Seminal proteoforms from bulls with contrasting semen freezability: a story deciphered by top-down mass spectrometry.

Top-down proteomics was employed to construct proteoform atlas of sperm and seminal plasma (SP) from bulls with low (LF) and high (HF) semen freezability. Sperm and seminal proteins were fractionated by tandem size exclusion chromatography (< 30 kDa) and analyzed by reversed-phase liquid chromatography-tandem mass spectrometry. This approach enabled the identification of 299 SP (from 46 families) and 267 sperm proteoforms (from 139 families).

Sperm proteins ODF2 and PAWP as markers of fertility in breeding bulls.

Low fertility is the single most important factor limiting livestock reproductive performance, adversely affecting the cattle industry and causing millions of dollars of economic loss. In the livestock industry, male fertility is of crucial importance for the reproductive performance of livestock. However, there is a lack of reliable biomarkers to predict bull fertility in artificial insemination service.

Lipidomic markers of sperm cryotolerance in cattle.

The objective of the current study was to determine the fatty acid composition of sperm from Holstein bulls with different freezability (Good and Poor; n = 12). Fatty acids were extracted from frozen sperm in 1:2 (v/v) chloroform-methanol solvent, fractionated into neutral and polar fractions, and composition determined by gas chromatography-mass spectrometry. Thirty-four fatty acids were quantified and their concentrations and percentages within each lipid fraction were calculated.

Cellular and Functional Physiopathology of Bull Sperm With Altered Sperm Freezability.

The objective of this study was to ascertain the cellular and functional parameters as well as ROS related changes in sperm from bulls with varied sperm freezability phenotypes. Using principal component analysis (PCA), the variables were reduced to two principal components, of which PC1 explained 48% of the variance, and PC2 explained 24% of the variance, and clustered animals into two distinct groups of good freezability (GF) and poor freezability (PF). In ROS associated pathophysiology, there were more dead superoxide anion positive (Dead SO+) sperm in GF bulls than those in PF (15.

Protein signatures of seminal plasma from bulls with contrasting frozen-thawed sperm viability.

The present study investigated the seminal plasma proteome of Holstein bulls with low (LF; n = 6) and high (HF; n = 8) sperm freezability. The percentage of viable frozen-thawed sperm (%ViableSperm) determined by flow cytometry varied from -2.2 in LF to + 7.

Amino Acids of Seminal Plasma Associated With Freezability of Bull Sperm.

Sperm cryopreservation is an important technique for fertility management, but post-thaw viability of sperm differs among breeding bulls. With metabolites being the end products of various metabolic pathways, the contributions of seminal plasma metabolites to sperm cryopreservation are still unknown. These gaps in the knowledge base are concerning because they prevent advances in the fundamental science of cryobiology and improvement of bull fertility.

Sperm cellular and nuclear dynamics associated with bull fertility.

The objective of this study was to ascertain cellular characteristics and the dynamics of the sperm chromatin proteins protamine 1 (PRM1) and protamine 2 (PRM2) in the sperm of Holstein bulls having a different fertility status. Important sperm variables were analyzed using computer-assisted sperm analysis (CASA). Sperm membrane, acrosome status, DNA integrity were also assessed using propidium iodide (PI), fluorescein isothiocyanate conjugated to Arachis hypogaea (FITC-PNA), and acridine orange (AO) followed by flow cytometry.

Sperm miR-15a and miR-29b are associated with bull fertility.

MicroRNAs modulate male fertility by regulating gene expression. In this study, dynamics of sperm miR-15a, miR-29b and miR-34a from high fertility (HF) and low fertility (LF) bulls using RT-qPCR were evaluated. Bioinformatic tools were employed to ascertain genes of interest of the sperm miRNAs.

Retained Acetylated Histone Four in Bull Sperm Associated With Fertility.

Bull fertility, ability of the sperm to fertilize and activate the egg and support embryo development, is vital for cattle reproduction and production. Even though majority of histones are replaced by protamines, some histones are retained in sperm. It is known that chromatin remodeling during spermatogenesis results in dynamic changes in sperm chromatin structure through post-translational modifications (PTM) of sperm histones, which are important for regulation of gene expression.

