黄曲霉毒素对肉鸡毒性作用的研究进展

黄曲霉毒素主要是由黄曲真菌和寄生曲真菌产生的一类高毒性次级真菌代谢物质,世界范围内大部分的粮食和动物饲料受到黄曲霉毒素的污染,对动物健康与畜禽养殖业可持续发展构成严重威胁。黄曲霉毒素B₁（aflatoxin B₁,AFB₁）是众多霉菌毒素中常见且毒性较强的一种,过量摄入AFB₁具有致癌、致畸、免疫抑制等毒性效应。大量研究证实AFB₁可对肉鸡的生长、免疫功能、器官发育等方面造成严重影响,威胁家禽业的健康发展。结合国内外研究报道,对黄曲霉毒素的性质、毒性进行概述,从肠道功能障碍、免疫抑制、器官损伤和遗传毒性四个方面阐述AFB₁对肉鸡毒性作用的研究进展,以期为进一步阐明黄曲霉毒素对肉鸡毒性作用的分子机制,同时为减轻黄曲霉毒素对肉鸡养殖造成的危害提供参考。     

LC-MS/MS测定猪尿中的黄曲霉毒素M1

建立LC-MS/MS检测猪尿中黄曲霉毒素M1的含量。猪尿样用超纯水稀释定容,充分漩涡振荡后经免疫亲和层析柱净化,甲醇洗脱,微孔滤膜过滤,经液相色谱分离,电喷雾离子源离子化,多反应离子监测(MRM)方式检测。外标法定量。采用0.1%甲酸:乙腈+甲醇溶液(1+1)为流动相,梯度洗脱。0.3mL/min的流速。在0.01μg/kg～0.50μg/kg范围内具有良好的线性关系,最低检测限为0.01μg/kg,回收率在70%～95%之间。此法操作简便、快速、灵敏、准确、样品处理简便易行,适用于测定猪尿中的黄曲霉毒素M1。     

乳及乳制品中黄曲霉毒素M_1研究进展

随着我国经济的发展与人们生活水平的提高,具有丰富营养价值的乳及乳制品逐渐成为人们日常生活的必需消费品。与此同时,人们对乳及乳制品的期待不再局限于量的提高,而是对其质量和安全提出了更高的要求。由于2011年发生的牛奶中黄曲霉毒素M_1(AFM_1)含量超标事件,以及相比于成人,婴幼儿更易受到牛奶中AFM_1的损害,人们开始更加重视乳及乳制品中存在的AFM_1污染问题。本文在国内外已有文献报道基础上,对乳及乳制品中AFM_1的来源与生物学性质、污染与限量标准、检测与防控技术进行综述。     

Impact of push–pull cropping system on pest management and occurrence of ear rots and mycotoxin contamination of maize in western Kenya

Push–pull involves intercropping of cereals with Desmodium as a “push” crop and planting Napier grass/Brachiaria as the “pull” crop at the border. The technology has been reported to effectively control stemborers, striga weed, and fall armyworm (FAW), and to improve soil nutrition, resulting in increased grain yield. This study evaluated the impact of stemborer and FAW management using this technology on incidence of maize ear rots and preharvest contamination of grains with aflatoxin and fumonisin in western Kenya. The study was conducted during three cropping seasons on maize grown under the push–pull system and as a monocrop. Incidence of stemborer and FAW damage was determined as percentage of damaged plants, while incidence of ear rots was determined as percentage of ears with symptoms. At harvest, fungi were isolated from kernels and aflatoxin and fumonisin were quantified using enzyme-linked immunosorbent assay. Stemborer and FAW damage was significantly (p = .001) reduced by over 50% under the push–pull system. There was also a significant (p < .001) reduction in the incidence of Fusarium verticillioides (60%) and Aspergillus flavus (86%), which was reflected in a reduced incidence of ear rots (50%) with the push–pull system (p = .001). Fumonisin in maize from push-pull farms was significantly (p = .048) reduced (39%) but the technology had no significant (p > .05) effect on aflatoxin. The study showed that push–pull is an effective strategy for managing maize ear rots and fumonisins, and therefore could play a role in improving food safety among smallholder maize farmers in the region.     

