l -Carnitine in rooster semen cryopreservation: Flow cytometric, biochemical and motion findings for frozen-thawed sperm

Supplementation of Rooster Semen Extender with Aqueous Extract of Urtica dioica for a Long Time Preservation by Low Temperature

The peroxidation of spermatozoa membrane phospholipids is a primary cause of irreversible changes in the preservation of avian semen. To address this issue, the objective of the present study was to assess the potential of Urtica dioica extracts in protecting avian spermatozoa during prolonged storage. Gas chromatography-mass spectroscopic techniques were employed to evaluate the bioactive compounds present in the aqueous and ethanolic extracts obtained from the aerial parts and roots of U. dioica. Semen samples were collected from 16 roosters twice a week and were diluted in Lake's extender containing different concentrations (0, 0.5, and 1 mg/100 mL) of the various extracts. Subsequently, the extended semen samples were cooled and stored at 5°C, and the sperm quality parameters were assessed at 0, 12, 24, and 36 hours of storage. The data from this experiment clearly demonstrate that the addition of nettle root aqueous extracts to the semen diluent, especially at a concentration of 0.5 mg/100 mL, resulted in a significant improvement in various sperm quality parameters. Notably, there were enhancements in total and progressive sperm motilities, viability, fertility, membrane integrity, acrosomal membrane integrity, and a reduction in malondialdehyde production in rooster semen stored in vitro for up to 36 hours. Interestingly, the present study reveals that the beneficial effects of the aqueous extracts from different parts of the nettle were supported not only by the conventional manual method but also by the computer-assisted sperm analysis system. This dual confirmation further emphasizes the positive impact of the aqueous extract on various sperm traits during cooled semen preservation. In conclusion, this study highlights the potential of U. dioica extracts, particularly the aqueous extract from nettle roots at a concentration of 0.5 mg/100 mL, in safeguarding avian spermatozoa during prolonged storage. The significant improvements in various sperm quality parameters and the validation of results through both manual and computer-assisted analysis methods provide strong evidence for the application of U. dioica extracts in avian breeding programs and artificial insemination practices.

Pre- and Post-Thaw Addition of L-Carnitine and Pyruvate: Effect on Stallion Sperm Parameters

The addition of antioxidants to cryopreservation media reportedly improves sperm post-thaw quality and reproductive performance after artificial insemination. Therefore, the objectives of this study were to evaluate if the addition of L-carnitine and pyruvate to freezing media, or their addition to samples after thawing, improves the post-thaw quality of equine spermatozoa. Thus, in Experiment 1, stallion semen samples were cryopreserved in: (1) EDTA-glucose-based extender with 20% egg yolk and 5% dimethylformamide (EDTA control); (2) skim milk-based extender with 20% egg yolk and 5% dimethylformamide (milk control); (3) Extender 1 supplemented with 50 mM L-carnitine and 10 mM pyruvate (EDTA-carnitine-pyruvate); and (4) Extender 2 supplemented with 50 mM L-carnitine and 10 mM pyruvate (milk-carnitine-pyruvate). In Experiment 2, 50 mM L-carnitine and 10 mM pyruvate were added post-thaw to samples cryopreserved with extenders 1 and 2 (EDTA control and milk control). Sperm kinematic parameters, DNA fragmentation, membrane lipid peroxidation, acrosome status and viability were evaluated after thawing. No significant differences (p > 0.05) were observed for most of the kinematic parameters, DNA fragmentation, membrane lipid peroxidation, acrosome status and viability of spermatozoa, between the samples frozen in the presence or absence of L-carnitine and pyruvate, nor between the samples after the post-thaw addition of these components. A higher (p < 0.05) mean velocity and higher (p < 0.05) amplitude of lateral head displacement were observed in the samples frozen in the milk-based extender with the addition of L-carnitine and pyruvate after thawing. The addition of 50 mM L-carnitine and 10 mM pyruvate, either to the freezing extenders or after thawing, was not deleterious for sperm; however, it did not improve equine sperm motility, viability, acrosome and DNA integrity, nor decrease membrane lipid peroxidation after thawing.

