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

1 st WorkshopXIII International Feed Technology SymposiumMECHANISM OF ACTIONMycotoxins cause health disturbances of all animals, but the effects are more noticeablein highly productive animals in the farm keeping due to significantly greaterconsumption of concentrated feed, although other feedinstuffs may be also contaminatedwith mycotoxins in considerable degree. Changes caused by mycotoxins depend on thetype and quantity of mycotoxins in feed, the time of entering the body, as well as genetic(species, breed of animals), physiological (category, age, diet, health status) and externalfactors (climate, keeping conditions) [14].In the body mycotoxins cause a range of disorders and the biochemical changes, fromfunctional and morphological damage to the appearance of clinical signs ofmycotoxicoses and subsequent mortality. Biochemical changes occur first, and are basedon disorders of resorption of nutrients, lack of protein transfer or the existence ofcompetition for the same receptor between nutrients and mycotoxins, and the existenceof a specific metabolic block of reserves of nutrients.Biochemical disorders of metabolism of certain nutrients primarily cause functionaldamage to certain target cells and organs. Functional impairment primarily affect thebiological membranes, which causes disruption of permeability. Metabolic disordercauses in some organelas ultrastructural first, and then histological changes [26]. Largeramounts of toxins and/or longer use of contaminated feed increases the level andintensity of pathohistological alteration progressing in patoanatomic changes that affectmost of the target organ. These disorders in the first stage go relatively unnoticed, andthen nonspecific signs of health disorders, in the form of reduced consumption,retardiranog growth, reduced productivity and increased feed conversion could beobserved. In the second stage of disease there are no clinical signs that have specialimportance for differential diagnosis, and symptoms are similar to diseases caused bydifferent etiologic factors. In the final stage, clinical signs are related to themanifestation of disorders of certain organs and/or system, and some mycotoxin maycause clinical signs that have certain differential diagnostic significance. Lethal outcomearises as a result of biochemical, metabolic, functional and morphological damage.TOXICITYDifferent mycotoxins exhibit varying degrees of toxicity, which depends on gender, age,species and breed of animals, quality of meals and the presence of other mycotoxins[14]. According to the degree of toxicity, mycotoxins are tentatively divided into threegroups. Extremely toxic mycotoxins (cyclohlorotin, rubratoxin B) cause lethal outcomein quantities of less than 1 mg/kg BW, a very toxic (aflatoxin B1, trichotecens,citreoviridin) cause the same effect in quantities between 1-10 mg/kg BW and othermycotoxins cause a lethal outcome in quantities greater than 10 mg/kg BW.Ruminants are generally resistant to most harmful effects of mycotoxins [24] due torumen microflora which effectively converts entered mycotoxins in less toxic or nontoxiccompounds. Among monogastric animals, pigs are extremely sensitive to the effectof zearalenone, while chickens are practically insensitive. Even within the same class(Aves) there are significant differences in sensitivity to certain mycotoxins (chickens areinsensitive to the F-2 toxin, but turkeys are sensitive). In the same animal species, some92