Effect of L-proline on sperm quality during cryopreservation of boar semen

L-proline has been reported to be useful in semen cryopreservation. However, its use has rarely been reported in the freezing of boar semen. The objective of this study was to evaluate the effects of different concentrations of L-proline (0, 10, 30, 50, and 90 mM) on the quality of boar semen after freezing and thawing. Semen samples from boars (n = 6) were frozen using freezing extenders with added concentrations of L-proline. Total sperm motility, progressive motility, survival time at 37 °C, acrosome integrity, mitochondrial activity, DNA integrity, the content of the lipid peroxidation product malondialdehyde (MDA), total antioxidant capacity (T-AOC) and, expression levels of apoptosis protein (cleaved caspase 3 and Bax) were evaluated after thawing. The results showed that total sperm viability (73.96% vs. 63.58%) and progressive motility (56.88% vs. 47.26%) after thawing were significantly higher in the 10 mM L-proline treatment group than in the control group. The survival time at 37 °C and the total motility of sperm in the 10 mM group within one hour after thawing were significantly higher than in the control group. Acrosome integrity and mitochondrial activity of sperm in the 10 mM group were significantly higher than those in the control, 50 mM, and 90 mM groups. The DNA integrity rate in the 10 mM group was significantly higher than in the control group. The L-proline treatment did not affect sperm MDA content or T-AOC. The expression levels of apoptosis protein (cleaved caspase 3 and Bax) in the 10 mM L-proline supplemented group were lower than those in the control group. In conclusion, the freezing extender containing 10 mM L-proline improved semen quality after freezing and thawing and thus would be a useful reagent for boar semen cryopreservation.

Relaxin (a regulatory-peptide) enhances cryotolerance, fertility potential and plasma reproductive hormones of Nili Ravi buffalo (Bubalus bubalis) during low breeding season

This study investigated the beneficial effects of relaxin on cryotolerance of buffalo spermatozoa and reproductive hormones during low breeding season. Collected semen was diluted in five aliquots with relaxin addition (0.25 mg/mL, 0.50 mg/mL, 0.75 mg/mL, 1 mg/mL, and control). After gentle dilution (37°C), cooling (4°C, 2 h), equilibration (4°C, 4 h), and packaging (straws, polyvinyl French, 0.5 mL), frozen (cell freezer), and thawed (37°C, 30 s) for analysis. Blood samples were collected at different time intervals i.e., -60, -30 and 0 min (pre-dose) and 30, 60, 90, 120 and 150 min (post-dose) from a jugular vein. This study manifest that adding relaxin (1 mg/ mL) in freezing medium ameliorates sperm motility, functionality (%), and seminal plasma total antioxidant capacity (TAC, μM/L) than control during low breeding season. Furthermore, we found that relaxin supplementation at 1 mg/mL significantly improves seminal plasma ATP concentrations (nmol/million) than control, 0.25 mg/mL, and 0.50 mg/mL, and fertility (control, and 0.75 mg/mL). Further, relaxin injection significantly improves plasma T, LH and IGF-1 levels (150 and 120 min vs. -60, and - 30), and FSH, KP, and GnRH concentrations (150 min vs. -60), during low breeding season. Taken together, this study revealed that relaxin ameliorates motility, functionality, and fertility of buffalo spermatozoa. Moreover, relaxin injection (1 mg/mL) improves essential reproductive hormones levels in buffalo signifying its importance in the field of reproductive physiology. Further studies are required to determine the exact mechanism of action of relaxin in enhancing semen quality, fertility and reproductive hormones.

Effect of dietary onion (Allium cepa L.) powder as an antioxidant on semen quality, blood biochemicals, and reproductive parameters, as well as immunological variables of rabbit bucks under severe heat stress

This study aimed to evaluate the antioxidant effects of onion (Allium cepa L.) powder on the immunological variables, redox state, and semen quality of rabbit bucks exposed to severe heat stress. Thirty-six mature bucks (7 months old) were divided into three groups consisting of 12 bucks each, namely group I, control; group II, 400 mg onion powder/kg diet; and group III, 800 mg onion powder/kg diet. The quality of semen was evaluated for volume, pH, motility, concentration, total sperm output, viability, and packed sperm volume. Blood samples were collected in the 12th week for estimation of red blood cells (RBC), white blood cells (WBC), and erythrocytic indices. Serum proteins, glutamate oxaloacetate (GOT), glutamate pyruvate transaminase (GPT), urea, creatinine, testosterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), immunoglobulins, malondialdehyde (MDA), total antioxidant capacity (TAC), glutathione, superoxide dismutase (SOD), and catalase (CAT) were measured. The temperature-humidity index (THI) obtained was within the range of 28.85-33.08 indicating severe heat stress. The results show that mass and individual motility, concentration, total sperm output, sperm viability, and packed sperm volume were higher (P < 0.05) in groups II and group III, with group III having the highest (P < 0.05) levels compared to group I. Compared to group I, groups II and III had higher (P < 0.05) concentrations of RBC, MCV, MCH, FSH, LH, SOD, and catalase. The highest concentration (P < 0.05) of GPT was obtained in group III compared to other groups. The highest concentration of IgG (P < 0.05) was obtained in group II while the lowest was in group I. In conclusion, dietary supplementation with onion powder at 400 or 800 mg/kg diet improves semen quality, RBC, FSH, LH, SOD, catalase, and IgG while ameliorating the adverse effects of heat stress and improve the health and reproduction of rabbits.

