Search

This study investigated the effects of oral administration of pioglitazone (PGT), a specific and synthetic ligand of peroxisome proliferator-activated receptors gamma (PPARγ), on follicular dynamics and corpus luteum (CL) functionality in dairy cows. Cows exhibiting strong signs of estrus after 2 injections of PGF2α (given14 d apart) at d 30 postpartum (n = 28) were allotted to four groups (n = 7 cows/treatment) and orally received 6 mg PGT/kg body weight/day according to the following protocol: no PGT (control); PGT for 14 d from 7 d before expected estrus (10 d after 1st injection of PGF2α) to 7 d after observed estrus (PGT14); PGT for 21 d after observed estrus (PGT21); and PGT for 28 d, 7 d before expected estrus to 21 d after observed estrus (PGT28). During the first follicular wave, number of follicles (total and small) increased in PGT14 and PGT28 cows compared to the control group (P < 0.05). During the ovulatory wave, number of total and small follicles increased in PGT28 (P < 0.05) and PGT21 (P < 0.10) compared with PGT14 and control cows. Size of the largest follicle at first wave was greater in PGT28 (P < 0.05), PGT14 (P < 0.05) and PGT21 (P < 0.10) compared to the control cows. Maximal size of the ovulatory follicle was greater in PGT28 (P < 0.05) and PGT21 (P < 0.10) groups compared to the control group. Growth rate of the largest follicle at first wave was higher (P < 0.05) in PGT-treated cows, while growth rate of the ovulatory wave was higher in PGT28 and PGT21 groups, leading to shorter days from luteolysis to ovulation. Pioglitazone administration did not affect CL size, but increased progesterone (P4) concentration. The PGT14 and PGT28 cows had higher maximal plasma P4 concentration and shorter intervals to reach maximal plasma P4 compared to the control group. In conclusion, oral administration of PGT had some positive effects on follicular development and circulating P4 levels which may be conducive to better reproductive performance.

The purpose of this study was to investigate the effects of gonadotropin-releasing hormone (GnRH) administration on the induction of multiple births in synchronized Afshari ewes. 16 cycling, multiparous fat-tailed Iranian Afshari ewes, weighing 66.5 ± 2.5 kg, were used in the trail. Estrus was synchronized using controlled internal drug release CIDR’s; inserted for 14 days. Pregnant mare serum gonadotrophin (PMSG) (300 IU) was injected to ewes a day before CIDR removal. The ewes was randomly allocated to two groups (n = 8). Synchronization treatment was initiated with a week interval in two groups (weeks 1 and 2). 24 h following CIDR removal (day 1), GnRH (50 μg) was administered to half of each group ewes (GnRH and control groups), and ewes mated with the proven rams. Pregnancy was diagnosed with the aid of transabdominal ultrasonograpy 30 days after mating. Ovarian follicular activity was monitored with the aid of transrectal ultrasonograpy on the days of CIDR removal and at estrus (approximately day 1). Following PMSG treatment, the mean number of large follicles on total ovaries increased from CIDR removal to estrus 1.48 ± 0.71 vs. 2.85 ± 0.82 (P < 0.05). Lambing rate in GnRH group (162.5%) was higher (P < 0.05) compared to the control group (125%). The mean weights of lambs born in the GnRH and control groups were 5.5 ± 0.1 and 5.2 ± 0.1, respectively.Key words: GnRH, estrus synchronization, Afshari, ewe, lambing rate.

According to the importance of lambing rate to profitability of sheep holders, this trial investigated the effects of pregnant mare serum gonadotropin (PMSG) injection a day prior or at controlled intravaginal drug-releasing device (CIDR) removal on multiple births in synchronized Afshari ewes. 16 cycling, multiparous fat-tailed Iranian Afshari ewes, weighing 66.5±2.5 kg, were used in the trial. The ewes were randomly allocated in equal numbers (n = 8) to two treatment groups. The estrous cycles were synchronized using CIDR’s inserted for a period of 14 days. In a group (PMSG/ d -1) of ewes, PMSG (300 IU) intramuscularly (IM) was injected a day (day = -1) prior to CIDR removal (day 0 = day of CIDR removal) and another group (PMSG/ d 0) received PMSG at CIDR removal (day 0). 48 following CIDR removal (day 1), GnRH (50 μg) was administered to half of each group of ewes and ewes were mated with the proven rams. Ovarian follicular activity was monitored with the aid of transrectal ultrasonograpy: on the day of CIDR removal (day 0) and a day later (at estrus, day 1). Pregnancy was diagnosed with the aid of transabdominal ultrasonograpy 30 days after mating. Following PMSG (day = -1) treatment, the mean number of large follicles on both ovaries increased from CIDR removal to estrus (1.50±0.61 vs. 2.78±0.69) (P < 0.05). Lambing rate in PMSG/ d -1+GnRH, PMSG/ d -1 noGnRH, PMSG/ d0+GnRH and PMSG/ d0 noGnRH groups was 175, 125, 175 and 150% respectively. The results show that PMSG injection a day prior or at CIDR removal, caused large follicles development, but no significant difference was seen between the two treatment lambing rates and also, the lambing rate increased in group treated with GnRH.Key words: Pregnant mare serum gonadotropin (PMSG), gonadotropin-releasing hormone (GnRH), Afshari ewes, lambing.

