Embryos were harvested at the blastocyst stage from nontreated outbred mice and were grown in vitro for 4 days. Embryos cultured in control medium hatched and grew to the egg cylinder stage. Purified zearalenone (ZEN) added to the culture medium at concentrations of 8.5 to 68 microgram/ml decreased the number of embryos growing, with a 50% decrease in the number growing in 32 micograms of ZEN/ml of medium. Embryos growing in ZEN had decreased numbers of cells derived from the inner cell mass, normal growth of the trophoblast, less cellular differentiation than was seen in control embryos, and increased numbers of phagosomes. Undifferentiated cells of the inner cell mass of control and treated embryos were of the same size, as determined by morphometric analysis. Addition of 25 micrograms of estradiol/ml of culture medium caused no decrease in number of embryos growing or in embryonic size. Saturation of culture medium with ZEN (68 microgram/ml) did not inhibit the growth of a tissue culture line of goat synovial cells. Seemingly, ZEN at concentrations near saturation inhibited the growth of mouse embryos in vitro. This effect was not duplicated with similar concentrations of estradiol and was not manifested in culture-adapted cells.

OBJECTIVE To determine the effect of subchronic oral exposure to zearalenone (ZEA) at a daily dose of 50 μg of ZEA/kg of body weight (an environmentally relevant concentration) on the reproductive system of rabbit bucks. ANIMALS 8 healthy sexually mature New Zealand White rabbits. PROCEDURES During the experimental period (March to June), each rabbit underwent a 7-week control protocol and then a 7-week treatment protocol. Water (0.5 mL) or ZEA solution (50 μg/kg [0.5 mL]) was administered orally once daily during the control and treatment period, respectively; ejaculates were collected weekly. Studied end points included semen quality variables (spermatozoa kinetics, morphology, viability, and DNA fragmentation), serum testosterone concentration, and results of histologic examination of the testes and epididymides following euthanasia at the end of the experimental period. RESULTS Treatment with ZEA solution resulted in significant increases in spermatozoa beat-cross frequency, in the percentages of spermatozoa with head and midpiece abnormalities, and in the percentages of DNA-fragmented spermatozoa, compared with effects of the control treatment. Serum testosterone concentration, other spermatozoa velocity variables, and percentages of progressive and total motility, rapidly or slowly moving spermatozoa, and live spermatozoa did not differ significantly between the 2 periods. Histologic examination revealed no patterns of abnormal findings in the testes and epididymides. CONCLUSIONS AND CLINICAL RELEVANCE Oral treatment with ZEA solution at an environmentally relevant concentration caused minor interference with rabbit bucks' sperm quality. Although mostly considered mild, the sperm quality changes warrant further investigation in terms of fertilizing capacity impairment.

Body and testis weights, serum luteinizing hormone, follicle-stimulating hormone, and prolactin values and volume fractions of Sertoli cells, spermatogonia, early and late primary spermatocytes, and round and long spermatids were evaluated in 70-day-old male rats treated orally with 20 mg of zearalenone/kg of body weight daily for 5 weeks. A significant (P < 0.05) increase in serum prolactin concentration was consistently observed during the 5 weeks of treatment with zearalenone. Significant changes were not observed in any of the other variables evaluated.

It has been shown that zearalenone disrupts early pregnancy in swine without altering intrauterine content of estradiol 17 beta or progesterone, embryo migration, or estradiol-17 beta thesis by blastocysts. However, serum concentrations of progesterone were reduced 2 to 3 weeks after mating in gilts that ingested zearalenone. Therefore, progesterone was administered to gilts during early pregnancy to determine whether it could counteract the detrimental actions of zearalenone on embryonic development. Thirty-two crossbred gilts (Hampshire X Chester White X Yorkshire X Duroc) were assigned randomly to a 2 X 2 factorial arrangement of treatments: zearalenone (Z); zearalenone plus progesterone (ZP); progesterone (P); or control (C). From postmating days 4 to 15, Z- and ZP-treated gilts were fed 1 mg of Z/kg of body weight, and P-treated and C gilts were fed ethanol as vehicle in a corn-soybean diet. On postmating days 3 to 15, P- and ZP-treated gilts were injected IM with 100 mg of progesterone, and C and Z-treated gilts were injected with progesterone carrier (15% ethanol, 15% benzyl alcohol, 70% propylene glycol). Blood was collected from gilts by puncture of the jugular vein daily from days 3 to 15, on alternate days from days 17 to 31, and then twice weekly until the end of the experiment. Fetal development was assessed in Z and ZP-treated gilts on postmating day 47.6 +/- 2.9 by cesarean section and in P-treated and c gilts at slaughter on postmating days 51.2 +/- 3.2. Serum concentrations of progesterone in P-treated gilts were greater on days 7 to 8, 10 to 15, 17, and 19 than in C gilts. Serum concentrations of progesterone were greater on days 8, 10, and 12 in ZP-treated than in C gilts. However, serum concentrations of progesterone were lower in ZP-treated gilts than in C gilts on postmating days 19 to 31. Serum concentrations of progesterone were lower in Z-treated gilts than C gilts on postmating days 15, 17, and 19. At slaughter or cesarean section, viable fetuses were not found in Z-treated gilts, but 80% of the C and P-treated gilts had viable fetuses. All Z-treated gilts were classified as pseudopregnant because uteri were turgid and the ovaries had functional corpora lutea. Uteri of ZP-treated gilts appeared normal. Corpora lutea of pregnancy had regressed by postmating day 35 in 7 of 8 ZP-treated gilts. Crown-to-rump length was similar between P-treated and C gilts (94 vs 92 mm). Fetal weight was similar between P-treated and C gilts (70 vs 62 g). These data demonstrate that 100 mg of progesterone/d failed to counteract the adverse effects of 1 mg of Z/kg of body weight on early pregnancy in primiparous gilts.