Comparative analysis of different metabolites in semen of Guanzhong dairy goats with different motility rates

In order to explore the different metabolites of buck semen with different motility stored at 4 °C, the semen of bucks was collected by artificial vagina. The collected semen was divided into high motility group and low motility group after treatment, with 6 replicates set for each group. The semen metabolites of high motility group and low motility group were detected by Liquid Chromatography-Mass Spectrometry (LC-MS). The results showed that 101 different metabolites were detected in the high and low motility groups of bucks, of which 48 metabolites were significantly up-regulated (P < 0.05) and 53 metabolites were significantly down regulated (P < 0.05). Most of these metabolites belonged to lipids and lipid-like molecules, organic acids and their derivatives, and organic oxygen compounds, which were mainly related to energy metabolism. According to the functional enrichment analysis of the former differential metabolites in KEGG database, the top 20 most representative metabolic pathways were detected, among which the glycerophospholipid metabolic pathways changed significantly. From the perspective of metabolomics, this study revealed the differences of metabolites and characteristic compounds of semen with different motility of bucks under low temperature preservation, which provided a scientific basis for the preservation and utilization of semen of Guanzhong dairy goats in the future.

Effects of supplementation of cryopreservation media with cysteine on the post-thaw quality and fertility of brown-marbled grouper (Epinephelus fuscoguttatus) spermatozoa

The cryopreservation process is associated with the generation of excessive reactive oxygen species, which causes a series of cellular damage to spermatozoa. The objective of the current study was to investigate the effect of different concentrations of cysteine on post-thaw sperm quality of brown-marbled grouper sperm. Semen samples were frozen with cysteine supplemented at 0.5, 1, 2, 5, 10 mM and the control group (no additive). After thawing, sperm quality parameters were analyzed. In comparison to the control, cysteine treatment groups yielded relatively higher sperm total motility, progressive motility, and curvilinear velocity. Different concentrations of cysteine had no effect on average path velocity, straight linear velocity and viability (P > 0.05), while an increase in the concentration of cysteine resulted in a significant improvement in the mitochondrial membrane potential, SOD activity, and ATP content (P < 0.05). As for lipid peroxidation, the extent of which in cysteine treated spermatozoa was less than the control, although the differences were not statistically significant (P > 0.05). In terms of fertilizing capacity, a greater hatching rate (91.7 ± 1.2%) was obtained in thawed sperm treated with 2 mM cysteine, compared to the control (84.3 ± 4.2%; P < 0.05). Overall, it is concluded that the addition of cysteine is helpful in maintaining the function of frozen-thawed brown-marbled grouper sperm, which can be recommended as an effective antioxidant to improve the semen cryopreservation efficiency.

Transcriptomic analysis of mechanism underlying the effect of induced molting on semen quality and reproductive performance in aged Houdan roosters

The reproductive performance of breeder roosters has significant economic importance in the poultry industry. Breeder roosters have severely reduced semen quality with age and will be at risk of culling in the following years. In order to extend the use of breeder roosters, we drew on the induced molting model of hens and selected 35 Houdan roosters aged 50 wk for induced molting. By comparing the body weight, testicular weight, semen quality, and reproductive performance before and after induced molting, we found that induced molting could restore the body weight and testicular weight to the levels before molting (P > 0.05). At the same time, it significantly improved sperm motility (P < 0.05) and also improved reproductive performance such as fertilization rate and hatching rate. To further reveal the mechanism underlying the effects of induced molting on semen quality and reproductive performance in aged Houdan roosters, we collected testes from 3 periods: 1 d before fasting (F0), 15 d after fasting (F15), and 32 d after recovery feeding (R32) for transcriptome sequencing analysis. A total of 5,671 genes were detected in F0, F15, and R32, and trend analysis of the 5,671 differential genes showed 2 significant trends (profile 5 and profile 2). KEGG enrichment analysis of the genes in the 2 profiles, revealed significantly enriched pathway regulation of actin cytoskeleton. In the regulation of actin cytoskeleton pathway, we found a protein kinase gene (SRC) and a senescence gene (ROCK2). SRC was highly expressed at F15, leading to the phosphorylation of key substrates, which in turn disrupted the Sertoli cell spermatid connection and the spermiogenesis process, resulting in no mature spermatozoa produced from F15, SRC expression was inhibited at R32, the expression level was reduced, and mature spermatozoa reappeared. The senescence gene ROCK2 was highly expressed at F15 compared to F0 and R32, which may have been responsible for inducing senescence atrophy in the testes.

