11. "Carry-over" of aflatoxins

Mycotoxins including Aflatoxins are metabolized in the gastrointestinal tract, liver or kidneys according to their chemical structure. Their transfer to poultry meat and eggs leads to undesirable effects on human health [18]. Agag [3] examined the "carry-over" of AFB1 from layer feed to eggs was examined in laying hens at dietary levels of 100–400 μg/kg AFB1. This resulted in 0.2 to 3.3 μg/kg in eggs, and AFs ratios in feeds and tissues found to be are very low ranging from 500:1 to 14,000:1 excluding the liver, particularly when compared with milk (70:1). On the other hand, Zaghini et al. [55] showed no measurable residual AFB1 or its metabolites in eggs. These contrasting findings may be ascribed to mannan oligosaccharides in naturally AFs contaminated feeds at different levels of toxicity [55].

In broilers and layer birds, the AFB1 residues have been reported to vary from no detection to 3.0 μg/kg in liver in birds fed 250–3310 μg/kg AFB1 over certain periods [71]. Fowler et al. [72] found no significant increase in AFs residues in liver until the 1800 μg/kg AF contaminated feed was fortified with AF at a concentration of 1200 μg/kg with no clay used as a binding agent. Younger birds were found to have significant increase in liver residues than those in non-exposed birds. Moreover, birds 3rd weeks of age that received 1800 μg/kg AFs were found to have detectable levels of AFB1 in the liver.

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, chem-

Aflatoxins: Their Toxic Effect on Poultry and Recent Advances in Their Treatment

http://dx.doi.org/10.5772/intechopen.80363

135

Thermal inactivation, cleaning of the kernel surface, and hence the removal of highly contaminated particulate matter, have proven effective in reducing moderate mycotoxins contamination of feed [43, 89]. However, it seems quite laborious to remove highly contaminated feedstuffs. On the other hand, a lot of chemicals e.g. acids (sulfuric acid, hydrochloric acid, phosphoric acid, benzoic acid, citric acid, acetic acid), alkaline compounds (ammonia, sodium bicarbonate, sodium hydroxide, potassium hydroxide, calcium hydroxide, caustic soda), salts (acetate ammonium, sodium bisulfite, sodium hydrosulfite, sodium chloride, sodium sulfate), oxidants (H2O2, sodium hypochlorite, ozone), reducing agents (bisulfites), chlorinated agents and formaldehyde, etc., are being used for the degradation of mycotoxins in feed [90]. These methods are inefficient but comparatively expensive. Ammoniation has been demonstrated to

High level dosages of methyl bromide, ethylene dibromide, propane/propene ethylene oxide, sulfur dioxide, phosphine propionic, acetic and isobutyric acids show fungicidal activity. However, these chemicals lower nutritional quality and are corrosive on human and animal tissues [92]. Therefore, the use of these chemicals is discouraged. Several related patents involving the use of ozone in agricultural products decontamination are found. This decontamination method involves placing the agricultural products in a treatment chamber, generating ozone in the vicinity of chamber, supplying ozone to the product through continuous flow and exposing the

agricultural product to ozone, which then reacts with the toxins and/or microorganisms.

There are different types of adsorbents, which can be used for the detoxification of AFs in the feed. The use of activated carbon for the detoxification of mycotoxins can also be another option but different activated charcoals have less/no effect against mycotoxins, which show their unspecified adsorbent nature. Moreover, certain essential nutrients are also adsorbed

The most applied method for protecting animals against mycotoxicoses is the utilization of adsorbents in the feed, aimed at binding mycotoxins efficiently in the gastrointestinal tract, thus limiting or at best preventing the toxins from being absorbed by the body thereby, preventing their toxic effects and "carry over" of the toxins to animal products [89]. Selected adsorbents added to AFs-contaminated feeds as feed additives can sequester AFs during the digestive process, allowing the mycotoxins to pass harmlessly through the gastrointestinal tract of animal [94]. This is one of the more effective and practical approaches to address the problem of AFs.

ical and biological treatments [88].

14. Physical and chemical methods

reduce AFs levels but not accepted in the United States [91].

when at higher concentration in as compared to mycotoxins [93].
