BACKGROUND: At present, several cross-sectional studies have found that exposure to metal/metalloid elements is closely associated with male reproduction. However, the long-term effects of metal exposure on male reproduction have not been explored.
METHODS: In 2013, 796 volunteers were recruited, followed by first and second follow-ups in 2014 and 2015. Urine, semen, and blood samples were collected at each stage to examine urinary metal/metalloid levels, sperm parameters, and sex hormones. Initially, the latent class trajectory model (LCTM) was utilized to analyze the trajectories of urinary metals. Subsequently, the effects of urinary metal trajectories on semen parameters and sex hormones were examined using the linear mixed model. Finally, the impact of urinary metal trajectories on the classification of semen quality (normal or abnormal) was evaluated using the generalized linear mixed model.
RESULTS: Among the 18 metals/metalloids studied, trajectories were formed by 6 of them (Li, Al, Fe, Zn, As, Rb). Further analysis using the linear mixed model and the generalized linear mixed model revealed that Li was negatively correlated with semen volume, and sperm motility (P<0.05). The maximum-decreasing trajectory group had a detrimental effect on semen quality (OR=1.75, 95%CI: 1.22, 2.53) compared to the minimum-stable trajectory group. Al showed negative associations with sperm concentration, total sperm count, and normal morphology (P<0.05). Rb was positively associated with progressive motility (P<0.05). The high-stable trajectory group exhibited a protective effect on semen quality (OR=0.66, 95%CI: 0.49, 0.90) compared to the low-stable trajectory group. Additionally, Fe was observed to have a negative relationship with follicle-stimulating hormone (FSH) (P<0.05), and Rb exhibited a negative correlation with progesterone (P) (P<0.05).
CONCLUSIONS: Our three-year cohort study provides new evidence that Li and Al have a negative impact on semen quality, whereas Rb is associated with beneficial effects. Additionally, Rb and Fe are endocrine disruptors of sex hormones.

Assessing canine semen quality helps to detect infertility in males, but identifying factors that influence canine semen quality is a complicated task. The objective of this study was the assessment of the potential influence of bacteria found in canine semen samples on the characteristics of dogs\' semen. In this study, semen samples were collected manually from 30 dogs and subjected to a comprehensive examination. The results of sperm motility, concentration, viability, and morphology were statistically analysed in relation to the number of bacteria in the semen (CFUs/mL) and the seminal microbiota. Samples with an increased bacterial count per millilitre were associated with lower-quality sperm motility (p < 0.05). The most frequently isolated bacterial genera from the analysed semen samples were Staphylococcus spp. (26.0%), Corynebacterium spp. (17.8%), and Streptococcus spp. (16.4%). The presence of β-haemolytic Escherichia coli bacteria was linked to suboptimal semen samples, characterised by significantly reduced semen viability and a lower proportion of morphologically normal spermatozoa (p < 0.05). Corynebacterium spp. was associated with reduced bacterial load and superior semen quality (p < 0.01). These findings highlight the importance of bacterial cell counts and microbiota diversity in relation to various factors influencing canine semen quality, providing a more comprehensive understanding of canine reproductive well-being.

UNASSIGNED: The global prevalence of infertility is 9%, with male factors potentially accounting for 40% to 60% of cases. Conventional treatments can be ineffective, invasive, costly, and linked to adverse effects and high risks. Previous studies have shown that, Chinese herbal medicine (CHM) can regulate the hypothalamus-pituitary-testis axis, improve sperm abnormalities and quality, mitigate oxidative stress, and decrease DNA fragmentation index (DFI). Yet, the evidence backing the use of Chinese herbal medicine (CHM) for treating male factor infertility lacks conviction due to study design limitations, and there remains a scarcity of studies on the live birth rate following CHM treatment for male factor infertility. Here, we describe the rationale and design of a randomized waitlist-controlled trial to evaluate the effect of CHM on the live birth rate among males with infertility.
UNASSIGNED: This study is a single-center, randomized, waitlist-controlled study. A total of 250 couples diagnosed with male factor infertility will be enrolled in this study and then randomly allocated into two groups in a 1:1 ratio. Male participants in CHM group (treatment group) will receive CHM once a day for 3 months. Male participants in the waitlist group (control group) will not receive any treatment for 3 months. After 3 months, participants in both groups need to be followed up for another 12 months. The primary outcome will be the live birth rate; secondary outcomes include semen quality parameters, DFI and pregnancy related outcomes. Safety will also be assessed.
UNASSIGNED: The purpose of this trial is to explore the effects and safety of CHM on the live birth rate among couples dealing with male factor infertility. The outcome of this trial may provide a viable treatment option for male factor infertility.
UNASSIGNED: Chinese Clinical Trial Registry: ChiCTR2200064416. Registered on 7 October 2022, https://www.chictr.org.cn.

