Porcine sperm binding to oviduct cells and glycans as supplements to traditional laboratory semen analysis1

Abstract

Accurate semen evaluation is necessary to maintain high reproductive efficiency but difficult to accomplish. The objective was to determine if the ability to bind oviduct cells or oviduct glycans are useful supplements to traditional semen analyses. Measuring binding to specific soluble glycans is less laborious than assessing binding to oviduct cell aggregates and more suitable for routine use. Previous work has shown that sperm binding to oviduct cells improves fertility prediction, possibly by estimating the ability of sperm to form an oviduct reservoir. The two oviduct glycan motifs, biantennary 6-sialylated N-acetyllactosamine (bi-SiaLN) and Lewis X trisaccharide (Le X), that bind boar spermatozoa with high affinity and specificity were tested. Semen from 30 boars was shipped overnight for laboratory analysis and for inseminations to determine fertility (n = 3 replicates). Oviduct cell binding and traditional sperm analyses including motility and morphology were completed. Additionally, binding to soluble fluoresceinated glycans bi-SiaLN, sulfated Le X (suLe X), and the control lactosamine disaccharide (LacNAc) was measured. Inseminations were at 15 farms (>50 matings per boar) in the Midwest and farrowing data from all matings were used. Pregnancy rate (PR) and litter size (LS) were adjusted to account for different farms, number of services, number of doses inseminated, and sow parity, using the MIXED procedure in SAS 9.4. A fertility index (FI) was generated, consisting of PR × LS, to estimate boar overall fertility. Finally, the GLMSELECT procedure was used to select variables having a significant impact on PR, LS, and FI. The predictive models constructed were further analyzed using the REG procedure and accounted for 58% or more of the variation in PR, LS, and FI [PR (P < 0.001, r 2 = 0.60), LS (P < 0.001, r 2 = 0.58), and FI (P < 0.001, r 2 = 0.63)]. The final model for PR includes oviduct cell binding as well as boar age, % distal droplets, head morphology, tail morphology, beat/cross frequency, and curvilinear velocity. The final model for LS includes boar age, % distal droplets, tail morphology, and overall morphology. Finally, the FI model included boar age, % distal droplets, head morphology, tail morphology, curvilinear velocity, and semen volume per ejaculate. Although binding to intact oviduct cells was impactful as a means to predict PR, binding to specific soluble oviduct glycans was not a useful supplement to traditional semen analysis.

The role of semen and seminal plasma in inducing large-scale genomic changes in the female porcine peri-ovulatory tract

“…Considerable novel evidence supports the involvement of glycans in oviductal sperm colonization 39 which includes the role played N-and O-linked glycans found in oviduct epithelial cells that, by binding specific receptors found in the sperm head membrane 40 , aid establishing the tubal reservoir in the pig 41 . Sperm binding to oviduct cells via glycans have been even proposed as additional biomarkers for semen analysis 42 . At 24 hours after semen deposition, ST3GAL5, MAN1C1, B4GALT1 and MAN2A1, which encode enzymes that modify already syntesized N-linked and/or O-linked glycans by adding or removing a single monosaccharide, were upregulated in the Isthmic segment after Mating and P1-AI treatments respectively.…”

New insights into molecular aspects of sperm–oviductal binding in Egyptian buffaloes using anin vitromodel: Effects of oviductal segments and media

“…In vitro sperm attachment to oviduct cell explants has been reported as a model for studying the sperm–oviduct interaction in different animals: bovine (Dutta et al., 2019), swine (Winters et al., 2018) and equine (Lefebvre & Samper, 1993). For successful fertilisation, the spermatozoa must overcome several in vivo physiological barriers.…”

A Higher Abundance of O-Linked Glycans Confers a Selective Advantage to High Fertile Buffalo Spermatozoa for Immune-Evasion From Neutrophils

“…The glycans present on the sperm surface assist the sperm in evading the immune response, mounted against these allogenic cells in response to insemination ( 3 , 14 , 20 , 21 ). In the uterus, the entry of the spermatozoa triggers a massive influx of leukocytes, mainly the neutrophils (PMNs) into its lumen ( 22 ).…”