Metabolomic markers of fertility in bull seminal plasma.

Metabolites play essential roles in biological systems, but detailed identities and significance of the seminal plasma metabolome related to bull fertility are still unknown. The objectives of this study were to determine the comprehensive metabolome of seminal plasma from Holstein bulls and to ascertain the potential of metabolites as biomarkers of bull fertility. The seminal plasma metabolome from 16 Holstein bulls with two fertility rates were determined by gas chromatography-mass spectrometry (GC-MS).

Sperm superoxide dismutase is associated with bull fertility.

Decreasing mammalian fertility and sperm quality have created an urgent need to find effective methods to distinguish non-viable from viable fertilising spermatozoa. The aims of the present study were to evaluate expression levels of ?-tubulin 2C (TUBB2C), heat shock protein 10 (HSP10), hexokinase 1 (HXK1) and superoxide dismutase 1 (SOD1) in spermatozoa from Holstein bulls with varying fertility using western blotting and to analyse the biological networks of these key sperm proteins using a bioinformatics software (Metacore; Thomson-Reuters, Philadelphia, PA, USA). The rationales behind this study were that the sperm proteins play crucial roles in fertilisation and early embryonic development in mammals and ascertaining the biological networks of the proteins helps us better understand sperm physiology and early mammalian development.

Sperm protamine-status correlates to the fertility of breeding bulls.

During fertilization, spermatozoa make essential contributions to embryo development by providing oocyte activating factors, centrosomal components, and paternal chromosomes. Protamines are essential for proper packaging of sperm DNA; however, in contrast to the studies of oocyte-related female infertility, the influence of sperm chromatin structure on male infertility has not been evaluated extensively. The objective of this study was to determine the sperm chromatin content of bull spermatozoa by evaluating DNA fragmentation, chromatin maturity/protamination, PRM1 protein status, and nuclear shape in spermatozoa from bulls with different fertility.

Molecular morphology and function of bull spermatozoa linked to histones and associated with fertility.

Sub-par fertility in bulls is influenced by alterations in sperm chromatin, and it might not be solved with increased sperm concentration in artificial insemination. Appropriate histone retention during sperm chromatin condensation plays critical roles in male fertility. The objective of this study was to determine failures of sperm chromatin condensation associated with abnormal persistence or accessibility of histones by aniline blue (ANBL) test, expression levels, and cellular localizations of one variant and two core histones (H3.

Dynamics of microRNAs in bull spermatozoa.

Background: MicroRNAs are small non-coding RNAs that regulate gene expression and thus play important roles in mammalian development. However, the comprehensive lists of microRNAs, as well as, molecular mechanisms by which microRNAs regulate gene expression during gamete and embryo development are poorly defined. The objectives of this study were to determine microRNAs in bull sperm and predict their functions.

Two-stage genome-wide association study identifies integrin beta 5 as having potential role in bull fertility.

Background: Fertility is one of the most critical factors controlling biological and financial performance of animal production systems and genetic improvement of lines. The objective of this study was to identify molecular defects in the sperm that are responsible for uncompensable fertility in Holstein bulls. We performed a comprehensive genome wide analysis of single nucleotide polymorphisms (SNP) for bull fertility followed by a second-stage replication in additional bulls for a restricted set of markers.

A triple-stain flow cytometric method to assess plasma- and acrosome-membrane integrity of cryopreserved bovine sperm immediately after thawing in presence of egg-yolk particles.

Simultaneously evaluating postthaw viability and acrosome integrity of spermatozoa by flow cytometry would provide a valuable testing tool in both research and routine work. In the present study, a new triple-stain combination was developed for the simultaneous evaluation of viability and acrosome integrity of bovine sperm processed in egg yolk-based extender by flow cytometer. SYBR-14 and propidium iodide (PI) enabled the discrimination of sperm cells from egg yolk and debris particles, which was instrumental for the flow cytometric analyses of frozen-thawed bovine sperm, because it implied that washing steps to remove egg yolk were no longer required.