Search

Ergot alkaloids, a class of mycotoxins associated with ergotism, act as agonists on serotonin (5HT) receptors, specifically 5HT2a, which mediate smooth muscle contraction and vasoconstriction. The objective of this study was to examine the impact of ergot alkaloid exposure during mid and late gestation on microscopic placental structure and vascular development. Ewes were fed endophyte-infected tall fescue seed containing ergot alkaloids (E+/E+, 1.77 mg ewe -1 d -1 ) or endophyte-free tall fescue seed (E-/E-, 0 mg ergot alkaloids) during both mid (d 35 to d 85) and late gestation (d 86 to d 133). On d 133 of gestation, a terminal surgery was performed and two placentomes of the type B morphology were collected for microscopic analyses. Amorphous connective tissue regions were larger ( p < 0.0001) and more numerous ( p = 0.025) in the placentome of ergot alkaloid exposed ewes. Staining showed no difference ( p = 0.83) in the number of vessels present, but luminal area of maternal vasculature was 117% greater ( p < 0.0001) in ergot alkaloid exposed ewes. Results showed that exposure to ergot alkaloids during gestation slowed maturation of the fetal villi as indicated by greater amorphous connective tissue regions, and altered size and shape of blood vessels to counteract reductions in blood flow caused by vasoconstriction. more...

Background: Ergot alkaloids (E+) are mycotoxins produced by the endophytic fungus, Epichloë coenophiala, in tall fescue that are associated with ergotism in animals. Exposure to ergot alkaloids during gestation reduces fetal weight and placental mass in sheep. These reductions are related to vasoconstrictive effects of ergot alkaloids and potential alterations in nutrient transport to the fetus. Cotyledon samples were obtained from eight ewes that were fed E+ (n = 4; E+/E+) or E- (endophyte-free without ergot alkaloids; n = 4; E-/E-) seed during both mid (d 35 to 85) and late (d 85-133) gestation to assess differentially expressed genes associated with ergot alkaloid induced reductions in placental mass and fetal weight, and discover potential adaptive mechanisms to alter nutrient supply to fetus., Results: Ewes fed E+/E+ fescue seed during both mid and late gestation had 20% reduction in fetal body weight and 33% reduction in cotyledon mass compared to controls (E-/E-). Over 13,000 genes were identified with 110 upregulated and 33 downregulated. Four genes had a |log2FC| > 5 for ewes consuming E+/E+ treatment compared to controls: LECT2, SLC22A9, APOC3, and MBL2. REViGO revealed clusters of upregulated genes associated glucose, carbohydrates, lipid, protein, macromolecular and cellular metabolism, regulation of wound healing and response to starvation. For downregulated genes, no clusters were present, but all enriched GO terms were associated with anion and monocarboxylic acid transport. The complement and coagulation cascade and the peroxisome proliferator-activated receptor signaling pathway were found to be enriched for ewes consuming E+/E+ treatment., Conclusions: Consumption of ergot alkaloids during gestation altered the cotyledonary transcriptome specifically related to macronutrient metabolism, wound healing and starvation. These results show that ergot alkaloid exposure upregulates genes involved in nutrient metabolism to supply the fetus with additional substrates in attempts to rescue fetal growth. more...

