Oviductal isthmic motility patterns as monitored by polyview in unrestrained sows around ovulation

Sperm distribution in the genital tract of the bitch following artificial insemination in relation to the time of ovulation

In the present study, sperm distribution in the genital tract of the bitch following artificial insemination (AI) in relation to the time of ovulation was investigated by histology, scanning electron microscopy (SEM) and flushing. Ten bitches were inseminated intravaginally with 500 × 106spermatozoa: three dogs before ovulation, four dogs during ovulation and three dogs after ovulation. Ovariohysterectomy was performed 24 h after AI. Half of the genital tract was divided into nine segments (cervix, corpus uteri, caudal, middle and cranial uterine horn (UTH), utero–tubal junction (UTJ), isthmus, ampulla and infundibulum), which were processed for histology and SEM. The contralateral UTH and uterine tube (UT) were flushed, and several sperm characteristics were assessed. Histology revealed that the spermatozoa were mainly located in the uterine glands and at the UTJ, while very few spermatozoa were detected in the UT. Insemination during ovulation resulted in higher percentages of glands with spermatozoa in the different parts of the uterus (P< 0.05). Evaluation by SEM showed higher numbers of spermatozoa in several parts of the uterus for bitches inseminated during ovulation (P< 0.05). The mean number of spermatozoa flushed from the UTH and the UT was low. No significant differences in the evaluated sperm quality parameters were found between the flushings of the UTH and the UT. In conclusion, based on our findings, the uterine glands and the UTJ might act as sperm reservoirs in the bitch and sperm transport in the genital tract is affected by the time of AI in relation to ovulation.

Postovulatory effect of repeated administration of prostaglandin F2α on the endocrine status, ova transport, binding of accessory spermatozoa to the zona pellucida and embryo development of recently ovulated sows

We investigated the postovulatory effect of repeated administration of prostaglandin F2alpha (PGF2alpha) on the endocrine status, ova transport, binding of accessory spermatozoa to the zona pellucida (ZP) and embryo development of recently ovulated sows. We used altogether 10 Swedish crossbred (Landrace x Yorkshire) multiparous sows. The treatment group (P-group) was administered 1 mg of PGF2alpha intravenously every 6 h via an indwelling jugular cannula, commencing 4-8 h after ovulation was detected in the second estrus after weaning. All sows were inseminated once and blood was sampled until the end of the experimental period. After slaughter, we immediately recovered the reproductive tracts and divided them into three equal isthmic segments (IST1, IST2 and IST3) and a third of the uterine horn from the utero-tubal-junction (UTJ), and we flushed each one with PBS for ova recovery. We immediately stained the ova and examined them under epi-fluorescence illumination. We found the highest proportion of ova in the P-group in IST1 (41.5%), while we found the highest proportion in the C-group in the uterus (40.7%). A total of 68.7% of ova in the P-group had more than 50 accessory spermatozoa attached to the ZP, compared with 36.7% in the C-group sows. A total of 77% of ova had more than three blastomeres in the P-group, compared with 73% in the C-group. PGF2alpha metabolite and cortisol levels were elevated (P < 0.05) following every PGF2alpha administration. Despite peaks, we saw no changes (P > 0.05) in progesterone levels between the P-group and the C-group. We saw no differences (P > 0.05) in estradiol-17beta levels between the P-group and the C-group. We concluded that PGF2alpha stimulates the hypothalamus-pituitary-adrenal axis, as evidenced by the elevation of cortisol and progesterone but not estradiol-17beta. Furthermore, repeated PGF2alpha administration might be associated with a delayed ova transport and an increased number of accessory spermatozoa bound to the ZP. However, the effect of PGF2alpha on embryo development is unclear.

Postovulatory effect of intravenous administration of lipopolysaccharide (E. coli, O55:B5) on the contractile activity of the oviduct, ova transport, binding of accessory spermatozoa to the zona pellucida and embryo development in sows

