Nicotinic Acid (Niacin) Supplementation in Cooling and Freezing Extenders Enhances Stallion Semen Characteristics

Oral nicotinic acid administration effect on lipids, thyroid hormones, and oxidative stress in intact adult dogs

BACKGROUND

Nicotinic acid (niacin, Vitamin B3) is one of the most effective medicines for improving high-density lipoprotein concentrations. Obesity and related diseases are life-threatening to dogs. This study investigated the niacin effect on triglyceride, cholesterol, lipoproteins, thyroid hormones, oxidative stress, and lipid peroxidation in intact adult dogs. Blood samples were taken from seven healthy, intact adult dogs as a control group (day 0). Then, the animals received 1000 mg/dog of oral nicotinic acid tab daily for 42 days, and blood sampling was performed on days 14, 28, 42, and 56.

RESULT

The results showed an increasing trend in high-density lipoprotein (HDL) concentration. The highest HDL concentration (138.85 ± 43.72 mg/dl) was related to day 56; the HDL level followed a statistically significant increase between day 14 and 56. Unlike HDL, there was a decreasing trend in low-density lipoprotein (LDL) concentration. The lowest LDL concentration (21.85 ± 18.60 mg/dl) was related to day 56. The concentration of apolipoprotein A-I (apoA1) was significantly increased during the study. The highest concentration of apoA1 (1.66 ± 0.06 g/l) was on day 42. There was a significant increase in apoA1 concentrations between days 0 and 14, 42, and 56. The apoA1 was significantly increased between days 14 and 42 and 56. The apoA1 followed a statistically significant increase between days 28 and 42. Changes in thyroid hormone levels did not show any constant increasing or decreasing trend. On day 14, a decreasing trend in the concentrations of TT4, FT4, and T3 was observed. However, an increasing trend was detected in the concentrations of TT4, FT4, and T3 on days 28 and 42. However, the increase in the concentrations of TT4 and FT4 was less than that on day 0. After treatment (day 56), a decreasing trend was observed in thyroid hormone concentrations. The negative correlation was detected between apoA1 and triiodothyronine (T3), total thyroxine T4 (TT4)), and free T4 (FT4) concentrations on day 42. Furthermore, a significant negative relationship was observed between HDL and T4 on day 42. However, the relationship between triglyceride and T3 was statistically positive on day 14. There was an increasing trend in serum total antioxidant capacity (TAC). The highest TAC concentration (3.83 ± 0.62 µmol /l) was on day 56; however, the malondialdehyde (MDA) concentration was decreased during the study. The total antioxidant level followed a statistically significant increase between days 0 and 56 compared to days 14 and 42.

CONCLUSION

The study demonstrated the efficacy of nicotinic acid in improving serum HDL, apoA1, and TAC, as well as decreasing serum MDA and LDL concentrations.

High-resolution LC-MS/MS combined with TMT quantitative proteomic analysis reveals regulatory mechanism of sperm capacitation by heparin, Ca2+ and BSA

Heparin, BSA, and CaCl2 have been demonstrated to induce sperm capacitation in vitro; however, the specific molecular mechanisms by which different chemokines regulate sperm capacitation remain incompletely elucidated. In previous studies, our laboratory utilized various chemokines to induce capacitation in porcine sperm in vitro and classified these chemokines into three categories based on changes in olfactory receptors. Therefore, this study aims to systematically investigate the molecular pathways and regulatory mechanisms underlying heparin, CaCl2, and BSA induced porcine sperm capacitation. Porcine sperm were treated with heparin, CaCl2, or BSA for 1-4 h, and capacitation was assessed by measuring mitochondrial membrane potential (MMP), intracellular Ca2+ concentration, and capacitation rate. Differential protein expression among the three groups was analyzed using TMT-based quantitative proteomics. The results demonstrated that heparin, CaCl2, and BSA significantly increased intracellular Ca2+ concentration in a time-dependent manner, reduced MMP, and successfully induced sperm capacitation. Proteomic analysis revealed that differentially expressed proteins between the heparin and BSA groups were primarily enriched in lipid metabolism-related signaling pathways, such as PPAR and AMPK, while differentially expressed proteins in the CaCl2 group were significantly enriched in B vitamin metabolic pathways, including riboflavin and nicotinic acid metabolism. Furthermore, olfactory receptors OR1J4 and OR4C13 were found to specifically bind chemokines and participate in the regulation of sperm capacitation. In conclusion, this study elucidates the distinct molecular mechanisms by which heparin, CaCl2, and BSA induce porcine sperm capacitation and provides the first evidence of the critical role of olfactory receptors OR1J4 and OR4C13 in regulating sperm capacitation, offering new theoretical insights into the molecular mechanisms underlying sperm capacitation.

The potential prophylactic and therapeutic impacts of niacin on ischemia/reperfusion injury of testis

INTRODUCTION

The testicular ischemia-reperfusion (I/R) injury is characterized by the excessive aggregation of un-scavenged reactive oxygen species, leading to the heightened levels of oxidative stress. This phenomenon plays a pivotal role in the pathophysiology of testicular torsion damage.

OBJECTIVE

The current study aimed to detect the prophylactic and therapeutic effects of niacin on testicular I/R injury.

STUDY DESIGN

Twenty-four healthy adult male Sprague Dawley rats were randomly allocated into three groups as follows: (1) sham group, (2) torsion/detorsion (T/D) group, and (3) treatment group which received 200 mg/kg niacin along with testicular T/D. Torsion/detorsion was induced by 2 h of torsion followed by 10 days of reperfusion period. In the treatment group, niacin was injected 30 min before the reperfusion period intraperitoneally and continued for 10 days by oral gavage.

