Srečanje mladih raziskovalcev

Dokazovanje mikotoksinov v živalski krmi in mleku

Šola: Biotehniški center Naklo

Avtorici: Petra Kopač, Špela Trop

Mentorica: mag. Marjetka Kastelic Švab

Številne glive tvorijo veliko različnih vrst biološko aktivnih sekundarnih metabolitov, med njimi tudi mikotoksine. Mikotoksini so strupeni presnovni produkti nekaterih plesni. Pri raziskovanju smo se predvsem osredotočili na plesni rodov Aspergillus, Fusarium in Penicillium, ki so bile v preteklih raziskavah največkrat dokazane kot plesni, ki izločajo mikotoksine v živalski krmi. Gojili smo jih na PDA gojiščih (krompirjev dekstrozni agar, v ugodnih pogojih za njihovo rast in razmnoževanje). Da bi plesni začele izločati mikotoksine (aflatoksine), smo jih po inkubaciji izpostavili neugodnim pogojem (nižja temperatura), polovico pa pustili na temperaturi za njihovo optimalno rast (24 °C). S pomočjo UV – svetlobe, ob kateri plesni, ki izločajo mikotoksine (aflatoksine), zafluorescirajo, smo dokazovali prisotnost le-teh v travni suhi krmi (senu), travnati silažni krmi (silaža) in v mleku. Po identifikaciji plesni smo ugotovili, da se v ugodnih razmerah na senu najbolje razmnožujejo plesni, ki izločajo mikotoksine (aflatoksine), rodu Aspergillus. V neugodnih razmerah so mikotoksine izločale tudi plesni rodu Fusarium. Raziskave vzorcev silaže so pokazale, da se na silaži v veliki meri razraščajo kvasovke, v neugodnih pogojih pa plesni rodu Aspergillus, ki izločajo aflatoksine. V vzorcih mleka ni bilo prisotne nobene vrste plesni, ki bi izločala mikotoksine.

A lot of funghus consist of many different kinds of biologically active secondary metabolites, including mycotoxins. Mycotoxins are toxic metabolistic products of some moulds. During our research we focused mainly on moulds Aspergillus, Fusarium and Penicillium, which were in previous researches proved that moulds produce mycotoxins in animal fodder. We bred them on PDA (potato dextrose agar), in beneficial conditions for their growth and reproduction. For mycotoxins to start discharging, after the incubation we exposed them to unfavourable conditions (low temperature) and let half of them on the optimal temperature for their growth (24 °C). With the UV – light, which helps the mould with fluorescence, we proved the presence of moulds in hay, silage and milk. After the identification, we concluded that in the optimal conditions the moulds that discharge mycotoxins (aflatoxins), Aspergillus. Reproduce the best in hay. In unfavourable conditions the mycotoxins started to discharge moulds Fusarium sp. The research with samples of silage shows that in the silage many yeasts are reproduced while in unfavourable conditions there are moulds Aspergillus sp that discharge aflatoxins. In samples of milk there were no presence of any moulds that discharge mycotoxins.