E-Screen evaluation of sugar beet feedstuffs in a case of reduced embryo transfer efficiencies in cattle: the role of phytoestrogens and zearalenone

Abstract

The E-Screen assay was used to evaluate the estrogenicity of sugar beet by-products obtained from a dairy farm experiencing low success rates of embryo transfer. The beet tailings had ~3-fold the estradiol equivalents of the pelleted beet pulp (3.9 and 1.2 μg estradiol equivalents or E(2)Eq/kg dry matter, respectively). Whole sugar beets, sugar beet pellets, and shreds from several Midwest US locations were also evaluated by E-Screen. All pellets examined were found to have some estrogenic activity (range ~0.1-2.0 μg E(2)Eq/kg DM) with a mean of 0.46 μg/kg dry matter and median of 0.28 μg/kg dry matter. Relative E(2)Eq ranked as follows: pellets > shreds > most unprocessed roots. Using recommended feeding levels and conservative absorption estimates (10%), the estrogenic activity in the original samples could result in blood estradiol equivalents ≥ those found at estrus (10 pg/mL, cows). Chemical analyses revealed no known phytoestrogens, but the estrogenic mycotoxin, zearalenone, was found in 15 of 21 samples. Of significance to those using the E-Screen are our findings that contradict previous reports: ß-sitosterol has no proliferative effect and genistein's glucuronidated form-genistin-is equal to genistein in proliferative effect. The latter is the result of deconjugation of genistin to genistein in the presence of fetal bovine serum (determined by LC MSMS). These data show the usefulness and caveats of the E-Screen in evaluation of feedstuffs, and indicate a potential for sugar beet by-products to contain zearalenone at concentrations that may impact reproduction.

The Effects of Steroid Implant and Dietary Soybean Hulls on Estrogenic Activity of Sera of Steers Grazing Toxic Endophyte-Infected Tall Fescue Pasture

“…Equol has been found not only in ruminal digesta of animals fed legumes, but bioavailability was confirmed by its presence in the kidneys and blood ( 9 , 52 ). Assay and tissue specificity was also a factor in assignment of a “relative potency factor,” as genistein evaluated by E-Screen (breast tissue origin) was ~6 times as potent as daidzein in eliciting MCF-7 cell proliferation ( 53 ), with daidzein and equol ~ equivalent, yet the two had different potencies based on E 2 -receptor affinities and transcriptional efficiencies ( 54 ).…”

Egg wash wastewater: Estrogenic risk or environmental asset?

“…Filtering was necessary to remove solids (primarily coagulated egg material typically removed from the waste stream and sold as a protein amendment for use in pet food). Filtrate was concentrated by solid phase extraction (SPE, OASIS HLB, 200 mg, 5 mL; Waters, Milford, MA) and taken to dryness exactly as described by Shappell et al (). Extraction volumes were 110 mL for October 2010 samples, and 250 mL for all subsequent samples.…”

Reproductive Performance of Mares Fed Dietary Zearalenone

“…Total estrogenicity (estradiol equivalents, E 2 Eqs) was measured by the in vitro E-screen assay using the MCF-7 BOS, estrogen-dependent cell line (derived from a human mammary epithelial carcinoma, provided by Drs. Ana Soto and Carlos Sonnenschein, Tufts University, Boston, MA USA) as previously described (3,30). Select serum samples (Days 0, 8) were extracted with acetonitrile (ACN 1:2 v/v), vortexed, centrifuged, and the serum/ACN supernatant dried and stored at −20 • C. Sample pellet weights were used to calculate serum recovery.…”

“…Zearalenone (ZON) is one of several stable mycotoxins produced by Fusarium species which contaminates a variety of forages and cereals such as barley, corn, oats, sorghum, soy, and wheat (1,2), and has been recently found in sugar beet pulp, a feedstuff often used as horse feed (3). Literature reports of hyperestrogenism, reproductive disruptions, and fetal abnormalities as a result of unintentional or intentional feeding of mycotoxin-contaminated feed have been recorded in numerous species (4)(5)(6)(7).…”