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

1 st WorkshopXIII International Feed Technology Symposiumshows and immunosuppressive and cytotoxic effect, and also causes the disorder of themechanism that regulates the use of vitamin A [27].Trichotecens are considered to be significantly more toxic than other metabolites ofFusarium fungi, and within them, type A is significantly more toxic than B-typetrichotecens. Toxicity depends on the animal species, sex and age, and the amount oftoxins. The effect in different animals, expressed as the relative toxicity, ranges 1-10mg/kg of BW, so therefore T-2 toxin belongs to a very toxic mycotoxins [21].T-2 intoxication is characterized by lower growth, with increased feed conversion, whilethe intensity of the disorder of production results is proportional to the amount ofmycotoxin and length of exposure [32]. Decrease in production is emphasized if thereare present other mycotoxins in feed. Clinical symptoms are manifested by depression,lethargy and breathing difficulties. Local effects are epithelonecrotic stomatitis, oralulceration and necrosis. Early occurrence of vomiting may be accompanied by diarrhea,which is often bloody. Extension of protrombin time and potential vascular damagecause widespread haemorrhage and haemorrhagic diathesis. Also, there is fever, anemia,growth inhibition and poor utilization of feed. Chronic toxic effects of T-2 toxinprimarily reflect on the production results [21].T-2 toxin causes pathomorphologic changes in the liver, digestive tract, kidneys, bonemarrow, skin and lungs, as well as in the heart, reproductive organs, spleen and nervoustissue [27].ZEARALENONEZearalenone (F-2 toxin) is a secondary metabolite of Fusarium fungi genus (F.graminearum, F. roseum, F. Nivala, F. tricinctum, F. sporotrichoides, F. oxysporum, F.moniliforme, F. lateritium) [22]. The major growth of mold occurs when relativehumidity is over 70%. The optimal temperature for development of fungi ranges from 18to 24 o C, with the greatest production of zearalenone noted during changes of mediumand higher temperatures [14]. Zearalenone belongs to the group of phytoestrogens. Sofar it has been registered over 15 different derivates that have different biologicalactivity. Basically, they have a similar configuration (phenolic core) as estrogenicsubstances.Zearalenone is resorbed from the digestive tract and by portal bloodstream is transportedto the liver where it accumulates and metabolized by the action of and reductase andesterasa enzymes. Metabolic half time of zearalenone is 86.6 hours and in 4-5 days it ismostly secreted from the body. Zearalenone and its derivatives are mostly eliminated inthe form of glucuronides via feces (40-60% of ingested amount), and to a lower extentvia the urine (only 2-4% of whole amount). This toxin is excreted in milk, even 42-44hours after ingestion of contaminated feed and continues during the next 5 days after thetermination of its consumption. Zearalenone residues and its derivatives can be found inthe edible parts of animals which were fed contaminated feed, but usually in the liverand muscles. Even in the meat of clinically healthy animals could be determined 10g/kg. Zearalenone was determined in the egg yolk also. Residues are carcinogenic, andtheir biological effects are compared with the effects of dietilstilbestrola or estradiol [10,33].96