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Biomedical subjects

G R Welch

Publications and source records attributed to G R Welch.

At least 19 recordsLinked to original sources
PubMed2006

Determination of intracellular reactive oxygen species and high mitochondrial membrane potential in Percoll-treated viable boar sperm using fluorescence-activated flow cytometry.

The use of frozen semen in the swine industry is limited by problems with viability and fertility compared with liquid semen. Part of the reduction in sperm motility and fertility associated with cryopreservation may be due to oxidative damage from excessive or inappropriate formation of reactive oxygen species (ROS). Chemiluminescence measurements of ROS are not possible in live cells and are problematic because of poor specificity. An alternative approach, flow cytometry, was developed to identify viable boar sperm containing ROS utilizing the dyes hydroethidine and 2', 7'-dichlorodihydrofluorescein diacetate as oxidizable substrates and impermeant DNA dyes to exclude dead sperm. The percentage of sperm with high mitochondrial transmembrane potential was determined by flow cytometry using the mitochondrial probe 5, 5', 6, 6'-tetrachloro-1, 1', 3, 3'-tetraethylbenzimidazolylcarbocyanine iodide with propidium iodide staining to exclude nonviable cells. Sperm were incubated with and without ROS generators and free radical scavengers. Basal ROS formation was low (less than 4%) and did not differ (P = 0.26) between viable fresh and frozen-thawed boar sperm. In addition, fresh and frozen-thawed viable sperm were equally susceptible (P = 0.20) to intracellular formation of ROS produced by xanthine/xanthine oxidase (94.4 and 87.9% of sperm, respectively). Menadione increased (P < 0.05) ROS formation, decreased (P < 0.05) JC-1-aggregate fluorescence intensity, and decreased (P < 0.05) motion variables by 25 to 60%. The mechanism of inhibition of motility by ROS formation may be related to a decrease in mitochondrial charge potential below a critical threshold. Catalase and superoxide dismutase treatment in the presence of xanthine/xanthine oxidase indicated that hydrogen peroxide was the primary intracellular ROS measured. Further, catalase, but not superoxide dismutase, was capable of attenuating ROS-induced inhibition of motility. Whereas basal intracellular hydrogen peroxide formation was low in viable fresh and frozen-thawed boar sperm, both were quite susceptible to external sources of hydrogen peroxide.

Animals↗
PubMed2005

Gain-swept superradiance applied to the stand-off detection of trace impurities in the atmosphere.

We show that gain-swept superradiance can be used to detect low (parts per million) concentrations of various gases at distances on the order of kilometers, which is done by using pulse timing to create small regions of gain at positions that sweep toward a detector. The technique is far more sensitive than previous methods such as light detection and ranging or differential absorption light detection and ranging.

Journal Article↗
PubMed2005

Impact of storage prior to cryopreservation on plasma membrane function and fertility of boar sperm.

Occasionally, boar semen must be shipped to another location for cryopreservation. We increased the initial holding time for the cooling of extended semen at 15 degrees C from 3 to 24 h to determine the effects on sperm characteristics and fertility. Thirty-one gilts and sows were inseminated once with subsequently cryopreserved and thawed semen. Increasing the holding time from 3 to 24 h had no significant effect on pregnancy rate 23 days after AI with frozen-thawed semen (64.5%) but decreased (P<0.05) embryo number from 15 to 9 and recovered embryos as fraction of CL from 73 to 47%. While the longer holding time at 15 degrees C did decrease potential litter size, the loss incurred was not too great to preclude the incorporation of a longer holding time into the cryopreservation protocol. An experiment was conducted to test the hypothesis that processing and freeze-thawing of boar semen would induce phospholipid scrambling in the plasma membrane similar to that evoked by incubation in bicarbonate-containing media. Merocyanine staining after incubation in the presence and absence of bicarbonate indicated that changes in plasma membrane phospholipid scrambling of processed and cryopreserved sperm differed from those in fresh semen undergoing bicarbonate-induced capacitation. The level of Annexin-V binding in boar spermatozoa increased from 1.6% in live spermatozoa in fresh semen to 18.7% in cryopreserved sperm. Apoptosis is unlikely to operate in mature spermatozoa. Apoptotic morphology in ejaculated spermatozoa is probably a result of incomplete deletion of apoptotic spermatocytes during spermatogenesis. Increased Annexin-V binding in thawed spermatozoa probably results from plasma membrane damage incurred during freezing and thawing.

