Effects of ginger (Zingiber officinale) supplementation on testicular histology, semen characteristic, blood plasma parameters and reproductive performance in aged broiler breeder roosters

Higher long-chain polyunsaturated fatty acids contents in roosters' sperm plasma membrane along with age-related decrease in antioxidant defense make the spermatozoa very susceptible to lipid peroxidation. Ginger root contains abundant amounts of gingerol, shogaols, gingerdiol and other active compounds, which known as antioxidant compounds to enhance semen quality. The goal of the study was to evaluate the effect of dietary supplementation of ginger root on semen quality, blood chemistry, immune response, testicular histology and reproductive performance of Ross-308 breeder roosters from 47 to 60 weeks of age. The feeding of ginger root resulted in an increase in parameters related to sperm forward motility and seminal total antioxidant capacity (TAC), and following there was a tendency to increase and decrease in seminal superoxide dismutase activity and malondialdehyde concentration, respectively; however, sperm concentration was not affected. There was an increase and tendency to increase in blood total protein and TAC in the supplemented group respectively. The roosters fed ginger supplemented diet had a higher spermiation index; and following there was tendency to increase seminal tubes spermatozoids number (p = 0.056) and repopulation index (p = 0.058). Despite the improved seminal antioxidant status and a tendency to lower embryonic mortality in the ginger-received group, the fertility and hatchability rate of roosters were statistically insignificant. Supplementations of ginger root in ageing rooster's diet had a beneficial effect on sperm motility, seminal antioxidant status and testicular spermiation index.

Testicular alterations and semen quality in a selected group of breeding buffaloes

Testicular ultrasound enables the evaluation of changes in the testicular parenchyma. This study aimed to report the occurrence of hypoechogenic testicular alterations and their relationship with semen quality in five breeding buffaloes. Two buffaloes presented with hyperechoic points characteristic of fibrosis and anechoic density content between the parietal and visceral tunica. The two bulls without ultrasonographic changes showed higher average trajectory speed, linear velocity, curvilinear velocity, amplitude of lateral displacement of the spermatic head, total motility, progressive motility, fast speed, and acrosomal membrane values within the normal range. The number of spermatozoa with major and total defects was higher in the group of animals without alterations. The three buffaloes that presented with testicular alterations produced semen within established freezing standards.

Single layer centrifugation (SLC) for bacterial removal with Porcicoll positively modifies chromatin structure in boar spermatozoa

The storage of boar semen samples at 17 °C for artificial insemination (AI) doses enables the proliferation of the bacteria, making antibiotics necessary. This can contribute to the development of antimicrobial resistance (AMR). This study tested bacterial presence and sperm chromatin structure after using a low-density colloid (Porcicoll) as an antibiotic alternative to eliminate bacteria. Ejaculates (8 boars, 3 ejaculates each) were split as control and low-density colloid centrifugation (single layer centrifugation, SLC, 20%, and 30% Porcicoll) into 500 ml tubes. Analyses were carried out at days 0, 3, and 7 (17 °C) for microbial presence and sperm chromatin structure analysis: %DFI (DNA fragmentation) and %HDS (chromatin immaturity), monobromobimane (mBBr; free thiols and disulfide bridges), and chromomycin A3 (CMA3; chromatin compaction). Besides comparing bacterial presence (7 species identified) and chromatin variables between treatments, the associations between these sets of variables were described by canonical correlation analysis (CCA). Results showed a significant decrease of some bacteria or a complete removal after SLC (especially for P30). SLC also caused a decrease of %HDS and an increase of disulfide bridges and low and medium mBBr populations, suggesting the removal of immature sperm (poor chromatin compaction). CCA showed an association pattern compatible with the degradation of sperm chromatin parameters with bacterial contamination, especially Enterobacteria, P. aeuriginosa, and K. variicola. In conclusion, bacterial contamination affects sperm chromatin beyond DNA fragmentation; SLC with low-density colloid not only removes bacteria from boar semen, but also chromatin structure is enhanced after selection.

MMPs, ADAMs and ADAMTSs are associated with mammalian sperm fate

Metalloproteinases include matrix metalloproteinases and disintegrin metalloproteinases. They are important members of the ECM degradation and reconstruction process and are associated with tissue development and disease. The ECM is a three-dimensional network of large molecules consisting of a variety of proteins. It is a physical scaffold for organs, and all types of cells can be found within the ECM. The testicle, where sperm are produced, is an organ that is constantly in dynamic flux. Metalloproteinases can regulate testicular tissue development and the maturation of sperm by affecting the ECM. Metalloproteinase disorders can lead to cryptorchidism, azoospermia, poor semen quality and other diseases. As a member of the metalloproteinase family, ADAMTS plays an important role in testicular slippage to the scrotum. ADAM is involved in the fertilization process, and excessive MMP can damage the BTB. In the testis, metalloproteinase stability represents the stability of the extracellular microenvironment in which germ cells are located and is associated with reproductive function. Metalloproteinases have a definite relationship with male reproduction, but the underlying mechanism is still unclear. This paper summarizes the literature on various metalloproteinases in testicular tissue physiology and pathology to elucidate their role in reproductive function and male reproductive mechanisms.

