Sperm distribution in the reproductive tract of sows after intrauterine insemination

Abstract

The purpose of the present study was to compare the number of spermatozoa obtained from different parts of the oviducts and the uterine horns of sows after intrauterine insemination (IUI) and conventional artificial insemination (AI), 24 h after insemination. Twelve crossbred (Landrace x Yorkshire) multiparous sows were used in the experiment. The sows were examined for standing oestrus using a back pressure test and were examined every 4 h after standing oestrus by real-time B-mode ultrasonography to estimate the time of ovulation. The sows were allocated to two groups, group I sows (n = 6) were inseminated by a conventional AI technique with 3 x 10(9) motile spermatozoa in 100 ml of extended semen, and group II sows (n = 6) were inseminated by an IUI technique using 1 x 10(9) motile spermatozoa in 50 ml of extended semen. A single dose of AI or IUI was given using the same boar, 8-10 h before the expected time of ovulation during the second oestrus after weaning. Twenty four hours after insemination, the sows were ovario-hysterectomized. The oviducts and the uterine horns were removed and divided into seven parts, the cranial, middle and caudal uterine horns, the utero-tubal junction (UTJ), the cranial and caudal isthmus, and the ampulla. All parts of the reproductive tract were flushed and the spermatozoa were counted using a haemocytometer. The results revealed that the spermatozoa were found in both the oviducts and the uterine horns in all animals. The number of flushed spermatozoa in the UTJ of groups I and II, was 142,500 and 131,167 (p > 0.05), and in the caudal isthmus was 1411 and 1280 (p > 0.05), respectively. The proportion of spermatozoa in different parts of the reproductive tract in relation to the total number of spermatozoa within the tract was not significantly different between groups I and II (p > 0.05). It could be concluded that IUI, with a three-time reduction in the number of spermatozoa used resulted in the same number of spermatozoa to be deposited in the sperm reservoir around ovulation time.

Infiltration of Local Immune Cells in the Sow Reproductive Tracts after Intra-Uterine and Deep Intra-Uterine Insemination with a Reduced Number of Spermatozoa is Less than Conventional Artificial Insemination

“…The low amount of neutrophils and macrophages indicates that the function of the non-specific immune system or phagocytosis is limited in the sperm reservoir as suggested in the previous study by Rodriguez-Martinez et al [13]. In general, the number of sperm used for IUI and DIUI was 3 and 20 times less than for CAI [17,20]. Our previous study has also demonstrated that the number of sperm in the crypt of the sperm reservoir (UTJ and caudal isthmus) in the DIUI groups was also lower than that with CAI [21].…”

“…In the present study, the numbers of inflammatory cells (neutrophils and plasma cells) in some part, especially in the UTJ, of the oviduct were higher in the CAI than the DIUI groups and also tended to be higher than in the IUI groups. The reason might be due to the number of spermatozoa depositing in the UTJ and oviduct of sows after DIUI with a reduced number of spermatozoa was significantly lower than that after CAI [17]. Since either the volume of semen or the total number of spermatozoa used for DIUI were 20 times less than CAI, some seminal plasma proteins that can induce PMN cells might be low.…”

“…The UTJ is an important barrier for the excessive sperm that attempt to reach the oviduct. It has earlier been demonstrated that the number of sperm in the female reproductive tract after CAI, IUI and DIUI was much higher in the UTJ than in the upper part of the oviduct [17,20,21].…”

“…The sows were inseminated with a single dose of the diluted semen during the second oestrus after weaning at 6 to 8 hr prior to the expected time of ovulation. The sows were inseminated by the CAI, IUI and DIUI techniques [17,20].…”

“…Furthermore, several studies have demonstrated that at the various sperm dosages used at present, the results of fertilization are quite good when the ovulation occurs within 24 hr after insemination [16]. In our previous study [17], the number of spermatozoa in the female reproductive tract at 24 hr after CAI, IUI and DIUI has been demonstrated but the infiltration of the local immune cells during this period has not been evaluated.…”