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The Carry-Over of Aflatoxins in Dairy Feed to Milk of Modern Holstein Dairy Cows

机译：现代荷斯坦奶牛的牛奶中黄曲霉毒素的残留量

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摘要

Aflatoxins are hepatotoxic and carcinogenic secondary metabolic products from the fungal species Aspergillus flavus and Aspergillus parasiticus. Aflatoxin M1 (AFM1) is the major metabolite of Aflatoxin B1 (AFB1) present in mammalian milk. The US Food and Drug Administration (FDA) dictates a maximum allowable concentration of 20 microg/kg total aflatoxin in food and feed intended for dairy consumption, and 0.5 microg/kg AFM1 in milk and milk products. The European Commission dictates a maximum allowable concentration of 4 microg/kg total aflatoxin and 0.05 microg/kg AFM1 respectively. The carry-over of AFB1 (the amount of AFB1 in the feed that is excreted as AFM1 in the milk) is a major factor used to create regulations for acceptable AFB1 concentrations in dairy cattle feed. It has been observed that higher producing dairy cows (30-40 kilograms of milk per day) have a higher carry-over rate, but current regulations use older studies using low-producing dairy cows (10-20 kilograms of milk per day) as a reference for risk. The objective of this project was to measure the carry-over rate of AFB1 from feed to AFM1 in the milk of modern, high-producing US Holsteins milked three times a day to provide a more relevant assessment for current regulations. Corn naturally infected with aflatoxin-producing fungi was used to imitate a real-world contamination scenario, an approach applied in only one previous study (Frobish et al., 1986). Three replications of a feeding trial to test carry-over in high-producing dairy cows were completed; each using 12 high-producing dairy cows in early- to mid-lactation, fed naturally contaminated corn meal top-dressed on their daily total mixed ration. Cows in each replication were assigned to: control (0 microg/kg), low (10 microg/kg), or high (20 microg/kg) AFM1 groups. Feed and milk samples were taken for seven (replicates 1 and 2) or two (replicate 3) days and analyzed with a VICAM fluorometer. Using linear regression, the direct carry-over rate was 6.5%, much higher than the 1 to 2% estimated by previous researchers using low-producing dairy cows. These findings suggest that the US regulatory limit of 20 microg/kg of total aflatoxin in the feed is not a guarantee of protection against violating the regulatory limit of 0.5 microg/kg of AFM1 in milk of high-producing dairy cows.
机译：黄曲霉毒素是来自真菌种黄曲霉和寄生曲霉的肝毒性和致癌性次生代谢产物。黄曲霉毒素M1（AFM1）是哺乳动物牛奶中存在的黄曲霉毒素B1（AFB1）的主要代谢产物。美国食品药品监督管理局（FDA）规定，用于乳制品消费的食品和饲料中总黄曲霉毒素的最高允许浓度为20微克/千克，奶和奶制品中的黄曲霉毒素最高允许浓度为0.5微克/千克。欧盟委员会规定最高总黄曲霉毒素浓度为4微克/千克，AFM1为0.05微克/千克。 AFB1的残留量（饲料中AFB1的含量以牛奶中AFM1的形式排泄）是用于制定法规以制定奶牛饲料中可接受的AFB1浓度的主要因素。据观察，高产奶牛（每天30至40公斤牛奶）的结转率较高，但目前的法规使用了使用低产奶牛（每天10至20公斤牛奶）的较早研究作为。风险参考。该项目的目的是测量每天喂奶3次的现代高产美国荷斯坦奶粉中，从饲料到AFM1的AFB1残留率，以便为当前法规提供更相关的评估。自然感染了产黄曲霉毒素的真菌的玉米被用来模拟现实世界中的污染情况，这种方法仅在以前的一项研究中应用（Frobish等，1986）。在高产奶牛中进行了三个重复试验，以测试残留量；在泌乳初期至中期，每头奶牛都使用12头高产奶牛，以自然混合的玉米粉作为饲料，每日补充其每日总定量。每次复制中的母牛被分为：对照组（0 microg / kg），低（10 microg / kg）或高（20 microg / kg）AFM1组。采集饲料和牛奶样品7天（重复1和2）或2天（重复3），并用VICAM荧光计进行分析。使用线性回归，直接结转率为6.5％，远高于先前研究人员使用低产奶牛估计的1-2％。这些发现表明，美国饲料中总黄曲霉毒素的法规限量为20微克/千克，不能保证防止高产奶牛的牛奶中AFM1的法规极限为0.5微克/千克。

著录项

  • 作者

    Churchill, Katherine Anne.;

  • 作者单位

    Cornell University.;

  • 授予单位 Cornell University.;
  • 学科 Animal sciences.;Nutrition.
  • 学位 Ph.D.
  • 年度 2017
  • 页码 46 p.
  • 总页数 46
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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