乳酸菌去除脱氧雪腐镰刀菌烯醇的研究进展

脱氧雪腐镰刀菌烯醇(deoxynivalenol, DON)是由镰刀菌属产生的真菌毒素,具有肠道和免疫毒性,在谷物和饲料中污染严重,威胁人类和动物的健康。利用微生物法去除真菌毒素特异性强,效率高且对环境安全,被广泛应用。乳酸菌作为一种益生菌,具有去除DON的能力,同时不会影响产品的品质,成为近年来去除DON的研究热点。本文主要阐述了具有去除DON能力的乳酸菌种类及乳酸菌去除DON的机制,并通过对比其他细菌降解DON的机制和降解酶,推测乳酸菌中可能存在生物降解作用,并对乳酸菌去除DON的应用前景进行了展望。     

玉米赤霉烯酮和脱氧血腐镰刀菌烯醇对雌性动物的生殖毒性及作用机制

镰刀菌毒素玉米赤霉烯酮(ZEA)和脱氧血腐镰刀菌烯醇(DON)广泛存在于受污染的谷物和饲料中。体内和体外研究表明,ZEA和DON均可影响雌性动物的繁殖性能,引起生殖器官、胎儿形态,生殖细胞成熟率,性激素分泌的改变。本文综述了ZEA和DON对雌性动物繁殖性能的影响及潜在的作用机制。     

一株毕赤酵母菌MC-1降解呕吐毒素、生物学特性及初步应用

呕吐毒素（DON）是危害动物健康的霉菌毒素之一，本研究旨在分离出能够降解DON的益生菌，以期应用于动物饲料中降解DON。本研究从普洱茶叶中分离出一株益生菌，经16S rDNA基因序列比对确定该菌株为毕赤酵母菌MC-1菌株；其在含有DON(1 mg/L)发酵液中DON降解率为59.21%。此外研究了毕赤酵母菌MC-1生物学特性，活性成分定位和应用试验。结果表明：毕赤酵母菌MC-1具有耐盐、耐酸、耐胆盐及在模拟消化液中存活的特性；其发酵上清液（DON 1 mg/L） DON降解率为54.76%，该菌株与（DON 1 mg/kg）豆粕共同发酵48 h后DON降解率为46.79%。综上，毕赤酵母菌MC-1能够用于动物发酵饲料中降解DON。     

呕吐毒素生物降解研究进展

镰刀菌产生大量呕吐毒素(DON),污染谷物和粮食。DON能引起人和动物中毒,症状表现为呕吐、消化道出血、炎症,甚至死亡。目前没有有效的去毒方法,吸附剂几乎没有作用;物理和化学方法效果不稳定、破坏营养成分和味觉。生物降解DON特异性强、效率高、对食物营养成分无影响、能将毒素转化为无毒代谢产物。已有的文章报道降解饲料DON的单一菌株非常少,更没有关于动物有效性的应用研究。文章就国内外呕吐毒素生物降解的研究做一综述,同时对生物降解应用前景进行展望。     

脱氧雪腐镰刀菌烯醇的毒性、作用机制以及对动物健康的危害(一)

脱氧雪腐镰刀菌烯醇(DON),通常称作"呕吐毒素",是最常被检测到的一种单端孢霉烯族毒素,通常以mg/kg(饲料,体重等)计。所有动物都对DON很敏感,由于DON在不同动物品种体内的吸收、代谢、分布和排出的方式不同,可导致对毒性敏感性的差异,其毒性大小顺序为:猪>小鼠>大鼠>家禽≈反刍动物。谷物籽实常有少量谷粒被3-乙酰基DON和15-乙酰基DON污染,毒素水平较低(等于或低于小鼠半数致死剂量)时不会对动物造成严重的危害。急性口服高剂量DON(≥27mg/kg体重)摄入引起试验动物死亡或者明显的组织损害。然而,对DON最敏感的猪,相对较低的剂量(≥50g/kg体重)就可以引起呕吐,其表现与人类食物中毒类似,原发性症状为恶心、腹泻和呕吐等。试验动物长时间饲喂DON污染的饲料,表现增重迟缓、食欲减退、养分利用率降低和免疫功能的改变,并且这种影响随种属差异变化较为明显。     

饲料中DON的污染及其对畜禽的危害

脱氧雪腐镰刀菌烯醇(DON)是谷物受镰刀菌污染而产生的一种常见的霉菌毒素。脱氧雪腐镰刀菌烯醇经动物吸收后能快速地排泄而在动物组织中很少残留。但该毒素对动物的采食量以及生长性能有一定影响。     