Effects of clarified neem oil on growth and aflatoxin B1 formation in submerged and plate cultures of aflatoxigenicAspergillus spp.

An increase of 11–31% of dry mycelial mass was observed along with a slight decrease (5–10%) in aflatoxin Bi production in 5-day-old aflatoxigenicAspergillus spp. submerged cultures containing either 0.5 ml or 1.0 ml clarified neem oil (CNO) in 0.1 % Triton solution. Fungal growth and aflatoxin B₁ production were also determined in potato-dextrose-agar petri plate cultures inoculated with aflatoxigenicAspergillus spp. containing an atmosphere of volatiles emitted from 0.25 ml, 0.5 ml, and 1.0 ml CNO added to the plates. After 5 days’ incubation, fungal radial growth was reduced by 7–29% and aflatoxin B₁ production by 0–67%. GC/MS analysis of the head space volatiles of the CNO indicated that the reduction of fungal growth and aflatoxin B₁ was probably due to low molecular weight hydrocarbons, aldehydes, alcohols, and sulfur compounds emitted at 30°C in the dry culture. These results suggest that volatiles emitted from CNO at 30° C in plate cultures were more fungistatic and consequently inhibited aflatoxin production more than neem oil added in liquid cultures.     

不同形式硒对大鼠生长及短期肝癌模型发生的影响

SD大鼠75只，体重50～60g，随机均分5组。组Ⅰ，正常对照组；组Ⅱ，试验对照组；组Ⅲ，高亚硒酸钠组；组Ⅳ，富硒麦芽组；组Ⅴ，富硒酵母组。组Ⅰ、Ⅱ、Ⅲ各组基础饲料中分别添加亚硒酸钠硒，含量分别为0．1、0．1、0．3mg／kg；组Ⅳ，基础饲料中添加富硒麦芽硒0．3mg／kg；组Ⅴ，基础饲料中添加富硒酵母硒0．3mg／kg。各组饲喂基础料第32天时，除组Ⅰ大鼠外，其余4组大鼠实施“AFB1致肝癌短期实验模型程序”。记录各组大鼠体重情况，测定血清碱性磷酸酶（ALP）、甲胎蛋白（AFP）、NO和γ-谷氨酰转移酶（γ-GTase）、SOD、MDA含量，以及肝、肾组织和全血中谷胱甘肽过氧化物酶（GSH—Px）、MDA、SOD、羟脯氨酸（HyP）的活性。结果：与对照组相比，富硒酵母硒和富硒麦芽硒能显著促进大鼠生长，提高大鼠增重率、降低料肉比，而亚硒酸钠硒作用不明显；并明显降低血清γ-GTase、HyP水平，提升全血GSH—Px活性及血清SOD水平，有效清除肾脏MDA；在降低血清ALP、AFP和快速提高全血GSH—Px活性方面，富硒麦芽硒作用优于富硒酵母硒。表明富硒酵母硒和富硒麦芽硒比亚硒酸钠硒能更有效提高大鼠生长速度，增强其抗氧化能力，从而抵抗AFB1所致肝肿瘤。     

加热对花生黄曲霉毒素含量的影响

将花生在不同加热温度和时间下进行加热,测定黄曲霉毒素(AFT)在不同温度及时间下的含量。结果表明,加热可降低花生中的黄曲霉毒素的含量,并随温度升高和加热时间的增加,毒素含量也明显下降。同时毒素含量的减少速率与样品最初被污染水平有关,AFTG1的热稳定性较AFTB1差。     

ELISA法检测花生酱中AFB1样品前处理方法的改进研究

通过ELISA法,对检测花生酱中AFB1含量的前处理方法进行了改进研究。通过对样品提取条件的优化,提取液稀释度的改变,建立了新的前处理方法,并利用回收率的测定与国标法进行比较。结果表明：利用改进的提取方法处理花生酱样品,对常见浓度加标回收率达75％～120％。新的提取方法不仅简化了操作步骤,减少了工作量,又提高了回收率。