Previous research has shown that exposure to ergot alkaloids found in endophyte-infected (Epichloë coenophiala) tall fescue (Lolium arundinaceum) results in decreased vasoactivity. Little is known regarding the effect ergot alkaloid exposure during gestation may have on vasculature supporting the fetus. The objective of this study was to evaluate contractile responses of uterine and umbilical arteries collected from ewes consuming ergot alkaloids during gestation. On d 35 of gestation, 36 Suffolk ewes (78.24 ±9.5 kg) were randomly assigned to endophyte-infected (E+) or endophyte-free (E-) tall fescue seed treatments that were fed either throughout or switched on d 86 of gestation, creating four seed treatments E+E+, E+E-, E-E+, E-E-. Ewes were fed E+ tall fescue seed to provide 1.77 mg of total ergovaline/head/d with E- ewes receiving the same quantity of E- seed. Gestation was terminated on d 133, and sections of uterine artery and umbilical cord were surgically collected. Only collections from 28 ewes (n = 7/treatment) were of sufficient viability to proceed with the contractility experiments. Arteries were cleaned, sliced into 2-mm cross sections, and suspended in multi-myograph chambers containing 5 mL of continuously oxygenated Krebs-Henseleit buffer. Vessels were exposed to increasing concentrations (5x10-8 to 1x10-4 M) of norepinephrine, serotonin, ergotamine, and ergovaline (5x10-9 to 1x10-5 M; extract of tall fescue seed) in 15-min intervals. Data were normalized as a percentage of the maximum contractile response induced by a reference dose of 120 mM KCl. Data from each artery were analyzed using mixed models of SAS as a split-plot with seed and myograph treatments as the whole and sub-plot treatments, respectively. Increasing concentrations of norepinephrine generated a moderate contractile response by the uterine artery (P < 0.05), but no response in the umbilical artery. Increasing concentrations of serotonin resulted in negligible responses in uterine preparations, whereas umbilical artery preparations were very responsive (P < 0.05) to serotonin. Ewes receiving E+E+ and E-E+ treatments had decreased vasoactivity in umbilical arteries to serotonin with a dextral shift in concentrations where the response curve initiated (P < 0.05). Interestingly, uterine arteries were not responsive to exposure to ergotamine or ergovaline, whereas umbilical arteries were very responsive. Umbilical arteries collected from ewes receiving E-E- and E+E- were more vasoactive to ergot alkaloids (P < 0.05) than other treatments. These findings indicate that maternal blood supply to the placenta is protected from negative effects of ergot alkaloids; however, umbilical vasculature is not and this could negatively affect fetal growth. [ABSTRACT FROM AUTHOR] more...

Consuming ergot alkaloids found in endophyte-infected tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] seed causes intrauterine growth restriction due to uteroplacental insufficiency. The objective of this study was to assess the impact on gene expression levels in placental tissue from feeding ergot alkaloids during gestation. Thirty-six Suffolk ewes (78.24 kg ± 9.5) estimated to be carrying twins at d 35 of gestation were randomly assigned to 1 of 2 treatments--endophyte-free tall fescue seed (E-; 0.0 μg ergovaline + ergovalinine/g) or endophyte-infected tall fescue seed (E+; 4.14 μg ergovaline + ergovalinine/g)--from d 35 through 85 and d 86 through 133 of gestation, creating 4 unique dietary treatments: E-E-, E-E+, E+E-, and E+E+. Endophyte-infected tall fescue seed was fed at a level to provide 1,772 μg of ergovaline + ergovalinine/ewe per day for E+ treatments, and an equal weight of endophytefree seed (0.0 μg ergovaline + ergovalinine) was fed for E-treatments. Ewes were pair fed across treatments in order to maintain equal DMI. Fetal and maternal necropsies were performed at d 133 of gestation. Placental samples were weighed, frozen in liquid nitrogen, and stored at -80°C. Total RNA was extracted from cotyledon placental tissue using TRIzol and a PureLink RNA Mini Kit (ThermoFisher Scientific). Total RNA was quantified and quality was assessed using an Agilent 2100 Bioanalyzer. Ribonucleic acid integrity numbers of >7 were considered sufficient quality. A subsample (n = 4) was selected for both the E+E+ and E-E-treatment groups, and total cotyledon RNA was submitted for gene expression profiling via Illumina RNA-Seq (LC Sciences). Numerous genes were upregulated (P ≤ 0.01; n = 131) in E+E+ compared with E-E- and included genes involved in angiogenesis and vasoconstriction (FGA, APOH, and HPX), hemostasis and coagulation (KNG1, FGA, PLG, and FGB), oxidative reduction (PYROXD2 and CYP2E1), cholesterol import and lipoprotein particles (APOC3, APOH, APOA2, GC, and PON1), cell activation (FGA), and immune response (KNG1 and AHSG). Several genes were downregulated (P < 0.01; n = 56) in E+E+ compared with E-E-, including genes involved in fatty acid metabolism, lipid oxidation, and beta-oxidation (ADIPOQ), G-protein coupled receptor (GPR151), signal transduction (HRH4), and cell proliferation (PODN). The consumption of ergot alkaloids during gestation directly effects the mRNA expression in cotyledon tissues. [ABSTRACT FROM AUTHOR] more...

