13. Safe level of aflatoxins and detoxification

Due to synergistic effect of Aflatoxin B1 and hepatitis B exposure, there are no specific safe levels for aflatoxin regarding resistance/tolerance to AFs. Ideally, there should be zero level for AFs in feed [83]. The Food and Drug Administration and European Union have established 20 μg/kg and 10 μg/kg AFs as maximum level for poultry, respectively. Based on feeds available, AF contaminated feeds should be fed at lowest possible level and for the shortest period of time [84]. The production of AFs can be controlled by maintaining physical integrity of cereal grains, drying and use of anti-fungal especially propionic acid to inhibits molds growth by decreasing pH and ATP formation through electron transport pathway. UV, X-rays or microwave irradiation and dilution of contaminated feed with AF free feed is also one of the methods to dilute the concentration of AFs [9]. However, AFB1 contamination of feed is practically unavoidable universally [85]. Mycotoxins decontamination refers to methods by which these metabolites are removed or neutralized in contaminated feed, while mycotoxins detoxification refers to methods by which the toxic properties of the mycotoxins are eliminated [86]. Since early 1990s, studies on mycotoxin adsorbents have yielded success but high inclusion rates and potential interactions with dietary nutrients are causes for concern [87]. Numerous strategies for the detoxification and inactivation of mycotoxins in feed have been tested but most of these are ineffective or impractical [22]. Dietary fortification with methionine, selenium, vitamins, plant and herbal formulations, etc. may detoxify the adverse effects of AFs by glutathione systems which contain cysteine (derivatives of methionine) in broilers [43, 86]. Approaches to detoxify contaminated grain and finished feed can be physical, chemical and biological treatments [88].
