ISSUE FOCUS FEED & ADDITIVE MAGAZINE March 2024 39 Mycotoxins pose risks to ruminant health due to their varied diet. Identifying issues is challenging, given nonspecific symptoms and the multitude of factors that can potentially be involved. While rumen microbiota can metabolize some mycotoxins, others persist, like Aflatoxin M1. Mitigation requires a multifaceted approach involving agricultural practices and antibiotoxin solutions in feed for effective control. Mycotoxins pose a significant threat to ruminant health and productivity. Their complex diet, comprising concentrates, forages, and silages, increases and diversifies the risk of mycotoxin exposure compared to monogastrics. Aflatoxins, fumonisins, ochratoxins, zearalenone, trichothecenes, ergot alkaloids, and patulin are the primary mycotoxins of concern in ruminants. Yet, identifying a mycotoxin issue (often termed 'mycotoxicosis') in ruminants is challenging, given that exposure to some mycotoxins manifests nonspecific symptoms. The consequences are typically chronic, with hidden disorders such as decreased ingestion, productivity, and fertility. Although more and more studies are being performed, it is still difficult to uniformly assess the effects of mycotoxins on dairy cows. This is due to the many factors that must be considered such as the type and level of mycotoxins ingested, the duration of the intoxication, the presence of masked mycotoxins, the diet, the animal, the environment and the additives, all influencing the magnitude of the effect on cow health. THE SPECIFIC CASE OF RUMINANTS In the realm of ruminants confronting mycotoxins, the dynamics present a unique scenario. Traditionally, mycotoxin impacts have been predominantly scrutinized in monogastric animals. Ruminants, however, are perceived as more resilient to the detrimental effects of mycotoxin exposure due to the transformative abilities of their rumen microbiota, which can convert certain mycotoxins into less harmful metabolites or even inert substances. Yet, recent research has illuminated that only select mycotoxins undergo metabolism, and in some instances, this process is only partial. Take aflatoxin, for instance. It undergoes conversion into aflatoxicol, a less toxic form compared to AFB1. Nevertheless, a portion of aflatoxin persists and is absorbed by the digestive tract, ultimately metabolizing into Aflatoxin M1 (AFM1) in the liver. While ruminants exhibit considerable resistance to aflatoxicosis, the transmission of AFM1 into milk warrants close monitoring due to its potential health risks, particularly for children with heightened milk consumption. Conversely, some mycotoxins are converted into more potent metabolites. Zearalenone, for example, transforms into α-zearalenol, a compound exhibiting three to four times greater oestrogenic activity. NAVIGATING MYCOTOXIN CHALLENGES IN RUMINANTS Anne-Laure Tournay Product Manager MiXscience, Avril Group
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