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Developing a deeper understanding of biological components of sperm is essential to improving cryopreservation techniques and reproductive technologies. To fully ascertain the functional determinants of fertility, lipidomic methods have come to the forefront. Lipidomics is the study of the lipid profile (lipidome) within a cell, tissue, or organism and provides a quantitative analysis of the lipid content in that sample. Sperm cells are composed of various lipids, each with their unique contribution to the overall function of the cell. Lipidomics has already been used to find new and exciting information regarding the fatty acid content of sperm cells from different species. While the applications of lipidomics are rapidly evolving, gaps in the knowledge base remain unresolved. Current limitations of lipidomics studies include the number of available samples to analyze and the total amount of cells within those samples needed to detect changes in the lipid profiles across different subjects. The information obtained through lipidomics research is essential to systems and cellular biology. This review provides a concise analysis of the most recent developments in lipidomic research. This scientific resource is important because these developments can be used to not only combat the reproductive challenges faced when using cryopreserved semen and artificial reproductive technologies in livestock such as cattle, but also other mammals, such as humans or endangered species.

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. Overall, saturated fatty acids (SFA) were predominant, accounting for 71 to 80% of fatty acids in neutral and polar lipid factions. There were marked differences in fatty acid composition between the lipid fractions (P < 0.001). The branched chain fatty acid (BCFA) concentration (15 to 18 µg) was almost twice as much as polyunsaturated fatty acids (PUFA) concentration found in the polar lipid fraction (8 to 9 µg; P < 0.001). Sperm with different freezability phenotypes only had a few differences in 22:0, 18:1 cis 9, and 14:0 13-methyl fatty acids (P ≤ 0.011). These results are significant because they reveal key understandings of fatty acid composition of sperm membrane and lay a foundation for the manipulation of membrane integrity, fluidity, and stability to advance the assisted reproductive technologies.

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 (15.72 and 12.00%; P = 0.024), and that Dead SO+ and live hydrogen positive cells (live H2O2+) were positively correlated with freezability, respectively (R-2 = 0.55, P < 0.0130) and (r(s) = 0.63, P = 0.0498). Related to sperm functional integrity, sperm from PF bulls had greater dead intact acrosome (DIAC) than those from GF bulls (26.29 and 16.10%; P = 0.028) whereas sperm from GF bulls tended to have greater live intact acrosome (LIAC) than those from PF bulls (64.47 and 50.05%; P = 0.084). Sperm with dead reacted acrosome (DRAC) in PF bulls were greater compared to those in GF (19.27 and 11.48%; P = 0.007). While DIAC (R-2 = 0.56, P = 0.0124) and DRAC (R-2 = 0.57, P < 0.0111) were negatively correlated with freezability phenotype, LIAC (R-2 = 0.36, P = 0.0628) was positively correlated. Protamine deficiency (PRM) was similar between sperm from GF and PF bulls (7.20 and 0.64%; P = 0.206) and (r(s) = 0.70, P = 0.0251) was correlated with freezability. Sperm characteristics associated with cryotolerance are important for advancing both fundamental andrology and assisted reproductive technologies across mammals.

WOS: 000482983900001, PubMed: 31552277, Cryopreservation of semen and artificial insemination have an important, positive impact on cattle production, and product quality. Through the use of cryopreserved semen and artificial insemination, sperm from the best breeding bulls can be used to inseminate thousands of cows around the world. Although cryopreservation of bull sperm has advanced beyond that of other species, there are still major gaps in the knowledge and technology bases. Post-thaw viability of sperm is still low and differs significantly among the breeding bulls. These weaknesses are important because they are preventing advances both in fundamental science of mammalian gametes and reproductive biotechnology. Various extenders have been developed and supplemented with chemicals to reduce cryodamage or oxidative stress with varying levels of success. More detailed insights on sperm morphology and function have been uncovered through application of advanced tools in modern molecular and cell biology. This article provides a concise review of progress in the cryopreservation of bull sperm, advances in extender development, and frontiers using diverse techniques of the study of sperm viability. This scientific resource is important in animal biotechnology because with the advances in discovery of sperm fertility markers, there is an urgent need to improve post-thaw viability and fertility of sperm through enhanced cryopreservation for precision agriculture to produce food animals to ensure food security on the global scale., Mississippi Agricultural Forestry and Experiment Station, USAID through Sustainable Higher Education Research Alliance (SHERA) Program-Center for Collaborative Research Animal Biotechnology and Coral Reef Fisheries (CCR ANBIOCORE); Agriculture and Food Research Initiative Competitive Grant from the USDA National Institute of Food and Agriculture [2017-67016-26507]; Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK); Turkish Ministry of National EducationMinistry of National Education - Turkey, This study was funded in part by the Mississippi Agricultural Forestry and Experiment Station, USAID through Sustainable Higher Education Research Alliance (SHERA) Program-Center for Collaborative Research Animal Biotechnology and Coral Reef Fisheries (CCR ANBIOCORE), and by Agriculture and Food Research Initiative Competitive Grant no. 2017-67016-26507 from the USDA National Institute of Food and Agriculture. MH was funded through a competitive international postdoctoral fellowship by the Scientific and Technological Research Council of Turkey (TUBITAK). MU was funded by a competitive graduate fellowship from Turkish Ministry of National Education.

