Zearalenone Symptoms
- Decrease in male libido
- Infertility
- Enlarged, swollen, distorted uteri
- Shrunken ovaries
- Cystic Ovaries
- Necrosis or reddening of the tail
- Vulva swelling and reddening
- Vaginal and rectal prolapse
- Immunosuppression
- Liver damage
- Decreased litter size and birth weights
Zearalenone Mycotoxicosis
Zearalenone is a non-steroidal estrogenic mycotoxin produced by several species of fusarium mold typically found in corn, wheat, rice, and barley. Although zearalenone has been identified as the cause of several outbreaks of mycotoxicosis in farm animals, swine are the most sensitive. It binds to receptors for estradiol-17-β and this complex binds to estradiol sites on DNA. Specific RNA synthesis leads to signs of estrogenism. Currently, the International Agency for Research on Cancer classifies zearalenone as a 2A carcinogen.
Physical and behavioral signs of estrus are induced in young gilts by as little as 1 ppm dietary zearalenone. In pigs, zearalenone primarily affects weaned, prepubertal gilts, causing hyperemia and enlargement of the vulva. There is hypertrophy of the mammary glands and uterus, with occasional prolapse of the uterus. Multiparous sows fed high concentrations of zearalenone (50 to 100 ppm) have experienced diminished fertility, reduced litter size, smaller offspring, and fetal resorption. Constant estrus and pseudopregnancy may be seen.
Zearalenone causes reproductive disease in sexually mature sows by inhibiting secretion and release of follicle-stimulating hormone (FSH) resulting in alteration of normal estrus cycle activity. Zearalenone fed at 3 to 10 ppm on days 12 to 14 of the estrus cycle in open gilts results in pseudopregnancy for up to 40 to 60 days.
Zearalenone Metabolism
Zearalenone is rapidly absorbed following ingestion and is metabolized by the liver, intestinal mucosa, and gut microflora of pigs into the toxic metabolites α and β-zearalenol and the glucuronide conjugates of both compounds. α-zearalenol has about three-fold more estrogenic potency than zearalenone.
Zearalenone and its metabolites have been found in the plasma of a pig less than 30 minutes after consumption. The gastrointestinal uptake in swine after a single oral dose of 10 mg/kg body weight has been estimated to be 80 to 85%. Zearalenone and its metabolites are excreted in the feces, most within 72 hours of ingestion. Extensive cycling of zearalenone and its metabolites via enterohepatic circulation increases its biological half life significantly extending toxic exposure.
Calibrin-Z quickly adsorbs mycotoxins and significantly reduces gastrointestinal uptake. Sequestering the toxins in the intestinal lumen so they are not absorbed reduces the animal's exposure by a factor of 25.