Color Doppler ultrasonography was used to assess ergot alkaloid-induced vasoconstriction in pregnant ewes (Ovis aries) that were fed diets with or without toxic endophyte-infected seed of tall fescue (Lolium arundinaceum). A fungal endophyte (Epicloë coenophialia)that infects most plants of the standard cultivar of tall fescue, 'Kentucky 31,' produces ergot alkaloids that can cause a persistent constriction of blood flow in grazing ruminants, which incapacitates the animal's ability to thermo-regulate core body temperature. Suffolk ewes were stratified by BCS for random assignment to four treatment groups (n = 15/treatment). Either endophyte-free (E-) or endophyte-infected (E+) tall fescue seed were fed in similar diet concentrations such that the daily consumption of ergovaline and ergovalanine for E+ was 1,772 µg/ewe/d mixed in a TMR (corn, soybean meal, and cottonseed hulls). The ewes were fed the TMR without seed for the first 35 d. On day 35, ewes were fed endophyte-free (E-) or endophyte-infected (E+) seed, and on day 86, half of each group was switched to the opposite treatment (E-E+ or E+E-) and half remained on the same treatment (E-E- or E+E+) to parturition. Ultrasound imaging of left carotid artery was done at the start of lambing and the range in days on fed seed ranged from 50 to 106 days. Color Doppler ultrasonography was performed using a Classic Medical TeraVet 3000 Ultrasound Unit (Classic Universal Ultrasound, Tequesta, FL) with a 12L5-VET (12 MHz) linear array transducer. Cross-sectional area of the left carotid artery was measured for each ewe to determine luminal area, and a Power Doppler image was collected for measuring peak systolic and end diastolic velocities, heart rate, and pulsatility and resistance indices. Luminal areas were similar (P > 0.5) between E-E- (28.8 ± 1.98 mm2) and E+E- (30 ± 1/85 mm2) treatments, and between E+E+ (17.0 ± 2.06 mm2) and E-E+ (17.5 ± 2.06 mm2). Carotid arteries with E-E- and E+E- treatments were relaxed (P < 0.001) in comparison to those with the E+E+ and E-E+ treatments. Although there were no treatment effects (P > 0.10) on peak systolic and end diastolic velocities or heart rate, pulsatility and resistance indices were greater (P < 0.05) for E+E+ and E-E+ than for E-E- and E+E- treatments. Results indicated a vasoconstrictive response of the carotid arteries in pregnant ewes exposed to ergot alkaloids, but vascular recovery was demonstrated for sheep that had been switched from E+ to E- diets. [ABSTRACT FROM AUTHOR] more...