Effect of pentoxifylline on the testicular hemodynamic, volume, testosterone, nitric oxide levels and semen quality in Ossimi rams during non breeding-season

During the non-breeding season, Ossimi rams have testicular regression, including reductions in blood flow, size and spermatogenesis. The objective was to determine the effect of pentoxifylline (PTX) on Ossimi rams during the non-breeding season. Fifteen sexually mature Ossimi rams were allotted to three groups: (1) G0 (n = 5) control group (basic diet, no PTX); (2) G1 (n = 5) 10 mg/kg BW PTX; and (3) G2 (n = 5) 20 mg/kg BW PTX. The PTX was given orally once daily for 7 weeks (wk1 to wk7), whereas ultrasonographic assessment of testes, and collection of semen and blood started 1 week before PTX and were done weekly for 8 weeks (wk0 to wk7). In G2, there was a decrease(P < 0.05) in both Doppler indices (resistive index, pulsatility index) in G2 from wk2 to wk4 and an increase(P < 0.05) in ultrasonographic testicular coloration from wk2 to wk7. Moreover, G2 had the highest (P < 0.05) testicular volume (wk5 to wk7), individual motility, sperm viability and acrosome integrity (wk4 to wk7) and sperm cell concentration (wk6 and wk7). Blood concentrations of testosterone and nitric oxide were increased (P < 0.05) concurrent with decreased Doppler indices. In conclusion, PTX enhanced testicular blood flow and volume, semen quality, and concentrations of testosterone and nitric oxide potential in Ossimi rams during the non-breeding season, with potential to ameliorate deleterious effects of heat stress and perhaps enhance ram fertility.

Evaluation of a novel microfluidic chip-like device for purifying bovine frozen-thawed semen for in vitro fertilization

The aim of this study was to validate a novel sperm purification device, the VetCount™ Harvester, for use in bovine in vitro fertilization (IVF). The device's performance was compared to BoviPure™ gradient centrifugation, a commercially available and accepted routine technique. Semen quality parameters were assessed for frozen-thawed semen from six different bulls (n = 6) following sperm purification. For each bull two semen subsamples were purified utilizing BoviPure™ gradient centrifugation and the VetCount™ Harvester, including a third subsample as untreated control. Both treatments significantly increased the proportion of progressively motile sperm cells (84.4 ± 14.1% and 85.1 ± 7.8%, respectively) compared to the untreated semen (41.9 ± 18.8%). BoviPure™ gradient and VetCount™ Harvester selected predominantly viable acrosome intact (VAI) sperm cells with low membrane fluidity and low free intracellular calcium concentration [Ca2+]i (76.5 ± 4.4% and 78.6 ± 6.0%). Normalizing [Ca2+]i of VAI sperm cells (non-treated semen: [Ca2+]i = 1) VetCount™ Harvester purified spermatozoa (0.67 ± 0.10) showed significantly lower [Ca2+]i than BoviPure™ treated sperm (0.84 ± 0.14; P < 0.05). Subsequently, the fertilizing ability of the spermatozoa was evaluated performing a competitive fertilization assay. Sperm cells from both treatment groups were fluorescently labelled using different dyes and added in equal amounts to in vitro matured oocytes. After 18 h co-incubation, the origin of the fertilizing sperm cell was evaluated via fluorescence microscopy. In two bulls, VetCount™ Harvester selected sperm that fertilized significantly more oocytes then BoviPure™ treated sperm, in another bull it was the opposite. For three bulls no difference was observed. We conclude that the VetCount™ Harvester selects a high-quality, fertile sperm fraction from frozen-thawed bull semen. However, some considerations have to be kept in mind for the direct use of the isolated sperm fraction in IVF.

Lipids in the reproduction of sires

The main class of nutritional interest for lipids are fatty acids (FA), which correspond to 90% of triglycerides, the main form of lipid storage in both plants and animals. FAs serve as a source of energy in the diet of cattle; however, they also have an important non-caloric effect on animal organisms as they are important components of the physical and functional structures of cells and participate in the composition of steroid hormones. As such, research has studied the improvement of semen quality through the provision of polyunsaturated FAs in bull diets, as well as the use of FAs in semen extenders in order to reduce damage to sperm cells, which can alter lipid composition and the quality of frozen sperm. Therefore, the objective of this work was to review the effectiveness of lipids on reproductive efficiency, based on their effects on semen quality and hormonal production. Supplementation with polyunsaturated FAs positively alters semen composition and in vitro fertility; however, results vary according to the type of FA used, the method of administration, and its quality. Fish oil and linseed oil showed better results in qualitative parameters in fresh and thawed semen. The use of cyclodextrins to incorporate or extract cholesterol from plasma membranes can also improve the viability of cryopreserved semen.

