鉴定猪产毒素大肠杆菌多重PCR方法的建立

根据GenBank数据库的基因序列建立了一种快速鉴定仔猪产毒素致病性大肠杆菌 3种常见毒素LTⅠ、STa和VT2e的多重PCR方法。将待检样本接种麦康凯琼脂平板 ,然后挑取单一的红色菌落直接作模板 ,加入预混好的PCR反应液进行PCR即可对产生这 3种毒素的猪大肠杆菌进行鉴定。 3种毒素基因的PCR产物的大小分别是 2 83bp、2 2 1bp和 4 87bp。     

科尔沁草地有毒植物及保障家畜安全的对策

为了保障家畜采食安全,对科尔沁草地有毒植物进行了大量的调查和资料整理,初步查明了科尔汤草地有毒植物植物共１６４种,隶属于４２科９３属,首次对这些有毒植物进行了生活型和水分生态类型分析,结果表明：有毒植物以多年生中生、中时时生草本植物占多数;在水分条件相对较好的草地类型或局部地段有毒植物分布较多,较常见的有毒植物所含有的主要毒物成分为生物碱、甙类化合物、匝类化合物、酚类及其衍生物、无机物和简单有机舶     

A review of nutritional and toxicological implications of castor bean (Ricinus communis L.) meal in animal feeding systems

The nutrient‐rich defatted castor meal has been tested as a potential source of protein in diets of many livestock species but has limitation due to challenges of toxins. This review was conducted to compile the relevant research information on advances in the use of raw and differently processed castor seed meal in animal feed. In this article, distribution and uses of castor and its products were identified. Research findings on the nutrients profile, principal toxins, various detoxification strategies, nutritional value and toxicity on common livestock species were compiled and reviewed. The defatted seed meal had crude protein range of 32–48%, gross energy of about 3200 kcal/kg. Ricin content was 9.3 mg/g seed, and the average RCA content was 9.9 mg/g. The meal had high activity of lectin, which produced agglutination at about 4.70 mg/ml minimum assays. Reports of detoxification strategies showed varying degrees of success but high pH, moist heating and microbial techniques appeared to exert greater effect on deactivating ricin. Detoxification strategy for the allergen component is inconclusive. Tannins and the phenolic contents were present at trace level and did not constitute notable threat. It was concluded that castor seed holds great potential as feedstuff when upgraded but such upgrading must be safe, cost‐effective and labour efficient for commercial acceptability.     

镰刀菌毒素污染饲粮导致的断奶仔猪肝脏损伤与自然修复研究

本试验旨在研究阶段性饲喂镰刀菌毒素污染饲粮对仔猪血清和肝脏生化指标、抗氧化指标以及肝脏炎性细胞因子白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)mRNA相对表达量的影响。选用体重为(8.45±0.94)kg的35日龄"杜×长×大"雌性仔猪30头,随机分为3组,每组10个重复,每个重复1头猪。对照组持续饲喂基础饲粮,镰刀菌毒素组持续饲喂镰刀菌毒素污染饲粮(玉米赤霉烯酮0.90 mg/kg,呕吐毒素1.43 mg/kg,烟曲霉毒素5.85 mg/kg),自然恢复组在饲喂镰刀菌毒素污染饲粮35 d后,改饲喂基础饲粮。预试期7 d,正试期56 d。结果表明:1)与对照组相比,镰刀菌毒素组仔猪肝脏相对重量显著升高(P0.05),血清谷丙转氨酶(ALT)、谷草转氨酶(AST)和碱性磷酸酶(ALP)活性显著升高(P0.05),血清总蛋白(TP)和球蛋白(GLB)含量显著降低(P0.05),血清谷胱甘肽过氧化物酶(GSH-Px)、血清和肝脏总超氧化物歧化酶(T-SOD)活性显著下降(P0.05),血清和肝脏丙二醛(MDA)含量显著升高(P0.05);肝脏炎性细胞因子IL-1β和IL-6 mRNA相对表达量显著升高(P0.05)。2)经21 d自然恢复后,与镰刀菌毒素组相比,自然恢复组仔猪肝脏相对重量有所降低(P0.05),血清AST、ALT和ALP活性显著降低(P0.05),血清TP和GLB含量显著升高(P0.05),血清T-SOD活性显著升高(P0.05),血清和肝脏GSH-Px、肝脏T-SOD活性有所升高(P0.05),血清和肝脏M DA含量显著降低(P0.05),肝脏炎性细胞因子IL-1β和IL-6 mRNA相对表达量显著降低(P0.05)。由此可见,本试验条件下,长期饲喂镰刀菌毒素能够造成仔猪肝脏损伤,影响肝脏的抗氧化、蛋白质合成和免疫功能,而经过21 d恢复期,仔猪肝脏抗氧化和免疫功能得到了一定程度的改善。     