The purpose of this study was to determine the impact of an antimicrobial peptide, BiF2_5K7K, on semen quality and bacterial contamination in boar semen doses used for artificial insemination. A key factor affecting semen quality and farm production is bacterial contamination in semen doses. Using antibiotics in a semen extender seems to be the best solution for minimizing bacterial growth during semen preservation. However, concern regarding antibiotic-resistant microorganisms has grown globally. As a result, antimicrobial peptides have emerged as interesting alternative antimicrobial agents to replace the current antibiotics used in semen extenders. BiF2_5K7K is an antimicrobial peptide that can inhibit Gram-negative and Gram-positive bacteria isolated from boar semen and sow vaginal discharge. In this study, ten fresh boar semen samples were collected and diluted with one of two types of semen extender: with (positive control) or without (negative control) an antibiotic (i.e., gentamicin). The semen extender without an antibiotic contained antimicrobial peptide BiF2_5K7K at different concentrations (15.625, 31.25, 62.5, and 125 µg/mL). The samples were stored at 18 °C until use. Semen quality parameters were assessed on days 0, 1, 3, and 5, and the total bacterial count was also evaluated at 0, 24, 36, 48, and 72 h after storage. A fertility test on a pig farm was also performed via sow insemination with a commercial extender plus BiF2_5K7K at a concentration of 31.25 µg/mL. No significant difference was found in terms of semen quality on days 0 or 1. On days 3 and 5, the total motility, progressive motility, and viability remained normal in the 15.625 and 31.25 µg/mL groups. However, the sperm parameters decreased starting on day 3 for the 125 µg/mL group and on day 5 for the 62.5 µg/mL group. For total bacterial count at 0, 24, 36, 48, and 72 h, the lowest bacterial count was found in the positive control group, and the highest bacterial count was found in the negative control group compared with the other groups. Comparing antimicrobial peptide groups from 0 to 48 h, the lowest bacterial count was found in the 125 µg/mL group, and the highest bacterial count was found in the 15.625 µg/mL group. For the fertility test, artificial insemination was conducted by using a commercial extender plus BiF2_5K7K at a concentration of 31.25 µg/mL. The results showed a superior pregnancy rate, farrowing rate, and total number of piglets born compared with artificial insemination conducted using a commercial extender plus antibiotic. In conclusion, BiF2_5K7K can inhibit bacterial growth in extended boar semen for 24 h, and thereafter, the bacterial count slightly increases. However, the increase in the number of bacterial counts from days 0 to 3 had no negative effect on sperm quality in the positive control, 15.625, or 31.25 µg/mL groups. This indicates that BiF2_5K7K might be an antimicrobial peptide candidate with potential for use as an alternative antimicrobial agent to replace the conventional antibiotic used in boar semen extenders.

OBJECTIVE: The impact of air pollution on semen quality has been confirmed, yet the joint effect remains unclear. We evaluate the individual and joint associations of particulate (PM2.5 and PM10) and gaseous pollutants (NO2, SO2, O3 and CO) with semen quality.
METHODS: We included 5,114 men in this study from 2014 to 2022. The individual and joint associations were measured by multiple linear regression models.
RESULTS: Sperm motility and semen volume were inversely associated with pollutant concentrations during every stage of sperm development, especially at lag days 0-9 and 10-14 (all P < 0.05). Stratified analyses showed that the study pollutants (except CO) had a positive effect on semen concentration during the stage of sperm development, especially in spring and autumn, while a decreased total sperm number was associated with CO (all P < 0.05). However, joint associations of particulate and gaseous pollutants with semen quality parameters were not statistically significant (all P > 0.05).
CONCLUSIONS: During all stages of sperm development, particulate and gaseous pollutants had individual negative impacts on sperm motility and semen volume, and these impacts were less pronounced in spring and autumn. Our findings highlight the importance and necessity of reducing the exposure to pollutants especially in the critical stage of sperm development to improve semen quality.

Coronavirus disease 2019 (COVID-19) has been reported to decrease semen quality in reproductive-age men. Semen quality in vaccinated men after SARS-CoV-2 infection remains unclear. We recruited reproductive-age Chinese men scheduled for COVID-19 vaccination from December 2022 to March 2023. Among 1,639 vaccinated participants, an upward trend was found in sperm concentration (p < .001), progressive motility (p < .001), total motility (p < .001), total motile sperm count (TMSC) (p < .001), and normal morphology (p = .01) over time following COVID-19 recovery. Among men with an SARS-CoV-2 infection that lasted less than 30 days, men who received an inactivated vaccine booster had higher sperm progressive (p = .006) and total motility (p = .005) as well as TMSC (p = .008) than those without a booster vaccine, whereas no difference was found in semen parameters among men who received a recombinant protein vaccine. Similarly, an upward trend in semen quality was found among 122 men who provided semen samples before and after COVID-19. Higher risks of asthenozoospermia (odds ratio [OR] = 2.23, p < .001) and teratozoospermia (OR = 2.09, p = .03) were found among men who had an SARS-CoV-2 infection that lasted less than 30 days than among those without COVID-19. Collectively, after receiving SARS-CoV-2 vaccination, adverse but reversible semen parameters were observed in men recovering from COVID-19 over time. Recombinant protein vaccines and inactivated vaccine boosters should be recommended to all reproductive-age men.