Genetic analysis for semen quality traits in buffalo bulls

This study was attempted to estimate the genetic parameters of semen quality traits in buffalo bulls. The study data consisted of 10975 ejaculates from 45 Murrah buffalo bulls (aged 24-72 months) used for breeding program during year 2010 to 2020. Semen quality traits (ejaculate volume, concentration of sperm, mass activity, initial and post-thaw motility, number of sperms per ejaculate, motile sperm number and discard rates) were studied. It was observed that average ejaculate volume was 2.82 ± 1.45 mL with mean concentration of 1040.12 ± 523.26 million/mL. Higher heritability was observed for number of sperms per ejaculate, number of motile sperm and sperm concentration. Significant phenotypic correlation was obtained between volume and number of sperms per ejaculate as well as volume and number of motile sperms. Likewise, significant phenotypic correlation was evident between sperm concentration with sperm number per ejaculate. Highest phenotypic correlation was obtained between sperm count per ejaculate and motile sperm count. Estimated genetic trends showed significant change in volume and motile sperm number. In conclusion, this study ascertains that genetic parameters of semen traits can be considered during the selection of buffalo bulls in breeding program.

Impact of inbreeding and genetic parameter estimates for seminal traits in Lusitano horses

The objectives of this study were to establish baseline information for seminal traits in Lusitano stallions, to assess the impact of inbreeding, interval between collections and age on semen quality during the breeding and non-breeding seasons, and to estimate the corresponding genetic parameters. A total of 2129 ejaculates by 146 Lusitano stallions used for artificial insemination, obtained from four equine reproduction centers distributed throughout Portugal, over a period of 14 years (2008-2021), were included in the study. The seminal traits analyzed, and the corresponding means and standard deviations, were gel-free volume (56.95 ± 28.76 mL), concentration (186.48 ± 104.68 × 106), motility (64.1 ± 16.9%), total number of spermatozoa (TNS) (9.271 ± 4.956 × 109) and total number of motile spermatozoa per ejaculate (TNMS) (5.897 ± 3.587 × 109). These results are in the normal range of values described for other breeds. In the stallions analyzed, the mean value for the inbreeding coefficient was 7.93 ± 5.29%, and for age it was 12.70 ± 6.83 years. A significant decline in sperm concentration, motility, TNS, and TNMS was observed as inbreeding increased. The season also influenced sperm concentration, motility, TNS and TNMS, with the highest values observed during the breeding season. When considering the impact of age on Lusitano seminal parameters, results showed a nonlinear relationship, with a positive effect until 18 years of age for volume, motility, TNS and TNMS and a negative effect after this age, with a slow decrease. However, age had a markedly negative effect on sperm concentration. The interval between semen collections only affected (P < 0.05) sperm motility, with a regression coefficient of +1.89 ± 2.17% per additional day. Genetic parameters were estimated with an Animal Model, and the estimated heritability (repeatability) was 0.27 (0.35) for volume, 0.02 (0.38) for sperm concentration, 0.24 (0.44) for motility, 0.29 (0.39) for TNS and 0.41 (0.41) for TNMS. These results suggest that it is possible to improve semen quality by selection and that the properties of semen produced by a stallion tend to remain consistent throughout its lifetime. Furthermore, the impact of inbreeding should be taken into consideration when selecting Lusitano stallions for fertility.

Preservation of the quality and fertility potential of post-thawed rooster sperm using MitoQ

Cryopreservation of rooster spermatozoa is an efficient procedure to spread qualified semen samples for reproductive goals in commercial flocks, but the freeze-thawing process reduces the quality and fertility potential of post-thawed sperm cells. This study was aimed to investigate the effect of the mitochondria-targeted antioxidant MitoQ on rooster sperm quality and fertility potential preservation during freeze-thawing process. Semen samples were collected and diluted in the Lake medium, assigned into five equal aliquots, supplemented with 0, 1, 10, 100 and 1000 nM MitoQ, and cryopreserved in liquid nitrogen. After thawing, sperm motility, membrane functionality, abnormal morphology, mitochondria active potential, acrosome integrity, viability, apoptosis status, lipid peroxidation, DNA fragmentation, ROS concentration and fertility potential were evaluated. According to the results, freezing extender supplementation with 10 and 100 nM MitoQ presented higher (P ≤ 0.05) total motility, progressive motility, average path velocity, membrane functionality, mitochondria active potential, acrosome integrity and viability compared to the other groups. On the other hand, lipid peroxidation, apoptosis rate, DNA fragmentation and ROS concentration were lower (P ≤ 0.05) in groups received 10 and 100 nM MitoQ compared to other groups. Moreover, fertility rate was higher in groups received 10 and 100 nM MitoQ compared to control group. Therefore, MitoQ is able to preserve quality parameters and fertility potential of post-thawed spermatozoa in rooster and it could be an effective additive for supplementation of rooster's semen cryopreservation medium during reproductive programs.