Low-moderate dietary phytoestrogens transiently disrupt spermatogenesis and the seminal plasma proteome in the ram

In brief

Dietary phytoestrogens disrupt a specific stage of ram spermatogenesis, causing subtle decreases in sperm quality by affecting the expression of pathways involved in the structural integrity of the spermatozoa. This paper demonstrates for the first time that ram reproduction is compromised by oestrogenic pasture, whilst also providing a longitudinal model for the impact of phytoestrogens on male fertility.

Abstract

Compounds with oestrogen-like actions are now common in both the Western diet. The long-term impacts and underlying mechanisms by which oestrogenic compounds alter male reproduction, however, are unclear. To investigate this, we used a longitudinal sheep model examining the impact of oestrogenic pasture consumption on semen quality and production, testicular size, sexual behaviour and the seminal plasma proteome of Merino rams (n = 20), over a full spermatogenic cycle and in the subsequent breeding season. Throughout the study period, sexual behaviour, sperm production and motility were similar between the exposed and non-exposed rams (P > 0.05). However, between 5 and 8 weeks of exposure to dietary phytoestrogens, rams produced a higher percentage of spermatozoa with a specific malformation of the sperm midpiece and reduced DNA integrity, compared to non-exposed rams (P < 0.001). Investigation into the seminal plasma proteome revealed 93 differentially expressed proteins between phytoestrogen-exposed and control rams (P < 0.05). Exposure to phytoestrogens increased the expression of proteins involved in cellular structure development, actin cytoskeleton reorganisation, regulation of cell function and decreased expression in those related to catabolic processes. The greatest fold changes were in proteins involved in the assembly of the sperm flagella, removal of cytoplasm, spermatid development and maintenance of DNA integrity. After returning to non-oestrogenic pasture, no differences in any measure were observed between treatment groups during the subsequent breeding season. We conclude that dietary phytoestrogens can transiently disrupt specific stages of ram spermatogenesis, causing subtle decreases in sperm quality by affecting the expression of pathways involved in the structural integrity of the spermatozoa.

Animal board invited review: An update on the methods for semen quality evaluation in swine - from farm to the lab

Pig breeding is mainly conducted through artificial insemination with liquid-stored semen. It is, therefore, crucial to ensure that sperm quality is over the standard thresholds, as reduced sperm motility, morphology or plasma membrane integrity are associated with reduced farrowing rates and litter sizes. This work aims to summarise the methods utilised in farms and research laboratories to evaluate sperm quality in pigs. The conventional spermiogram consists in the assessment of sperm concentration, motility and morphology, which are the most estimated variables in farms. Yet, while the determination of these sperm parameters is enough for farms to prepare seminal doses, other tests, usually carried out in specialised laboratories, may be required when boar studs exhibit a decreased reproductive performance. These methods include the evaluation of functional sperm parameters, such as plasma membrane integrity and fluidity, intracellular levels of calcium and reactive oxygen species, mitochondrial activity, and acrosome integrity, using fluorescent probes and flow cytometry. Furthermore, sperm chromatin condensation and DNA integrity, despite not being routinely assessed, may also help determine the causes of reduced fertilising capacity. Sperm DNA integrity can be evaluated through direct (Comet, transferase deoxynucleotide nick end labelling (TUNEL) and its in situ nick variant) or indirect tests (Sperm Chromatin Structure Assay, Sperm Chromatin Dispersion Test), whereas chromatin condensation can be determined with Chromomycin A3. Considering the high degree of chromatin packaging in pig sperm, which only have protamine 1, growing evidence suggests that complete decondensation of that chromatin is needed before DNA fragmentation through TUNEL or Comet can be examined.

Protective effects of different doses of MitoQ separately and combined with trehalose on oxidative stress and sperm function of cryopreserved Markhoz goat semen

The mitochondria-targeted antioxidant MitoQ has been regarded as an effective antioxidant agent against cryo-induced oxidative cellular damage. This study aimed to evaluate the use of different doses of MitoQ combined with trehalose to minimize mitochondrial impairment and oxidative stress during sperm cryopreservation of Markhoz goat. For this, semen samples (n = 50) were collected by electroejaculation every 5 days from 5 bucks in 10 replicates. On each collection day, 5 ejaculates (one ejaculate for each buck) were pooled and then diluted in eight different Tris-based extenders as follows: no additives (control), 20, 200, 2000 nM of MitoQ (MT20, MT200, MT 2000, respectively), 150 mM of trehalose (Tr), MT20+Tr, MT200+Tr, MT2000+Tr. The semen samples were frozen using a standard protocol, and sperm function and oxidative stress were evaluated after thawing. The semen extender supplemented with MT200+Tr had higher (P < 0.05) total and progressive motility, acrosome and membrane integrity, superoxide dismutase, glutathione peroxidase, total antioxidant capacity, and lower (P < 0.05) DNA fragmentation, malondialdehyde and intracellular hydrogen peroxide levels than the all other groups except MT200; meanwhile, MT200 was also improved (P < 0.05) in these parameters than in the control group. Furthermore, MT200 and MT200+Tr showed higher (P < 0.05) percentages of live cryopreserved sperm with high mitochondrial activity than other groups. However, abnormality percentage and catalase activity of frozen-thawed sperm were not affected by treatments (P > 0.05). To conclude, we have found that supplementation of 200 nM MitoQ alone or in combination with 150 mM trehalose to semen extender improved the quality of cryopreserved sperm in goats, which is associated with enhanced antioxidant enzymatic defense and mitochondrial activity and reduced DNA fragmentation.

