The Hazards of Mycotoxins and Animals Removing Mechanism

The contamination of mycotoxins in food and feed worldwide is a serious problem. Mycotoxins are secondary metabolites of molds, which have adverse effects on humans, animalsand crops, leading to diseases and economic losses. Aflatoxins, ochratoxins, melamine, zelenon, fumonisins, tremortoxins and ergot alkaloids are the most important mycotoxins in the agricultural economy. Some molds can produce more than one mycotoxin, and some mycotoxins are produced by more than onefungus. Usually more than one mycotoxins can be found on the contaminated substrate.

The factors affecting the presence of mycotoxins in food or feed include environmental conditions relating to controllable storage. Other external factors such as climate, orinternal factors such as the specificity of fungal strains, strain variation and the instability of toxin-producing characteristics are more difficult to control. Mycotoxins can cause various acute and chronic effects on humans and animals (especially monogastric), depending on the species and susceptibility of the animal. However, ruminants are generally more resistant to the hazards of mycotoxins duing to the rumen microbiota candegrade mycotoxins.

The economic impacts of mycotoxins include theloss of human and animal lives, increased in health care and veterinary carecosts, reduction of livestock production, disposal of contaminated food andfeed, and the invest on research of mycotoxins to reduce mycotoxin the severity problems. Although efforts has been focusing on developing guidelines tocontrol mycotoxins worldwidely, but practical measures have not yet been fully implemented.

The characteristics of human or animal fungalpoisoning are related to food or feed. It is non-infectious, non-transferable,non-infectious, and untraceable for microorganisms other than fungi. Theclinical symptoms usually can be relieved after removal the contaminated foodor feed. But for the breeding industry, fungal poisoning on breeding animals can leading to vomiting, weakened immunity, decreased feed intake,and reduced growth performance, which will finally affect the efficiency ofbreeding. How to prevent mycotoxins hazards from harming farmed animals has become a major dilemma in the livestock breeding industry.

Natural antifungal substances are receiving moreand more attention. In fact, as early as the 1980s, German scientist Gareis used an in vitro experiment-liver circulation perfusion system to simulate the function of removal mycotoxins by animal liver.

Now people already know that there are two stages in the removal of mycotoxins from body:

Firstly, mycotoxins such as vomiting toxin (DON),T-2 toxin, and snake toxin (DAS ) aredecomposed by microsomal cytochrome P450, flavin-containing monooxygenase, prostaglandin synthetase, amino oxidase, and alcohol. Hydrogenase participates in the oxidation reaction, and the reduction reactionis controlled by epoxy hydrolase, aldehyde reductase orketoreductase. Mammalian tissues and body fluids contain a large number ofnon-specific esterases and amidases that can hydrolyze heterogeneous biologicalmolecules.

Secondly, the later formed molecules are linked tothe main coupling enzymes, microsomal glucuronyl transferase, cytoplasmicsulfur transferase, methyltransferase, aminoacyl transferase, s-glutathione transferase and n-acetyl transferases etc.. to occur conjugation reaction, thuscan reduce the toxicity of mycotoxins, increase their solubility in waterand facilitate their excretion in the urine (and milk) and finally protect theanimals health.

The above two stages of the reaction need tobe carried out in the environment of bile (bile acids). The unique hydrophilic and lipophilic properties of bile acids can combine mycotoxins with various enzymes. Without the bile acids in the environment, the oxidation, reduction, hydrolysis and conjugation reactions of mycotoxins would not be completed.

In addition, mycotoxins control should begin fromthe source. The development of physical, chemical, and biotechnological tools to improve seed production, planting, harvesting, and storage of forages and grains is critical to reducing the level of contamination of food and feed.