The pattern of growth and regression of ovarian follicles was characterized during the estrus cycle in 5 Najdi goats by daily ultrasonographic examination of the ovaries. Follicles 2 mm was measured and their relative locations within the ovary were determined to follow the sequential development of each individual follicle. Results indicated the presence of either four (n = 2 estrus cycles) or five (n = 3 estrus cycles) waves of follicular growth during the interovulatory interval. Each wave was characterized by the development of at least 1 large follicle (dominant) and a variable number of small follicles (subordinate). The mean number of follicular waves in Najdi goats is 4.6 ± 0.55, the days of wave emergence were on -0.8 ± 1.06, 3.2 ± 0.4, 7.0 ± 0.6, 12.3 ± 1.72 and 13.0 ± 1.63, for the first to fifth follicular waves, retrospectively. In goats with four or five follicular waves the dominant follicle in forth or fifth wave was ovulatory follicle. The mean number of ovulations in Najdi goats is 1.8 ± 0.4. Means of values were analyzed by repeated measures test using general linear model (GLM).Key words: Goats, estrous, follicles, ultrasonography.

The objective of the present study was to evaluate the hormonal responses of buffaloes to GnRH injections given at different moments of the estrous cycle. The estrous cycles of 15 buffaloes were synchronized with 2 im injections of prostaglandin F2α given 11 days apart. The buffalos were randomly assigned to 1 of 3 groups. Buffaloes in the control group received no treatment, whereas GnRH6 buffaloes received a GnRH injection between days 5 and 7 and GnRH16 buffaloes received a GnRH injection between days 15 and 17 of the estrous cycle (estrus = day 0). Up to day 6, the plasma progesterone levels in the three groups were low (1 ± 0.16 ng/ml) but gradually increased until day 12 (4.62 ± 0.41 ng/ml). The amount of plasma progesterone concentrations decreased from day 15 of the estrous cycle in all groups of buffaloes. No significant differences were observed in the plasma level of progesterone and estradiol concentrations of the three groups during the estrous cycle. The peak levels of plasma estradiol were observed on day 20 and the differences were not significant (11.34 ± 1.77, 11.74 ± 1.91 and 12.72 ± 2.49 pg/ml in the control, GnRH6 and GnRH16 groups, respectively (P> 0.05). In conclusion, GnRH given at the beginning or at the end of the estrous cycle did not alter the profile of progesterone and estradiol concentration in buffaloes.

Ascorbic acid has long been associated with fertility. This study was designed to determine the effects of ascorbic acid on in vitro maturation of mouse oocyte with or without cumulus cells. In this study, 508denuded oocytes (DOs) and 527 cumulus–oocyte complexes (COCs) from mice stimulated with pregnant mare’s serum gonadotrophin (PMSG) were incubated for 24 h in medium containing 0, 80, 250 and 750 &#956 M/ml of ascorbic acid prior to in vitro maturation. Maturation rate was compared. A significant decrease in the maturation rate was observed only when the DOs and COCs were exposed to 750 &#956 M/ml of ascorbic acid (P < 0.05). The maturation rate in COCs was significantly higher than DOs in all groups (P < 0.05). These results indicate that exposure ascorbic acid promotes the development of mouse DOs and COCs from germinal vesicle breakdown (GVBD) to metaphase II (MII) and prevents cumulus celldegeneration at certain levels, especially 250 &#956 M/ml of ascorbic acid (P < 0.05). However, further studies on the potential effects of different concentrations of ascorbic acid on oocyte maturation are needed.

In the present study, the effect of all-trans retinoic acid (t-RA) administration during in vitro maturation (IVM) on bovine oocytes maturation was determined. Concentrations of t-RA (RA; 0, 0.25, 0.5 and 1 μM) and 0.1% ethanol (vehicle) were included in the maturation medium. Ovaries collected from the local abattoir were transported to the laboratory in in 0.9% NaCl with 100 IU/ml penicillin and 100 in vitro maturation (IVM) on bovine oocytes maturation was determined. Concentrations of t-RA (RA; 0, 0.25, 0.5 and 1 μM) and 0.1% ethanol (vehicle) were included in the maturation medium. Ovaries collected from the local abattoir were transported to the laboratory in in 0.9% NaCl with 100 IU/ml penicillin and 100 in vitro maturation (IVM) on bovine oocytes maturation was determined. Concentrations of t-RA (RA; 0, 0.25, 0.5 and 1 μM) and 0.1% ethanol (vehicle) were included in the maturation medium. Ovaries collected from the local abattoir were transported to the laboratory in in 0.9% NaCl with 100 IU/ml penicillin and 100 g/ml streptomycin at 30 - 35°C within 1-2 h after collection. The oocytes of antral follicles, 2 to 8 mm in diameter, were recovered by aspiration. After preliminary evaluation, the oocytes were selected and washed four times in HEPES-TCM 199 supplemented with 2% FBS, 0.2 mM sodium pyruvate, 100 IU/ml penicillin and 100 g/ml streptomycin. Then 10 cumulus-oocyte complexes (COCs) were subjected to each droplet of maturation medium and incubated at 38.5°C, 5% CO2 and 95% humidity for 24 h. Maturation medium was bicarbonate-buffered TCM199 supplemented with 10% FBS, 0.2 mM sodium pyruvate, 5 μg/ml bovine FSH, 0.01 IU/ml bovine LH, 100 IU/ml penicillin and 100 g/ml streptomycin. Results show different concentrations of t-RA have no effect on cumulus expansion. The rate of oocytes developing to the MII stage compared to control, vehicle, and 0.25 μM groups was significantly increased with 1 μM t-RA treatment (p