Animals↗
PubMed2005

Follicular expression of a human beta-cell leukaemia/lymphoma-2 (Bcl-2) transgene does not decrease atresia or increase ovulation rate in swine.

Transgenic (TG) gilts carrying a human Bcl-2 cDNA transgene driven by mouse inhibin-alpha subunit promoter were produced and evaluated to determine if ectopic expression of Bcl-2 in the ovaries would decrease the frequency of atresia in antral follicles and increase ovulation rate. Immunohistochemical analysis showed that the Bcl-2 transgene protein was expressed in granulosa and theca cells, in 86% of healthy and 54% of atretic follicles analysed in TG prepubertal and Day 50 pregnant gilts combined (n = 24). In contrast, Bcl-2 transgene protein was expressed in only 1.4% of healthy and 0% of atretic follicles in non-TG littermates (n = 13). Real-time reverse transcription-polymerase chain reaction analysis confirmed that human Bcl-2 was expressed in follicles of TG gilts. The atresia rate for the TG and non-TG groups did not differ (P > 0.05) for prepubertal (45 v. 59%) and Day 50 pregnant gilts (53 v. 52%) respectively. The mean +/- s.e.m. ovulation rate did not differ (P > 0.5) between TG (15.9 +/- 0.8, n = 12) and non-TG (16.4 +/- 0.6, n = 7) Day 50 pregnant gilts. The molecular basis of the failure of ectopic Bcl-2 expression to increase the ratio of healthy to atretic follicles is unknown, but it is possible that the activity of the mitochondrial-dependent cell death pathway was not neutralized by ectopic expression of human Bcl-2 or that other cell death pathways compensated for the decreased mitochondrial-dependent cell death.

Animals↗
PubMed2005

Effects of hypothermic liquid storage and cryopreservation on basal and induced plasma membrane phospholipid disorder and acrosome exocytosis in boar spermatozoa.

Flow cytometry was utilised to determine whether short-term (Day 1) or long-term hypothermic liquid storage (Day 5), or cryopreservation of boar spermatozoa (1) caused changes in plasma membrane phospholipid disorder (MPLD) and acrosome exocytosis (AE), indicative of an advanced stage of capacitation or acrosome status, and (2) facilitated or inhibited the induction of capacitation and the acrosome reaction. Merocyanine with Yo-Pro-1 and peanut agglutinin-fluorescein isothiocyanate with propidium iodide were used to identify MPLD and AE, respectively, in viable spermatozoa. The incidence of basal sperm MPLD and AE in fresh semen was very low (1.1 and 2.2%, respectively) and was increased (P < 0.05) only a small amount in Day 5 and cryopreserved semen (3-8%). Compared to no bicarbonate, incubation with bicarbonate increased MPLD, but the response was greatest (P < 0.05) in fresh sperm (52.3%) compared with Day 1 (36.6%), Day 5 (13.9%) and cryopreserved sperm (13.6%). Incubation with calcium ionophore A23187 increased AE in spermatozoa, but the response was less (P < 0.05) for fresh (34%) and cryopreserved (27%) semen than for Day 1 (45%) and Day 5 (57%) semen. In summary, hypothermic liquid storage and cryopreservation of boar spermatozoa did not advance capacitation or acrosome status in viable spermatozoa, but did alter their responses to induction of capacitation and the acrosome reaction.

Acrosome↗
PubMed2003

Enhancement of Kerr nonlinearity by multiphoton coherence.

We propose a new method of resonant enhancement of optical Kerr nonlinearity that uses multilevel atomic coherence. The enhancement is accompanied by suppression of the other linear and nonlinear susceptibility terms of the medium. We show that the effect results in a modification of the nonlinear Faraday rotation of light propagating in an 87Rb vapor cell by changing the ellipticity of the light.

Journal Article↗
PubMed2002

Transporting and time reversing light via atomic coherence.

We study basic issues central to the storage of quantum information in a coherently prepared atomic medium such as the role of adiabaticity. We also propose and demonstrate transporting, multiplexing, and time reversing of stored light.

Journal Article↗
PubMed2002

Flow cytometric sperm sorting: effects of varying laser power on embryo development in swine.

