镰刀菌毒素发生的比较分析

小麦、大麦和玉米是饲料工业使用的主要谷类作物。对这些谷物中的镰刀菌毒素进行的研究,已经获得了与其他单端孢霉烯有关的大量信息,而不是脱氧雪腐镰刀菌烯醇(Deoxynivalenol,DON),如乙酰基形式、瓜蒌镰菌醇和A型单端孢霉烯族毒素类。     

饲料中的霉菌毒素(续完)

单端孢霉烯毒素 单端孢霉烯毒素(trichothecene)是包含200～300种化合物的一类毒素,其中包括T-2毒素、二乙酰藨草镰刀烯醇(diacetooxyscirpenol,DAS)和脱氧雪腐镰刀菌烯醇(deoxynivalenol,DON),这些毒素常见于农产品中(Desjardins等,1993).它们通过在核糖体水上抑制蛋白质的合成而发挥其毒性作用,具有免疫抑制性和细胞膜毒性,可诱使细胞凋亡(Sharma,1993;Shifrin和Anderson,1999).单端孢霉烯毒素的毒性作用包括对胃肠道的影响,如引起呕吐、腹泻和肠炎;此外,贫血、白细胞减少、皮肤刺激、拒食、生长减缓和繁殖障碍等症状也很普遍.若干种镰刀菌及相关属的真菌会产生单端孢霉烯毒素.看来,除了DON外,大多数单端孢霉烯毒素污染发生在谷物收割前.     

脱氧雪腐镰刀菌烯醇的毒性、作用机理以及对动物健康的危害

在镰刀菌繁殖期间产生的单菌孢霉烯族化合物（Trichothecene，TCH）对小麦、大麦和玉米等主要农作物的污染已经逐渐成为一个普遍的问题，这很有可能是由于非耕农业的迅速发展和气候变化等因素引起的。被TCH污染的食物和饲料已经成为人类与动物食品中毒的重要因素之一，其中脱氧雪腐镰刀菌烯醇（Deoxynivalenol，DON）是最易检测到的TCH，又名呕吐毒素，通常可达mg／kg水平。供试动物对DON均敏感，猪〉小鼠〉大鼠〉家禽≈反刍动物。其在动物体内的代谢、吸收、分布以及消除的不同可能是敏感性不同的原因。3-乙酰基DON（3-ADON）和15-乙酰基DON（15-ADON）有时会同时出现在少量谷物中，依据小鼠的LD50，其毒性小于或等于DON。     

6种益生菌对玉米赤霉烯酮和呕吐毒素降解能力的研究

为了寻求能降解饲料中玉米赤霉烯酮(Zearalenone,ZEN)和呕吐毒素(Deoxynivalenol,DON)的高效、安全的生物脱毒方法,试验选择6种饲料中允许添加的益生菌(迟缓芽孢杆菌、短小芽孢杆菌、罗伊氏乳杆菌、乳酸片球菌、嗜热链球菌、米曲霉)分别与ZEN和DON共培养,采用高效液相色谱-质谱(HPLC-MS)联用法检测两种毒素的残留量和降解产物。结果表明:迟缓芽孢杆菌对DON和ZEN的降解效果最好,降解率分别为79.59%和46.93%,降解率显著高于其他几种菌(P0.05);迟缓芽孢杆菌降解ZEN的降解产物中不含玉米赤霉醇和玉米赤霉烯醇,降解DON的降解产物中含有3-乙酰-脱氧雪腐镰刀菌烯醇(3-Ac-DON)和脱氧雪腐镰刀菌烯醇(DON-3-Glu)。说明迟缓芽孢杆菌可以作为饲料添加剂用于降解饲料中的DON和ZEN。     

饲料呕吐毒素生物降解研究进展

呕吐毒素（Vomitoxin）,又名脱氧雪腐镰刀菌烯醇（deoxynivalenol,DON）,是一种无色针状结晶,熔点为151-152℃,具有较强的热抗力,121℃高压加热25min仅少量破坏。呕吐毒素是由镰刀菌属（Fusarium）产生的毒性代谢产物,属于单端孢霉烯族化合物（Desjardins，2006）图1。     

单端孢霉烯族毒素生物脱毒技术研究进展

单端孢霉烯族毒素在粮食和饲料中污染严重,主要是T-2毒素和脱氧雪腐镰刀烯醇(DON)等,其毒性作用强,对人和动物产生严重危害.因此,单端孢霉烯族毒素的脱毒方式逐渐成为研究热点,尤其是生物脱毒.很多微生物被证实能够降解霉菌毒素,包括细菌、真菌和酵母菌,可将毒素降解成低毒或无毒的产物.论文以生物脱毒为出发点,从细菌、真菌和...     