The aim of the study was to determine the optimum concentration of the mare serum (MS) for sheep in vitro oocyte maturation. Sheep ovaries were collected from a local abattoir and transported within 1 h tothe laboratory in a warm saline solution (30 – 35oC), supplemented with 100 IU penicillin G and 100 g streptomycin sulfate/ml. Cumulus-oocyte complexes (COC’s) were obtained by slicing of follicles, washed in TCM-199 modification with NaHCO3 and supplemented with 50 g/ml gentamycin, and 0.25 mM sodium pyruvate without any serum supplementation. The COC’s were randomly divided into four groups. Group 1 (n = 105) COC’s were fresh control and cultured in TCM-199 medium without serum supplementation. Group 2 (n = 108) COC’s were washed five times and cultured in TCM-199 medium supplemented with 10% MS. Group 3 (n = 112) COC’s were washed five times and cultured in TCM-199medium supplemented with 15% MS. Group 4 (n = 114) COC’s were washed five times and cultured in TCM-199 medium supplemented with 20% MS. After 38 - 42 h of IVM, oocytes were denuded with the aidof 0.1% hyaluronidase and passing them through a fine pipette, fixed for 24 – 48 h in a mixture of acetic acid and alcohol (1:3) at room temperature, stained for 10 min with 1% (w/v) orcein in 45% acetic acid and examined for the evidence of different stages of maturation. Significantly higher (p < 0.05) maturation rates of oocytes (69 – 72%) were observed in all concentrations of mare serum compared tothose without serum supplementation. However, no significant difference was observed between the 10, 15 and 20% serum supplemented group.

Background The basal medium that supports Isolated Mouse Oviduct (IMO) is important for supporting embryo development and quality. Methods The culture of ovine IVM/IVF zygotes was done in IMO using SOFaaciBSA and SOFaaBSA as basal medium of IMO and in SOFaaBSA alone as control. For preparation of IMO mature inbred strain C57BL/6 female mice were synchronized and mated with vasectomized males. The females with vaginal plug were sacrificed and the zygotes were transferred in to the isolated oviduct at 20 hpi. The oviducts were cultured with SOFaaciBSA and SOFaaBSA for 6 days. Another group of zygotes were cultured in SOFaaBSA alone as control. Results Culture of zygotes in the IMO with SOFaaciBSA and SOFaaBSA, did not significantly affect the development and quality of embryos (p > 0.05). The hatching rate, total and trophectoderm cells number in IMO groups’ blastocysts were significantly higher than SOFaaBSA alone. The morphological appearance of IMO blastocysts was superior to SOFaaBSA alone. When the quality of oocytes was poor, IMO could better support ovine embryo development either with SOFaaBSA or SOFaaciBSA than SOFaaBSA alone and there was a significant difference in blastocyst formation at day 6 with SOFaaBSA alone. Conclusion The culture of ovine IVM/IVF zygotes in IMO using two highly efficient ruminant embryo culture media not only could support development of ovine embryos similar to the level in non IMO culture system (SOFaaBSA alone) but also could improve the quality of resulting embryos. Additionally, IMO could better support the development of ovine embryos derived from poor quality oocytes compared to the SOFaaBSA alone.

Different mutations in the bone morphogenetic protein-15 (BMP-15) and the Growth Differentiation Factor-9 (GDF-9) genes have increased ovulation rate and infertility in a dosage-sensitive manner insheep. To test the polymorphisms of genes in goat, which have been demonstrated as major genes of fecundity in sheep, the genetic polymorphism of FecXB and FecXG loci in BMP-15 gene were studied in109 Iranian native goats. Blood samples were collected in EDTA coated tubes from Jugular vein and genomic DNA was extracted from whole blood samples. Single nucleotide polymorphism of FecXB and FecXG loci in BMP-15 gene were determined using PCR-RFLP technique. There was no evidence of mutation in FecXB and FecXG in these goats, all of which were monomorph for exon 2 BMP-15 gene.