The influence of inhibited prostaglandin biosynthesis on post-ovulatory oviductal ova transport in sows

Transport of fertilised and unfertilized ova in sows

Transport of fertilised and unfertilized ova was studied in 22 crossbred (Landrace x Yorkshire) multiparous sows. Sows in the inseminated group (I-group, n=11) were inseminated once with 100ml of BTS extended semen from two fertile boars with a total of 10 x 10 (9) spermatozoa during the second oestrus after weaning between 18 and 8h prior to estimated time of ovulation, as estimated from the first oestrus after weaning. All the sows were slaughtered between 36 and 48 h after ovulation in the second oestrus after weaning by stunning and bleeding. After slaughter, the reproductive tract was immediately recovered, the isthmus was divided into three equal segments, and the number of ova was determined in each segment and in the upper third of the uterine horn from the UTJ. There were no significant differences (P>0.05) either in the intervals from ovulation to slaughter (42.3+/-6.2h versus 43.2+/-5.4h) or in the numbers of corpora lutea (CL) (18.2+/-5.5 versus 15.9+/-3.5) between the non-inseminated (N-group) and the inseminated groups (I-group), respectively. Ova recovery rate was 92.5% in the N-group and 82.9% in the I-group (P>0.05). In the I-group, ova had passed 2.2+/-0.3 segments whereas in the N-group, ova had passed 2.6+/-0.3 segments (P=0.38). It can be concluded that there is no difference in the transportation of either fertilised or unfertilized ova in the reproductive tract of pigs.

Effect of repeated ACTH-stimulation on early embryonic development and hormonal profiles in sows

This study was conducted to evaluate the effect of adrenal stimulation by synthetic adrenocorticotrophic hormone (ACTH) on the first 2 days of pregnancy in 22 multiparous sows. The experiment was performed during the second oestrus after weaning and the sows were divided into one control (C-group) and one experiment group (E-group). To determine the time of ovulation, transrectal ultrasonographic examination was performed. E-group sows were treated repeatedly with 0.1 mg/kg bodyweight of synthetic ACTH (tetracosactide) i.v. 4-8h after ovulation and continuing every 6h, until slaughter. Blood samples were collected every second hour from about 12h before expected ovulation until slaughter and were analyzed for cortisol, prostaglandin F(2 alpha) -metabolite, and progesterone (P(4)). All sows were slaughtered approximately 48 h after ovulation and the isthmic part of the oviduct was divided into three equally long segments and flushed separately with phosphate buffered saline (PBS). The uterine horns were also flushed with PBS. The embryos of the E-group sows tended (P=0.056) to have a lower cleavage rate than the embryos of the C-group sows but there was no difference between groups in oviductal transport rate of the embryos. In the E-group, significantly (P<0.05) more sows had only embryos with <20 spermatozoa attached to the ZP compared with the C-group. The plasma concentration of cortisol was significantly higher (P<0.0001) in the E-group sows during the time of treatment while the baseline level of prostaglandin F(2 alpha) -metabolite was significantly lower. The baseline level of progesterone increased in both groups after ovulation but there was no significant difference between the groups. Repeated ACTH-stimulation (1) had no effect on the oviductal transport rate of the embryos, (2) had a negative effect on the embryo development, (3) and caused a changed endocrine profile that might have changed oviductal milieu affecting embryo development.

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.

Impact of postovulatory food deprivation on the ova transport, hormonal profiles and metabolic changes in sows

The effect of food deprivation on ova transport, hormonal profiles and metabolic changes was studied in 20 crossbred multiparous sows during their second oestrus after weaning. To determine the time of ovulation, transrectal ultrasonographic examination was performed. The sows were divided into 2 groups, one control group (C-group), which was fed according to Swedish standards, and one experimental group (E-group). The E-group sows were deprived of food from the first morning meal after ovulation until slaughter. Blood samples were collected every second hour from about 12 h before expected ovulation in the second oestrus after weaning until slaughter and were analysed for progesterone, prostaglandin F2 alpha-metabolite, insulin, glucose, free fatty acids and triglycerides. All sows were slaughtered approximately 48 h after ovulation and the genital tract was recovered. The isthmic part of the oviduct was divided into 3 equally long segments and flushed separately with phosphate buffered saline (PBS). Uterine horns were also flushed with PBS. A significantly greater number of ova were found in the first and second part of the isthmus in the E-group (p = 0.05) while in the C-group most of the ova were found in the third part of the isthmus or the uterus (p = 0.01). The level of prostaglandin F2 alpha-metabolite was significantly higher in the E-group compared with the C-group. The concentration of progesterone increased in both groups after ovulation but there were no significant differences between the groups. The other blood parameters showed that the food-deprived sows were in a catabolic state. The 48 h period of fasting results, directly or indirectly in an delayed ova transport, which may be due to a delayed relaxation in the smooth circular muscle layer of the isthmus.

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.