Relationship between biochemical parameters and paraoxonase 1 activity of boar seminal plasma and semen quality

The aim of this study was to examine the biochemical components and the parameters of antioxidant protection in the seminal plasma (SP) of boars, as well as their relationship with semen quality parameters. Thirty-six boars were included in the study, whose ejaculates were divided into two groups: Group I (good quality semen, > 70% progressively motile sperm, < 20% spermatozoa with abnormal morphology, n = 16), and Group II (poor quality semen, < 70% progressively motile sperm, > 20% spermatozoa with abnormal morphology, n = 20). Significantly higher concentrations of ionized calcium (iCa), total cholesterol (TC), lactate-dehydrogenase (LDH) activity, as well as significantly higher values ​​of antioxidant protection parameters: thiol groups (-SH), paraoxonase 1 (PON1), and total antioxidant capacity (TAC) ) were found in the good quality semen, while higher phosphorus (P) concentrations and increased alkaline-phosphatase (ALP) activity were found in the semen of poor quality. A negative correlation of total and progressive sperm motility with P and ALP was found in all examined semen samples, while a positive correlation was found with PON1 and TAC. The percentage of fast sperm cells positively correlated with iCa, chlorine (Cl), lactate, LDH and TAC, while a negative correlation was found with P, magnesium (Mg) and the enzyme creatine-kinase (CK). The percentage of immobile sperm positively correlated with P and ALP, and negatively correlated with TC, CK, PON1 and TAC. Elevated values ​​of PON1 and TAC in SP and a positive correlation with sperm motility indicate the possible use of these parameters as sensitive biomarkers of boar semen quality. To the best of our knowledge there are no published data on association between PON1 activity and boar semen quality.

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.

Effect of vitamin D metabolites and gene expression of vitamin D receptor, and 1-alpha-hydroxylase related to the sperm quality

The incidence of male fertility disorders has increased greatly due to various genetic and lifestyle factors. Recently, it has been hypothesized that vitamin D may be involved with idiopathic infertility. The goal of the study was to determine the effect and relationship between blood vitamin D metabolites, intracellular sperm vitamin D levels, and gene expression of 1-α-hydroxylase and VDR, with regard to semen quality. Seventy volunteers aged 25-45 were involved in the study. According to spermogram analysis, participants were stratified into normozoospermic control group, non-normozoospermic target group, and oligoasthenoteratozoospermic group. Vitamin D metabolites (total 25-hydroxycholecalciferol, 1,25-dihydroxycholecalciferol) in blood and spermatozoa were determined by ELISA. Free and bioavailable 25-hydroxycholecalciferol were calculated using the Vermeulen equation. mRNA expression of VDR and 1-α hydroxylase was evaluated by qPCR. Free and bioavailable 25-hydroxycholecalciferol were significantly higher in the control group compared to the target group and compared to the oligoasthenoteratozoospermic group . Intracellular sperm 1,25-dihydroxycholecalciferol was higher in the control group compared to the target group. The mRNA levels of 1- α-hydroxylase were significantly higher in the control samples, while VDR expression was significantly higher in the target group. Significant positive correlations were established between free and bioavailable 25-hydroxycholecalciferol with sperm motility and morphology. Vitamin D metabolites in blood and intracellular sperm 1,25-dihydroxycholecalciferol seem to exert beneficial effects on sperm motility and morphology. Regarding sperm quality, these effects are more pronounced in the free and bioavailable 25OHD compared to the total 25OHD in blood. Higher expression of 1-α-hydroxylase likely leads to higher intracellular levels of 1,25-dihydroxycholecalciferol, which could contribute to sperm motility and morphology. Higher VDR expression may be a compensatory mechanism related to lower intracellular sperm 1,25-dihydroxycholecalciferol.

Analysis of changes in the morphological structures of sperm during preservation of liquid boar semen in two different seasons of the year

Animal fertility is the result of a combination of genetic, physiological and environmental factors. Assessment of semen quality plays a key role in determining the reproductive performance of boars. The aim of the study was to determine the effect of two seasons of the year on the morphology, morphometry, cell membrane integrity and mitochondrial activity of sperm during storage of liquid boar semen at 17 °C. The study was carried out using 20 boars. Four ejaculates were collected from each boar in each of two seasons of the year. All tests were carried out five times: at 1, 24, 48, 96 and 168 h during storage. The results showed that sperm in ejaculates collected in summer are more sensitive to storage conditions than those from ejaculates obtained in winter. The percentage of sperm with morphological defects was shown to increase with the storage time of the diluted ejaculates, particularly between 96 and 168 h of preservation. In summer, the percentage of sperm with an intact cell membrane and the percentage with high mitochondrial membrane potential are much lower than in winter, at every hour of semen preservation. In the case of boars used for artificial insemination, it is worth taking into account the season when the semen is collected, especially if it is to be stored in liquid form. Assessment of sperm cell structures during storage of liquid semen should be implemented at insemination stations and should be carried out more often in summer.