The effect of lipopolysaccharide (LPS) (E. coli, O55:B5), administered 18 h after ovulation in the second oestrus after weaning, on the contractile activity of the oviduct, ova transport, sperm binding to zona pellucida (ZP) and embryo development, was studied in 14 Swedish crossbred (Landrace Yorkshire) multiparous sows. The endotoxin group (E-group) sows were administered with 300 ng/kg of LPS while the control group (C-group) sows were administered with 5 ml of saline i.v. via an indwelling jugular cannula. Immediately after evidence of standing oestrus, a Millar pressure transducer was placed intraluminally about 3 cm into the mid-isthmus, via laparotomy. Pressure recordings of the oviduct were collected from all conscious sows until slaughter. After slaughter, the genital tract opposite to the side with the transducer was retrieved, and three equal isthmic segments and the first third of the uterine horn part adjacent to the utero-tubal-junction (UTJ) were flushed separately to recover the ova. The intervals (mean+/-SD) from ovulation to slaughter (OS) and insemination to ovulation (IO) were not different between the E-group (44.5 +/- 5.7 h; 13.3 +/- 6.5 h) and the C-group (42.7 +/- 5.9 h; 14.8 +/- 4.1 h), respectively. Ova recovery rate (RR) in the E-group (80.2 +/- 22.9%) did not differ from that in the C-group (85.2 +/- 4.5%). The frequency distribution of ova recovered in the different segments did not significantly (p > 0.05) differ between the groups. The E-group showed higher cleavage rate than controls. A higher proportion of spermatozoa bound to the ZP was also found in the E-group compared with controls. The isthmic intraluminal pressure slightly increased (p = 0.07) 18 h after ovulation and immediately following LPS in the E-group, compared with the C-group. The frequencies of phasic pressure fluctuations were significantly (p < 0.05) lower at 30 and 38 h after ovulation in the E- than in the C-group. It can be concluded from the present study that a single i.v. administration of LPS (300 ng/kg body weight) to sows, 18 h after ovulation might be associated with changes in isthmic pressure and the frequency of phasic pressure fluctuations, increased numbers of spermatozoa attached to the ZP and an enhanced embryo development but not with ova transport rates.

The influence of pre- and post-ovulatory insemination on sperm distribution in the oviduct, accessory sperm to the zona pellucida, fertilisation rate and embryo development in sows

The aim of present study was to investigate the influence of pre-compared with post-ovulatory insemination, on the distribution of spermatozoa in the oviduct, the accessory sperm counts on the zona pellucida and early embryonic development. Thirty-six crossbred multiparous sows (Swedish Landrace x Swedish Yorkshire) were artificially inseminated once either at 20-15 h before (group AIB) or at 15-20 h after (group AIA) ovulation by using a pooled semen of two boars. Thereafter, they were randomly allocated to one of five groups: slaughter at 5-6h after AI (group I-AIB), at 20-25 h after ovulation (groups II-AIB and II-AIA), at 70 h after ovulation (groups III-AIB and III-AIA), on day 11 (groups IV-AIB and IV-AIA, first day of standing oestrus=day 1) and on day 19 (groups V-AIB and V-AIA). The plasma levels of oestradiol-17beta and progesterone differed significantly (P<or=0.05 and P<or=0.001, respectively) between AI before (group AIB) and after (group AIA) ovulation. All sows inseminated before ovulation (group I-AIB) had spermatozoa in the UTJ but this was found only in one of the late inseminated sows (group II-AIA). The number of oocytes with spermatozoa in the ZP differed significantly (P<or=0.001) between 'group II-AIB' and 'group II-AIA'. Comparing fertilisation rate, the fertilisation rate in 'group III-AIB' was significantly (P<or=0.001) higher than in 'group III-AIA'. A larger number of recovered embryos (on days 11 and 19) per sow in groups IV-AIB and V-AIB compared with IV-AIA and V-AIA were found. The embryos in group IV-AIB were also larger than embryos in group IV-AIA. In group V-AIA, no embryos were found.In conclusion, the results of this study showed that if insemination was performed at 15-20 after ovulation in sows that still were in standing oestrus, the transport of spermatozoa to the UTJ and oviduct was impaired and a lower proportion of oocytes with accessory spermatozoa to the zona pellucida was found compared with insemination before ovulation. In the late inseminated sows, fertilised oocytes and developed embryos were observed up to day 11 but no embryos were found at day 19.

