100 ppb B1 added to the cornmeal and peanut butter were 91 and 95.4%, respectively. The interwell and interassay coefficient of variation was 10% or less at the 20 ppb level and above. Agreement for B1 levels in more than 30 naturally contaminated corn, mixed feed, and peanut butter samples was excellent between the ELISA data and the data obtained from different independent laboratories using TLC or other analytical methods.     

Beta-cyclodextrin post-column fluorescence enhancement of aflatoxins for reverse-phase liquid chromatographic determination in corn

beta-Cyclodextrin enhances the fluorescence of aflatoxins B1 and G1 in aqueous systems. This effect was utilized in developing a unique reverse-phase liquid chromatographic (LC) method for determination of aflatoxins B1, B2, G1, and G2 (B1 detection limit 1 ppb), without preparing derivatives of B1 and G1. The aflatoxins are dissolved in methanol or the mobile phase for injection onto the LC system. Using a mobile phase of methanol-beta-cyclodextrin (1 + 1), the aflatoxins are resolved on a C18 column. Fluorescence of the aflatoxins is enhanced by post-column introduction of an aqueous concentrated beta-cyclodextrin solution. All 4 aflatoxins elute within 10 min in the order G2, G1, B2, B1. Fluorescence responses for B1 and G1 standards were linear over the concentration range 0.5-10 ng, yielding correlation coefficients (r) of 0.9989 and 1.000, respectively. The average peak response ratio for G1:B1 for the mobile phase-enhancement solution described was 0.765 with a coefficient of variation (CV) of 0.98%. CVs were 6.2, 9.0, and 7.5% for multiple assays of aflatoxin B1 in 3 samples of naturally contaminated corn. For samples of corn spiked to a total B1 content of 8.3 ng/g, average B1 recovery was 90% (CV 11.7%).