Progressive motility refers to sperm’s forward movement, which is essential for male reproductive performance. The mechanism underlying the acquisition and maintenance of progressive motility is not yet clear. Thus, our aim was to examine the association between progressive motility and the metabolomic and lipidomic profiles of bovine the seminal fluid. Fresh ejaculates from 12 bulls were classified by computer-assisted sperm analysis as high (>74%), medium (60–74%), or low (<60%) progressive motility (HPM, MPM, and LPM, respectively). Then, seminal fluid was separated from the ejaculate and subjected to metabolomics (n = 4 samples per group) and lipidomic (n = 3 samples per group) analysis. Findings revealed differential contents of 58 metabolites, in particular between the HPM vs. LPM and between MPM vs. LPM seminal fluids. KEGG annotation identified several metabolic pathways potentially associated with progressive motility phenotypes, including arginine biosynthesis, arginine and proline metabolism, riboflavin metabolism, taurine and hypotaurine metabolismand beta-alanine metabolism. As a proof of concept, an in-vitro experiment was conducted with riboflavin; sperm incubation with 0.1, 1 or 10 µM riboflavin for 1 h enhanced the progressive motility of LPM sperm to some extent. Lipidomic analysis of the seminal fluid revealed 39 lipid species that differed between groups, with a main difference between HPM and MPM groups. In addition, glycerophosphocholines and phosphatidylcholines lipids were differentially expressed across HPM vs. LPM and HPM vs. MPM comparisons. The findings suggest an association between sperm progressive motility and the seminal fluid extracellular metabolites; these metabolites might serve as biomarkers for ejaculate quality.
Ovarian aging is a major factor contributing to the decline in egg production in laying hens, particularly during the late laying period. Female germline stem cells (FGSCs), which possess self-renewal and differentiation capacities, are considered important for replenishing the oocyte pool and maintaining ovarian function. However, the mechanisms regulating FGSC function during ovarian aging remain largely unknown. In this study, we investigated the role of glial cell line-derived neurotrophic factor (GDNF) in FGSC proliferation. We found that aged hens with high laying performance exhibited significantly greater FGSC abundance and higher ovarian expression of GDNF and its receptors, GFRα1 and RET, than low-laying hens. In vitro experiments further showed that GDNF significantly promoted FGSC proliferation. Transcriptome analysis revealed that GDNF treatment was associated with enhanced PI3K-Akt and mTOR signaling and reduced FoxO- and p53-related signaling, indicating a transcriptional shift toward cell proliferation and survival. Consistently, GDNF increased the expression of multiple proliferation-associated genes and significantly expanded endogenous FGSC populations in ovarian organ cultures. Collectively, these findings demonstrate that exogenous GDNF promotes FGSC proliferation, while higher GDNF expression is associated with greater FGSC abundance in high-laying aged hens. These results suggest that GDNF may contribute to FGSC maintenance by modulating signaling networks related to cell proliferation and survival, providing new insights into the cellular and molecular mechanisms underlying ovarian aging and reproductive decline in laying hens.
This study aimed to evaluate for the first time the protective effects of kappa-carrageenan (κ-carrageenan; CAR) on cryopreserved camel epididymal spermatozoa. To achieve this, we assessed post-thaw sperm motility, kinematic parameters, oxidative stress biomarkers, subcellular ultrastructure, apoptotic profiles, microbial load, and molecular docking interactions. Epididymal spermatozoa were harvested from 40 pairs of dromedary camel testes. The samples were cryopreserved using a freezing tris-SHOTOR extender alone (CAR0) or supplemented with κ-carrageenan (CAR) 0.25 (CAR0.25), or 0.5 (CAR0.5) mg/mL prior to cryopreservation via a standard protocol. Supplementation of the cryopreservation medium with CAR markedly preserved camel epididymal sperm viability, plasma membrane integrity, and motion kinetics post-equilibration, immediately after thawing, and following 2 h of incubation (P < 0.05). Notably, the CAR0.5 treatment improved key kinematic parameters specifically progressive motility, average path velocity (VAP), amplitude of lateral head displacement (ALH), and beat-cross frequency (BCF) while yielding lower wobble (WOB), linearity (LIN), and straightness (STR) values compared to the untreated control (P < 0.05). Additionally, CAR supplementation significantly increased the percentage of viable spermatozoa and reduced necrotic populations, with the CAR0.5 group demonstrating the most favorable outcomes (P < 0.05). Treatment with CAR also enhanced acrosome integrity and antioxidant defense mechanisms (TAC and catalase), while decreasing acrosomal damage and oxidative stress biomarkers (NO and malondialdehyde; P < 0.05). Transmission electron microscopy confirmed these protective effects on the acrosome, plasma membrane, and overall subcellular ultrastructure. Furthermore, all CAR-treated samples exhibited a significant reduction in total bacterial and coliform counts relative to the control (P < 0.05). In silico docking revealed weak-to-modest interactions between CAR and three target proteins ferritin, calmodulin-2 B, and the EF-hand calcium-binding domain-containing protein providing structural insights into potential binding mechanisms. Overall, κ-carrageenan improved post-thaw sperm quality, boosted antioxidant capacity, attenuated oxidative damage and declined microbial counts, and warrants further evaluation in fertility trials.