Sixteen primiparous sows were bred and fed either a control ration (n = 8) or a diet containing purified zearalenone (n = 8; 1 mg/kg of body weight) from days 7 to 10 after breeding. On day 7 after breeding, the jugular vein of each sow was cannulated and blood was collected at 20-minute intervals for 4 hours before feeding and 4 hour after feeding. On day 10 after breeding, blood samples were collected from 4 control sows and 4 zearalenonefed sows at 20-minute intervals for 4 hours before collection of blastocysts. A similar blood sampling schedule was followed for the remaining 4 control and 4 zearalenone sows on day 14 after breeding. On day 10 after breeding, spherical blastocysts were recovered from all control sows and from 3 of 4 zearalenone-treated sows. Average diameter of blastocysts from zearalenone-treated sows were similar to that of control sows. On day 14 after breeding, blastocysts were recovered from all control sows and 3 of 4 zearalenone-treated sows. Blastocysts from the control sows were filamentous, whereas blastocysts from zearalenone-treated sows were fragmented and contained foci of necrosis. Incidence of luteinizing hormone (LH) secretory spikes per sow was less (P less than 0.01) in zearalenone-treated sows (0.25 +/- 0.25/4 h) than control sows (1.75 +/- 0.25/4 h) on day 10 after breeding. Incidence of follicle-stimulating hormone (FSH) secretory spikes was simillar (P = 0.45) among treatments on days 7, 10, and 14 after breeding. Mean serum concentrations of LH were less on day 10 (P = 0.07) and day 14 (P less than 0.01) in zearalenone-treated sows than in control sows (3.3 +/- 0.2 ng/ml vs 6.2 +/- 1.3). These data indicate that administration of zearalenone on days 7 to 10 after breeding altered secretory patterns of serum LH during days 10 and 14 after breeding, which may have contributed to the death of blastocysts by day 14 after breeding.

A corn culture of Fusarium roseum was added to a standard corn-soybean swine gestation ration. Low, middle, and high dosage mixed feeds contained 7, 38, and 64 mg of zearalenone/kg of feed (7, 38, and 64 ppm) and 0.5, 2.5, and 4.5 mg of deoxynivalenol/kg, respectively. Control feed was the standard ration without added F roseum corn culture. Mature gilts were bred by natural service and fed control or F roseum molded feed from 3 to 34 days after breeding. The main effect of the molded feed was an inhibition of fetal development, with decreased numbers of fetuses present in treated animals at slaughter (38 to 43 days after breeding). Normal litters were present in 7 of 8 control animals, in 2 of 4 gilts given the low-dosage feed, in 1 of 4 gilts given the medium dosage, and in 0 of 4 given the high-dosage feed. Corpora lutea were maintained in all treated animals, as evidenced by serum progesterone concentrations. Serum estradiol concentrations were decreased in gilts in the middle- and high-dosage groups. The genital system of the gilts fed low- and middle-dosage feeds had a gross and microscopic appearance similar to that of the pregnant controls and reflected prolonged progesterone stimulation. Morphologic changes in the genital system of the high-dosage group were intermediate between changes induced by progesterone and those induced by estrogen. Clinical signs of hyperestrogenism and partial feed refusal were noticed in only some of the high-dosage group animals.