Non-genetic effects and repeatability estimates of semen production traits in Murrah buffalo bulls

The objectives of this study were to determine the repeatability estimates and the effect of ejaculate, season, period, age, and bull on semen production traits in Murrah buffalo bulls maintained in an organized semen station. A data set comprising 54,268 ejaculates from 76 Murrah buffalo bulls collected across 12 years were analyzed. The analysis of variables included non-genetic factors as the fixed effects and bull as the random effect. The repeatability was estimated by the restricted maximum likelihood method (REML) using WOMBAT program. The overall least-squares means for semen volume, sperm concentration, total sperm/ejaculate, mass activity, individual motility, post-thaw motility, and frozen semen straws/ejaculate were 2.65 ml, 1222.04 million/ml, 3030.10 million, 2.64, 67.45%, 51.73%, and 128.80 doses. The repeatability estimates were 0.27, 0.25, 0.22, 0.28, 0.34, 0.27, and 0.23, respectively. The studied non-genetic factors influenced (P < 0.01) all seminal traits. Likewise, variation (P < 0.01) due to individual bull was also observed. The first ejaculate was superior in terms of ejaculate volume, sperm concentration, total sperm/ejaculate, and frozen semen straws than the second ejaculate. The south-west monsoon and summer seasons were the best seasons with better semen quality and frozen semen production. Compared to the remaining periods, during Period V (2014-2016), greater values for most seminal traits were found. Bulls above 8 years of age expressed higher semen production than the younger bulls below 4 years, whereas the best performance was observed in the age group of 12 years and above. The repeatability estimates were low to moderate ranging from 0.22 for total sperm/ejaculate to 0.34 for individual motility. A significant (P < 0.01) positive correlation was observed between the seminal traits except the negative correlation in semen volume and total sperm/ejaculate. It was concluded that all the non-genetic factors considered in this study exerted influence on studied seminal traits. Therefore, appropriate management practices can be applied to improve semen quality and quantity.

Differences of semen microbiota among breeding boars with different reproductive ages

In this study, we investigated 18 healthy and fertile Duroc boars, dividing them into two groups based on their reproductive age: 9 boars aged 18 mo and 9 boars aged 36 mo. Prior to semen sampling, all boars were raised together under identical management conditions for a period of 3 mo. Our findings revealed that older boars exhibited lower sperm motility and a higher proportion of abnormal sperm morphology compared to younger boars. Furthermore, older boars demonstrated lower anti-oxidant capacity in their semen, as indicated by elevated levels of malondialdehyde and decreased levels of superoxide dismutase and glutathione peroxidase. Microbiota analysis utilizing the 16S rRNA technique showed that the semen microbiota of older boars had reduced alpha-diversity and beta-diversity in comparison to younger boars. We identified the Streptococcus genus and Streptococcus gallolyticus subsp macedonicus species served as biomarkers for semen from younger breeding boars, while the Bacteroides pyogenes species as a biomarker for semen from older breeding boars. Additionally, the semen from older boars exhibited a higher abundance of Aerococcus, Gallicola, Ulvibacter, and Proteiniphilum compared to younger boars. Spearman correlation analysis showed that these four bacteria were negatively correlated with semen quality. The abundance of Gallicola and Proteiniphilum were negatively correlated with semen anti-oxidant capacity. Additionally, the reduction of semen anti-oxidant capacity was correlated to the decrease of semen quality. Based on these findings, we concluded that the semen of older boars contains a higher abundance of harmful bacteria, which contributes to the observed reduction in semen anti-oxidant capacity and overall semen quality in this group.

Whole transcriptome sequencing reveals core genes related to spermatogenesis in Bactrian camels

Bactrian camels survive and reproduce better in extreme climatic conditions than other domestic animals can. However, the reproductive efficiency of camels under their natural pastoral conditions is low. Several factors affect mammalian reproductive performance, including testicular development, semen quality, libido, and mating ability. Testis is a main reproductive organ of the male and is responsible for producing spermatozoa and hormones. However, our understanding of the expression patterns of the genes in camel testis is minimal. Thus, we performed total RNA-sequencing to investigate the gene expression pattern. As a result, 1,538 differential expressed mRNAs (DEmRNAs), 702 differential expressed long non-coding RNAs (DElncRNAs), and 61 differential expressed microRNAs (DEmiRNAs) were identified between pubertal and adult Bactrian camel testes. Then the genomic features, length distribution, and other characteristics of the lncRNAs and mRNAs in the Bactrian camel testis were investigated. Target genes of the DEmiRNAs and DEmRNAs were further subjected to gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Genes, such as AMHR2, FGF1, ACTL7A, GATA4, WNT4, ID2, LAMA1, IGF1, INHBB, and TLR2, were mainly involved in the TGF-β, PI3K-AKT, Wnt, GnRH, and Hippo signaling pathways which relate to spermatogenesis. Some of the DEmiRNAs were predicted to be associated with numerous DElncRNAs and DEmRNAs through competing endogenous RNA (ceRNA) regulatory network. At last, the candidate genes were validated by RT-qPCR, dual fluorescent reporter gene, and a fluorescence in situ hybridization (FISH) assay. This research provides high-throughput RNA sequencing data of the testes of Bactrian camels across different developmental stages. It lays the foundation for further investigations on lncRNAs, miRNAs, and mRNAs that involved in Bactrian camel spermatogenesis.