脱氧雪腐镰刀菌烯醇的毒理学特征及对猪业生产危害的研究进展

脱氧雪腐镰刀菌烯醇(Deoxynivalenol,DON),是一种单端孢霉烯族镰刀菌属毒素,在自然界中分布广泛。DON在机体内可与核糖体结合诱发核糖体毒性应激反应和氧化应激反应等,还会引起细胞周期发生阻滞,导致细胞凋亡。文章对DON毒理学的最新研究进展和对养猪业的危害做一综述,以期为生猪生产提供参考。     

饲料中T-2毒素的毒性作用研究进展

T-2毒素是由多种镰刀菌产生的单端孢霉烯族化合物中的一种毒素,广泛存在于谷物和饲料中。本文就饲料中T-2毒素的污染现状及其毒性作用作一综述。     

脱氧雪腐镰刀菌烯醇的免疫毒性研究进展

脱氧雪腐镰刀菌烯醇（deoxynivalenol,DON）是一种单端孢霉烯族毒素,主要由禾谷镰刀菌、尖孢镰刀菌、串珠镰刀菌、拟枝孢镰刀菌、粉红镰刀菌、雪腐镰刀菌等镰刀菌产生,由于它可以引起猪的呕吐,故又名呕吐毒素（vomitoxin,VT）。DON纯品1970年首先从日本香川县感染赤霉病的大麦中分离到并命名。这种毒素广泛存在于霉变的小麦、大麦、燕麦、玉米等谷类作物、发霉的饲料以及被污染的肉、奶等动物性食品中,人畜摄入了被DON污染的食物后,会导致厌食、呕吐、腹泻、发烧、站立不稳和反应迟钝等中毒症状,严重时损害造血系统造成死亡（Plattneretal,2003;敖志刚和陈代文,2008）。     

单端孢霉烯族毒素抑制动物生长作用的研究进展

单端孢霉烯族毒素是主要的饲料污染物,包括T-2毒素、脱氧雪腐镰刀菌烯醇(DON)等,具有较强的毒性作用,能引起动物体多种病理变化。其毒性作用能改变真核翻译起始因子2α(EIF2α)、丝裂原激活的蛋白激酶(MAPK)、热休克蛋白90(Hsp90)、胰岛素样生长因子1(IGF-1)等细胞因子的活性,调节多种胺酰tRNA合成酶的活性,进而抑制蛋白质合成,阻滞动物生长。论文从单端孢霉烯族毒素对生长激素影响的角度,综述了该类毒素对动物生长的抑制作用,以期为阐明单端孢霉烯族毒素抑制动物生长的毒性作用机制奠定基础。     

Heartworm in dogs in Canada in 1984

In late December 1984, 1853 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1984 and 35% of them responded. Veterinarians reported that 97,794 dogs were blood-tested to check for microfilariae and 1417 dogs (1.45% of those tested) were found with heartworm. Another 34 dogs were amicrofilaremic, but were diagnosed as having heartworm disease, to give the total number diagnosed in 1984 as 1451 (1.48%). Heartworm was reported from all provinces except Prince Edward Island and Newfoundland but most (1310) of the cases were in Ontario. In Quebec, 126 cases were reported mostly from west of Montreal.

Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 27% of the cases were observed with clinical signs of heartworm disease and 72% had a history of not having left Canada. Southwestern Ontario continued to be the primary focus of the infection.

     

Heartworm in dogs in Canada in 1983

In late December 1983, 2 800 veterinarians across Canada were sent a questionnaire in order to assess the status of heartworm disease in Canada in 1983 and 26% of them responded. Veterinarians reported that 59 504 dogs were blood-tested to check for microfilariae and 771 dogs (1.30% of those tested) were found with Dirofilaria immitis. Heartworm disease was diagnosed in all provinces except New Brunswick and Newfoundland but most (733) of the cases were in Ontario.