This study aimed to assess the ten-year trend in semen quality among couples referred to the Infertility Center in Kerman between 2008 and 2017. The study included 2952 semen samples from men 18 to 60 years old referred to the infertility center as infertile couples living in Kerman province, Iran, whether they had normal or abnormal semen analysis. A total of 2952 sperm samples were included. Statistically significant changes were observed in semen parameters. Particularly, significant changes were observed for volume (-0.08 mL/year), sperm concentration (-2.34 (mio/mL)/year), total sperm count (-13.17 (mio/ejaculate)/year), progressive motility (-2.62%/year), non-progressive motility (-0.59%/year), immotile sperm (2.49%/year), and normal morphology (-0.134%/year). In bivariate analysis, the prevalence of oligozoospermia in this study showed a statistically significant association with age (OR = 1.019; 95% CI = 1.007-1.032; p = 0.003). Likewise, there was a statistically significant association with the year (OR = 1.087; 95% CI = 1.050-1.125; p = 0.000). Semen quality parameters showed a downtrend during the last 10 years in this study, emphasizing the importance of male reproductive health monitoring and warning public health coordinators to pay more attention to this important issue.

Semen quality is an important indicator that can directly affect fertility. In mammals, miRNAs in seminal plasma extracellular vesicles (SPEVs) and sperms can regulate semen quality. However, relevant regulatory mechanism in duck sperms remains largely unclear. In this study, duck SPEVs were isolated and characterized by transmission electron microscopy (TEM), western blot (WB), and nanoparticle tracking analysis (NTA). To identify the important molecules affecting semen quality, we analysed the miRNA expression in sperms and SPEVs of male ducks in high semen quality group ((DHS, DHSE) and low semen quality group (DLS, DLSE). We identified 94 differentially expressed (DE) miRNAs in the comparison of DHS vs. DLS, and 21 DE miRNAs in DHSE vs. DLSE. Target genes of SPEVs DE miRNAs were enriched in ErbB signaling pathway, glycometabolism, and ECM-receptor interaction pathways (P < 0.05), while the target genes of sperm DE miRNAs were enriched in ribosome (P < 0.05). The miRNA-target-pathway interaction network analyses indicated that 5 DE miRNAs (miR-34c-5p, miR-34b-3p, miR-449a, miR-31-5p, and miR-128-1-5p) targeted the largest number of target genes enriched in MAPK, Wnt and calcium signaling pathways, of which FZD9 and ANAPC11 were involved in multiple biological processes related to sperm functions, indicating their regulatory effects on sperm quality. The comparison of DE miRNAs of SPEVs and sperms found that mir-31-5p and novel-273 could potentially serve as biomarkers for semen quality detection. Our findings enhance the insight into the crucial role of SPEV and sperm miRNAs in regulating semen quality and provide a new perspective for subsequent studies.

The study aimed to to evaluate the effect of feeding protected maggot oil at different levels on the ram sperm quality. The study used 15 local rams with an age of approximately 10-12 months and an initial weight of 19.99 ± 3.97 kg. The feeding rate was 4% of body weight per day. Feed was given 3 times a day, specifically in the morning (08.00 WIB), afternoon (12.00 WIB) and evening (16.00 WIB). Water was provided ad libitum. This study used 3 treatments and 5 groups as replicates. The treatments used concentrates with different levels of protected maggot oil: P0(0% protected maggot oil (control)), P1(4% protected maggot oil), and P2(8% protected maggot oil). The variables measured were nutrient consumption, blood cholesterol levels, scrotal circumference, and sperm quality. Blood cholesterol and scrotal circumference measured at the end of the experimental diet. Semen samples were collected and analysed before and at the end of the experimental diet. The data obtained were analysed using ANOVA, with further testing using Duncan\'s test for significant differences. The results showed that there were no significant differences in the consumption of dry matter, crude protein, crude fiber, scrotal circumference, volume, colour, pH of semen, sperm concentration, live percentage, abnormal percentage, plasma membrane, and acrosome integrity of spermatozoa. There were significantly (p < 0.05) produced higher consumption of oleic and palmitic acids in 8% protected maggot oil compared to 4% treatments, the treatments containing 4% and 8% protected maggot oil produced significantly (p < 0.05) higher consumption of lauric and myristic acids, blood cholesterol levels, and sperm motility than the control. The result indicates that protected maggot oil up to 8% in the ram diet have positive effect on improving the microscopic quality of ram sperm, i.e. increased sperm motility.

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