The objective of this study was to evaluate uteroplacental sufficiency, fetal growth, and development in ewes consuming ergot alkaloids found in endophyte-infected tall fescue [Lolium arundinaceum (Schreb.) Darbysh; Schedonorus phoenix (Scop.) Holub] seed at two stages of gestation. Thirty-six Suffolk ewes (78.24 kg ± 9.5) estimated to be carrying twins at d 35 of gestation were randomly assigned to one of two treatments: endophyte-free tall fescue seed (E-; 0.0 µg ergovaline + ergovalinine/g) or endophyte-infected tall fescue seed (E+; 4.14 µg ergovaline + ergovalinine/g) from d 35 - d 85 and d 86 - d 133 of gestation creating four unique dietary treatments: E-E-, E-E+, E+E-, and E+E+. Endophyte-infected tall fescue seed was fed at a level to provide 1772 µg of ergovaline + ergovalinine/hd/d for E+ treatments while an equal weight of endophyte-free seed (0.0 µg ergovaline + ergovalinine) was fed for E- treatments. Ewes were pair-fed across treatments in order to maintain equal DMI. Fetal and maternal necropsies were performed at d 133 of gestation. Muscle, organ, and placental samples were weighed and stored at -20°C and -80°C for later analysis. Data were analyzed as a randomized block design using a 2 x 2 factorial with alkaloid consumption (Eor E+), gestational time period (d 35 - d 85 or d 86 - d 133), and interaction as fixed effects. There was no significant difference (P > 0.05) in actual placental or fetal weights based on E+ or E- treatment between d 35 - d 85. A significant (P = 0.036) interaction between treatment and time was observed wherein the placentome weight to BW ratio was highest for E+E- ewes. Ewes receiving E+ treatment between d 86 - d 133 had lower (P = 0.003) uterine weights and lower (P = 0.0005) placentome weights. Cotyledon and caruncle tissue weights were reduced (P < 0.002) in ewes on E+ treatment between d 86 - d 133 compared to E- treatment. Cotyledon and caruncle weights were reduced by 25% and 19%, respectively. Overall fetal weight was decreased (P = 0.002) by 10% for ewes on E+ treatment compared to E- treatment between d 86 - d 133. Ergot alkaloid exposure during late gestation induces uteroplacental insufficiency and leads to reduced fetal growth. [ABSTRACT FROM AUTHOR] more...

The objective of this study was to evaluate uteroplacental sufficiency, fetal growth, and development in ewes consuming ergot alkaloids found in endophyte-infected tall fescue [Lolium arundinaceum (Schreb.) Darbysh; Schedonorus phoenix (Scop.) Holub] seed at two stages of gestation. Thirty-six Suffolk ewes (78.24 kg ± 9.5) estimated to be carrying twins at d 35 of gestation were randomly assigned to one of two treatments: endophyte-free tall fescue seed (E-; 0.0 μg ergovaline + ergovalinine/g) or endophyte-infected tall fescue seed (E+; 4.14 μg ergovaline + ergovalinine/g) from d 35 - d 85 and d 86 - d 133 of gestation creating four unique dietary treatments: E-E-, E-E+, E+E-, and E+E+. Endophyte-infected tall fescue seed was fed at a level to provide 1772 μg of ergovaline + ergovalinine/hd/d for E+ treatments while an equal weight of endophyte-free seed (0.0 μg ergovaline + ergovalinine) was fed for E- treatments. Ewes were pair-fed across treatments in order to maintain equal DMI. Fetal and maternal necropsies were performed at d 133 of gestation. Muscle, organ, and placental samples were weighed and stored at -20°C and -80°C for later analysis. Data were analyzed as a randomized block design using a 2 x 2 factorial with alkaloid consumption (Eor E+), gestational time period (d 35 - d 85 or d 86 - d 133), and interaction as fixed effects. There was no significant difference (P > 0.05) in actual placental or fetal weights based on E+ or E- treatment between d 35 - d 85. A significant (P = 0.036) interaction between treatment and time was observed wherein the placentome weight to BW ratio was highest for E+E- ewes. Ewes receiving E+ treatment between d 86 - d 133 had lower (P = 0.003) uterine weights and lower (P = 0.0005) placentome weights. Cotyledon and caruncle tissue weights were reduced (P < 0.002) in ewes on E+ treatment between d 86 - d 133 compared to E- treatment. Cotyledon and caruncle weights were reduced by 25% and 19%, respectively. Overall fetal weight was decreased (P = 0.002) by 10% for ewes on E+ treatment compared to E- treatment between d 86 - d 133. Ergot alkaloid exposure during late gestation induces uteroplacental insufficiency and leads to reduced fetal growth. [ABSTRACT FROM AUTHOR] more...