OCHRATOXIN A AND ZEARALENON: CEREALS AND FEED CONTAMINATION IN CROATIA (1977-2007) AND INFLUENCE ON ANIMAL AND HUMAN HEALTH

Mikotoksini kao sekundrani metaboliti plijesni usko su povezani s distribucijom plijesni, njihovim vrstama i toksinogenim sojevima, mikroklimom, načinom sabiranja i skladištenja usijeva. Naša istraživanja u proteklih 30 godina pokazuju da Fusarium i Penicillium vrste podjednako (40-60%) dominiraju u usjevima zbog čega su žitarice i krmiva često kontaminirani okratoksinom A (OTA) i zearalenonom (ZEA). OTA je nefrotoksin s potencijalnim karcinogenim djelovanjem u ljudi, koji se dovodi u vezu s razvojem endemske nefropatije (EN). ZEA je mikotoksin s uterotropnim, estrogenim i anaboličkim djelovanjem u domaćih životinja s potencijalnim negativnim učinkom na ravnotežu spolnih hormona u ljudi. Tijekom 30-godišnjih istraživanja OTA i ZEA su u prosjeku dokazani u 20%, odnosno u 30% uzoraka. Znatno veće koncentracije ovih mikotoksina nađene su tijekom izuzetno vlažne 1978. (68900 μg OTA/kg i 275800 μg ZEA/kg) i 1980. (4700 μg OTA/kg), za vrijeme domovinskog rata (3200 μg OTA/kg i 19900 μg ZEA/kg) te u izrazito hladnoj (temperaturni stres) i vlažnoj 2004. (29430 μg ZEA/kg). Tijekom ostalih godina koncentracije ovih mikotoksina kreću se od 0,26 do 220 μg/kg (OTA) te od 0,39 do 3000 μg/kg (ZEA). U posljednje vrijeme sve se više važnosti pridaje ko-kontaminciji usjeva mikotoksinima zbog njihovog mogućeg sinergističkog učinka. Tako je posljednjih godina dokazana ko-kontaminacija kukuruza i drugih žitarica sa OTA i ZEA u 37% odnosno 13,5% uzoraka. Međutim, zadnjih godina utvrđene koncentracije su niže u odnosu na prethodna razdoblja što se može pripisati relativno sušnom razdoblju. Iako je zbog toga smanjen rizik trovanja to ne isključuje sustavni unos subtoksičnih koncentracija mikotoksina u organizam te njihov mogući toksinopatogeni sinergizam koji se negativno odražava na enzimatske i imunološke funkcije u ljudi i životinja.Mycotoxins are secondary metabolites produced by various mould species. Contamination of cereals and feeds with mycotoxins depends on distribution of toxigenic mould strains, micro-climate, harvesting techniques and storage conditions. Our research in the past 35 years shows that Fusarium sp. and Penicillium sp. dominated in the crops (40-60%). Consequently, ochratoxin A (OTA) and zearalenone (ZEA) were frequently found in cereals and feed. OTA is a nephrotoxin with a potential carcinogenic activity in humans and is connected with development of endemic nephropathy (EN). ZEA shows uterotropic, estrogenic and anabolic activity in domestic animals and it has been implicated in hormonal interruption in humans. In the past three decades OTA and ZEA were detected in 20% and 30% of samples. High concentrations were found in extremely humid and/or cold years; in 1978 (68900 μg OTA/kg and 2758000 μg ZEA/kg), in 1980 (4700 μg OTA/kg), and in 2004 (29430 μg ZEA/kg) as well as during wartime in Croatia (3200 μg OTA/kg and 19900 μg ZEA/kg). In other years of sampling concentrations were between 0.26 and 220 μg/kg (OTA) and between 0.39 and 3000 μg/kg (ZEA). Recently, many reports were focused on mycotoxin co-contamination of crops, since they could produce synergistic toxic effects in animals and humans. In the past few years simultaneous occurrence of OTA and ZEA were detected in 37% and 13.5% of samples, respectively. However, levels of these toxins are significantly lower compared to previous sampling which is probably a consequence of relatively dry microclimatic conditions. Even low concentrations of mycotoxins reduce the risk of acute poisoning, chronic intake of subtoxic concentrations and their possible synergistic interactions could have an impact on biochemical and immunological functions in animals and humans