Influence of sampling factors on canine sperm motility parameters measured by the Sperm Class Analyzer

Melatonin Supplementation for the Cryopreservation of Canine Sperm

Antioxidants can be used in sperm cryopreservation protocols to reduce oxidative stress that occurs due to the cryopreservation process. The aim of this study was to evaluate the effects of melatonin supplementation on quality and oxidative stress parameters in cryopreserved canine sperm. Eighteen sperm ejaculates were collected from 6 Frenchie Bulldog males (3 collections per male). Sperm motility parameters, membrane integrity, and sperm morphology were analyzed before the cryopreservation process. The extender used in cryopreservation was composed of Tris-egg yolk and ethylene glycol 5% was added as a cryoprotectant. The cryoprotective medium was supplemented with 1.0, 1.5, 2.0, 2.5, and 3.0 mM melatonin, and the control group (without melatonin). Post-thaw sperm was evaluated as described for fresh sperm and oxidative stress parameters (lipid peroxidation, catalase, and superoxide dismutase). Post-thaw sperm motility parameters, membrane integrity, sperm morphology, and oxidative stress parameters did not differ (p > 0.05) among the control group and samples supplemented with melatonin. The results of this study showed that melatonin supplementation had no positive or negative effect on the parameters evaluated. Thus, it is suggested that different concentrations of melatonin be tested to assess its effectiveness as an antioxidant in the cryopreservation process in canine sperm.

Management of dog sperm parameters and gut microbiota composition with Lactobacillus rhamnosus supplementation

The effects of probiotics supplementation on the reproductive function have been evaluated in many species, but no study has evaluated the changes in the gut microbiome along with the sperm quality changes simultaneously. This study evaluated the effects of dietary supplementation with probiotics on the gut microbiome, sperm quality and gene expression, along with possible correlations between these parameters in dogs. The dogs were supplemented with Lactobacillus rhamnosus for six weeks, and fecal and semen samples were collected at 0, 3, and 6 weeks. Fecal samples were assessed using 16S Metagenomic Sequencing for gut microbiome analysis; and semen samples were analyzed using computer-assisted sperm analysis, DNA and acrosome integrity assessment, viability and morphology assessment, and real-time PCR. The analyses suggested that probiotic supplementation improved kinematic parameters, viability, DNA and acrosome integrity, and morphology of sperms. The mRNA levels of genes associated with fertility, DNA repair and integrity, and antioxidation were also upregulated. The sperm parameters were positively correlated with the relative abundance of Actinobacteria, Allobaculum, Phascolarctobacterium and Catenibacterium, and negatively correlated with Faecalibacterium and Streptococcus. Taken together, the sperm quality enhancement through the gut-testis axis may be due to a change in the gut microorganisms populations.

Commensal Lactobacilli Enhance Sperm Qualitative Parameters in Dogs

Although several methods have been developed to improve male fertility and sperm quality, subfertility remains a primary clinical issue in male reproduction worldwide. The aim of this study was to determine the effects of the oral administration of three commensal Lactobacillus spp. on healthy normozoospermic dogs and the qualitative parameters of their sperm. Three weeks of supplementation induced a significant decrease of two phyla, Proteobacteria and Tenericutes, and an increase of phylum Firmicutes. At the species level, the number of Fusobacterium perfoetens and Anaerobiospirillum succiniciproducens decreased, while Limosilactobacillus reuteri increased. Parallel to these results, qualitative sperm parameters such as total and progressive motility, acrosome integrity, and other kinematic parameters were significantly enhanced after commensal lactobacilli supplementation. In addition, we showed that Firmicutes were positively correlated with sperm qualitative parameters, while Proteobacteria, F. perfoetens, and A. succiniciproducens were negatively correlated. Considering the similarities between the gut microbiome of dogs and humans, these results provide more insight into how gut microbiota regulation could improve male sperm quality in both species.

A triple stain method in conjunction with an in-depth screening of cryopreservation effects on post-thaw sperm in dogs

In order to accurately analyze the possible side effects of sperm cryopreservation, an in-depth screening of post-thaw sperm status is necessary. Thus, this study aimed to identify thorough effects of sperm cryopreservation, by evaluating the integrity of all specific structures of the canine spermatozoa. Thirteen (n = 13) mature dogs of different breeds were selected. Six dogs (n = 6) were subjected to sperm cryopreservation, whereas seven dogs (n = 7) were used as semen donors to validate a simultaneous assessment of sperm plasmatic, acrosomal, and mitochondrial membranes (triple stain) by fluorescent probes. Fresh and post-thaw semen samples were evaluated through a computer-assisted analysis of sperm motility, sperm morpho-functional evaluation, triple stain and sperm DNA integrity. Post-thaw semen samples had lower total and progressive motility, as well as higher percentage of minor and major defects. Moreover, post-thaw samples had higher percentage of sperm with plasma membrane and mitochondrial damage but intact acrosome, and also sperm with simultaneous damaged plasma, acrosomal and mitochondrial membranes. Furthermore, post-thaw sperm had higher protamination deficiency and DNA fragmentation. In conclusion, cryopreservation has a broad impact in sperm morphology and function, altering motility patterns, plasma, acrosome and mitochondrial membranes integrity, as well as sperm DNA.