Seminal plasma metabolomics analysis of differences in liquid preservation ability of boar sperm

The preservation of semen is pivotal in animal reproduction to ensure successful fertilization and genetic improvement of livestock and poultry. However, investigating the underlying causes of differences in sperm liquid preservation ability and identifying relevant biomarkers remains a challenge. This study utilized liquid chromatography-mass spectrometry (LC-MS) to analyze the metabolite composition of seminal plasma (SP) from two groups with extreme differences in sperm liquid preservation ability. The two groups namely the good liquid preservation ability (GPA) and the poor preservation ability (PPA). The aim was to explore the relationship between metabolite composition in SP and sperm liquid preservation ability, and to identify candidate biomarkers associated with this ability of sperm. The results revealed the identification of 756 metabolites and 70 differentially expressed metabolites (DEM) in the SP from two groups of boar semen with differing liquid preservation abilities at 17 °C. The majority of identified metabolites in the SP belonged to organic acids and derivatives as well as lipids and lipid-like molecules. The DEM in the SP primarily consisted of amino acids, peptides, and analogs. The Kyoto Encyclopedia of Genes and Genomes analysis also demonstrated that the DEM are mainly concentrated in amino acid synthesis and metabolism-related pathways (P < 0.05). Furthermore, eleven key metabolites were identified and six target amino acids were verified, and the results were consistent with the non-targeted metabolic analysis. These findings indicated that amino acids and their associated pathways play a potential role in determining boar sperm quality and liquid preservation ability. D-proline, arginine, L-citrulline, phenylalanine, leucine, DL-proline, DL-serine, and indole may serve as potential biomarkers for early assessment of boar sperm liquid preservation ability. The findings of this study are helpful in understanding the causes and mechanisms of differences in the liquid preservation ability of boar sperm, and provide valuable insights for improving semen quality assessment methods and developing novel extenders or protocols.

Characterization of boar semen microbiome and association with sperm quality parameters

Elevated levels of bacteria within fresh extended boar semen are associated with decreased sperm longevity, therefore reducing the fertility of a semen dose. The objective of this study was to characterize the bacterial communities using 16S rRNA sequencing in freshly extended boar semen samples and relate the prevalence and diversity of the microbial population to sperm quality parameters 1) between studs, 2) between pooled and single-sire doses, and 3) over a 5-day period. Eight single-sire (n = 4 per stud) and eight pooled (n = 4 per stud) non-frozen extended semen doses were obtained from two boar studs (A and B). Pooled doses were the composite of the boar's ejaculates used in single-sire doses. Doses were subsampled for 5 d post-collection. Ten negative controls of each pooled dose (n = 2) and single-sire dose (n = 8) remained sealed until the last day. Microbiome analysis was achieved by examining the V4 hypervariable region of the 16S rRNA gene of flash-frozen samples. Two evaluators determined the average sperm motility and agglutination (0: no adhesion to 3: >50% adhesion) by averaging their estimates together at 10 random locations per slide. Stud A had greater sperm agglutination (1.6 vs. 1.0 ± 0.1; P < 0.01) than stud B. Sperm motility decreased over the 5-day period (P < 0.01) and tended (P = 0.09) to be greater in stud B than A (67.4% vs. 61.5% ± 0.02%). Compared with stud A, stud B had a greater relative abundance of Proteobacteria (60.0% vs. 47.2% ± 1.5%; P < 0.01) and a lower relative abundance of Firmicutes (22.5% vs. 31.9% ± 1.4%; P < 0.01). Moreover, stud A had a greater relative abundance of Bacteroidetes (6.3% vs. 5.3% ± 0.4%; P < 0.01) and Actinobacteria (11.5% vs. 10.1% ± 0.5%; P = 0.05) than stud B. Differences were found in alpha diversity for both Chao1 (P < 0.01) and Shannon (P < 0.01) diversity indexes among days 2, 3, 4, and 5 post-collection to day 1. For beta diversity, unweighted UniFrac metric on days 2, 3, 4, and 5 post-collection differed from those on day 1 (P < 0.01). There were significant correlations between sperm motility and relative abundance of Prevotella (r = -0.29), Ruminococcus (r = -0.24), and Bacteroides (r = -0.32). Additionally, there were significant correlations between sperm motility and Chao1 (r = -0.50) and Shannon's index (r = -0.36). These results demonstrate that differences in bacterial communities over time and between boar studs can be associated with variation in sperm quality.

Analysis of artificial insemination center management factors that contribute to sperm parameters and boar longevity with a major focus on PGF2α treatment

