MicroRNAs (miRNAs) are endogenous ∼23 nt RNAs that play important gene-regulatory roles in animals and plants by pairing to the mRNAs of protein-coding genes to direct their posttranscriptional repression. This review outlines the current understanding of miRNA target recognition in animals and discusses the widespread impact of miRNAs on both the expression and evolution of protein-coding genes.

MicroRNAs: Target Recognition and Regulatory Functions

Redox regulation and oxidative stress have become areas of major interest in spermatology. Alteration of redox homeostasis is recognized as a significant cause of male factor infertility and is behind the damage that spermatozoa experience after freezing and thawing or conservation in a liquid state. While for a long time, oxidative stress was just considered an overproduction of reactive oxygen species, nowadays it is considered as a consequence of redox deregulation. Many essential aspects of spermatozoa functionality are redox regulated, with reversible oxidation of thiols in cysteine residues of key proteins acting as an “on–off” switch controlling sperm function. However, if deregulation occurs, these residues may experience irreversible oxidation and oxidative stress, leading to malfunction and ultimately death of the spermatozoa. Stallion spermatozoa are “professional producers” of reactive oxygen species due to their intense mitochondrial activity, and thus sophisticated systems to control redox homeostasis are also characteristic of the spermatozoa in the horse. As a result, and combined with the fact that embryos can easily be collected in this species, horses are a good model for the study of redox biology in the spermatozoa and its impact on the embryo.

https://www.mdpi.com/2076-3921/8/11/567/pdf

Redox Regulation and Oxidative Stress: The Particular Case of the Stallion Spermatozoa.

Sperm cryopreservation facilitates the storage and transport of germplasm for its use in artificial insemination (AI) and other advanced reproductive technologies. The cryopreservation process can damage sperm and compromise functionality. Several cryobiological studies have found that the physical and biological factors that affect sperm survival at low temperatures during the cryopreservation process often involve the integrity of sperm membrane. In this review, the behaviour of the sperm membrane against cooling, cold shock, ice crystal formation, oxidative stress, osmotic changes, reorganization of the lipid bilayer and addition of cryoprotective agents (CPA) is discussed. In addition, the phenomenon of reactive oxygen species (ROS) and its relationship with the cryopreservation process is also described. Semen cryopreservation techniques have progressed slowly in past years, and the current performance, measured as post-thawed survival, is not very different compared to past decades. Recent advances in understanding the structure of the cell membrane, its function and metabolism have driven to new conservation systems, including lyophilization and vitrification. However, none of these technologies is commercially available, although its future appears very promising.

Recent advances in bovine sperm cryopreservation techniques with a focus on sperm post-thaw quality optimization.

Almost 50% of infertility cases are associated with human male infertility. The sperm membrane is a key structure influencing sperm morphology and function in normal and pathological conditions. The fatty acid profile determines the performance not only of sperm motility but also of acrosomal reaction and sperm-oocyte fusion. This review presents available knowledge on the role of fatty acid composition in human sperm and spermatogenesis and discusses the influence of dietary fatty acids on the sperm fatty acid profile. Recent studies in biological sciences and clinical researches in this field are also reported. The topic object of this review has potential application in medicine by identifying potential causes of infertility.

https://downloads.hindawi.com/journals/omcl/2020/7038124.pdf

Relevance of Fatty Acids to Sperm Maturation and Quality

Many of the readers of Food Security may find themselves being critical of animal science in the context of food security and sustainability, rather than trying to see what animal science research can contribute to this area of study. After all, food animals are implicated in rain forest destruction, water pollution and greenhouse gas emissions (methane emissions in particular have been emphasised). Also, it is argued that land used to produce feed for animals could be used to produce food for humans instead, and that excessive consumption of animal products is harmful to human health. The emphasis in sustainability debates has therefore tended to be on advocating reduced meat consumption (and more rarely, reduced consumption of dairy products). Why then should readers of Food Security be interested in this book? Many will argue that food animals have an important role in food security, although it is not the place of this review to make those arguments. Suffice to mention that key arguments advanced include the ability of animals to convert grass and waste products not usable by humans into valuable sources of protein, the role of grazing animals in maintaining biodiversity, the role of manure in maintaining soils and the ability of food animals to sustain rural livelihoods in marginal areas. Whatever the case, the premise of this book is the often quoted statistic that global demand for animal products is predicted to almost double by 2050. This book is one of a series of expert reports produced by the USNational Research Council, and their website indicates that one of its intentions is informing government policies. It is a result of the deliberations of an ad hoc Committee of ten specialists, including animal scientists but also specialists in nutrition, human-environment relationships, human and veterinary medicine and aquaculture, plus representation from industry. This group was tasked with evaluating animal agriculture research needs in order to meet future global demand for animal products, in the face of climate change and limited natural resources. Examining these underlying assumptions was explicitly excluded from the remit. The book covers a huge range of subjects, including breeding and genetics, nutrition, and animal health and welfare, as well as emphasising socioeconomic considerations and integration of research areas. It is refreshing to see aquaculture included, as this is often left out of such discussions. A particularly interesting aspect of the coverage is the Committee’s reflections on the need for trained human capital and infrastructure. Some of the recommendations relate to production orientation, for example understanding animal nutrient metabolism. Others are more systems oriented, for example identifying alternative animal feed ingredients from human food waste, biofuels and industrial production processes. Animal welfare research and identifying alternatives to the use of antibiotics are also mentioned. Research related to climate change includes both adaptation to the effects of climate change and a better understanding of greenhouse gas emissions from animal agriculture. The book doesn’t shy away from considering some of the more controversial aspects of animal agriculture, such as genetic modification, the use of growth-promoting feed additives such as beta-agonists, and irradiating meat to kill potential pathogens. But in a book of this kind, none of these issues can be covered in depth. As well as identifying the research needs of the United States, global needs are also given a chapter, with an emphasis * Ann Bruce ann.bruce@ed.ac.uk