Addition of butylated hydroxytoluene (BHT) in tris-based extender improves post-thaw quality and motion dynamics of dog spermatozoa

The aim of this study was to evaluate the interaction of different concentrations of butylated hydroxytoluene (BHT) in a tris-based extender on semen quality parameters in post-thawed dog semen. Twenty-four ejaculates were collected from eight male Beagle dogs using an artificial vagina. Pooled semen was diluted with a tris-based extender supplemented with 0 (control), 0.5, 1.0, 1.5, and 2.0 mM BHT, at a final concentration of 200 × 10⁶ spermatozoa/mL. After thawing, sperm samples were assessed for motility parameters (CASA), membrane integrity (SYBR-14/PI), acrosome integrity (FITC-PNA), mitochondrial activity (JC-1/PI), malondialdehyde (MDA) concentration, and glutathione peroxidase (GPx) activity. The total motility, progressive motility, and average path velocity of the frozen-thawed sperm were significantly higher in the BHT1.5 group than in the control and the other sample groups (P < 0.05). Higher values of straight-line velocity, curvilinear velocity, amplitude of the lateral head displacement, and linearity were observed in the BHT1.0, BHT1.5, and BHT2.0 groups than in the control (P < 0.05). The BHT1.0 and BHT1.5 groups had higher percentages of straightness and acrosome integrity than the other groups (P < 0.05). Beat cross frequency, plasma membrane integrity, and GPx activity of the BHT1.5 and BHT2.0 groups were higher than those of the control (P < 0.05). A lower concentration of MDA was observed in the BHT1.0, BHT1.5, and BHT2.0 groups than in the control (BHT0) (P < 0.05). Our results indicate that 1.5 mM BHT is the optimal concentration for improving the post-thaw quality of canine spermatozoa.

Ethanol-induced male infertility: Effects of aqueous leaf extract of Tetracarpidium conophorum

This study investigated the effects of Tetracarpidium conophorum leaf extract on infertility induced by ethanol in male rats. Thirty rats were randomly divided into six groups of five animals each: Group 1 (positive control) received 0.9% saline only; Group 2 (ethanol alone) were given only 30% ethanol orally at 7 ml/kg body weight per day, thrice in a week; groups 3, 4 and 5 were given ethanol and co-treated with 50, 500 and 1,000 mg/kg body weight of leaf extract, respectively, while Group 6 was given ethanol and co-treated with a fertility drug, clomiphene citrate. Ethanol treatment resulted in significant (p < .05) decrease in LDH activity, G-6PDH activity, glycogen content, 3β and 17β HSD activities and testicular and epididymal Zn and Se contents and furthermore decrease in testicular sperm count, viability and marked increment in total sperm abnormalities, rate of sperm analysis parameters and consequently decreased reproductive hormone levels. Interestingly, co-administration of ethanol with either T. conophorum extract or drug almost ameliorated the toxic assault imposed by ethanol on reproductive organs and improved seminal qualities of the rats.

Walnut leaf extract acts as a fertility agent in male Wistar albino rats - A search for herbal male fertility enhancer

Background Walnut leaf is one of the many medicinal plants used in folklore as male fertility enhancers. The present work was therefore undertaken with an aim to scientifically validate this claim. As such, we evaluated the effect of the aqueous extract from walnut leaves on biomolecules related to fertility in adult male rats and its mode of action as fertility-enhancing agent. Methods Twenty-five rats were randomly divided into five groups of five animals each; Group 1 served as control and received normal (0.9%) saline only; Groups II, III, IV received 50, 500, 1,000 mg/kg body weight (BW) of T. conophorum leaf extract orally, while Group V served as standard and was given suspension of clomiphene citrate orally at the dose of 1.04 mg/kg/ml BW. The extract and drug were given daily and the experiment lasted for 21 consecutive days. Results The testicular biochemical parameters in treated groups showed significant (p<0.05) increase in lactate dehydrogenase activity activity, Glucose-6-phosphate dehydrogenase (G-6PDH) activity, glycogen content, 3β and 17β hydroxysteroid dehydrogenase activities and testicular and epididymal Zn and Se contents with a significant decrease in cholesterol content. A significant increase in testis weight and epididymis weight were also observed. Also, a significant (p<0.05) increase in the level of serum testosterone, luteinizing hormone (LH), follicle-stimulating hormone, sperm count, motility, viability and a decrease in sperm abnormality were observed in the various treated groups when compared with the control group. This increment was concentration dependent, while the extract at the highest concentration showed a more pronounced effect than the standard drug. Also, no sperm DNA fragmentation index was found in all the treatment groups. Photomicrographs from light and scanning electron microscopy showed large fenestrae of interstitial tissue, large fluid space and intact seminiferous epithelium layers fully packed with spermatogenic cells in treated groups than the control group. Conclusions The present study has demonstrated that Tetracarpidium conophorum leaf possesses fertility-enhancing property and have useful effects on spermatogenesis and sperm parameters in rats.