Artificial insemination (AI) centers' economic profitability is directly impacted by the amount of high-quality sperm doses. Many internal and external factors contribute to the quality of ejaculates. To enhance the libido and to reduce the time that is required to train boars for semen collection, prostaglandin products are used routinely at AI centers. The objectives of this study were to analyze sperm parameters of 40,765 ejaculates and the survival of 406 PGF2α-treated and 417 untreated AI boars of five breeds (Duroc [DU], Large White [LW], Landrace [LR], Pietrain [PI], and Large White Sire Line [LS]). Data were assessed in one AI center in Switzerland from 2018 to 2022 and sperm parameters were determined by computer-assisted sperm analysis immediately after semen collection. For further calculations, the ejaculates were divided into four groups depending on the boar's age at semen collection day: 7 to 11, 12 to 18, 19 to 24, and 25 to 87 mo. Along with the boar age, breed, season, and semen collection frequency even the treatment with PGF2α had significant influence on sperm parameters. Overall, 19.5% ejaculates were collected after PGF2α treatment. For every age and breed group, higher ejaculate volume was found for untreated boars than for PGF2α-treated boars (P < 0.001). Higher values for total and progressive sperm motility, total sperm number, and the proportion of morphologically normal sperm were observed in untreated boars across several age and breed groups. Only for sperm concentration, higher values were found for treated boars older than 11 mo (P < 0.001) and the breeds DU, LW, and LR (P < 0.001). The chance of ejaculates being rejected for AI purposes because of low sperm quality was 21% greater for treated boars. There was no difference in survival between treated and untreated boars. The hazard for boar removal increased with decreasing age at first semen collection and decreasing semen collection frequency. The results reveal better sperm quality for untreated boars than for PGF2α-treated boars, which might indicate that the underlying fertility of boars necessitating treatment is inferior compared to boars that can be collected without further treatment. Therefore, AI boar stations that are aiming to reduce PGF2α treatment should pay special attention to high libido and fertility of young prospective AI boars.

Identification of potential candidate genes and regulatory pathways related to reproductive capacity in hypothalamus and pituitarium of male ducks (Anas platyrhynchos) by differential transcriptome analysis

The improvement of reproductive capacity of poultry is important for the poultry industry. The existing studies on reproductive capacity mainly focus on the testis tissue, but few reports on regulationary effect of brain neuroendocrime on reproductive capacity have been available. The hypothalamus-pituitarium-gonad (HPG) axis is an important pathway regulating spermatogenesis and sexual behavior. This study analyzed the gene expression in the hypothalamus and pituitary tissues of male ducks in high-semen-quality group (DH), low-semen-quality group (DL), and non-response group (DN) by RNA-sequencing. A total of 1980 differentially expressed genes (DEGs) were identified, and significantly less DEGs were found in pituitary gland than in hypothalamus. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed that these DEGs were mainly enriched in nerve-related and synapse-related biological processes, mitochondrial inner membrane formation pathway, and ribosome structure pathway. Notably, the neuroactive ligand-receptor interaction pathway significantly enriched in all three comparisons (DH vs. DL, DH vs. DN, and DL vs. DN) was related to different reproductive performance such as semen quality and sexual response. Furthermore, six genes, including POMC, CPLX2, HAPLN2, EGR4, TOX3, and MSH4, were identified as candidate genes regulating reproductive capacity. Our findings provide new insights into the regulation mechanisms underlying the reproductive performance of male poultry, and offer a valuable reference for duck breeding programs aimed at promoting reproductive capacity.

Integrating sperm cell transcriptome and seminal plasma metabolome to analyze the molecular regulatory mechanism of sperm motility in Holstein stud bulls

Considering that artificial insemination is the most widely used assisted reproductive technique in the dairy industry, the semen quality of bulls is very important for selecting excellent stud bulls. Sperm motility is one of the important traits of semen quality, and related genes may be regulated by environmental factors. Seminal plasma can affect sperm cell transcriptome and further affect sperm motility through exosome or other processes. However, the molecular regulation mechanism of bull sperm motility has not been studied by combining the sperm cell transcriptome with seminal plasma metabolome. The number of motile sperm per ejaculate (NMSPE) is an integrated indicator for assessing sperm motility in stud bulls. In the present study, we selected 7 bulls with higher NMSPE (5,698.55 million +/- 945.40 million) as group H and 7 bulls with lower NMSPE (2,279.76 million +/- 1,305.69 million) as group L from 53 Holstein stud bulls. The differentially expressed genes (DEGs) in sperm cells were evaluated between the two groups (H vs. L). We conducted gene co-expression network analysis (WGCNA) on H and L groups of bulls, as well as two monozygotic twin Holstein bulls with different NMSPE values, to screen candidate genes for NMSPE. The regulatory effect of seminal plasma metabolome on the candidate genes of NMSPE was also investigated. A total of 1,099 DEGs were identified in the sperm cells of H and L groups. These DEGs were primarily concentrated in energy metabolism and sperm cell transcription. The significantly enriched Kyoto encyclopedia of genes and genomes (KEGG) pathways of the 57 differential metabolites were the aminoacyl-tRNA biosynthesis pathway and vitamin B6 metabolism pathway. Our study discovered 14 genes as the potential candidate markers for sperm motility, including FBXO39. We observed a broad correlation between transcriptome of sperm cells and seminal plasma metabolome, such as three metabolites, namely, mesaconic acid, 2-coumaric acid, and 4-formylaminoantipyrine, might regulate FBXO39 expression through potential pathways. The genes related to seminal plasma metabolites expressed in sperm cells are not only located near the quantitative trait loci of reproductive traits, but also enriched in the genome-wide association study signal of sire conception rate. Collectively, this study was the first to investigate the interplays among transcriptome of sperm cells and seminal plasma metabolome from Holstein stud bulls with different sperm motility.

