ISSUE FOCUS 38 FEED & ADDITIVE MAGAZINE April 2023 ly for aflatoxins, however all of these products are not equivalent considering their level of efficacy, their activity spectrum, their interaction with other essential nutrients or their quality in terms of contaminants (dioxins, heavy metals, …), specially for clays-based products. Figure 1 shows variable levels of efficacy of some binding agents (clays, Yeast-cell wall) toward different mycotoxins. Since multi-mycotoxin contamination is a topic of great concern and that synergic interactions between mycotoxins but equally with other biotoxins such as endo or exo-toxins, are more and more documented as exacerbating the adverse effects on animal, the rigorously selection and combination of the most efficient adsorbing agents, can allow maximum protection against challenges posed by broad-spectrum mycotoxin and bacterial toxins contamination. An alternative strategy to deactivate mycotoxins in animal feeds is the use of microorganisms or enzyme systems having the capability to detoxify mycotoxins by metabolisation or degradation prior to their resorption in the gastro-intestinal tract. Indeed, this approach can be a specific, irreversible and environmentally friendly way of detoxification because it leaves neither toxic residues nor undesirable by-products. Zearalenone (ZEA) and their derivatives metabolites are amongst main mycotoxins that require particular attention and interests to manage using biotransformation or biodegradation. Zearalenone has been shown to negatively affect the reproductive function of pigs and other animal species due to estrogenic effects. Indeed, it fits to the estrogen receptors triggering the wrong hormonal responses and upsetting the reproductive system. Interestingly, it has recently shown that effects of their derivatives can be up 60 times more toxic than parent ZEA molecule. Animals can be exposed to these derivatives through naturally contaminated feeds but equally after metabolization of zearalenone in environments with other micro-organisms such as the gut or he rumen. A recent example for high degradation potential has been shown with Bacillus strains that were able to degrade zearalenone and their main metabolites, with levels up to 99.9% degradation using in vitro conditions, i.e ZEA at 1 ppm, initial Bacillus strains inoculum at 6 log CFU/mL and optimal incubation assays (pH7, 30°C, 24h) (Figure 2). These results, comforted in different other oxygen conditions, pH and temperature, also highlight the Bacillus potential efficacy in various physico-chemical and physiological environment (all along the digestive tract) and in different animal species. • Support global animal health by bioprotection effects – In vivo results in piglet Through the term bioprotection, it can be found a wide variety of action mechanisms and also numerous types of compounds. Bioprotection can be defined as all physiological action mechanisms that Figure 1. Mycotoxins adsorption capacity (%) of different binding agent (C1 to C11; Techer et al., 2019). *Average adsorption for all tested toxins. Figure 2. Percentage of zearalenone and its derivatives reduction by Bacillus strains (Techer et al., 2020).
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