This study was conducted to determine fertilization rate and embryo development using the Beltsville Sperm Sexing Technology with two different laser power outputs, 25 and 125 milliwatts (mW). Freshly ejaculated boar semen was diluted; one aliquot was not stained or sorted (nonsort) and a second aliquot was stained with Hoechst 33342 and sorted as a complete population, not separated into X and Y populations (all-sort). Ovulation controlled gilts were surgically inseminated with 2 x 10(5) spermatozoa (44-46 hr after human chorionic gonadotropin (hCG)) into the isthmus of each oviduct, one oviduct receiving nonsort and the other all-sort at 25 or 125 mW. A total of 426 embryos were flushed from oviducts at slaughter 43 hr after laparotomy and prepared for determination of fertilization and cleavage rates using confocal laser microscopy for analysis of actin cytoskeleton and chromatin configuration. The percentage of fertilized eggs and embryos was less for the 25 mW all-sort compared to nonsort or the 125 mW all-sort (77.9 vs. 96.3 and 96.2%, P < 0.05). The percentage of fragmented embryos was greater for the 25 mW all-sort than the nonsort (15.2 vs. 4.5%, P < 0.05), but did not differ significantly from 125 mW all-sort mean (7.2%). The percentage of normal embryos (80.4% overall) did not differ (P > 0.05) among treatments. However, the rate of embryo development was slower (P < 0.05) after insemination with the 25 mW all-sort spermatozoa compared to nonsort spermatozoa. Embryos in the 3-4 and 5-9 cell stages for the 25-mW all-sort and nonsort were 78 and 20% vs. 49 and 50%, respectively. The embryo percentages for the 125 mW (3-4 and 5-9 cell stages, 59 and 35%) did not differ significantly (P > 0.05) from the nonsort or 25 mW all-sort. We conclude that the use of 125 mW laser power for sorting boar spermatozoa is advantageous to maintain high resolution separation and has no detrimental effect on embryo development compared to 25 mW.

Analysis of Variance↗
PubMed2001

Radiation trapping in coherent media.

We show that the effective decay rate of Zeeman coherence, generated in a (87)Rb vapor by linearly polarized laser light, increases significantly with the atomic density. We explain this phenomenon as the result of radiation trapping. Our study shows that radiation trapping must be taken into account to fully understand many electromagnetically induced transparency experiments with optically thick media.

Journal Article↗
PubMed1999

Sex preselection: high-speed flow cytometric sorting of X and Y sperm for maximum efficiency.

Sex preselection that is based on flow-cytometric measurement of sperm DNA content to enable sorting of X- from Y-chromosome-bearing sperm has proven reproducible at various locations and with many species at greater than 90% purity. Offspring of the predetermined sex in both domestic animals and human beings have been born using this technology since its introduction in 1989. The method involves treating sperm with the fluorescent dye, Hoechst 33342, which binds to the DNA and then sorting them into X- and Y-bearing-sperm populations with a flow cytometer/cell sorter modified specifically for sperm. Sexed sperm are then used with differing semen delivery routes such as intra-uterine, intra-tubal, artificial insemination (deep-uterine and cervical), in vitro fertilization and embryo transfer, and intra-cytoplasmic sperm injection (ICSI). Offspring produced at all locations using the technology have been morphologically normal and reproductively capable in succeeding generations. With the advent of high-speed cell sorting technology and improved efficiency of sorting by a new sperm orienting nozzle, the efficiency of sexed sperm production is significantly enhanced. This paper describes development of the these technological improvements in the Beltsville Sexing Technology that has brought sexed sperm to a new level of application. Under typical conditions the high-speed sperm sorter with the orienting nozzle (HiSON) results in purities of 90% of X- and Y-bearing sperm at 6 million sperm per h for each population. Taken to its highest performance level, the HiSON has produced X-bearing-sperm populations at 85 to 90% purity in the production of up to 11 million X-bearing-sperm per h of sorting. In addition if one accepts a lower purity (75 to 80%) of X, nearly 20 million sperm can be sorted per h. The latter represents a 30 to 60-fold improvement over the 1989 sorting technology using rabbit sperm. It is anticipated that with instrument refinements the production capacity can be improved even further. The application of the current technology has led to much wider potential for practical usage through conventional and deep-uterine artificial insemination of many species, especially cattle. It also opens the possibility of utilizing sexed sperm for artificial insemination in swine once low-sperm-dose methods are perfected. Sexed sperm on demand has become a reality through the development of the HiSON system.

