Embryo-maternal communication mediated by extracellular vesicles in the early stages of embryonic development is modified by in vitro conditions

Extracellular vesicles (EVs) have become important in embryo-maternal communication during early development. The aim of this study was to evaluate the effect of an in vitro system on early bidirectional embryo-maternal communication mediated by EVs. For this purpose, two experiments were performed: one to evaluate the effect of embryonic EVs on maternal cells and the second to determine the effect of maternal EVs on early embryonic development. For the first in vitro (IVP) and in vivo (IVV) experiments, bovine blastocysts were selected and individually cultured for 48 h to collect embryonic EVs secreted during days 7-9 of embryonic development. Embryonic EVs were added to the medium of in vitro-cultured bovine endometrial cells to evaluate their effect on the expression pattern of genes associated with endometrial function and response to interferon tau (IFNT). Non-classical interferon-stimulated genes (ISGs) were only induced by in vitro-derived embryos. In the second experiment, EVs released by endometrial cells cultured in vitro (EVC) and collected from uterine fluid (EV-UF) of cows in the early luteal phase were added to the culture medium of bovine embryos produced in vitro during days 5-9 of development. The effect of maternal in vitro or in vivo-derived EVs differs in the quality of bovine embryos produced in vitro during the pre-implantation period. The expression of IFNT in bovine embryos is increased by the effect of EV-UF treatment. Additionally, EV-UF treatment induces a sustained increase in diameter during embryonic development and a tendency towards a greater number of expanded and hatched blastocysts. However, some genes related to embryo quality are induced by EVC treatment.

Bridging the Gap: Animal Models in Next-Generation Reproductive Technologies for Male Fertility Preservation

This review aims to explore advanced reproductive technologies for male fertility preservation, underscoring the essential role that animal models have played in shaping these techniques through historical contexts and into modern applications. Rising infertility concerns have become more prevalent in human populations recently. The surge in male fertility issues has prompted advanced reproductive technologies, with animal models playing a pivotal role in their evolution. Historically, animal models have aided our understanding in the field, from early reproductive basic research to developing techniques like artificial insemination, multiple ovulation, and in vitro fertilization. The contemporary landscape of male fertility preservation encompasses techniques such as sperm cryopreservation, testicular sperm extraction, and intracytoplasmic sperm injection, among others. The relevance of animal models will undoubtedly bridge the gap between traditional methods and revolutionary next-generation reproductive techniques, fortifying our collective efforts in enhancing male fertility preservation strategies. While we possess extensive knowledge about spermatogenesis and its regulation, largely thanks to insights from animal models that paved the way for human infertility treatments, a pressing need remains to further understand specific infertility issues unique to humans. The primary aim of this review is to provide a comprehensive analysis of how animal models have influenced the development and refinement of advanced reproductive technologies for male fertility preservation, and to assess their future potential in bridging the gap between current practices and cutting-edge fertility techniques, particularly in addressing unique human male factor infertility.

Effects of recombinant FSH (bscrFSH) and pituitary FSH (FSH-p) on embryo production in superovulated dairy heifers inseminated with unsorted and sex-sorted semen

Superovulation is a drug-based method used in cattle to stimulate the ovarian folliculogenesis and the number of oocytes and transferable embryos. The present study aimed to test the effects of recombinant FSH (bscrFSH) and pituitary FSH (FSH-p) on ovarian response and in vivo embryo production in superovulated dairy heifers inseminated with unsorted and sex-sorted semen. Forty healthy Holstein heifers subjected to a superovulation (SOV) protocol by using FSH-p or bscrFSH were divided randomly into four groups: a) FSH-p inseminated with unsorted semen (USP; n = 10), b) FSH-p inseminated with sex-sorted semen (SSP; n = 10), c) bscrFSH inseminated with unsorted semen (USR; n = 10), and d) bscrFSH inseminated with sex-sorted semen (SSR; n = 10). Ultrasonography was carried out on Day 8 (estrus) and Day 15 (embryo collection) to evaluate the ovarian structures [follicles (FL), corpora lutea (CL), and non-ovulated follicles (NOFL)]. Embryonic-derived parameters were scored on Day 15 [total structures collected (TS), unfertilised oocytes (UFOs), total embryos (TEs), transferable embryos (TFEs), freezable embryos (FEs), and degenerated embryos (DEs)]. No differences were observed regarding ovarian structures (FL and NOFL) irrespective of SOV protocol or group assessed (P > 0.05). CL increased in bscrFSH-derived SOV protocol (P < 0.05). On Day 15, the embryonic-derived parameters TEs, TFEs, and FEs decreased in SSP/SSR compared to USP/USR (P < 0.05). Differences were observed regarding UFOs, with a greater number in SSP and SSR (P = 0.01). In conclusion, the bscrFSH-derived SOV protocol showed improved results compared to FSH-p-derived SOV protocol regarding ovarian (CL) and embryo-derived (TFE) parameters irrespective of the type of semen used.