Influence of incorporating L-carnitine or Moringa oleifera leaves extract into semen diluent on cryosurvival and in vitro fertilization competence of buck sperm

This study aimed at scrutinizing efficiency of incorporating L-carnitine or M. oleifera leaves extract into semen diluent on improving cryopreservation capacity and in vitro fertilization ability of buck spermatozoa. Ejaculates (n=48) were collected by an artificial vagina from six adult Damascus bucks twice weekly during the breeding season (September-October). Following initial evaluation, ejaculates of each collection session from the same bucks were pooled, diluted (1:10) with glycerolized (3 % glycerol, v/v) tris-citric acid egg yolk diluent and were split into three aliquots. The first aliquot served as control, whereas the second and third aliquots were supplemented with 4 μL/mL L-carnitine and 400 μL/mL moringa leaves extract (v/v), respectively. Thereafter, all specimens were processed for cryopreservation and were stored in liquid nitrogen (-196 °C) for 12 months before post-thaw sperm criteria were analyzed by a computer-assisted sperm analysis (CASA) system. Integrity of sperm DNA post thawing was visualized in all semen groups by fluorescence imaging, and in vitro fertilization ability of spermatozoa was also determined. Inclusion of L-carnitine or moringa leaves extract into the diluent improved (P<0.05) post-thaw sperm physical, morphofunctional and kinematic attributes, whilst maintaining (P<0.05) integrity of sperm DNA throughout the freezing and thawing cycle. Consequently, both supplemented groups yielded higher (P<0.05) in vitro fertilization rates compared to control. These results accentuate the protective roles of these antioxidants on buck sperm against consequences of cryopreservation-induced oxidative stress, hence ameliorating post-thaw sperm quality and fertilization competence. This is crucial for successful application of AI and IVF in goat selective breeding programs.

L-carnitine supplementation in conventional slow and ultra-rapid freezing media improves motility, membrane integrity, and fertilizing ability of dog epididymal sperm

This study aimed to assess the impact of L-carnitine (LC) supplementation in conventional-slow (CS) and ultra-rapid (UR) freezing media on post-thaw quality and fertilizing ability of dog epididymal spermatozoa. Sperm samples were collected from 60 epididymides obtained from 30 adult orchiectomized dogs via retrograde flushing. Twenty pooled sperm samples were then created (3 epididymal samples/pool). Four treatments were established according to the freezing method (CS and UR) and LC supplementation (5 and 0 mM [control, Co]): CS-LC5, CS-Co, UR-LC5, and UR-Co. The CS freezing involved exposing 0.25 mL straw to liquid nitrogen vapors (LN2), while UR freezing submerged 30-µL drops of sperm samples directly into LN2. Sperm kinematics, membrane integrity, and fertilizing ability (by heterologous in vitro fertilization using bovine oocytes) were evaluated for all treatments. Post-thaw results revealed that the CS freezing treatments resulted in significantly higher values (P < 0.05) of curvilinear and average-path velocities, and beat-cross frequency compared to the UR freezing treatments, regardless of LC supplementation. The CS-LC5 and UR-LC5 treatments cryoprotected the sperm by increasing (P < 0.05) the percentage of 'live-sperm/intact-acrosome' compared to their controls treatments CS-Co and UR-Co. Regarding fertilizing ability, the CS-LC5 treatment yielded a higher percentage (P < 0.05) of pronuclei formation compared to both UR treatments. The UR-LC5 treatment, however, obtained greater percentage (P < 0.05) than their control UR-Co. In conclusion, supplementation with L-carnitine in conventional-slow and ultra-rapid freezing improved sperm motility, plasma, and acrosome membranes integrity and fertilizing ability of dog epididymal spermatozoa.