Animals↗
PubMed1999

Sex preselection: laboratory validation of the sperm sex ratio of flow sorted X- and Y-sperm by sort reanalysis for DNA.

Laboratory validation is essential in developing an effective method for separating X and Y sperm to preselect sex. Utilizing sexed sperm from a particular experiment to test fertility and achieve the subsequent phenotypic sex without knowing the likely outcome at conception is too costly for most applications. Further, research advances need to be built on an ongoing assessment with respect to the collection of data to continue progress towards achieving a successful outcome. The Beltsville Sperm Sexing Technology, which is based on the sorting of X- and Y-bearing sperm through the process of flow-cytometric sperm sorting, is also well suited for validation in the laboratory by "sort reanalysis" of the sperm X- and Y-bearing fractions for DNA content. Since the sexing technology is based on the use of Hoechst 33342, a permeant nuclear DNA stain for sorting X- and Y-bearing sperm, it also can be the marker for determining the proportions of X and Y populations by sort reanalysis. The process consists of using an aliquot of the sorted sperm and sonicating to obtain sperm nuclei. The uniformity of the nuclear staining is re-established through the addition of more Hoechst 33342. Separate analysis of each aliquot produces a histogram that is fitted to a double gaussian curve to determine proportions of X and Y populations. The relative breadths of the distributions of DNA of X- and Y-bearing sperm within a species affects interpretations of the histogram. Sort reanalysis is consistently repeatable with differences in X/Y DNA equal to or greater than 3.0%. This information on sex ratio of the sperm then provides the precise tool by which one can predict the outcome in terms of sex, from a particular sample of semen. Simple analysis of unsorted sperm to determine the proportions of X- and Y-bearing sperm based on DNA content is also an effective tool for validating sperm-sex ratio, whether it is in a sample assumed to be 50:50 or predicted to be something other than 50:50. This simple analysis provides for a check on the potential sex ratio of any sample of semen.

Animals↗
PubMed1999

In vitro production of sexed embryos for gender preselection: high-speed sorting of X-chromosome-bearing sperm to produce pigs after embryo transfer.

The objectives for the present experiments were to apply sperm sexing technology to an in vitro production system with porcine oocytes obtained from slaughterhouse material. On six experimental days, ovaries were obtained from an abattoir, and cumulus-oocyte-complexes were matured in vitro. Semen was collected from mature boars of proven fertility and was sorted for X-chromosome-bearing sperm, using the Beltsville Sperm Sexing Technology incorporating the use of high-speed sorting. A total of 5,378 oocytes were submitted for in vitro fertilization (IVF). Of these, 559 ova were stained for cytogenetic analysis 18 h after IVF. From the remaining 4,819 ova, 1,595 cleaved, and 1,300 of the cleaved embryos were transferred into 26 synchronized recipients (5 control gilts for unsorted sperm, 21 gilts for X-sorted sperm). In a test of two fertilization media (FERT-A vs FERT-B) higher cleavage rates (P<.05) were obtained when FERT-B was used as a fertilization medium for unsorted (43.4+/-5.1%) and sorted sperm (43.1+/-1.1%;), whereas in FERT-A unsorted sperm gave a cleavage rate of 17.9+/-4.4% and sorted sperm gave 30.4+/-1.4%. Additionally, cleavage rates were higher (P<.05) after fertilization with sorted sperm vs unsorted sperm, independent of fertilization medium. Cytogenetic analysis of ova revealed that more oocytes with unsorted than with sorted sperm remained in Metaphase 2 arrest (P<.05). This was also independent of the fertilization medium. Monospermic fertilization rates were the same for IVF with unsorted or sorted sperm, independent of the fertilization system, except FERT-A with unsorted sperm (P<.05). Polyspermic fertilization rates were highest in FERT-B (37.6+/-6.6). A total of 57 pigs were born from nine litters. Six litters from sexed sperm (X-sorted) produced 33 females (97%) and one male. Three litters from control transfers produced 23 pigs, 11 of which were female (48%). The sex ratio of the offspring was predicted based on the sort reanalysis of the sorted sperm for DNA content.

Animals↗
PubMed1999

The Beltsville sperm sexing technology: high-speed sperm sorting gives improved sperm output for in vitro fertilization and AI.

