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

1 st WorkshopXIII International Feed Technology Symposiumreaction. Economic losses caused by contamination with mycotoxins are almostinvaluable. They occure in different stages of production of cereals.Fusarium species attack crops during growth and produce the so-called polishmycotoxins, or toxins present in the grain growth. Aspergillus and Penicillium speciesusually develop after harvest and therefore they make storage mycotoxins. Mycotoxinscontamination is limited by moisture content in grain, which should not exceed 15%.Opportunities for fungal contamination of grain increases due to stress from drought.Practical experience shows that in the infected feed different mycotoxins could be found,and their type and concentration depend on the climate and storage conditions. Moderatecontinental climate, which is characterized by high humidity, such as in Canada, USAand Europe, were favorable for the development of Fusarium and Penicillium species,and DON, ZEA, OTA, and T-2 toxins.Mycotoxins lead to health disorders in all animals, but the effects are more noticeable inhighly productive animals in the farm keeping due to significantly greater consumptionof concentrated feed, although other feedinstuffs may be also contaminated withmycotoxins. Acut mycotoxicoses rarely occur in conditions of modern livestockproduction, however, small doses of mycotoxins can lead to decrease of productivity,immunity and create a disease. Another problem is that in the organism of animals thathave taken contaminated feed can be found residues (mycotoxins and their metabolites)in different concentrations, which may be a cause of harmful effects for people.Disturbing data on the situation in our country indicate that the problem of permanentecontamination of feed with different mycotoxins is still present [31, 1, 17, 9].FUNGI - PRODUCERS OF MYCOTOXINSConditions for the fungi growth and mycotoxin production depend on the type of fungus,but also on the presence of spores, organic substrate and the appropriate humidity, thepresence of oxygen, temperature and pH. For the growth fungi need moisture over 12%,and the activity of water over 0.7. Temperature for the production of toxins can rangefrom 4-60 o C and the electrochemical reaction of 5 to 7. Aspergillus species grow inconditions of low water activity and at higher temperatures than Fusarium species thatrequire higher water activity, but can grow at a lower temperature. Penicillium speciesgrow at relatively low water activity and low temperatures. It is necessary to highlightthat the optimal conditions for growth and development of molds are not identical tooptimal conditions for the production of toxins [14].It is important to emphasize that the presence of fungi in feed need is not always relatedwith the presence of mycotoxins [29]. On the other hand, due to stability of mycotoxins,feed may contain mycotoxins although mycologic test gave a negative result. Also, bycommon analytical procedures, it is impossible to detect mycotoxins which arechemically modified ("masked" mycotoxins) under the influence of the interaction ofplants, microflora and toxinproductive fungi. However, in the gastrointestinal tractbinded mycotoxins are released and exhibit their primary harmful action. In our climatemost mycotoxins are secondary metabolites of mainly Aspergillus, Fusarium andPenicillium mold.91