NAVLE Multisystemic

Porcine Mycotoxin Toxicity Study Guide

November 14, 2026 25 min read
Mycotoxins are secondary metabolites produced by fungi (primarily Fusarium, Aspergillus, and Penicillium species) that contaminate feed grains before harvest or during storage.

Overview and Clinical Importance

Mycotoxins are secondary metabolites produced by fungi (primarily Fusarium, Aspergillus, and Penicillium species) that contaminate feed grains before harvest or during storage. Swine are among the most sensitive domestic animals to mycotoxins, and mycotoxicosis causes significant economic losses estimated at $147 million annually in the United States alone. Multiple mycotoxins often coexist in contaminated feed, producing additive or synergistic toxic effects.

The seven clinically important mycotoxins in swine are: aflatoxins (hepatotoxic), zearalenone (estrogenic), deoxynivalenol/vomitoxin (feed refusal), fumonisins (pulmonary edema), trichothecenes (immunosuppressive), ochratoxin A (nephrotoxic), and ergot alkaloids (gangrenous/agalactia).

Mycotoxin Fungal Source Target System Key Clinical Signs FDA Level
Aflatoxin B1 Aspergillus flavus, A. parasiticus Hepatic, Immune Poor growth, icterus, immunosuppression, hemorrhage Less than 20 ppb (piglets); Less than 200 ppb (finishers)
Zearalenone (F-2) Fusarium graminearum Reproductive (Estrogenic) Vulvar swelling, prolapse, anestrus, pseudopregnancy No FDA level; EU: 0.1 mg/kg (gilts)
DON (Vomitoxin) Fusarium graminearum GI, Immune Feed refusal, vomiting, poor growth 5 ppm (swine)
Fumonisin B1 Fusarium verticillioides Pulmonary, Hepatic Pulmonary edema (PPE), dyspnea, sudden death Less than 10 ppm total diet
Ochratoxin A Penicillium, Aspergillus Renal, Hepatic Polydipsia, polyuria, poor growth, nephropathy No FDA level
T-2 Toxin Fusarium spp. GI, Dermal, Immune Skin necrosis (snout, lips), hemorrhagic diarrhea No FDA level
Ergot Alkaloids Claviceps purpurea Vascular, Reproductive Agalactia, gangrene of extremities, weak piglets No FDA level

Major Mycotoxins in Swine: Quick Reference

Animal Class Clinical Signs Threshold Level
Prepubertal Gilts (1-6 months) Swollen, reddened vulva; mammary gland enlargement; rectal and vaginal prolapse; splay leg in piglets 1-5 ppm produces vulvar swelling within 5-7 days
Mature Gilts/Sows Variable estrous cycles (prolonged or shortened); anestrus; pseudopregnancy (40-60 days); retained corpora lutea; reduced litter size 1-3 ppm causes cycle disruption; 5-10 ppm causes anestrus
Boars Feminization, gynecomastia, preputial edema, testicular atrophy, decreased libido, reduced sperm quality Greater than 30 ppm affects semen quality
Neonatal Piglets Splay leg syndrome; enlarged vulvas at birth (via milk/placental transfer); weak piglets Transmitted through sow milk and placenta

Zearalenone (F-2 Toxin) - Estrogenic Mycotoxicosis

Pathophysiology

Zearalenone (ZEN) is a potent mycoestrogen that competitively binds to estrogen receptors (17?-estradiol receptors), causing hyperestrogenism. Swine are the most sensitive species due to hepatic conversion of ZEN to ?-zearalenol, which has 3-4 times greater estrogenic activity than ZEN itself. This explains why pigs show clinical signs at much lower concentrations than other species.

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