Effect of male age on semen quality in domestic animals: potential for advanced functional and translational research?

Age and other factors like season and breed are often associated with sperm quality and fertility in domestic animals. Even though many studies assessed the relationship between the age of the male and sperm parameters, the effects have not been comprehensively evaluated. Changes in semen quality from pubertal (young) to adult and old age were identified in the bull, ram, buck, boar, dog, and stallion, respectively. The review discusses the association between male age and semen volume, the total number of spermatozoa per ejaculate, sperm concentration, motility, morphology, sperm cell function, sperm DNA integrity, oxidative stress, and antioxidant activity in these species of animals. Generally, semen characteristics improve to a certain age, which declines as the animal ages. Only a few studies evaluated the impact of advanced age or employed advanced functional sperm assessment methods to assess age-related changes in sperm quality and male fertility. Such studies in the dog or stallion, for instance, may contribute to advancing knowledge in human-assisted reproductive techniques used in patients of advanced paternal and maternal age.

Effect of ascorbic acid on metabolic status, lipid peroxidation, antioxidant activity and quality of frozen Indian red jungle fowl (Gallus gallus murghi) semen

The Indian red jungle fowl population is decreasing in its natural habitat. Its conservation through semen cryopreservation with sufficient live sperm recovery rate is requisite where ascorbic acid could play significant role to mitigate cryo-incited injuries. The objective was to elucidate the effect of ascorbic acid on freezability of Indian red jungle fowl sperm. Pooled semen was aliquoted and diluted (1:5) with red fowl extender having ascorbic acid: 0.0 (control), 1.0, 2.0 and 4.0 mM. Diluted samples were cryopreserved and semen quality was assessed at post-dilution, cooling, equilibration and freeze-thawing stages. Sperm metabolic status, antioxidant potential and lipid peroxidation were studied at post-dilution and freeze-thawing. Sperm motility did not differ (p > .05) in experimental extenders and control at post-dilution and cooling; however, it was recorded higher (p < .05) with ascorbic acid at 2.0 mM compared with other levels at post-equilibration and post-thawing stage. Sperm viability, plasma membrane and acrosome intactness were recorded higher (p < .05) with 2.0 mM ascorbic acid compared with other concentrations of ascorbic acid at all stages of cryopreservation. Sperm metabolic status and antioxidant potential were recorded higher (p < .05), while lipid peroxidation was recorded lowest (p < .05) with 2.0 mM ascorbic acid compared with 1.0, 4.0 mM and control. In conclusion, ascorbic acid at 2.0 mM in red fowl extender improves quality, metabolic status and antioxidant potential of frozen Indian red jungle fowl semen through ameliorating lipid peroxidation.

Effect of season on the dynamics of cat sperm DNA fragmentation

BACKGROUND

Feline species undergo reproductive seasonality; thus, sperm characteristics, such as DNA integrity, can be affected by the photoperiod. This study was conducted to determine the effect of seasonal changes on sperm quality and on the dynamics of sperm DNA fragmentation. Epididymal spermatozoa were collected from 36 tomcats subjected to bilateral orchiectomy during breeding (BS) and non-breeding (NBS) seasons. Sperm samples were obtained by cutting the cauda epididymis and assessed for sperm motility, concentration, acrosome integrity, plasma membrane integrity and sperm morphology. Sperm DNA fragmentation was evaluated by the sperm chromatin dispersion test after 0, 6, and 24 h of incubation at 37 °C.

RESULTS

The total sperm motility and plasma membrane integrity values were greater during the BS, while the percentages of abnormal sperm and head defects were lesser (p < 0.05). No significant differences in DNA fragmentation were found between seasons after sperm collection. DNA damage was greater after 24 h of incubation at 37 °C in both seasons, although the percentage of spermatozoa with fragmented DNA was significantly lesser in the BS than in the NBS at 24 h (p < 0.05).

CONCLUSIONS

The study suggests seasonal changes in some of the quality parameters of cat sperm. DNA fragmentation dynamics were affected by the time of incubation and reproductive season; therefore, this technique might be used as an additional tool to test the potential fertility of semen samples used in feline-assisted reproduction.