脱氧雪腐镰刀菌烯醇的代谢特征

脱氧雪腐镰刀菌烯醇(DON)对以谷物为基础的食物和饲料的污染是一个全球性问题,严重危害了人和动物的健康。DON在人和动物体内的代谢特征是开展DON暴露评估、毒性作用机制和干预技术等研究的基础。近年来有关DON的吸收、分布、代谢和排泄等毒物动力学的研究引起了国内外广泛关注。本文将DON代谢特征的最新进展进行了全面的综述。     

消除由DON引起的氧化应激

由于脱氧雪腐镰刀菌烯醇(Deoxynivalenol,DON)大量存在于饲料谷物中,同时能导致动物中毒,因此霉菌毒素引起了人们的广泛关注。DON通过提高动物体内自由基的浓度,会引起细胞抗氧化能力的失衡。然而,应对DON的这种抗氧化效应是有可能的。     

脱氧雪腐镰刀菌烯醇体外对绵羊瘤胃发酵的影响

为确定脱氧雪腐镰刀菌烯醇(DON)在体外对绵羊瘤胃发酵的影响,本试验通过评估pH值、总气体、挥发性脂肪酸(VFA)的产量,及DON在两种碳源(玉米淀粉、纤维素)下的降解情况确定DON体外对绵羊瘤胃发酵的影响。结果表明,DON显著影响瘤胃发酵的所有参数(P<0.05),降低了氨和总产气量,特别是乙酸和丙酸产量降低(P<0.01),对瘤胃发酵具有抑制作用。不同碳源会影响DON被降解的程度,提高草料比例有助于DON的降解。     

饲料中呕吐毒素的危害和生物脱毒方法研究进展

呕吐毒素又称脱氧雪腐镰刀菌烯醇(deoxynivalenol,DON)是谷物中最为常见的一种真菌毒素,其降低畜禽的生产性能,并且对动物免疫系统、 细胞信号传导和基因的表达均有不同程度的影响.随着我国灾害气候的频频发生,呕吐毒素的污染程度呈现加剧趋势,因此呕吐毒素污染的控制迫在眉睫.传统控制脱氧雪腐镰刀菌烯醇的方法主要有物理法和化学法,但上述两种方法都具有局限性.本文阐述了脱氧雪腐镰刀菌烯醇的化学性质、 毒性作用以及生物脱毒方面的研究进展,为研究生物学方法控制粮食与饲料中呕吐毒素含量提供参考.     

Ingestion of low doses of deoxynivalenol does not affect hematological, biochemical, or immune responses of piglets

Deoxynivalenol (DON), a mycotoxin produced by Fusarium spp., is a frequent contaminant of cereals. Because of their rich cereal diet, pigs could be exposed to this mycotoxin. Pigs are among the animal species showing the greatest sensitivity to DON. Effects of intermediate to high levels of DON on pigs are well known and include feed refusal, decreased feed intake, and alteration of the immune response. Effects of low levels of DON, which are commonly detected in contaminated feed, remain unknown. The aim of this study was to investigate the effect of a diet naturally contaminated with a low concentration of DON (0, 280, 560, or 840 microg/kg of feed) on performance of weanling piglets and on 34 hematological, biochemical, and immune variables. Low doses of DON did not alter the animal performances (feed intake and BW gain). Such low levels of DON did not modify the 9 hematological variables measured (including white blood cell, red blood cell, and platelet counts, relative numbers of neutrophils and lymphocytes, and hematocrit and hemoglobin concentrations) or the 18 biochemical variables tested (including cations, glucose, urea, creatinine, bilirubin, cholesterol and triglyceride concentrations, and plasma enzyme activity). Similarly, no effect of low doses of DON was observed on the immune responses of the animals (immunoglobulin subset concentration, lymphocyte proliferation, and cytokine production).     

An immunologist's perspective on nutrition,immunity, and infectious diseases: Introduction and overview