Lifetime and removal reasons for Pietrain boars in European AI centers: a retrospective analysis

Currently, artificial insemination (AI) is the most common reproductive method used in swine production. The economic profitability of AI centers is closely linked to a boar's retention rate and the purchase of replacement boars. The objectives of this study were to examine data of selection process and lifetime of a total of 6,496 purebred Pietrain AI boars and to analyze the frequency and reasons of removal in eight European countries. Data were obtained from two German boar multiplication farms as well as 53 AI centers from 2018 to 2022. The retention time was analyzed from the selection process until replacement and to the end of the examination, respectively. The selection process of the boars took place at 168 ± 5 (mean ± SD) days of age. For further calculations, the removal reasons were divided into nine groups: breeding (BR), died (DI), euthanasia (EU), health (HE), genetics (GE), low libido (LI), sperm quality (SQ), structure (ST), and other (OT). Overall, 56.1% of the examined boars were removed, with 17.5% being removed within the same year they entered the AI center. The annual removal rate for the 53 AI centers averaged 42.4%. The most frequent removal reason was low SQ (45.1%), followed by genetics (28.6%) and low libido (10.6%). The highest relative frequency of removals was observed for an age of 2 yr (34.0%). The highest removal risk was calculated for boars in Czech AI centers (P < 0.001), while the lowest removal risk occurred in Dutch (P = 0.006) and Portuguese AI centers (P = 0.01). The comparison of removal groups revealed, inter alia, higher body weight at selection process for the BR group (117.9 ± 9.0 kg) and longer quarantine periods for LI group (45.9 ± 17.6 d). Boars in the GE group were characterized by the oldest age at removal (934.0 ± 272.8 d) and longest period of exploitation (672.5 ± 266.8 d). The results could be helpful to detect the most common reasons for production failure of AI Pietrain boars and beneficial for establishing an economical removal policy in AI centers and for improving boar management through problem-based selection in boar multiplication farms.

Cryoprotectant effects of natural honey on spermatozoa quality of pre-freezing and frozen-thawed boar semen

Natural honey has been successfully used in the preservation of mammalian gametes because of its beneficial properties. The objectives of this study were to determine the inclusion level of honey in extender for improving boar semen quality before freezing and to investigate the effects of honey inclusion in extender and freezing media on post-thaw quality of frozen-thawed boar semen samples. Ejaculates from six terminally crossbred boars were collected using the gloved-hand technique for two experiments. Experiment 1 was a randomized block design, evaluating four inclusion levels of honey in boar semen extender [Control (0H)-Androhep Plus or Androhep Plus with 0.25%, 0.50%, and 0.75% honey (0.25H, 0.50H, and 0.75H respectively)]. Ejaculates were pooled, aliquoted according to treatments, and cooled for 24 h at 17 ºC. The results of this experiment were used to determine inclusion levels in exp. 2. Experiment 2 was a 2 x ×3 factorial design, evaluating the inclusion of honey in boar semen extender and freezing media. Semen samples from individual boars were cooled in extender with or without honey (C0: Androhep Plus; C1: Androhep Plus + 0.25% honey). After 24 h, semen samples were evaluated, diluted in lactose-egg yolk (LEY) media, and one of three freezing media types; F0: 93% LEY + 6% glycerol + 1% Equex-STM Paste (ESP); F1: 93% LEY + (3% glycerol and 3% honey) + 1% ESP; and F2: 93% LEY + 6% glycerol + (0.5% ESP and 0.5% honey). Samples were frozen in 0.5 mL straws using a controlled-rate freezer and stored in liquid nitrogen. In exp. 1, 0.25H and 0.50H improved motility (P = 0.033) and progressive motility (P = 0.001) of cooled boar semen. Nevertheless, 0.25H was selected for exp. 2. In exp. 2, post-thaw motility and progressive motility were highest (P < 0.05) in C0F2 but not different from C1F2. Morphologically normal cells and acrosomes were higher with all inclusion levels of honey (P < 0.05). In conclusion, 0.25% and 0.50% inclusion of honey in Androhep Plus improves motility and progressive motility of cooled boar semen samples after 24 h. Supplementing Androhep Plus with 0.25% honey maintains higher normal sperm cells and acrosomes of cryopreserved boar semen. Replacing 50% Equex-STM paste with honey in freezing media improves post-thaw sperm motility, progressive motility, percentage of normal sperm, and acrosome of cryopreserved boar semen.

Cooled storage of semen from livestock animals (part I): boar, bull, and stallion

This review is part of the Festschrift in honor of Dr. Duane Garner and provides an overview of current techniques for cooled storage of semen from livestock animals. The first part describes the current state of the art of liquid semen preservation in boars, bulls, and stallions, including the diluents, use of additives, processing, temperature, and cooling of semen. The species-specific physiology and varying extents of cold shock sensitivity are taken into consideration. In addition, factors influencing the quality of cooled-stored semen are discussed. Methods, trends, and the most recent advances for improving sperm quality during cold-temperature storage are highlighted and their respective advantages and disadvantages are contrasted. There has been much progress in recent years regarding cold-temperature storage of boar sperm and there is great potential for a large-scale use to replace the current 17 °C temperature storage regime and the associated use of antibiotics in the future. For stallion sperm, there is an opposite trend away from previous low-temperature storage towards storage at higher temperatures to increase sperm viability and longevity. In bulls, liquid storage of sperm is mostly used in the seasonal dairy production systems of New Zealand and Ireland, but with further research focusing on shelf-live elongation of liquid preserved sperm, there is potential for an application in breeding programs worldwide.