Heartworm disease was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 31% of the cases were observed with clinical signs of heartworm disease and 64% had a history of not having left Canada. Southwestern Ontario continues to be the focus of the infection and most of the dogs there had not left the province previously.

     

Heartworm in dogs in Canada in 1991

In late November 1991, 1883 clinics in Canada were sent a questionnaire to assess the status of Dirofilaria immitis in dogs in 1991 and there was a 60.0% response. There were 344,031 dogs tested for heart-worm (HW), 627 were found infected and the prevalence of HW infection was 0.18%. There were 417 dogs with HW in Ontario, 116 in Manitoba, 38 in Quebec, 53 in British Columbia, three in Alberta, and one in Nova Scotia. In British Columbia, all of the infected dogs but one were from the Okanagan valley which, as from 1991, is a new focus of infection in Canada. Most dogs with HW had not been on preventive medication in 1990, and the prevalence among dogs tested and unprotected was 0.59%. That prevalence was considerably higher in endemic areas. Companion dogs, over three years of age and maintained primarily outdoors in rural areas, were most frequently infected. One cat was diagnosed with D. immitis and 33 dogs had Dipetalonema reconditium.     

Heartworm in dogs in Canada in 1985

In late December 1985, 1485 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1985 and 44% of them responded. Veterinarians reported that 137,300 dogs were blood-tested to check for microfilariae and 1210 dogs were found with heartworm. Another 36 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number diagnosed in 1985 as 1247 (0.91%).

Heartworm was reported from all provinces except Prince Edward Island, Newfoundland and Saskatchewan but most (1126) of the cases were in Ontario. Southwestern Ontario continued to be the primary focus of the infection in Canada. From Quebec, 91 cases were reported mostly from and around Montreal. From Manitoba, 19 cases were reported from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 28% of the cases were observed with clinical signs of heartworm disease and 78% had a history of not having left Canada.

     

Heartworm in dogs in Canada in 1988

In late November 1988, 1581 small and mixed animal clinics and institutional veterinarians across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1988, and 46% of them responded. Veterinarians reported that 181,577 dogs were blood-tested for heartworm disease and 367 dogs were found with D. immitis microfilariae. Another 60 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1988 as 441 (0.24%).     

Heartworm in dogs in Canada in 1989

In late November 1989, 1732 clinics and institutional veterinarians were sent a questionnaire to assess the status of Dirofilaria immitis, and 51.7% responded. Of 247,716 dogs tested, 394 had D. immitis microfilariae and 51 were amicrofilaremic for a total of 445 cases and heartworm prevalence of 0.17%. Most (408) of these dogs had no preventive medication and the prevalence among dogs tested and unprotected was 1.01%. That prevalence was considerably higher in endemic areas. Thirty-seven dogs with heartworm had preventive medication. Heartworm was most frequent in companion dogs over three years of age maintained outdoors in rural areas. About 75% of the cases had never left Canada, 26% had clinical signs and 125 were not treated.

Heartworm was reported from British Columbia, Manitoba, Ontario, Quebec, Nova Scotia and Newfoundland, but 383 cases were in Ontario. South-western Ontario was the primary focus of infection. There were 33 cases in Quebec and 24 in Manitoba, mainly found in and around Metropolitan Montreal and Winnipeg respectively.

     

Heartworm in dogs in Canada in 1987

In late November 1987, 1246 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1987, and 50% of them responded. Veterinarians reported that 165,428 dogs were blood tested for heartworm disease and 511 dogs were found with D. immitis microfilariae. Another 78 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1987 as 589 (0.35%).     

Heartworm in dogs in Canada in 1986

In late December 1986, 1224 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1986; 46% of them responded. Veterinarians reported that 150,989 dogs were blood-tested for microfilariae and 869 dogs were found with heartworm. Another 65 dogs were amicrofilaremic but diagnosed with heartworm disease and one was found with heartworm at necropsy to give the total number diagnosed in 1986 as 935 (0.62%).

Heartworm was reported from Manitoba, New Brunswick, Ontario and Quebec, but most (810) of the cases were from Ontario. South-western Ontario continued to be the primary focus of the infection in Canada. There were 103 cases reported from Quebec, mostly from and around Montreal, and 21 cases from Manitoba, from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 33% of the cases were observed with clinical signs of heartworm disease and 81% had a history of not having left Canada.