Barley sprouts and D-Aspartic acid supplementation improves fertility, hatchability, and semen quality in aging male broiler breeders by up-regulating StAR and P450SCC gene expressions

At 50 wk of age, broiler breeder roosters exhibit a significant decline of fertility. Therefore, the aim of this study was to assess the impact of incorporating barley sprout (BS) powder, D-aspartic acid (DA), or their combination into the diet on fertility, hatchability, semen quality, and the relative expression of StAR and P450SCC genes in aging broiler roosters. Aging (50 wk) male broiler breeders (n=32) were randomly assigned to one of four dietary treatments (2 × 2 factorial) with 2 levels of BS (0 or 2% basal diet) and DA (0 or 200 mg/kg/BW) for 12 wk. Roosters were individually housed under a 14-h light and 10-h dark cycle, with 150 g/d feed allocation and free access to fresh water, then euthanized. Throughout the study, the body weight of the broiler breeders was measured, along with various parameters related to semen quality, on a weekly basis. Additionally, artificial insemination was performed during the last 2 wk to evaluate reproductive endpoints. The results revealed that both BS and DA decreased (P < 0.01) body weight. Interestingly, the inclusion of BS, either alone or in combination with DA, resulted in a significant increase in total and forward sperm motility. Furthermore, it was demonstrated that the seminal concentration of malondialdehyde, a marker of oxidative stress, was significantly decreased by more than 20% in all groups compared to the control. The combination of both BS and DA led to the highest levels of circulating testosterone, as well as the functionality and membrane integrity of sperms. Additionally, it resulted in increased sperm concentrations, production, and penetration, ultimately leading to improved fertility rate and hatchability percentage. Moreover, a positive association between total motility and fertility was observed (P < 0.01). Furthermore, the combined supplementation of BS and DA up-regulated the relative mRNA expression of P450scc and StAR (P < 0.01). To summarize, dietary inclusion of BS, DA, or their combination have a potential to improve various aspects of reproductive performance in aging roosters.

l-carnitine enhances the kinematics and protects the sperm membranes of chilled and frozen-thawed Peruvian Paso horse spermatozoa

l-carnitine (LC) transports fatty acids to the mitochondria for energy production, reducing lipid availability for peroxidation through β-oxidation. This research examines the effect of LC supplementation to two skimmed milk-based extenders on the cryosurvival of chilled (5°C) and frozen-thawed Peruvian Paso horse spermatozoa .An initial experiment determined the optimal LC concentration (0, 1, 5, 10, 25, and 50 mM) when added to INRA-96® and UHT (skimmed milk + 6% egg yolk) extenders, using nine ejaculates from three stallions chilled for up to 96 h. Subsequently, the effect of 25 mM LC supplementation (the optimal concentration) on chilling (INRA-96) and freezing (INRA-Freeze®) extenders was evaluated using eight pooled samples from sixteen ejaculates (2 ejaculates/pool) from four stallions. Results indicated that all LC concentrations produced significantly higher values (P<0.05) for kinematic variables (total [TM] and progressive motilities, curvilinear [VCL] and straight-line [VSL] velocity, and beat-cross frequency [BCF]), and the integrity of plasma/acrosome membranes (IPIA) compared to non-supplemented chilled sperm samples for up to 96 h with both extenders. Moreover, the use of 25 mM LC was more efficient (P<0.05) in preserving the post-chilled values of velocity, BCF, and IPIA for the long term than lower LC concentrations (1-10 mM). Post-thaw values of total motility, the amplitude of lateral head displacement (ALH), and IPIA were significantly improved (P<0.05) when INRA-Freeze extender was supplemented with 25 mM LC. In conclusion, supplementation of l-carnitine to skimmed milk-based extenders enhanced kinematic variables and protected the membrane integrity in chilled and frozen-thawed Peruvian Paso horse spermatozoa.