The Beltsville sperm sexing technology is currently the only effective means of altering the sex ratio of offspring in livestock. The method is based on the flow-cytometric separation of X- and Y-chromosome-bearing sperm based on X/Y DNA content difference. It is an effective means of producing progeny of predetermined sex in cattle, swine, sheep, and laboratory animals. The method involves treating sperm with a DNA-binding fluorochrome, Hoechst 33342, and flow-cytometrically sorting them into separate X and Y populations that can subsequently be used for surgical intratubal or intrauterine insemination, deep-uterine insemination, regular artificial insemination in some cases, in vitro fertilization to produce sexed embryos for transfer, and intracytoplasmic sperm injection of ova. Skewed sex ratios of 85 to 95% of one sex or the other have been repeatably achieved in most species. The method has been used worldwide to produce several hundred morphologically normal animal offspring of the predicted sex. It has also been validated in the laboratory using DNA reanalysis of the sorted sperm populations and by fluorescence in situ hybridization and PCR of individual sperm. We developed a new orienting nozzle that we have fitted to both conventional and high-speed cell sorters that have been modified for sperm sorting. Recently we completed the adaptation of the new orienting nozzle to a Cytomation MoFlo high-speed cell sorter modified for sperm. This adaptation of the nozzle has increased the overall production rate of sorted X and Y sperm from about .35 million/h to 5 or 6 million sperm/h (each population). Calves have been born from cows artificially inseminated using conventional technique and sexed sperm. In addition, numerous litters of pigs have been born after transfer of embryos produced from X or Y sorted sperm.

Animals↗
PubMed1998

A novel nozzle for more efficient sperm orientation to improve sorting efficiency of X and Y chromosome-bearing sperm.

Efficient high-resolution detection of DNA for flow cytometric sorting of X and Y chromosome-bearing sperm is dependent on effectively orientating the sperm head to the laser beam in orthogonally configured flow systems. Normally, a beveled needle is required to enlarge the fraction of properly orientated sperm (flat side facing the laser beam). In this report, a modification to a standard jet-in-air nozzle for improved sperm orientation is presented. Inside the modified nozzle (novel nozzle), orientation forces are applied lower in the nozzle than in the current beveled injection needle system. The nozzle was tested with sperm heads from several species. This study shows that use of the nozzle to orientate cattle, swine, rabbit, mouse, and human sperm effectively improves the percentage of sperm that are properly oriented. The percentage of sperm heads oriented by use of the former system (beveled needle) ranges around 30% for most species. With the newly designed nozzle, that percentage ranges around 60%. At least a twofold increase in analysis is achieved. It was found that, unlike results with the beveled needle, the percentage of properly oriented sperm was independent of the sample rate. The introduced nozzle is a significant improvement over the beveled needle system for the analysis and sorting of sperm on the basis of DNA content. In addition to the improvement in sorted sperm production brought about by the novel nozzle when fitted to standard-speed cell sorters, it clearly also has significant potential for improving the efficiency of the Beltsville Sperm Sexing Technology for separating X and Y chromosome-bearing sperm when adapted to high-speed cell-sorting systems.

Animals↗
PubMed1998

Comparative motility of X and Y chromosome-bearing bovine sperm separated on the basis of DNA content by flow sorting.

A combination of flow cytometric sperm sorting of X and Y chromosome-bearing sperm (X and Y sperm) and computer-assisted sperm analysis (CASA) for measuring sperm motility allows assessment of motion parameters in the two populations. Bull sperm were separated into X and Y populations by flow cytometry following staining with the DNA-binding dye Hoechst 33,342. The motion parameters differed depending on sperm concentration. Decreasing sperm concentration resulted in higher velocities and straighter trajectories. The concentrations of control (stained-unsorted and unstained-unsorted) and flow-sorted sperm were therefore adjusted to similar numbers (5 x 10(6) sperm per milliliter). Samples of sorted X and Y sperm and control sperm were transferred to prewarmed slides on a heated stage (37 degrees C) and their motion video recorded for 2 min using a magnification of x 100 and a high-resolution camera. The sperm analysis was carried out on a Hobson Sperm Tracker (HST) using HST 7 software. The following motion parameters were measured: curvilinear, straight-line, and average path velocity; mean angular displacement (MAD); beat cross-frequency; amplitude of lateral head displacement; linearity (LIN); and straightness of path (STR). Sperm movement was unaffected by staining with Hoechst 33,342, excitation by ultraviolet (UV) light, or the physical process of cell sorting. Significant differences were seen between X and Y sperm for MAD, LIN, and STR. No difference was observed for the other parameters. The results indicate that in a simple salts solution, Y bull sperm do not swim faster than X sperm but may be distinguished from X sperm on the basis of LIN and STR.