The immune system is a multifaceted arrangement of membranes (skin, epithelial, and mucus), cells, and molecules whose function is to eradicate invading pathogens or cancer cells from a host. Working together, the various components of the immune system perform a balancing act of being lethal enough to kill pathogens or cancer cells yet specific so as not to cause extensive damage to “self” tissues of the host. A functional immune system is a requirement of a healthy life in modern animal production. Yet infectious diseases still represent a serious drain on the economics (reduced production, cost of therapeutics, and vaccines) and welfare of animal agriculture. The interaction involving nutrition and immunity and how the host deals with infectious agents is a strategic determinant in animal health. Almost all nutrients in the diet play a fundamental role in sustaining an optimal immune response, such that deficient and excessive intakes can have negative consequences on immune status and susceptibility to a variety of pathogens. Dietary components can regulate physiological functions of the body; interacting with the immune response is one of the most important functions of nutrients. The pertinent question to be asked and answered in the current era of poultry production is whether the level of nutrients that maximizes production in commercial diets is sufficient to maintain competence of immune status and disease resistance. This question, and how to answer it, is the basis of this overview. Clearly, a better understanding of the interactions between the immune signaling pathways and productivity signaling could provide the basis for the formulation of diets that optimize disease resistance. By understanding the mechanisms of nutritional effects on the immune system, we can study the specific interactions that occur between diet and infections. This mechanism-based framework allows for experiments to be interpreted based on immune function during an infection. Thus, these experiments would provide a “real world” assessment of nutritional modulation of immune protection separating immune changes that have little impact on resistance from those that are truly important. Therefore, a coordinated account of the temporal changes in metabolism and associated gene expression and production of downstream immune molecules during an immune response and how nutrition changes these responses should be the focus of future studies. These studies could be answered using new “-eomics” technologies to describe both the local immune environments and the host-pathogen interface.     

脱氧雪腐镰刀菌烯醇导致厌食和呕吐的机制研究进展

由镰刀菌产生的脱氧雪腐镰刀菌烯醇(DON)广泛存在于谷物及其加工产品中,对动物和人类健康有着潜在的危害。DON具有多方面的毒性作用,而厌食和呕吐是机体摄入DON后出现的最典型症状,厌食和呕吐的产生主要归因于DON对中枢神经系统和胃肠道食欲因子的影响。DON可直接作用于中枢神经系统的呕吐中枢产生呕吐反射,同时激活下丘脑神经元分泌食欲调节因子影响采食;DON可诱导肠内分泌细胞分泌肽YY、胆囊收缩素等食欲调节因子从而引发厌食;DON对中枢神经系统和胃肠道分泌的影响又可通过肠-脑轴产生关联;此外,细胞因子及肠道微生物也部分参与了反应的介导。本文综述了DON诱发机体出现厌食和呕吐的可能机制,以期为找到相应解决措施提供理论指导。     

呕吐毒素对动物肠道结构与功能影响研究进展

脱氧雪腐镰刀菌烯醇(DON)对食物和饲料的污染已成为全球化的问题,人们也逐渐开始重视饲料污染物DON对动物机体造成的影响。随着科学的不断发展,DON神秘的面纱已被逐渐揭开。近年来的研究证实了随饲料经消化道进入动物机体的DON,在通过改变肠道组织形态学,影响肠道功能的同时,也可通过改变肠道营养物质运输载体、紧密链接蛋白、mRNA转录以及某些炎性物质等的表达,影响肠道营养吸收作用、屏障功能、免疫功能以及渗透作用等,最终导致动物机体产生营养不良、腹泻、呕吐和肠道炎症等不良反应。研究还表明,不同情况下DON对不同的动物肠道可以产生不同的影响。     

视黄酸诱导基因-Ⅰ在家禽天然免疫应答中作用的研究进展

家禽的天然免疫应答在抵抗病毒感染的过程中起着关键性作用，视黄酸诱导基因-Ⅰ（retinoic acid inducible gene-Ⅰ，RIG-Ⅰ）作为细胞质内一类识别病毒双链RNA的模式识别受体，与天然免疫应答密切相关。它可通过RNA配体结合病原相关分子模式监测细胞质中的病毒RNA，此过程激活了RIG-Ⅰ及下游线粒体抗病毒信号蛋白（MAVS），最终导致干扰素调节因子（IRF3/7）和核因子κB （NF-κB）活化，诱导产生Ⅰ型干扰素等免疫细胞因子，进而使细胞做出相应的抗病毒天然免疫反应。但由于鸡体内缺乏RIG-Ⅰ基因，目前大多将鸭源或鹅源RIG-Ⅰ基因转染鸡成纤维母细胞（DF-1）研究RIG-Ⅰ基因在鸡感染禽类病毒时是否具有免疫功能。文章介绍了RIG-Ⅰ在家禽体内的表达及其介导的抗病毒天然免疫信号通路，并简述了RIG-Ⅰ在家禽体内抗病毒作用的研究概况，为抑制家禽病毒的感染和免疫系统研究，以及研制新型抗病毒疫苗或免疫佐剂等提供参考。     

