Hormonal responses to GnRH injection given at different stages of the estrous cycle in water buffaloes

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

Effect of the presence of corpus luteum on the ovary and the new oocyte recovery method on the oocyte recovery rate and meiotic competence of ovine oocytes

This study was designed to identify the effects of the presence of corpus luteum (CL) on the meiotic competence of the ewe oocytes. In addition, due to the pivotal roles of oocyte recovery methods on efficiency of in vitro maturation and in vitro fertilization, this study considered the new oocyte recovery method “Oocyte Recovery with Centrifuge” (ORC); Ovine ovaries were obtained from local abattoir at Karaj, Iran. The ovaries were placed in 0.9% saline which was supplemented with penicillin/streptomycin in thermo flask at 37°C and transported to the laboratory within 1 to 2 h of slaughter. The ovaries were assigned to two groups; group-1 with functional CL and group-2 without CL. The oocytes were recovered by means of aspiration pump or ORC. After oocyte recovery, they were cultured in TCM-199 for 24 h. The mean number of oocyte recovery per ovary in group 1 ovaries (1.8 ± 0.01 via aspiration and 3.84 ± 0.05 via ORC) was lower (P<0.05) than group 2 ovaries (2.2 ± 0.00 via aspiration and 5.43 ± 0.01 via ORC). There were no significant differences (P>0.05) between percentage of nuclear maturation in oocytes which were recovered from group 2 ovaries via aspiration and ORC (75.20 ± 0.00 vs. 74.95 ± 0.00, metaphase II; M-II) method. The nuclear maturation in oocytes which were obtained via ORC from group 2 ovaries was higher (P<0.05) than group 1 ovaries (74.95 ± 0.00 vs. 60.07 ± 0.00b). Nuclear maturation for oocytes obtained via ORC from group 1 ovaries was (P<0.05) lower than oocytes obtained via aspiration (60.07 ± 0.00 vs. 74.70 ± 0.00). Result of the present study showed that the presence of CL on ovaries lead to decrease in the quality and the quantity of oocytes. ORC method increased the quantity and quality of recovered oocytes.Key words: Aspiration, corpus luteum, in vitro maturation (IVM), oocyte recovery

Ascorbic acid effects on in vitro maturation of mouse oocyte with or without cumulus cell

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

Effect of gonadotropin-releasing hormone (GnRH) treatment on multiple births in Afshari ewes

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 &lt; 0.05). Lambing rate in GnRH group (162.5%) was higher (P &lt; 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

The effects of pregnant mare serum gonadotropin (PMSG) injection a day prior or at controlled intravaginal drug-releasing (CIDR) removal on multiple births in Afshari ewes

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 &lt; 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

Retinoic acid effects on nuclear maturation of bovine oocytes in vitro

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 (

Follicular and ovulatory responses of the right versus left ovaries to eCG treatment in Shall Iranian ewes

The present study considers the right versus the left ovarian responses to the different doses of eCG treatment in ewe. The estrous cycles of 32 adult Shall Iranian ewes were synchronized by CIDR during breeding period. At the time of CIDR removal, 0 (n = 8), 450 (n = 8), 550 (n = 8) and 650 (n = 8) IU of eCG (Intervet, Booxmer, Netherlands) was administered to ewes. The number of large follicles (&gt; 3 mm, LF) and CL in the right and left ovaries was monitored by transrectal ultrasonography on the day of estrus and 6 days later. In another analysing view, all ewes (n = 32) were set into 3 groups. Following superovulation, groups A and D ewes had at least one extra large follicle and CL, respectively, in their right ovary than that of the left one. Group B and E had the opposite position and group C and F had equal LF in their ovaries. The data were analysed by GLM procedure of SAS. The mean number of LF in the right (2.35 &#177; 0.14) was higher (P &lt; 0.001) in comparison to the left (1.42 &#177; 0.14) ovaries in all treatment groups. Also, the mean number of LF in the right was higher (P &lt; 0.05) than that in the left ovaries between every treatment group. In addition, the mean number of CL in the right (1.92 &#177; 0.47) was higher (P &lt; 0.05) in comparison to the left (1.33 &#177; 0.25) ovaries in all treatment groups. Furthermore, in the other analysis, we observed 62.5% of the ewes were in group A (n = 20) which was a higher (P &lt; 0.001) percentage compared to group B (n = 4, 12.5%) and group C (n = 8, 25%). Also, it is observed that 44% of the ewes were set into group D (n = 16) (the right ovary had at least one CL extra in comparison with the left ovary) which was a higher (P &lt; 0.05) percentage compared to groups E and F; and that both groups had equal number of ewes. The results suggest that the greater responses of follicular development occur in the right ovaries after eCG treatment in Shall Iranian ewes

Ovarian follicular dynamics during the interovulatory interval in Najdi goats

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 effects of different levels of sodium caseinate on rumen fermentation pattern, digestibility and microbial protein synthesis of Holstein dairy cows

This study was conducted to investigate the effects of different levels of peptide supplementation on rumen fermentation pattern, digestibility and microbial protein synthesis. Three rumen-cannulated Holstein dairy cows were used in a 3 &#215; 3 Latin square experiment within 21 days period. The ruminal infusion of sodium caseinate (CN) was 0 (control), 50 and 100 g/d. Dry matter intake, milk yield and composition , total tract apparent digestibility of nutrient, rumen parameters and purine derivatives inurine of cows were measured. Results showed that dairy cows received sodium caseinate, had significantly increased microbial protein synthesis, milk fat yield, acetate and branched chain fatty acids concentrations in rumen fluid and fiber digestibility compared with the control treatment (P &lt;0.05). CN significantly affected the concentrations of rumen ammonia nitrogen (NH3-N), rumen peptide nitrogen (Pep-N) and the ratio of rumen ammonia nitrogen/ rumen peptide nitrogen (P &lt; 0.05) and consequently blood urea nitrogen, milk urea nitrogen and urinary urea nitrogen concentrations. However digestibility of dry matter and crude protein did not differ among treatments. In conclusion, if the optimum level of NH3-N/Pep-N was the best compromise among the need for rumen fermentation, microbial protein synthesis and nitrogen excretion through urine in animal, the recommended level from this study would be 0.86 in rumen fluid