Reproductive Performance of Mares Fed Dietary Zearalenone

Abstract

It is known that zearalenone (ZON) interacts directly with estrogen receptors, and its in vivo effects on reproduction have been well-documented in several species. In contrast, reports of ZON's impact on horse reproduction are conflicting and inconclusive, some studies confounded by the presence of mycotoxins such as deoxynivalenol in the feed. This study assesses the effect of chronic consumption of zearalenone on reproduction in cycling mares fed >95% pure ZON (0, 2, or 8 mg/da; n = 7 mares/treatment) for three estrous cycles, followed by artificial insemination, through 16 days of pregnancy. Animals were on ZON treatment for between 70 and 121 days (average 84) depending on individual cycle patterns. ZON-induced changes in serum concentration of estradiol (E 2) and progesterone (P 4), and total estrogenicity were measured using RIAs and the E-screen assay, respectively. Effects on reproductive physiology and pregnancy were monitored by ultrasound and clinical parameters. No significant changes were found in reproductive hormone levels of E 2 , or P 4 for mares on ZON treatments compared to controls, although there was a significant (P < 0.01) increase in P 4 levels across Cycle number in High ZON (8 mg/da) treated mares. There was also an increasing trend in the interovulatory interval in the High ZON treatment group. The overall estrogenicity was similar across treatments and over time, not differing from controls or between ZON treatment groups. Adverse uterine and ovarian effects were also not observed, but pregnancy rates were mixed with only 4 of 7 mares on Low ZON becoming pregnant, and only 3 maintaining pregnancy and fetal heartbeat by Day 30, compared to 5 of 6 control mares and all 7 mares on High ZON. Because reproductive efficiency and hormone concentrations are highly variable across individuals, this study did not demonstrate that ZON at 2 or 8 mg/da was detrimental to mares' reproduction. Yet, inferring that ZON treatments were completely without effect is also not appropriate, as the absence of measurable significant differences could be attributed to the limited sample size. Most importantly, there were no extreme signs of toxicology, in contrast to previous reports when ZON was fed at these "doses."

Bacillus subtilis Simultaneously Detoxified Aflatoxin B1 and Zearalenone

“…ZEN is one of the most prevalent mycotoxins in cereals and foodstuffs worldwide and poses a significant threat to food/feed security as well as human and animal health [16]. It primarily affects the reproductive system of animals and can elevate estrogen levels [17][18][19][20][21][22]. In cases of acute poisoning, ZEN can have detrimental effects on vital organs including the heart, liver, kidney, lung, and nervous system [23,24].…”

Fertility restoration of racing mare with persistent corpus luteum

“…Hormone concentrations are highly vital to the reproductive efficiency of mares [17]. Here, serum P4 concentrations were reduced from day 0 to 24 and 48 h following PGF2α treatment and stabilized in 48-72 h. The reduction in the P4 percentage was getting more significant daily (Table-1).…”