Genomic Analysis, Progress and Future Perspectives in Dairy Cattle Selection: A Review

Genomics comprises a set of current and valuable technologies implemented as selection tools in dairy cattle commercial breeding programs. The intensive progeny testing for production and reproductive traits based on genomic breeding values (GEBVs) has been crucial to increasing dairy cattle productivity. The knowledge of key genes and haplotypes, including their regulation mechanisms, as markers for productivity traits, may improve the strategies on the present and future for dairy cattle selection. Genome-wide association studies (GWAS) such as quantitative trait loci (QTL), single nucleotide polymorphisms (SNPs), or single-step genomic best linear unbiased prediction (ssGBLUP) methods have already been included in global dairy programs for the estimation of marker-assisted selection-derived effects. The increase in genetic progress based on genomic predicting accuracy has also contributed to the understanding of genetic effects in dairy cattle offspring. However, the crossing within inbred-lines critically increased homozygosis with accumulated negative effects of inbreeding like a decline in reproductive performance. Thus, inaccurate-biased estimations based on empirical-conventional models of dairy production systems face an increased risk of providing suboptimal results derived from errors in the selection of candidates of high genetic merit-based just on low-heritability phenotypic traits. This extends the generation intervals and increases costs due to the significant reduction of genetic gains. The remarkable progress of genomic prediction increases the accurate selection of superior candidates. The scope of the present review is to summarize and discuss the advances and challenges of genomic tools for dairy cattle selection for optimizing breeding programs and controlling negative inbreeding depression effects on productivity and consequently, achieving economic-effective advances in food production efficiency. Particular attention is given to the potential genomic selection-derived results to facilitate precision management on modern dairy farms, including an overview of novel genome editing methodologies as perspectives toward the future.

Differential role of r-met-hu G-CSF on male reproductive function and development in prepubertal domestic mammals

The understanding of mammalian spermatogenesis niche factors active during sexual development may be leveraged to impact reproduction in farm animals. The aim of this study was to evaluate the effects of r-met-hu/G-CSF (filgrastim) on prepubertal sexual development of guinea pigs (Cavia porcellus) and ram lambs (Ovis aries). Individuals of both species were administered r-met-hu/G-CSF daily for 4 days. During and after administration protocols, testicular function and development were assessed through hematological responses, hormonal profiles (gonadotropins, testosterone and cortisol) testicular morphometry and germ cell kinetics. As expected, r-met-hu/G-CSF acutely mobilized white-lineage blood cells in both species. LH was increased by r-met-hu/G-CSF in guinea pigs (P<0.01) but T remained unchanged. In ram lambs gonadotropins and T increased in dose-response fashion (P<0.01) while cortisol values were stable and similar in treated and control animals (P>0.05). In guinea pigs there were no differences in testicular weights and volumes 2-mo after r-met-hu/G-CSF application (P>0.05). However, ram lambs showed a dose-response effect regarding testis weight (P<0.05). 66.66% of ram lambs had initial testes not yet in meiosis or starting the first spermatogenic wave. After 60-days only 25% of control animals were pubertal while all treated animals (1140-μg) had reached puberty. We propose an integrated hypothesis that G-CSF can stimulate spermatogenesis through two possible ways. 1) r-met-hu/G-CSF may go through the brain blood barrier and once there it can stimulate GnRH-neurons to release GnRH with the subsequent release of gonadotrophins. 2) a local testicular effect through stimulation of steroidogenesis that enhances spermiogenesis via testosterone production and a direct stimulation over spermatogonial stem cells self-renewal. In conclusion, this study shows that r-met-hu/G-CSF differentially affects prepubertal sexual development in hystricomorpha and ovine species, a relevant fact to consider when designing methods to hasten sexual developmental in mammalian species.