Effect of chamber characteristics, loading and analysis time on motility and kinetic variables analysed with the CASA-mot system in goat sperm

Several factors unrelated to the semen samples could be influencing in the sperm motility analysis. The aim of the present research was to study the effect of four chambers with different characteristics, namely; slide-coverslip, Spermtrack, ISAS D4C10, and ISAS D4C20 on the sperm motility. The filling procedure (drop or capillarity) and analysis time (0, 120 and 240s), depth of chamber (10 or 20μm) and field on motility variables were analysed by use of the CASA-mot system in goat sperm. Use of the drop-filling chambers resulted in greater values than capillarity-filling chambers for all sperm motility and kinetic variables, except for LIN (64.5% compared with 56.3% of motility for drop- and capillarity-filling chambers respectively, P<0.05). There were no significant differences in total sperm motility between different chamber depths, however, use of the 20μm-chambers resulted in greater sperm progressive motility rate, VSL and LIN, and less VCL and VAP than chambers with a lesser depth. There was less sperm motility and lesser values for kinetic variables as time that elapsed increased between sample loading and sperm evaluation. For sperm motility, use of droplet-loaded chambers resulted in similar values of MOT in all microscopic fields, but sperm motility assessed in capillarity-loaded chambers was less in the central fields than in the outermost microscopic fields. For goats, it is recommended that sperm motility be analysed using the CASA-mot system with a drop-loaded chamber within 2min after filling the chamber.

Effect of cryopreservation and single layer centrifugation on canine sperm DNA fragmentation assessed by the sperm chromatin dispersion test

The aims of this study were: 1) to assess the effect of freezing and thawing on dog sperm DNA fragmentation index (sDFI) using the sperm chromatin dispersion test (SCDt); and 2) to determine whether or not the sperm selection by single layer centrifugation (SLC) using Androcoll-C improves sperm DNA longevity in SLC-selected frozen-thawed dog semen samples. Semen samples were collected from 4 dogs using digital manipulation. After collection, ejaculates were pooled and cryopreserved following a standard protocol. Sperm motility and morphology were assessed before freezing and after thawing as a control for the cryopreservation method used. In experiment 1, sDFI was analyzed immediately before freezing and after thawing (baseline values), showing no significant differences between fresh and frozen-thawed semen samples. In experiment 2, frozen-thawed semen samples were processed or not by SLC using Androcoll-C and longevity of DNA were assessed in terms of sDFI after 24h of in vitro incubation at physiological temperature (38°C). The results showed low values of sDFI in SLC-selected semen in comparison to unselected samples. In conclusion, no effect of cryopreservation was observed on baseline values of dog sperm DNA fragmentation. Additionally, SLC-selection using Androcoll-C improved longevity of frozen-thawed sperm DNA assessed by the SCDt.

Computer-assisted sperm analysis in dogs and cats: an update after 20 years

In dogs and cats, computer-assisted sperm analysis (CASA) was originally described almost 20 years ago. Subsequently, numerous CASA systems were validated and used for various applications in dogs and to a lesser extent in cats. CASA systems offer an accurate, rapid, objective and simultaneous assessment of different semen parameters allowing the visualization of subtle changes in sperm characteristics, which cannot be identified by conventional semen analysis. The main problems of these computerized measuring devices are the relatively high investment costs and the need for standardization and validation before any practical use is possible. In comparison with automated motility and concentration assessment, automated morphometry and morphology assessment is more complex and time-consuming. Once validated, CASA systems can be routinely used in veterinary centres for assessment of fertility and for the improvement of sperm diluters, cooling and cryopreservation procedures in dogs and cats. Furthermore, information obtained by CASA systems could also be important when monitoring for example the effect of environmental stress on spermatozoa and for toxicity studies. In cats, CASA is less documented, and most studies describe the characteristics of epididymal sperm, which is frequently used for in vitro fertilization in cats. Implementation of the CASA technique in cat reproduction could be interesting to further optimize assisted reproductive techniques in domestic cats and endangered wild felids.