Phytotoxicity of solanapyrones A and B produced by the chickpea pathogen Ascochyta rabiei(Pass.) Labr. and the apparent metabolism of solanapyrone A by chickpea tissues

When chickpea shoots were placed in solanapyrone A, the compound could not be recovered from the plant and symptoms developed. These consisted of loss of turgor, shrivelling and breakage of stems and flame-shaped, chlorotic zones in leaflets. In similar experiments with solanapyrone B, only 9.4% (22 μ g) of the compound taken up was recovered and stems remained turgid but their leaflets became twisted and chlorotic and some abscized.Cells isolated from leaflets of 12 chickpea cultivars differed by up to five-fold in their sensitivity to solanapyrone A and this compound was 2.6–12.6 times more toxic than solanapyrone B, depending on cultivar.Glutathione reacted with solanapyrone A in vitro reducing its toxicity in a cell assay and forming a conjugate. Measurement of reduced glutathione concentration and glutathione-S-transferase (GST) activity among cultivars showed that the differences of their means were highly significant and both were negatively and significantly correlated with their sensitivity to solanapyrone A. Treatment of shoots with solanapyrone A enhanced total, reduced and oxidized glutathione content as well as GST activity 1.26-, 1.23-, 1.50- and 1.94-fold, respectively. Similarly, treatment of shoots with the safener, dichlormid, also raised total, oxidized and reduced glutathione levels and GST activity 1.42-, 1.07-, 1.43-, 1.42-fold, respectively. Cells isolated from shoots treated with dichlormid at 150 and 300 μ g per shoot were 2.45 and 2.66 times less sensitive to solanapyrone A, with LD₅₀values of 71.5 and 77.8 μ g ml⁻¹, respectively, as compared to 29.2 μ g ml⁻¹for controls.     

Inhibition of germination of<Emphasis Type="Italic">Orobanche ramosa</Emphasis> seeds by<Emphasis Type="Italic">Fusarium</Emphasis> toxins

Eighteen toxins produced byFusarium species were tested at different concentrations onOrobanche ramosa seeds to evaluate their effectiveness in inhibiting germination. Many of the toxins were active at the highest concentration used. Seven of them,viz. fusarenon X, nivalenol, deoxynivalenol, T-2 toxin, HT-2 toxin, diacetoxyscirpenol and neosolaniol, were highly active at 10μM, causing 100% inhibition of germination. Many of them were still active when assayed at a concentration ten times lower, with T-2, HT-2, nivalenol, neosolaniol and diacetoxyscirpenol still able to cause total inhibition; the last mentioned was very active also at 0.1μM, causing more than 90% inhibition. The results show that the use of toxic secondary metabolites could represent a useful alternative strategy in the management of parasitic weeds, by interfering with the induced germination process, and that fungal culture extracts could be an interesting source of new compounds acting as natural and original herbicides. http://www.phytoparasitica.org posting Sept. 18, 2002.     

Detection of Diarrheic Shellfish Poisoning and Azaspiracid Toxins in Moroccan Mussels: Comparison of the LC-MS Method with the Commercial Immunoassay Kit

Diarrheic shellfish poisoning (DSP) is a recurrent gastrointestinal illness in Morocco, resulting from consumption of contaminated shellfish. In order to develop a rapid and reliable technique for toxins detection, we have compared the results obtained by a commercial immunoassay-“DSP-Check” kit” with those obtained by LC-MS. Both techniques are capable of detecting the toxins in the whole flesh extract which was subjected to prior alkaline hydrolysis in order to detect simultaneously the esterified and non esterified toxin forms. The LC-MS method was found to be able to detect a high level of okadaic acid (OA), low level of dinophysistoxin-2 (DTX2), and surprisingly, traces of azaspiracids 2 (AZA2) in mussels. This is the first report of a survey carried out for azaspiracid (AZP) contamination of shellfish harvested in the coastal areas of Morocco. The “DSP-Check” kit was found to detect quantitatively DSP toxins in all contaminated samples containing only OA, provided that the parent toxins were within the range of detection and was not in an ester form. A good correlation was observed between the two methods when appropriate dilutions were performed. The immunoassay kit appeared to be more sensitive, specific and faster than LC-MS for determination of DSP in total shellfish extract.