Zearalenone

Zearalenone (ZEN) is a mycotoxin produced mainly by strains of Fusarium graminearum, F. culmorum, F. cerealis, F. equiseti and F. verticillioides.3, 7 Generally crops are attached by the fungus during moist and cool conditions on the field, although Fusarium growth was observed during storage as well.3 ZEN often co-occurs with deoxynivalenol, other trichothecenes and Fusarium mycotoxins.2, 7 ZEN is a phenolic resorcylic acid lactone and it is a fungal metabolite with primarily an estrogenic effect on animals.7 Biotransformation of ZEN carried out by animals leads to the formation of two metabolites: α-zearalenol and β-zearalenol. All ZEN forms are estrogenic, with the α-zearalenol being the highest.3, 7

Toxicity

ZEN is highly estrogenic due to its affinity to the estrogen receptor. This mycotoxin is rapidly absorbed by the gastrointestinal tract, with absorption rates up to 80-85% in some animal species like swine.3, 4, 5 ZEN is capable of inducing sub-acute, chronic and genotoxicity, but it exhibits relatively low acute toxicity, (with oral LD50 values of >2000–20000 mg/kg b.w. after oral administration in mice, rats and guinea pigs).2, 5, 7

Estrogenic effects of ZEN differ from males and females. In males, major effects of this mycotoxin are immunosuppression, reduction in testosterone level, lower testes weight, reduced spermatogenesis, feminization and reduction of libido.2, 3, 5, 7 In females ZEN causes immunosuppression, reduced survival of embryos, reduced fetal weight, vulvar dilatation and redness, vulvovaginitis, retention or absence of milk, rectal prolapse.2, 3, 5, 7

Furthermore ZEN is capable of inducing cancer, genotoxic and endocrine effects.5, 7

Regulation

In the USA no regulation has ever been issued by the FDA. In EU the guidance values for the maximum amount of ZEN in feed material are listed in table 1.1

Table 1. EU legislation regarding ZEN in feed material.1
Products intended for animal feedGuidance value in mg/kg (ppm) relative to a feedingstuff with a moisture content of 12 %
Cereals and cereal products (2) with the exception of maize by-products2
Maize by-products3
Complementary and complete feedingstuffs for piglets and gilts (young sows)0.1
Complementary and complete feedingstuffs for sows and fattening pigs0.25
Complementary and complete feedingstuffs for calves, dairy cattle, sheep (including lamb) and goats (including kids)0.5
References
  1. Commission regulation (EC) No 1881/2006. Communities, The commission of the European (2006).
  2. Grenier B., Applegate T.J., (2013). Modulation of Intestinal Function Following Mycotoxin Ingestion: Meta-Analysis of Published Experiments in Animals. Toxins (5) 396-430.http://www.fao.org/docrep/X5036E/x5036E1e.htm
  3. Krska R., Nährer K., Richard J. L., Rodrigues I., Schuhmacher R., Slate A. B., Whitaker T. B., (2012). Guide to Mycotoxins featuring Mycotoxin Risk Management in Animal Production. BIOMIN edition 2012.
  4. Lemmens M., (2016). Mycotoxin Summer Academy – Module 1. IFA Tulln
  5. Marin S., Ramos A.J., Cano-Sancho G., Sanchis V., (2013). Mycotoxins: Occurrence, toxicology, and exposure assessment. Food and Chemical Toxicology (60) 218-237.
  6. Richard J.L., (2007). Some major mycotoxins and their mycotoxicoses - an overview. International Journal of Food Microbiology (119) 3-10.
  7. Zinedine A., Soriano J.M., Molto J.C., Man J., (2007). Review on the toxicity, occurrence, metabolism, detoxification, regulations and intake of zearalenone: An estrogenic mycotoxin. Food and Chemical Toxicology (25) 1-18.