Effects of experimental exposure to zearalenone on reproductive system morphometry, plasma oestrogen levels, and oocyte quality of beef heifer

Abstract

The aim of the present study was to evaluate the effects of zearalenone (ZEA) on the reproductive system morphometry, oestrogen (E2) levels and oocyte quality of beef heifers. Twenty non‐pregnant purebred Nellore (Bos indicus) heifers [age, ≥18 months; initial body weight, 348 ± 30 kg (mean ± standard deviation)] were used. The animals were randomly divided into experimental group and a control group of 10 animals each. Group experimental was administered 300 ppb ZEA per os for 98 days, and the control group was administered placebo per os for 98 days. The administration of ZEA was carried out daily by adding mycotoxin to the diet. All heifers were evaluated weekly via rectal ultrasound examinations (12 weeks). Diameters of the right and left uterine horns, right and left ovaries, largest antral follicle and corpus luteum were measured. Vulva size was also measured. Blood samples were collected to estimate E2 levels. At the end of 12 weeks, the heifers were slaughtered, and the ovaries were sent to the laboratory for in vitro embryo production. A completely randomized design was adopted, and repeated measures analysis of variance (p < .05) was performed (except for oocyte quality). Vulva size (p = .0985); diameters of uterine horns (p = .0522), ovaries (p = .6955), antral follicles (p = .6355) and corpus luteum (p = .3808); and E2 levels (p = .3379) were not affected by the treatments. ZEA‐contaminated diet significantly reduced (p = .05) the proportion of viable oocytes (49.4%, n = 207) compared with the control diet (59.9%, n = 222); however, the blastocyst rate did not differ between the groups (p = .9418). The results indicate that contamination of beef heifer's diet with 300 ppb ZEA affected neither morphometric parameters nor plasma oestrogen levels; however, ZEA contamination was detrimental to oocyte quality.

Fate of Milk Yield and Fertility Parameters in Holstein Dairy Cows Simultaneously Exposed to Zearalenone, Deoxynivalenol and Fumonisin B1 Mycotoxicity

“…The data obtained in this study provide new evidence that multiple mycotoxin exposure may play an important role in milk yield and especially in the fertility performance of dairy cows. It has been documented that corn grain (Abnet, 2007;Silva et al, 2020), corn gluten meal (Rodrigues and Naehrer, 2012), corn silage (Aragon et al, 2011), DDGS (Rodrigues and Chin, 2012), straw and silage (Duffield, 2000) are the most susceptible feedstuffs in which Fusarium species generally produce mycotoxins such as DON, ZEA and fumonisins (Rodrigues, 2014). The present study demonstrated the effect of Fusarium mycotoxins in feedstuffs with relevance to corn grain or corn by-products.…”

Adverse Effects of Fusarium Toxins in Ruminants: A Review of In Vivo and In Vitro Studies

“…The findings from [144] suggest that by increasing AMH synthesis, ZEN may accelerate the depletion of the ovarian reserve of gametes. At a lower level in the diet (0.3 mg/kg), ZEN decreases the oocyte quality but does not interfere in the endocrine profiles or further embryo development [179].…”

Duration of Zearalenone Exposure Has Implications on Health Parameters of Lactating Cows

“…In the literature, there is a knowledge gap in terms of controlled experiments evaluating the animal health response variables of lactating cows exposed to ZEN, since most of the old and recent publications focused on reproductive parameters [ 32 , 33 , 34 , 35 ]. This study aimed to evaluate a 3-week-length exposure to ZEN in lactating cows and its impact on animal health parameters, milk characteristics, rumen and fecal fermentation, and chewing activity.…”