Effects of dietary n-3 polyunsaturated fatty acids and ... - FINS

1 st WorkshopXIII International Feed Technology SymposiumZearalenone and its metabolites have anabolic effects, similar to estrogen andfoliculostimulative hormone. Biological activity can be explained by competition with17- -estradiol for specific binding sites on estrogen receptors and interference withenzymes involved in metabolism of steroides. The mechanism of action is based onbinding to estrogenic receptors in the cytosol, and the mycotoxin-receptor complex istransported into the cell nucleus. F-2 demonstrates the effects of toxins in all themetabolic processes affected by estrogen hormones [18], but usually in the genitalorgans and in the process of reproduction. The consequence is, primarily, prematuresexual development in immature female and inhibition of normal development of thetestecles in males.Zearalenone is characterized by slightly less toxicity, compared to other metabolites ofFusarium fungus. Toxic effect in different animal species, or the relative toxicity (LD50)ranges from 1-10 mg/kg BW zearalenone and therefore belongs to a very toxicmycotoxins. Pigs are more sensitive to its effects [6] then other animal species, such asruminants and poultry, especially chickens. F-2 toxin has cytotoxic and genotoxic effects[4].The type and intensity of symptoms of zearalenontoxicoses depends on the animalspecies, age and gender. In the clinical picture is dominant estrogen syndrome which ismanifested by edema and vulvar hyperemia, with slightly muculagineus vaginaldischarge. In severe cases, prolapsus of vagina and rectum could be seen. F-2 toxin atlow doses increases the size of the milk glands and reproductive organs and/or causesearly maturation. In higher doses, negatively affects the conception, ovulation,implantation, fetal development and vitality of newborn animals. In addition, in theclinical picture also may occur diarrhea, vomiting, feed refusal, loss of weight andhemorrhages. Characteristic pathomorphologic changes in the external genital organs inoften are observed in the form of edema and hyperemia [20].AFLATOXINAflatoxins are a mixture of similar chemical compounds labeled by fluorescing coloursas B (blue), which are significantly more toxic, and G (green). They are products ofsecondary metabolism of molds Aspergillus flavus and Aspergillus parasiticus, althoughthere are opinions that other strains and species also have the ability of synthesis of thesetoxins in the traces. Aspergillus fungi are capable of growth and sporulation in thetemperature range 6-54 0 C, while the optimal are temperature 30-35 0 C, minimum of 0.78aw for growth and optimal pH is 5.5.Ingested aflatoxin is effectively resorbed in the digestive tract and reaches thebloodstream for 30 minutes and the hepatocytes for 1 hour where its biotransformationsstarts. It is believed that among the metabolites aflatoxicol is the most mutagen agentthat causes carcinogenic changes in the liver. Excretion is mostly done via bile and urineand to a lesser extent by milk (aflatoxins M). After 24 hours in the body remains 20-30%of the entered aflatoxin. The biological half-time decay is 72-96h, and 7 days after use ofcontaminated feed aflatoxin residues and its metabolites were found only in eggs andmilk. Aflatoxin tends to be deposited in all soft tissues and fat depots, mostly in the liverand kidneys. Detection of residues is relatively difficult and possible only for the originalform of toxin and its metabolite M1 [24].97