Aflatoxin M₁ (AFM₁) is a hydroxylated metabolite of aflatoxin B₁ (AFB₁) and can be excreted in milk of cows after consuming aflatoxin (AF)-contaminated feed. The aim of this research was to assess the levels of total AFs in samples of feedingstuff for dairy cows (n = 193) and the levels of AFM₁ in raw bulk tank milk samples (n = 375), in order to estimate the ratio of “AFB₁ feed input” versus “AFM₁ milk output” in four specific regions of Spain. Moreover, the correlation between the raw materials used as ingredients of the total mixed ration (TMR) and the presence of AFs was studied. About one-third (34.7%) of the feed samples were positive for total AFs in a range of 0.05–6.45 μg/kg, and 12.4% were positive for AFB₁. AFM₁ was detected in 18.9% of bulk milk samples, with concentrations ranging from 0.009 to 1.36 μg/kg. While none of the feed samples exceeded the European Union (EU) maximum content for AFB₁ in feedingstuff for dairy animals of 5 μg/kg, three bulk milk samples exceeded the EU maximum level for AFM₁ in milk of 50 ng/kg. The transfer ratio AFB₁/AFM₁, which was derived from AFB₁ levels in feed, AFM₁ levels in bulk tank milk, feed intake, and milk yield data, was 0.6–6%, which corresponded well with the range of published carry-over data for aflatoxins. Statistical analyses showed that the main sources of AFB₁ in TMR were maize silage, bagasse, soya bean husk, maize, alfalfa hay, cotton seed and compound feed, thus special attention should be paid in controlling these raw materials when used in TMR preparation. Although the analysis of AFs in feed did not correlate with the presence of AFM₁ in milk, monitoring feedstuffs is a useful tool in order to try and minimise AF-contamination of milk.

中文翻译：

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乳牛饲料中黄曲霉毒素的分析控制对预防牛奶中黄曲霉毒素M1的有用性。

黄曲霉毒素M ₁（AFM ₁）是黄曲霉毒素B ₁（AFB ₁）的羟基代谢产物，食用受黄曲霉毒素（AF）污染的饲料后，可以在牛乳中排出。这项研究的目的是评估奶牛饲料样品中的总AF水平（n  = 193）和生料罐奶样品中的AFM ₁水平（n  = 375），以估算“ AFB ₁馈送输入”与“ AFM _1”西班牙四个特定地区的牛奶产量”。此外，还研究了用作总混合日粮（TMR）成分的原材料与AF的存在之间的相关性。饲料样本中约三分之一（34.7％）的总房颤阳性率为0.05–6.45μg/ kg，AFB ₁阳性的为12.4％。在18.9％的散装牛奶样品中检测到AFM ₁，浓度范围为0.009至1.36μg/ kg。尽管所有饲料样品均未超过欧盟（EU）奶类动物饲料中AFB _1的最高含量5μg/ kg，但三个散装奶样品均超过了50 ng / kg牛奶中AFM ₁的欧盟最高含量。传输比AFB ₁ / AFM ₁从饲料中的AFB ₁水平，散装罐装牛奶中的AFM ₁水平，饲料摄入量和产奶量数据得出，其值为0.6–6％，与已发表的黄曲霉毒素残留数据范围相当。统计分析表明，TMR中AFB ₁的主要来源是玉米青贮饲料，蔗渣，大豆皮，玉米，苜蓿干草，棉籽和配合饲料，因此在用于TMR制备时应特别注意控制这些原料。尽管对饲料中AF的分析与牛奶中AFM ₁的存在并不相关，但是监控饲料是一种有用的工具，可以尝试将牛奶的AF污染降至最低。