/pdf/critical-role-of-animal-science-research-in-food-security-3kcm23y2bg.pdf

Critical role of animal science research in food security and sustainability

Seminal plasma (SP), the non-cellular component of semen, is a heterogeneous composite fluid built by secretions of the testis, the epididymis and the accessory sexual glands. Its composition, despite species-specific anatomical peculiarities, consistently contains inorganic ions, specific hormones, proteins and peptides, including cytokines and enzymes, cholesterol, DNA and RNA-the latter often protected within epididymis- or prostate-derived extracellular vesicles. It is beyond question that the SP participates in diverse aspects of sperm function pre-fertilization events. The SP also interacts with the various compartments of the tubular genital tract, triggering changes in gene function that prepares for an eventual successful pregnancy; thus, it ultimately modulates fertility. Despite these concepts, it is imperative to remember that SP-free spermatozoa (epididymal or washed ejaculated) are still fertile, so this review shall focus on the differences between the in vivo roles of the SP following semen deposition in the female and those regarding additions of SP on spermatozoa handled for artificial reproduction, including cryopreservation, from artificial insemination to in vitro fertilization. This review attempts, including our own results on model animal species, to critically summarize the current knowledge of the reproductive roles played by SP components, particularly in our own species, which is increasingly affected by infertility. The ultimate goal is to reconcile the delicate balance between the SP molecular concentration and their concerted effects after temporal exposure in vivo. We aim to appraise the functions of the SP components, their relevance as diagnostic biomarkers and their value as eventual additives to refine reproductive strategies, including biotechnologies, in livestock models and humans.

/pdf/seminal-plasma-relevant-for-fertility-28o74mqan7.pdf

Seminal Plasma: Relevant for Fertility?

Seasonal changes in the sperm fatty acid composition of Shetland pony stallions.

Reproductive biotechnologies have been developed for routine, microbiologically-safe propagation of genetic material among breeding populations. Moreover, they also shorten generation intervals and allow for selection of specific traits in a given population. Semen still is the “cheapest” component of artificial breeding. Therefore, AI is the most prevalent reproductive biotechnology used on a global scale and, depending on the species, requires the preparation of liquid, chilled, or frozenthawed insemination doses (Rodriguez-Martinez, 2012a). Consequently, research efforts still focus on improving the quality of sperm exposed to manipulations required during their preparation for AI, especially the ones associated with sperm cryobiology. Successful freezing of semen from of all livestock is a high priority due to its numerous advantages including biosecurity and disease monitoring, conservation of specific genetics, and global commercialization of superior genotypes. Cryopreservation success is linked not only to acceptable survival and lifespan post-thaw, but also to acceptable fertility after AI. If fertility levels with frozen semen are ever going to be similar to those with fresh semen, then a holistic approach for improving semen processing technologies must be used. This requires a critical assessment of semen and sperm function. Semen is heterogeneous population of sperm bathed in seminal plasma of heterogeneous composition (Rodriguez-Martinez et al., 2011). The spermatozoa in semen have the following unique characteristics that need to be considered during their manipulation: 1) their head contains substantially less free water than their neck and tail segments (Morris et al., 2012); 2) they use both anaerobic glycolysis and aerobic respiration for energy production (Silva and Gadella, 2006); 3) their plasma membrane contains water channels including glycerol-transporting aquaglyceroporins (Ekwall, 2007); and Semen technologies in domestic animal species

Semen technologies in domestic animal species

http://liu.diva-portal.org/smash/get/diva2:433995/FULLTEXT01.pdf

Effect of Different Extenders and Seminal Plasma on the Susceptibility of Equine Spermatozoa to Lipid Peroxidation After Single-Layer Centrifugation, Through Androcoll-E

Fernando Juan Peña Vega

Papers

Seminal Plasma: Relevant for Fertility?

Seasonal changes in the sperm fatty acid composition of Shetland pony stallions.

Semen technologies in domestic animal species

Effect of Different Extenders and Seminal Plasma on the Susceptibility of Equine Spermatozoa to Lipid Peroxidation After Single-Layer Centrifugation, Through Androcoll-E

Sperm Susceptibility to Oxidative Stress in the Retuertas Endangered Horse