RESULTS

T/D was associated with marked decreases in terms of sperm count, viability, and kinematic parameters versus the sham group (P < 0.05), which niacin significantly reverted the kinematic parameters (P < 0.05). I/R injury caused a significant increase in the number of abnormal epididymal sperms compared to the sham group (P < 0.05). Niacin decreased the epididymal sperm abnormality significantly compared to the T/D group (P < 0.05). Tissue abnormalities in T/D group, such as edema, hyperemia, inflammation, and necrosis were completely visible histopathologically, while the histological changes in the niacin-treated group were better than those in the T/D group. Regarding the pathological parametric evaluations, I/R injury significantly reduced the mean testicular biopsy score (MTBS), germinal epithelial cell thickness (GECT), and mean seminiferous tubular diameter (MSTD), and increased the tubular hypoplasia/atrophy (THA) compared to the sham group (P < 0.05), which niacin treatment significantly improved the MTBS and GECT compared to the T/D group (P < 0.05). T/D significantly increased the oxidative stress index (OSI) and lipid peroxidation (MDA) (P < 0.05). Niacin significantly reduced the OSI and MDA levels compared to the T/D group (P < 0.05).

DISCUSSION

The current study found that niacin has preventive/therapeutic effects against the elevation of oxidative stress markers and depletion of antioxidants during I/R injury. Following administration of niacin, a reduction in histologic injury was observed in rats. In our study, we showed the antioxidant properties of niacin and its capacity to protect against I/R damage.

CONCLUSION

The findings of the present investigation revealed that niacin, as an antioxidant agent, can suppress the oxidative stress induced by testicular I/R injury, and can be used as a supplementary agent in the treatment of those undergoing testicular torsion surgery.

Effect of nutraceutical supplementation on semen quality in stallions

BACKGROUND

The use of reproductive biotechnologies in equine practice has shown that some stallions are subfertile, so ways to improve fertility have been sought.

OBJECTIVE

This study aimed to evaluate the effect of nutraceutical supplementation on improving semen quality in Quarter Horse stallions.

METHODS

Semen from six Quarter Horse stallions was assessed for 4 months every 20 days using the computer-assisted semen analysis system. They were evaluated for 60 days before supplementation; then, the same stallions were re-evaluated for 60 days with nutraceutical supplementation (30 g/day).

RESULTS

Volume showed no significant difference (p > 0.05) with nutraceuticals. Sperm concentration (10x6 ) was significantly higher with supplementation (339.4 ± 17.5 sperm/mL) than without supplementation (224.6 ± 19.9). Sperm abnormalities (%) were significantly (p < 0.05) lower with supplementation (14.3 ± 0.6) than without supplementation (19.1 ± 0.4). Sperm kinematic parameters, total motility (TM), progressive motility (PM), rectilinear velocity (VSL), the velocity of the trajectory (VAP) and curvilinear velocity (VCL), were significantly better with supplementation (p < 0.05).

CONCLUSIONS

Based on the results, it is concluded that nutraceutical supplementation improved semen parameters in Quarter Horse stallions.

Cellular and Molecular Consequences of Stallion Sperm Cryopreservation: Recent Approaches to Improve Sperm Survival

Cryopreservation of stallion semen does not achieve the post-thaw quality or fertility results observed in other species like cattle. There are many reasons for this, but the membrane composition and intracellular changes in stallion sperm predispose them to low resistance to the cooling, freezing, and subsequent thawing process. Damage to the sperm results from different processes activated during cryopreservation, including oxidative stress, apoptosis, and structural modifications in the sperm membrane that increase the deleterious effect on sperm. In addition, significant individual variability is observed among stallions in the ability of sperm to survive the freeze-thaw process. Recent advances in genomics, transcriptomics, proteomics, metabolomics, and epigenetics are making it possible to advance our understanding of the cellular and molecular processes involved in the cryopreservation process, opening new possibilities for improvement. This review addresses the ongoing research on stallion semen cryopreservation, focusing on the cellular and molecular consequences of this procedure in stallions and discusses the new tools currently available to increase the tolerance of equine spermatozoa to freeze-thaw.

Characterization of freezability-associated metabolites in boar semen

Sperm cryopreservation maintains the diversities of porcine genetic resources and improves utilization efficiency of boar semen in artificial insemination practices. Freezability of boar semen presents remarkable differences among individuals. However, metabolic markers for boar semen freezability in both sperm and seminal plasma largely remain unknown. The present study thus aims to determine differences in metabolites of sperm and seminal plasma between poor (PF) and good (GF) freezability semen from a Chinese native pig and screen potential markers for semen freezability. A total of 72,048 metabolites in sperm and 66,551 metabolites in seminal plasma were identified by liquid chromatography-mass spectrometry, respectively. The proportion of lipid molecules among all metabolites in both sperm and seminal plasma was the maximum regardless of negative or positive mode. Furthermore, we identified 21 differentially expressed metabolites (DEMs) in sperm and 185 DEMs in seminal plasma between PF and GF group. Additionally, clustering analysis showed that DEMs in sperm and seminal plasma exhibited significant changes between PF and GF group. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that DEMs in sperm were mainly enriched in metabolic pathways of amino acids and caffeine. DEMs in seminal plasma were associated with AMPK and cAMP signaling pathways. Taken together, these results demonstrate that sperm and seminal plasma of native pigs present differential metabolome between PF and GF semen.