Effect of seasons and photoperiods on seminal attributes and sperm morphology in Holstein Friesian × Sahiwal crossbred dairy bulls

Cattle being non-seasonal breeding species, effects of photoperiods on sperm traits and morphology had been reported inadequately in breeding bulls. To elucidate the plausible existence of effects of photoperiods and seasons, seminal traits of Holstein Friesian × Sahiwal crossbred dairy bulls (N = 557) were analysed using different statistical models. A present study revealed that the biological rhythm of reproduction oscillated almost in parallel to the annual changes of natural photoperiods even in non-seasonal breeding species like cattle bulls. Semen traits diminished to the lowest in winter solstice (WS ± 45 days), progressively increased with the rising day length of spring (vernal equinox ± 45 days), reached a peak in summer solstice (SS ± 45 days), and then gradually reduced with decreasing photoperiod of the autumn equinox (AE ± 45 days). From summer solstice to winter solstice, sperm concentration reduced by 90.53 million/ml (8.85%), total sperm count/ejaculate decreased by 785 million (13.87%), total motile sperm count/ejaculate reduced by 17.59%, and total post-thaw motile sperm counts/ejaculates diminished by 38.64%. In short-duration photoperiods (≤ 12 h), bulls had a significantly (P < 0.01) higher incidence of major, minor, tail abnormality and total aberrant sperm% compared to that of long-duration photoperiods (> 12 h). Solstice equinox-based seasonal classification provided better insight into photoperiodicity on bulls' semen quality and sperm traits as compared to conventional meteorological classification of seasons. It was concluded that photoperiods affect sperm productivity, semen quality, and sperm morphology in non-seasonal breeding species like dairy bulls, maintained at transitional latitude (29° N) tropical climate. Bulls' reproductive ability was more influenced by the phases of increasing/decreasing day length duly primed by climax/trough of photoperiods, compared to mere long/short duration of photoperiods.

Infertility In Toms: Clinical approach, experiences and challenges

PRACTICAL RELEVANCE

An infertile tom used to be a relatively rare presentation in feline practice. However, as a result of breeding strategies targeting specific morphological/behavioural traits, and the influence of inbreeding (especially practised in rare breeds), among other factors, feline infertility has become a genuine clinical problem. Furthermore, increased interest among cat breeders and pet owners in diagnosing and treating an 'unsuccessful' tom (including using assisted reproductive techniques [ARTs]), has made such patients more commonplace in veterinary practice.

CLINICAL CHALLENGES

A definitive cause for male infertility is often difficult to identify. One of the biggest challenges is the lack of fertility-based reference values for semen quality and hormone levels. Moreover, the literature in this field is scant and many reproductive tract conditions described in other species have not been reported in cats. The establishment of diagnostic tools and algorithms is essential to facilitate a reliable assessment of fertility potential.

GLOBAL IMPORTANCE

There is a growing demand for appropriate veterinary care relating to feline reproduction. There is an expectation among breeders, particularly of pedigree cats of high breeding value, that the same options widely used for dogs (including ARTs) should also be available for cats.

EQUIPMENT AND TECHNICAL SKILLS

Equipment required for investigating male infertility includes a microscope and ultrasound machine; a blood analyser may also be useful, but samples can instead be sent to a laboratory. The skills required are often already performed by veterinarians; for example, catheterising the urethra, performing ultrasonography and blood sampling.

EVIDENCE BASE

There are some reports of fertility problems in male cats in the literature, but this area of feline reproduction is still relatively undeveloped. This review draws on the comprehensive knowledge developed and shared by specialists in this field, and is supported by the authors' own clinical experience.

Induced Stress and Tactile Stimulation Applied to Primiparous does and their Consequences on Maternal Behavior, Human-Animal Relationships, and Future Offspring's Sexual Disorders

The aim of this study was to investigate whether tactile stimulation in rabbits during the gestation phase improve the maternal behavior and human-animal relationships as well as the effects on reproductive behavior of male kits when reached maturity compared to induced stress. A total of 33 primiparous New Zealand does were selected after pregnancy confirmation and allocated in a randomized complete block design. The treatments applied were as follows: (C) animals not stimulated during the experimental period; (TS) animals that received tactile stimulation; and (SS) does which were immobilized. The nest building behavior as well as the weight, sexual behavior, mortality, and semen analysis of the offspring was recorded. In addition, the novel object, flight distance, social isolation, and human-approach tests were conducted. Under the conditions of the present trial, TS animals showed more trust in the unfamiliar observer when compared to the other two treatments. The treatments applied to the females (TS and SS) were sufficient to confirm that the control group presented better values for the number of stillbirths and the proportion of deaths in the first week. Finally, the handling of does reduce the males' ejaculation and sperm presence but not inhibited sexual behavior or impaired semen quality. It is possible to conclude that TS did not impair does welfare or maternal behavior and it improved the human-animal relationship, however there was a negative impact on the litter. More studies that directly assess impact on the future reproductive capacity of the offspring are necessary.