Animals↗
PubMed1998

Verification of flow cytometorically-sorted X- and Y-bearing porcine spermatozoa and reanalysis of spermatozoa for DNA content using the fluorescence in situ hybridization (FISH) technique.

Flow cytometric sperm sorting based on X and Y sperm DNA difference has been established as the only effective method for sexing the spermatozoa of mammals. The standard method for verifying the purity of sorted X and Y spermatozoa has been to reanalyze sorted sperm aliquots. We verified the purity of flow-sorted porcine X and Y spermatozoa and accuracy of DNA reanalysis by fluorescence in situ hybridization (FISH) using chromosome Y and 1 DNA probe. Eight ejaculates from 4 boars were sorted according to the Beltsville Sperm Sexing method. Porcine chromosome Y- and chromosome 1-specific DNA probes were used on sorted sperm populations in combination with FISH. Aliquots of the sorted sperm samples were reanalyzed for DNA content by flow cytometry. The purity of the sorted X-bearing spermatozoa was 87.4% for FISH and 87.0% for flow cytometric reanalysis; purity for the sorted Y-bearing spermatozoa was 85.9% for FISH and 84.8% for flow cytometric reanalysis. A total of 4,424 X sperm cells and 4,256 Y sperm cells was examined by FISH across the 8 ejaculates. For flow cytometry, 5,000 sorted X spermatozoa and 5,000 Y spermatozoa were reanalyzed for DNA content for each ejaculate. These results confirm the high purity of flow sorted porcine X and Y sperm cells and the validity of reanalysis of DNA in determining the proportions of X- and Y-sorted spermatozoa from viewing thousands of individual sperm chromosomes directly using FISH.

Animals↗
PubMed1998

Birth of piglets preselected for gender following in vitro fertilization of in vitro matured pig oocytes by X and Y chromosome bearing spermatozoa sorted by high speed flow cytometry.

The present study examined the ability to establish pregnancies after transfer of pig embryos derived from in vitro fertilization (IVF) of in vitro matured (IVM) oocytes by X and Y chromosome-bearing spermatozoa sorted by flow cytometry. Cumulus-oocyte complexes (COC) were cultured in BSA-free NCSU-23 medium containing porcine follicular fluid (10%), cysteine (0.1 mg/mL), epidermal growth factor (10 ng/mL), LH (0.5 microgram/mL) and FSH (0.5 microgram/mL) for 22 h, then the oocytes were cultured without hormonal supplements for an additional 22 h. Boar semen was collected and prepared by flow cytometry sorting of X and Y chromosome bearing spermatozoa. After IVM, cumulus-free oocytes were co-incubated with sorted X or Y spermatozoa (2 x 10(4)/mL) for 6 to 7 h in modified Tris-buffered medium containing 2.5 mM caffeine and 0.4% BSA. After IVF, putative embryos were transferred to NCSU-23 medium containing 0.4% BSA for culture. A portion of the oocytes was fixed 12 h after IVF, the remainder were cultured up to 96 h. At 96 h after IVF, 8-cell to morula stage embryos (n = 30 to 35) from each gender were surgically transferred to the uterus of recipient gilts. Insemination of IVM pig oocytes with X- or Y-bearing sperm cells did not influence the rate of penetration (67 vs 80%), polyspermy (40 vs 53%), male pronuclear formation (95 vs 96%), or mean number of spermatozoa per oocyte (1.6 vs 1.6), respectively. Furthermore, no difference was observed between cleavage rates at 48 h after IVF (X, 49 vs Y, 45%). Transfer of embryos derived from X-bearing spermatozoa to 18 recipients resulted in 5 pregnancies and delivery of 23 females and 1 male piglet. Similarly, transfer of embryos derived from Y-bearing sperm cells to 10 recipients resulted in 3 pregnancies, with 9 male piglets delivered. The results show that X- and Y-bearing spermatozoa sorted using USDA sperm sexing technology can be successfully used in an IVM-IVF system to obtain piglets of a predetermined sex.

Animals↗