Essential role of ZP molecules in tubal transport of embryos in mice

Our understandings of the molecular and cellular mechanisms underlying tubal transport of embryos are poor. This study describes the essential role of the molecules on the zona pellucida (ZP) in the tubal transport of mouse embryos. The bovine and porcine embryos that were interspecifically transferred to the mouse oviduct were selectively retained in the oviduct and rarely transported to the uterus. Antiserum ZP3-9 against synthetic peptides that are specific for mouse ZP3, significantly interfered with tubal transport of the treated embryos. The treatment of mouse embryos with antiserum ZP2-20 against the synthetic peptides, deduced from the sequences that are conserved in the structure of ZP2 from mouse and human, also inhibited their tubal transport. Among various proteolytic and glycosidic enzymes, treatments with trypsin and beta-glucosidase prior to transfer to the oviduct, significantly interfered with the tubal transport of the enzyme-treated mouse embryos. We hypothesize that species-specific epitopes on the ZP may be recognized by the oviductal cilia and/or the epithelial cells of ducts for tubal transport.

Postovulatory effect of repeated intravenous administration of ACTH on the contractile activity of the oviduct, ova transport and endocrine status of recently ovulated and unrestrained sows

The effect of repeated intravenous administration of ACTH (Synacthen depot) on the contractile activity of the oviduct, ova transport and endocrine status was studied in 11 Swedish crossbred (Landrace x Yorkshire) multiparous sows. In the second estrus after weaning, the ACTH group (Group A, n=6) sows were administered 0.01 mg/kg body weight of ACTH every 6 h commencing 4 to 8 h after ovulation, whereas the control group (Group C, n=5) sows were administered saline solution. Immediately after standing estrus, a Millar pressure transducer was placed about 3 cm into the isthmus via a laparotomy. Blood samples for hormonal analyses and pressure recordings of the oviduct were collected from all sows until slaughter. After slaughter, the genital tract opposite to the side with the transducer was retrieved, and 3 equal isthmic segments and the first third of the uterine horn portion adjacent to the UTJ were flushed separately for ova recovery. Cortisol levels were significantly (P<0.05) elevated after ACTH administration. Progesterone and PGF2alpha metabolite levels were significantly (P<0.05) elevated only after the first ACTH administration. No significant differences (P>0.05) were seen in the mean pressure and frequencies of phasic pressure fluctuations either before or after every ACTH administration between Groups A and C. No significant difference (P>0.05) was seen in the proportion of ova recovered in the different segments between Groups A and C. It can be concluded from the present study that the administration of ACTH (0.01 mg/kg body weight) to sows at 4 to 8 h after ovulation, and after each subsequent ACTH administration, elevates cortisol levels, whereas progesterone and PGF2alpha metabolite levels are elevated only after the first treatment, and that this has no effect on the mean isthmic pressure, the frequency of phasic pressure fluctuations or ova transport.

Effects of post-ovulatory food deprivation on the hormonal profiles, activity of the oviduct and ova transport in sows

The objective of the present study was to investigate the effect of post-ovulatory food deprivation on the hormonal profiles and consequently on the activity of the oviduct and ova transport in sows. Sows were randomly allocated to the control (C-group, n=6) or fasted (F-group, n=5) group. The F-group sows were fasted for four meals starting with the morning meal after detection of ovulation in the second oestrus after weaning. Ovulation was checked by transrectal ultrasonography. Blood was collected for the analyses of progesterone, oestradiol-17beta, prostaglandin F(2 approximately ) metabolite, insulin, free fatty acids and triglycerides. Oviductal isthmic motility was monitored on Polyview before and after ovulation until the time of slaughter. After slaughter, the isthmus opposite the side with transducer was divided into three equal segments and flushed separately and a third of the uterine horn part from the utero-tubal-junction (UTJ) was also flushed. A high proportion of ova in the F-group was found in the first and second parts of the isthmus. In the C-group, a high proportion of ova was found in the third part of the isthmus and the uterus. The mean isthmic pressure in the C-group decreased significantly (P<0.05) during the period immediately after ovulation while in the F-group mean pressure remained unchanged. The frequency of phasic pressure fluctuations were significantly (P<0.05) higher in the F- than in the C-group 13 to 24 h after ovulation. No significant differences in progesterone concentrations were seen between the two groups of sows. Prostaglandin metabolite levels were significantly (P<0.05) higher in the F-group than in the C-group. Oestradiol-17beta levels significantly (p<0.05) decreased earlier in the F- than in the C-group. Serum insulin levels were significantly (p=0.05) lower in the F- than in the C-group while free fatty acids were significantly (p<0.01) higher in the F- than in the C-group. There were no significant differences in the serum levels of triglycerides between the F- and the C-group. Therefore, it can be concluded in the present study that food deprivation is associated with changes in the hormonal profiles, activity of the oviduct and a delay of ova transport in sows.