Impacts of Epigenetic Processes on the Health and Productivity of Livestock

The dynamic changes in the epigenome resulting from the intricate interactions of genetic and environmental factors play crucial roles in individual growth and development. Numerous studies in plants, rodents, and humans have provided evidence of the regulatory roles of epigenetic processes in health and disease. There is increasing pressure to increase livestock production in light of increasing food needs of an expanding human population and environment challenges, but there is limited related epigenetic data on livestock to complement genomic information and support advances in improvement breeding and health management. This review examines the recent discoveries on epigenetic processes due to DNA methylation, histone modification, and chromatin remodeling and their impacts on health and production traits in farm animals, including bovine, swine, sheep, goat, and poultry species. Most of the reports focused on epigenome profiling at the genome-wide or specific genic regions in response to developmental processes, environmental stressors, nutrition, and disease pathogens. The bulk of available data mainly characterized the epigenetic markers in tissues/organs or in relation to traits and detection of epigenetic regulatory mechanisms underlying livestock phenotype diversity. However, available data is inadequate to support gainful exploitation of epigenetic processes for improved animal health and productivity management. Increased research effort, which is vital to elucidate how epigenetic mechanisms affect the health and productivity of livestock, is currently limited due to several factors including lack of adequate analytical tools. In this review, we (1) summarize available evidence of the impacts of epigenetic processes on livestock production and health traits, (2) discuss the application of epigenetics data in livestock production, and (3) present gaps in livestock epigenetics research. Knowledge of the epigenetic factors influencing livestock health and productivity is vital for the management and improvement of livestock productivity.

Comparison of the structure of chinchilla sperm isolated from semen and from the tail of the epididymis

Sperm cells isolated from the tail of the epididymis and from the semen of the same individuals were analysed. The use of silver nitrate to stain sperm cells isolated from the tail of the epididymis made it possible to identify structures that were not visible in the sperm from semen. Silver nitrate very clearly distinguished the acrosomal and distal parts of the sperm head. Following silver nitrate staining, the sperm isolated from the tail of the epididymis were characterized by dark 'collars' in the distal part of the head. These 'collars' are not visible in the sperm cells isolated from semen. The results of the study indicate differences in the dimensions of sperm isolated from the tail of the epididymis and sperm in semen. Sperm isolated from the tail of the epididymis had smaller heads, despite their longer length, and had longer midpieces and tails than ejaculate sperm. Silver nitrate staining is a simple and fast technique. Silver nitrate makes it possible to identify the acrosome and post-acrosomal region of the sperm head and to clearly identify the midpiece. Therefore, it can be successfully used to supplement routine techniques for evaluating sperm morphology or as an independent technique.

The effect of the staining technique on morphological and morphometric parameters of boar sperm

Sperm morphology and morphometry are important parameters in predicting fertility. Sperm are considered to be normal if the shape and size of the head, midpiece and tail fall within the classification for a given species. It is important to select the appropriate technique for staining the semen of a given species, because, as many authors have pointed out, some methods work well for one species but are not suitable for analysing another. The aim of the study was to assess the morphometric parameters of boar sperm following the use of different staining techniques and to verify the hypothesis that the staining technique affects the morphometric parameters of sperm. The staining method was found to significantly affect the dimensions of the boar sperm head. The semen stained by the SpermBlue technique had the closest morphometric sperm head parameters to those of the unstained sperm, so this technique, rather than the routinely used eosin and gentian complex, should be the leading technique in the evaluation of boar sperm morphometry. Silver nitrate staining reveals the structure of the sperm in the most detail; this method can be considered universal, and can be used independently or to supplement routine diagnostics. As the staining technique should interfere as little as possible with the structure of the sperm, while revealing its morphology in as much detail as possible, it is crucial to establish the natural dimensions of the unstained sperm head before determining the optimal technique and its reference values. The recommended or most commonly-used techniques are not always the best options for the staining and analysis of sperm of a given species.

Cell Identity, Proliferation, and Cytogenetic Assessment of Equine Umbilical Cord Blood Mesenchymal Stromal Cells

The aim of the present work was to determine proliferation capacity, immunophenotype and genome integrity of mesenchymal stromal cells (MSCs) from horse umbilical cord blood (UCB) at passage stage 5 and 10. Passage 4 cryopreserved UCB-MSCs from six unrelated donors were evaluated. Immunophenotypic analysis of UCB-MSC revealed a cell identity consistent with equine MSC phenotype by high expression of CD90, CD44, CD29, and very low expression of CD4, CD11a/18, CD73, and MHC class I and II antigens. Proliferative differences were noted among the UCB-MSC cultures. UCB-MSCs karyotype characteristics at passage 5 (eg, 2n = 64; XY, or XX) included 20% polyploidy and 62% aneuploidy. At passage 10, the proportion of polyploidy and aneuploidy was 21% and 82%, respectively, with the increase in aneuploidy being significant compared with passage 5. Furthermore, conventional GTG-banded karyotyping revealed several structural chromosome abnormalities at both passage 5 and 10. The clinical relevance of such chromosome instability is unknown, but determination of MSC cytogenetic status and monitoring of patient response to MSC therapies would help address this question.

The use of two staining methods for identification of spermatozoon structure in roosters

Many of the methods used to stain semen result in very pronounced coloring of the sperm, but unfortunately they do not distinguish their individual structures, which play a key role in the fertilization process. Hence the aim of this study was to identify sperm structures using two staining techniques in the semen of roosters from breeding flocks. The subject of the study was the sperm of roosters from a Ross 308 breeding flock. To capture the differences in the dimensions of sperm subjected to the effect of different chemical substances in dyes, microscope slides were stained by two techniques: with an AgNO3 solution and by a differential method (eosin-nigrosin test). Assessment was made of the degree of coloration and the number of details that could be identified in the morphological structure of the sperm. The use of AgNO3 allowed accurate identification of the acrosome, nucleus, and midpiece, which were visible in the slides stained with eosin-nigrosin, but only in dead spermatozoa. The AGNO3 staining technique used in this study reveals the cell nucleus within the head and can be an alternative method to analysis with a scanning electron microscope. This staining technique can be used to stain sperm structures that cannot be seen in other methods of slide preparation, which means that it can be considered for routine use in assessing the fertility of roosters in breeder flocks.

Immunophenotypic characterisation and cytogenetic analysis of mesenchymal stem cells from equine bone marrow and foal umbilical cords during in vitro culture

Introduction: The objective of the study was immunophenotypic and cytogenetic analysis of mesenchymal stem cells from equine bone marrow and foal umbilical cords during in vitro culture.

Material and Methods: The mesenchymal stem cells were obtained from equine bone marrow of three horses and from foal umbilical cords of six foals. The cells were cultured in CO2 incubators by standard procedure. Quantitative abnormalities of chromosomes, i.e. aneuploidy and polyploidy, and structural aberrations, i.e. breaks in chromosomes and chromatid, were taken into account during the study.

Results: The results of cytogenetic analysis of equine bone marrow mesenchymal stem cells at the third and fourth passages indicated that the level of karyotype variability of these cells corresponded to the spontaneous level of karyotype variability typical of the peripheral blood lymphocytes of this species. Equine bone marrow contained several clones of stem cells that differed in the expression of specific nuclear markers characteristic of proliferating cells.

Conclusion: Mesenchymal stem cells from foal umbilical cords during in vitro cultivation are characterised by quantitative abnormalities of the chromosomal apparatus.