Controlling Mycotoxins Issues in Ruminants
It is a common belief that ruminants are less sensitive to the effect of mycotoxins than other species. This hypothesis is derived mainly from the fact that rumen microflora is able to degrade mycotoxins present in the feed. Research reports the hypothesis that rumen microflora, and in particular the protozoa, are able to breakdown part of the mycotoxin molecule, allowing the production of a different metabolite. In some cases and for certain mycotoxins, degradation levels of 90% of the initial contamination are reached.1 When analysing papers, contradictory results are unfortunately published. More importantly, field experience demonstrates that ruminants suffer from mycotoxin challenges. How can these apparently contradictory data be explained?
Prof Fink-Gremmels (2008) in her review on the effect of mycotoxins in ruminants already gave some explanations, and these are validated by further studies. In fact, while from one side it is true that rumen microflora can degrade mycotoxins, from the other side their ability to work effectively depends on different factors2.
Why There Needs to be Mycotoxin Control Programs
First of all, rumen microflora are sensitive to mycotoxins that can have an antibiotic-, antiprotozoal- or antifungal activity. We just need to think about penicillin, the first widely used antibiotic that is a mycotoxin produced by fungi from Penicillium group. Recent research in ruminants demonstrated the ability of Fusarium mycotoxins to inhibit Ruminoicoccus albus and Methanobrevibacter ruminantium, while patulin has both antiprotozoal and broad anti-microbial activity against Gram + and Gram – bacteria.
The degradation activity by the rumen microflora requires time, so when we formulate rations with faster transit time in the rumen (i.e. diets reach in concentrates), this is negatively correlated with the ability to degrade mycotoxins. At the same time, these rations are mainly designed for high producing cows that will results thus in higher sensitivity to mycotoxicosis.
In addition, the efficacy of the rumen depends on its status. It is proven that ruminants suffering acute but also sub-clinical acidosis (normally occurring in high yield dairy farms) have a lower ability to degrade mycotoxins. This is mainly linked to the rumen pH, in fact, at normal rumen pH (6.5) mycotoxins such as Deoxynivalenol, T-2 and HT-2 toxins are degraded to the less toxic compound de-epoxy- Deoxynivalenol and deepoxy T-2 toxin. At a pH below 5.6 this ability is strongly compromised. As demonstrated by our surveys, on average more than 50% of samples analysed showed 3 or more mycotoxins present in one single sample. The copresence of different mycotoxins in synergism will also influence the efficacy of rumen microflora to degrade them. Finally, for certain mycotoxins such as Zearalenone, the rumen degradation brings along the production of the more toxic metabolite α-zearalenol.
All the above-mentioned reasons clearly demonstrate that ruminants need a mycotoxins control program like all others animal species. It is key to remember the importance of controlling Aflatoxins especially in dairy cows. In fact the mycotoxin metabolite Aflatoxin M1 is transferred in the milk and due to its toxicity represents a possible issue for milk consumption. Due to the low limit allowed in milk (in EU we have the highest restriction with max 50 ppt allowed), and consequently the lowest limit in dairy feeds (5 ppb), we can sometimes register excess levels in milk. This is because the transfer rate of Aflatoxin B1 in feed and M1 in milk can vary from 1 to 6%. So at higher transfer rate, even when we have feed within legal limit, we can have an excess in the milk. This is the reason why the inclusion of a valid mycotoxin binder is fundamental in a dairy ration.
How Kemin is Combatting Mycotoxin
Kemin is continuously looking for effective solutions to limit mycotoxin risks in dairy. Therefore Kemin has developed TOXFIN™ M, a specific mycotoxin binder for ruminants including a high level of 1m558 Bentonite. This new formula is specifically designed for ruminants where Aflatoxins represent a risk and need to be controlled, both for its influence of animal health but also because strictly regulated by law for its toxicity when transferred in milk as Aflatoxin M1. TOXFIN M guarantees a broad spectrum binding efficacy. For this reason, it also represents the first option for ruminant farms with low or moderate mycotoxin challenges. Protect your cows from mycotoxin risks to secure top performing animals.
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1. All about feed, 2016, Mycotoxins, Lessons-on-mycotoxins-in-dairy-A-case-study
2. The role of mycotoxins in the health and performance of dairy cows J. Fink-Gremmels Utrecht University, The Veterinary Journal 176 (2008) 84–92