Age-Dependent Variations in Functional Quality and Proteomic Characteristics of Canine (Canis lupus familiaris) Epididymal Spermatozoa

Increased male age is associated with a significant reduction in semen quality. Little is known about the sperm proteome changes resulting from the aging process. This study aimed to investigate the relationship between the functional quality and proteome of epididymal spermatozoa of dogs that were differing in age. The study was conducted on 30 male dogs that were divided into three age groups. G1—12 to 41 months old, G2—42 to 77 months old, and G3—78 to 132 months old. The sperm samples were assessed using a computer-assisted semen analysis (CASA). The epididymal sperm proteins were analyzed using gel electrophoresis (SDS-PAGE), nano-liquid chromatography coupled to quadrupole time of flight mass spectrometry (NanoUPLC-Q-TOF/MS) and bioinformatic tools. The sperm quality parameters were significantly lower in older dogs. NanoUPLC-Q-TOF/MS identification resulted in 865 proteins that were found in the G1, 472 in G2, and 435 in G3. There were seven proteins that were present in all three age groups, and four of them (ACTB, CE10, NPC2, CRISP2) showed significant changes among the studied groups. Age-dependent variations were detected in the sperm proteome composition and were related to important metabolite pathways, which might suggest that several proteins are implicated in sperm maturation and could be potential aging biomarkers.

Seasonal variations on semen quality attributes in turkey and egg type chicken male breeders

A biological experiment was carried out in twenty-four adult healthy breeder males each in turkey (Beltsville small white) and egg type chicken (White Leghorn Babcock) in order to assess the seasonal influence on semen production and quality. The birds were maintained in individual cages under uniform husbandry conditions throughout the year. The birds were fed with breeder ration and water ad libitum was offered with a constant photoperiod of 14 h/day. Physical and biochemical characteristics of semen, serum hormones (testosterone and thyroxine), and antioxidant activity (catalase and lipid peroxidation) were evaluated throughout the year (January-December). Based on the THI calculations, the observations were classified under three different seasons, namely, winter (November-February), spring (March, April, and October), and summer (May-September). Semen physical parameters, sperm concentration, motility, live sperm percentage, and sperm plasma membrane integrity were superior during the winter season. In seminal plasma, biochemical parameters (phosphorus, ALT, ALP, AST, and uric acid) had a significant (P < 0.05) difference between seasons. There was a significant difference (P < 0.05) among serum hormones (testosterone and thyroxine) that were higher during the winter season. Significant variation was observed in catalase and lipid peroxidation antioxidant enzyme activities (seminal and blood plasma) in winter than in the other two seasons. Both the turkey and egg type chicken breeders exhibited superior seminal characteristics, sex hormone profile, and antioxidant enzyme activity during winter seasons.

Pikeperch (Sander lucioperca) spermatozoa motility and volume regulation under different osmotic and ionic conditions

Pikeperch (Sander lucioperca) is a highly profitable commercial species whose economic value has greatly increased in the last decade. As in other species, the quality of spermatozoa in this species is a principal feature inherent in fertilization success and efficient natural and artificial reproduction. The capacity of fish spermatozoa to be activated and tolerate environmental changes (in osmolality, ion composition, external pH, temperature, etc.) during the motility period contributes to fertilization success. In this study, we investigated the effects of environmental osmolality and ion composition on spermatozoa motility. To determine if the activation mechanism is affected by sperm quality parameters, we measured semen characteristics such as semen volume, spermatozoa concentration, seminal fluid osmolality and ion composition, and spermatozoa lipid composition. An additional parameter of sperm quality reflecting spermatozoa osmoresistance, the swelling rate, was measured by the nephelometry method. We detected that sperm samples with the highest content of palmitic (C16:0) and palmitoleic (C16:1) acids showed the lowest motility activation under the studied conditions, suggesting that these fatty acids are possible markers for the determination of spermatozoa quality in fish. Our results show that pikeperch spermatozoa can be activated under different osmotic conditions and that cell swelling always accompanies motility. However, spermatozoa sustain their volume under hypotonic conditions when motility is not initiated, suggesting that pikeperch spermatozoa activation is mainly controlled by ion composition rather than the osmolarity of the surrounding medium.

Comparison of the performance of targeted mitochondrial antioxidant mitoquinone and non-targeted antioxidant pentoxifylline in improving rooster sperm parameters during freezing and thawing

Oxidative stress is associated with impaired sperm quality after thawing. Since mitochondria are the main source of reactive oxygen species (ROS) in sperm, the aim of this study was to investigate the effects of targeted mitochondrial antioxidant mitoquinone (MitoQ) and non-targeted mitochondrial antioxidant pentoxifylline (PTX) during cooling and cryopreservation of rooster sperm. Sperm samples were collected from 15 roosters aged 28 wk and diluted with Beltsville extender. After dilution and addition of treatments (50, 100, and 200 pMol MitoQ and 0.5, 0.75, and 1 μM PTX), samples were cooled for 2 h to 4°C and they were first analyzed at this stage and were frozen and re-evaluated after thawing. After the freezing and thawing, level of 100 pMol MitoQ significantly increased total motility (TM), progressive motility (PGM), curvilinear velocity (VCL), membrane integrity, viability, total antioxidant capacity (TAC) and the glutathione peroxidase (GPx), as well as the level of 50 pMol significantly increased TM, PGM, average path velocity (VAP), straight-line velocity (VSL), membrane integrity, viability, and mitochondrial activity. Moreover, these 2 levels (50 and 100 PMol) decreased malondialdehyde and sperm with abnormal morphology. Addition of 0.75 μM PTX also increased total motility compared to the control group and levels of 0.5 and 0.75 μM decreased sperm with abnormal morphology. It could be concluded the addition of MitoQ and PTX can be useful for sperm cryopreservation industry and reduce the harmful effects of freeze-thawing.