Coat color affects the resilience against heat stress impacts on testicular hemodynamics, reproductive hormones, and semen quality in Baladi goats

Drastic climatic changes threaten animal productivity and prolificacy, whose adaptability is governed by its pheno- and genotypic traits. This study was aimed at investigating the effect of coat color on the adaptability of goat bucks under heat stress conditions from the perspectives of testicular blood flow (TBF) and biometry, reproductive hormones, and semen quality. Twenty bucks (Capra hircus) bearing different coat colors were selected from a large flock and divided into four equal groups (n = 5 each) as follows: black coat (BC; 100% black), brown coat (BrC; 100% dark brown), white coat (WC; 100% white), white-black coat (WBC; 50-60% white). Bucks were examined for TBF [Doppler ultrasonography and serum nitric oxide (NO)], testosterone (T) and luteinizing hormone (LH), seminal plasma oxidative biomarkers [catalase (CAT), total antioxidant capacity (TAC), and malondialdehyde (MDA)], and sperm traits percentages [progressive motility (PM), viability (SV), normal morphology (NM), and sperm concentration (SC) once a week for seven consecutive weeks (W1-W7) in the summer season (temperature humidity index = 88.4-92.2). Specifically, at W3-W7, darker bucks (BC and BrC) testicular volume, testicular colored area, T, NO, CAT, TAC, PM, SV, NM, and SC (W7 only) differed significantly (P < 0.05) by decrease than the lighter ones (WC and WBC). Both Doppler indices and serum MDA concentrations were elevated (P < 0.05) at W3-W7 in the BC and BrC bucks compared to WC and WBC groups. In conclusion, bucks with lighter coats were more resistant to the negative effects of HS on TBF, seminal oxidative biomarkers, and semen quality.

Mitigation of endogenous oxidative stress and improving growth, hemato-biochemical parameters, and reproductive performance of Zaraibi goat bucks by dietary supplementation with Chlorella vulgaris or/and vitamin C

This study was conducted to explore the effects of dietary inclusion of Chlorella vulgaris (CV) or/and vitamin C (VC) on growth, hemato-biochemical parameters, oxidative and antioxidant status, reproductive hormones, and semen quality variables, and scrotal-testicular dimensions of Zaraibi goat bucks. Twenty sexually mature bucks (41.49 ± 0.91 kg BW) were randomly divided into 4 groups (5 bucks/group). The control group was fed the control diet, while the other three groups received a diet supplemented with VC (2 g/animal /day), CV (5 g/animal/day), and CV plus VC (the same levels), respectively, for 8 weeks (treatment period), and then semen was collected for 8 weeks. Results showed that dietary supplementation with CV-VC combination significantly increased the final body weight, weight gain, packed cell volume, hemoglobin, red blood cells, white blood cells, and lymphocytes; elevated serum total protein, globulin, testosterone, estradiol, superoxide dismutase, glutathione peroxidase with a significant reduction in Malondialdehyde in serum and seminal plasma. Also, the CV-VC combination significantly improved the ejaculate volume, total sperm output, sperm concentration, and live sperm, and reduced reaction time and sperm abnormality of bucks. Either CV or VC given separately or in combination, at the chosen levels, had no detrimental effects on animal physiological responses with normal hepatic and renal functions. Therefore, the CV-VC combination could be safely utilized as a dietary supplement in buck's diets to improve antioxidant defenses, scavenge free radicals, and potentiate buck's reproductive activities under normal conditions.

Estimation of genetic parameters for semen traits in Egyptian buffalo bulls

This study was conducted to characterize semen traits (ejaculate volume (VOL), mass motility (MM), sperm livability (LS), percentage of abnormal sperms (AS), and sperm concentration (CONC)) of Egyptian buffalo bulls and evaluate the importance of some nongenetic factors (year (YC) and season (SC) of semen collection and age of bull genetically and environmentally at collection (ABC)) affecting the investigated traits. A total of 7761 normal semen ejaculates were collected from 26 bulls from 2009 to 2019. Single-trait and bivariate repeatability animal models using Bayesian methods were used to estimate variance components, heritability, repeatability, and genetic correlations among the investigated semen traits. YC and ABC exerted significant effects on most semen traits, whereas SC exerted no significant effect on all the investigated semen traits. Heritability estimates were 0.08, 0.52, 0.51, 0.04, and 0.49 for VOL, MM, LS, AS, and CONC, respectively. Repeatability estimates were 0.14, 0.82, 0.79, 0.06, and 0.78 for VOL, MM, LS, AS, and CONC, respectively. The genetic correlations between MM and each of LS and CONC were highly significant (0.99 ± 0.01 and 0.95 ± 0.14, respectively), and that between LS and CONC was also highly significant (0.92 ± 0.20). The high heritability estimates for MM, LS, and CONC combined with the favorable high significant genetic correlations between these traits indicated that direct selection for MM may be an effective method to enhance semen quality in Egyptian buffalo bulls and consequently improve fertility.