WOS: 000505610200030, PubMed: 31671225, 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. The expression levels of p53, BCL2, BAX and DNMT1 in bull spermatozoa were determined by immunoblotting. MicroRNA levels of miR-15a and miR-29 were higher in LF sires when compared with those present in HF bulls. Expression levels of miR-34a did not differ between the two groups. We found an inverse correlation between miR-15a and bull fertility. MiR29-b was also negatively associated with fertility scores. BCL2 and DNMT1 were higher in HF bulls while BAX was higher in the LF group. Our data showed a positive correlation between BCL2 and bull fertility. In addition, DNMT1 was positively associated with bull fertility. Furthermore, levels of BAX were negatively linked with bull fertility scores. Identification of miRNAs found in the spermatozoa of sires with different in vivo fertility helps understand the alterations in the fertilising capacity from cattle and other mammals. These potential biomarkers can be used in reproductive biotechnology as fertility markers to assess semen quality and predict male fertility., Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) of BrazilNational Council for Scientific and Technological Development (CNPq); Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) of BrazilCAPES; Higher Education Commission of Pakistan under International Research Support ProgramHigher Education Commission of Pakistan; Arab Republic of Egypt; The Republic of Turkey, Ministry of National Education, Directorate General for Higher and Foreign Education; Alta Genetics, Inc; Mississippi Agricultural Experiment Station

PubMed: 31785643, 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. In addition, abundances of PRM1 and PRM2 were analyzed using flow cytometry experiments. Differences in sperm decondensation capacity were assessed in bulls of varying fertility using a decondensation assay. As determined using CASA, average pathway velocity, amplitude of lateral head displacement and straightness were different (P < 0.05) for sperm from high and low fertility bulls. There, however, were no differences between the high and low fertility bulls for characteristics of sperm plasma membrane, acrosome, and DNA integrity (P > 0.05). Relative abundances of PRM1 and PRM2 in sperm from the high and low fertility bulls were inversely related (P < 0.0001). Percentages of decondensed sperm were different between high and low fertility bulls (P < 0.0001) and total numbers of decondensed sperm were greater in low fertility bulls than high fertility bulls (R2 = 0.72). Results of the present study are significant because molecular and morphological phenotypes of sperm that were detected affect fertility in livestock species., Conselho Nacional de Desenvolvimento Científico e Tecnológico Mississippi Agricultural and Forestry Experiment Station, Mississippi State University Conselho Nacional de Desenvolvimento Científico e Tecnológico Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Alabama Commission on Higher Education, The research was partially supported in part by Mississippi Agricultural and Forestry Experiment Station, Alta Genetics. Inc. , Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) of Brazil , Foundation for Research and Scientific Development of the State of Ceara , Brazil (FUNCAP) , and by Selcuk University, Konya, Turkey . NAK was funded by the Netaji Subhas-Indian Council of Agricultural Research for International Fellowships 2015–2017, India (NS-ICAR) . ESB Menezes was supported by a competitive fellowship from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) of Brazil . MRU was funded by the Turkish Ministry of National Education . Hazem ElDebaky, was funded by Arab Republic of Egypt . Asma Ul Husna was funded by Higher Education Commission of Pakistan under International Research Support Program. MR Ugur was founded by a competitive fellowship from Ministry of National Education of Turkey .