Zearalenone estrogenic effects are primarily observed in which species?

• A. Swine
• B. Cattle
• C. Sheep
• D. Poultry

Answer: (A)

Zearalenone is a mycotoxin with estrogen-like effects, so the question centers on which species are most susceptible to these hormonal disruptions. Swine are the most affected because they absorb zearalenone and rapidly metabolize it to potent estrogenic derivatives, such as alpha-zearalenol, which bind strongly to estrogen receptors and disrupt reproductive function. This leads to clear signs like vulvar swelling, irregular estrous cycles, and reproductive inefficiency in pigs. In contrast, ruminants like cattle and sheep have microbial activity in the rumen that detoxifies zearalenone, reducing its estrogenic impact, and poultry metabolize it even more quickly, resulting in milder or less consistent effects. Thus, the estrogenic impact of zearalenone is primarily observed in swine.