Science-based quality control in boar semen production

The ever-increasing understanding of sperm physiology, combined with innovative technical advances, continuously furthers the development of boar semen production management. These improvements pave the way for the future implementation of modified quality assurance concepts. This review provides an overview of current trends and new approaches in boar semen production, focusing on: the improvement of hygienic standards, alternatives to the use of antibiotics including the application of cold temperature storage and the utilization of antimicrobial additives, as well as the implementation of new quality control tools. Furthermore, the influence of dilution and temperature management, as well as new possibilities for an improvement of boar semen shipping and storage conditions are reviewed.

Freezability and Fertility Rates of Stallion Semen Supplemented With Trehalose in Lactose Extender

Cryopreservation of stallion semen is often associated with poor post-thaw sperm quality. One of the reason for this diminished quality is osmotic stress that spermatozoa experiences during freezing and thawing process. The aim of the present study was to evaluate the cryoprotective effect of trehalose on stallion sperm quality and field fertility rates subjected to cooling and freeze-thawing process. Semen samples were collected from six Marwari breed stallions, divided into three different treatments in a final concentration of 150 × 106 sperm/mL by using Lactose based extender containing 0, 50, and 150 mM of trehalose then subjected to cryopreservation after equilibration. Sperm motility, acrosome integrity, plasma membrane integrity, mitochondrial membrane potential, DNA integrity and oxidative stress related parameters of the stallion spermatozoa were analyzed at fresh, prefreeze and post thaw stages. Thirty (30) reproductively healthy mares were inseminated with frozen-thawed semen either supplemented with (treatment) or without (control) trehalose to evaluate the field fertility. Results of the current study indicated that, the extender containing 50 mM trehalose has enhanced the functional plasma membrane, acrosomal, DNA integrities and augmented the mitochondrial membrane potential. Trehalose supplementation to the semen extender not only ameliorated the semen quality parameters, but also protected the stallion sperm from oxidative stress by reducing the levels of reactive oxygen species (ROS) and lipid peroxidation (LPO). The inclusion of 50 mM trehalose in semen extender resulted in significantly (P < .05) increased post-thaw progressive motility and viability compared to the control group. Mares inseminated with frozen-thawed semen supplemented with 50 mM trehalose tended to have better pregnancy rates than controls (non-significant [P < .05]) although a larger fertility trial is required to determine if this effect reaches the level of significance. In conclusion, addition of 50 mM trehalose yielded in better quality stallion semen after cooling and post-thawing in terms of reducing the oxidative stress and enhancing the motility, integrities of acrosome, plasma membrane, mitochondrial potential and DNA.

Influence of spirulina supplementation on growth performance, puberty traits, blood metabolites, testosterone concentrations, and semen quality in Barki male lambs

Background

The fertility and genetic value of the flock can be enhanced by selecting lambs with highly developed early puberty characteristics. Spirulina (SP) has been evaluated as a natural product supplement to boost lamb growth, immunity, and productivity.

Aim

Study growth performance, blood metabolites, puberty development traits, semen quality, and seminal plasma biochemical concentrations of growing Barki lambs when supplemented with SP at different levels.

Methods

in a 24 weeks study, 30 Barki male lambs weighing an average of 21.78 ± 2.56 kg, with a body condition score of 3.20 ± 0.55 and an age of about 16 ± 0.24 weeks were used. The lambs were randomly assigned to three groups (10 lambs each) of daily SP supplementation levels per lamb of 0 ml (control), 50 ml (SP1), and 100 ml (SP2). The SP powder was made into a water suspension using SP to water ratio of 1 g:10 ml. The growth characteristics, as well as the development of puberty, blood metabolites, and semen quality analysis of every lamb, were measured.

Results

The growth performance was greater (p < 0.05) in SP2 lambs compared with other lambs. While daily dry matter intake was not affected by SP treatment, feed efficiency had significantly improved in SP2 groups. Furthermore, the SP2 lambs have attained puberty at early ages than the control lambs. The testes volume of SP2 lambs was bigger (p < 0.05) than other groups throughout the pre-pubertal up to the puberty stage. The addition of SP had no effects on the total protein, glucose, and triglycerides concentrations. Meanwhile, the cholesterol concentration was lowest (p < 0.05) in the SP2 lambs. The blood and seminal plasma levels of alanine aminotransferase and aspartate aminotransferase decreased (p < 0.05) in the SP lambs more than their control counterparts. The levels of superoxide dismutase reduced glutathione, and total antioxidants had increased (p < 0.05) in the treated lambs compared with the control group. Further, the malondialdehyde levels decreased (p < 0.05) in the SP-treated lambs. Additionally, the SP2 lambs produced better semen quality than the control lambs.

Conclusion

SP supplementation (100 ml/head/day) enhanced growth performance, feed efficiency, and antioxidative status, exerting a positive influence on the physiological parameters and sexual behavioral patterns at puberty in Barki lambs.