Deoxynivalenol-contaminated wheat in swine diets

Two studies were conducted using Fusarium graminearum-infected (scabby) wheat containing 6.8 ppm deoxynivalenol (DON), commonly called vomitoxin, substituted for normal wheat in starter pig diets to give varying levels of DON. After 3 wk on experimental treatments, one-half of the pigs in trial one were sacrificed to evaluate the effects of DON on heart, kidney, spleen and liver. Analyses for DON residues in these tissues were also performed. The remaining 16 pigs were placed on a conventional diet for 4 wk to evaluate effects of DON on subsequent animal performance. A different sample of scabby wheat containing 4.9 ppm of DON was substituted for sorghum grain in growing-finishing pig diets to give varying concentrations of DON. At the end of the 42-d feeding period, eight pigs were slaughtered to evaluate the effects of DON on selected tissues. Results of the three trials suggest that feed intake was reduced when DON concentrations in the swine diets neared or exceeded 1 ppm. No apparent signs of disease, including vomiting, were observed in experimental animals. Histological evaluation revealed no significant lesions or abnormalities related to DON ingestion in tissues examined. Traces of DON (8 to 28 ppb, wet weight) were found in kidney, liver, spleen and heart of starter pigs consuming the diets containing DON up to time of slaughter. No DON was found in tissues of growing-finishing pigs that were withdrawn from feed about 12 h before slaughter.     

An impact of Deoxynivalenol produced by Fusarium graminearum on broiler chickens

Deoxynivalenol (DON) is a major mycotoxin from the trichothecene family of mycotoxins produced by Fusarium fungi that cause disease in grains. Food and feed contaminated with DON cause a variety of adverse health effects in humans and farm animals. However, the fermentation conditions of DON for toxicological study remain to be optimised. Deoxynivalenol levels were increased in a constant temperature of 20°C after fermentation for 7 and 14 days compared with cycling temperatures between 10–20°C and 15–20°C. We have established that optimum conditions for DON production on rice‐based medium is constant temperature at 20°C. In feeding experiments, the villus height and the ratio of villus height and crypt depth were reduced in the duodenum of DON‐fed broiler chickens, whereas a mycotoxin degradation agent efficiently reversed the abnormal morphology of the small intestine in the DON‐fed broilers. The expression of pro‐inflammatory gene, COX‐2, was induced in the spleen and bursa of Fabricius of DON‐fed broilers. This effect was alleviated in the presence of mycotoxin degradation agent. DON produced in solid‐state fermentation is able to cause toxic effects in broilers and induce an abnormal morphology of the small intestine, particularly the duodenum.     

Development of a monoclonal antibody against deoxynivalenol for magnetic nanoparticle-based extraction and an enzyme-linked immunosorbent assay

Monoclonal antibody (mAb, NVRQS-DON) against deoxynivalenol (DON) was prepared. DON-Ag coated enzyme linked immunosorbent assay (ELISA) and DON-Ab coated ELISA were prepared by coating the DON-BSA and DON mAb. Quantitative DON calculation ranged from 50 to 4,000 ng/mL for DON-Ab coated ELISA and from 25 to 500 ng/mL for DON-Ag coated ELISA. 50% of inhibitory concentration values of DON, HT-2, 15-acetyl-DON, and nivalenol were 23.44, 22,545, 5,518 and 5,976 ng/mL based on the DON-Ab coated ELISA. Cross-reactivity levels of the mAb to HT-2, 15-acetyl-DON, and nivalenol were 0.1, 0.42, and 0.40%. The intra- and interassay precision coefficient variation (CV) were both <10%. In the mAb-coated ELISA, mean DON recovery rates in animal feed (0 to 1,000 µg/kg) ranged from 68.34 to 95.49% (CV; 4.10 to 13.38%). DON in a buffer solution (250, 500 and 1,000 ng/mL) was isolated using 300 µg of NVRQS-DON and 3 mg of magnetic nanoparticles (MNPs). The mean recovery rates of DON using this mAb-MNP system were 75.2, 96.9, and 88.1% in a buffer solution spiked with DON (250, 500, and 1,000 ng/mL). Conclusively we developed competitive ELISAs for detecting DON in animal feed and created a new tool for DON extraction using mAb-coupled MNPs.     

The Fusarium toxins deoxynivalenol (DON) and zearalenone (ZON) in animal feeding

The contamination of cereal grains with toxic secondary metabolites of fungi, mycotoxins, is a permanent challenge in animal nutrition as health and performance of the animals may be compromised as well as the quality of animal derived food. Therefore the present article reviews the issue of mycotoxins in animal nutrition. As the Fusarium toxins deoxynivalenol (DON) and zearalenone (ZON) are of particular importance under the production conditions in central Europe and Germany, with respect to their frequent occurrence in toxicologically relevant concentrations, special emphasis is layed on those mycotoxins. The effects of DON and ZON on susceptible animals as well as management strategies to cope with the contamination of grain with those toxins are reviewed.