Evaluation of the effect of the addition of an olive oil-derived antioxidant (Pectoliv-80A) in the extender for cryopreservation of rooster sperm through the use of a discriminant statistical tool

During the poultry sperm cryopreservation process, an excess of reactive oxygen species is generated resulting in oxidative stress which harms the quality of avian spermatozoa. To counteract this effect, the addition of exogenous antioxidants, such as Pectoliv-80A (a by-product of olive oil), to the cryopreservation diluent is interesting. For this purpose, 16 roosters belonging to the Utrerana avian breed were used. Six semen pools (from the 6 different replicates) were divided into 4 aliquots corresponding to different concentrations of Pectoliv-80A that were tested (0, 300, 400, and 500 μg/mL), and the cryopreservation process was carried out. To evaluate post-thawing semen quality, different parameters such as motility, membrane functionality, reactive oxygen species production, lipid peroxidation, and acrosome integrity were studied. A discriminant canonical analysis was used to determine both the differences between the Pectoliv-80A concentration groups and the discriminant power of the aforementioned parameter used for semen evaluation. Total motility and membrane functionality were reported to be the most discriminant variables for differentiating the different antioxidant enrichment groups and concluded that concentrations of 300 μg/mL showed the most desirable quality of post-thawing semen. The present study could lead to the optimization of both cryopreservation and quality evaluation techniques of the sperm of rooster species, that support the conservation program of endangered local breeds.

Alpha-lipoic acid improves cryopreservation of rooster semen by reducing oxidative stress

Inhibiting oxidative stress is key for ensuring sperm motility during semen cryopreservation. The aim of this study was to investigate the effect of adding alpha-lipoic acid (ALA) as an extender in rooster semen cryopreservation. Different concentrations of ALA were added to the frozen diluent of rooster semen; subsequently, computer-aided semen analysis was used to determine membrane functional integrity, acrosome integrity, antioxidant capacity (based on T-AOC, GSH-Px, SOD, CAT, and MDA contents), and mitochondrial integrity. The frozen sperm ultrastructure was observed using transmission electron microscopy. The results showed that the addition of different concentrations of ALA partially to greatly improved the quality of frozen sperm; in particular, 8 μg/mL ALA significantly improved multiple parameters of sperm quality, including sperm motility and antioxidant enzyme activity, after freeze-thaw. The results of this study provide empirical and theoretical support for effective rooster semen cryopreservation and can inform the development of new protective agents in the field of livestock reproduction.

Improving chilled and frozen buck sperm characteristics by adding melatonin and L-carnitine to the preservation medium

This study evaluated the effects of melatonin (MLT) and L-carnitine supplementation on sperm quality and antioxidant capacity during chilled and cryopreservation. Twenty-four ejaculates were collected from six Damascus bucks, 4 ejaculates each, from mid-September to mid-October 2022. The pooled semen from each collecting session was divided into 5 equal aliquots after being diluted (1:10) with Tris-citric acid egg yolk extender. The first aliquot served as a control (treatment-free). MLT was added to the second and third aliquots at low and high doses (LD: 4 and HD: 8 μL/mL) (v/v), respectively, while L-carnitine (LC) was added to the fourth and fifth aliquots at the same aforementioned doses. The aliquots were stored at 4°C for 48 h to assess sperm physical and morphological characteristics, alongside lipids peroxidase (LP) production and glutathione peroxidase (GPX) activity. The optimum doses of MLT and LC that showed potential for maintaining sperm characteristics throughout the chilled storage period were further investigated for protecting the spermatozoa after exposure to cryopreservation stress compared to the control. The results showed higher sperm motility (%) in the MLT-HD group, higher (p ≤ .05) sperm viability (%) in the MLT-LD, and both aliquots of LC at T24 hours of chilled preservation. Normal sperm (%) was higher (p ≤ .05) in both LC-LD and MLT-LD groups than other groups, while sperm acrosome integrity (%) was higher (p ≤ .05) in the LC-LD group. Morphological abnormalities (%) were improved (p ≤ .05) in all treated aliquots compared with control. The mean value of GPX activity was higher (p ≤ .05) in both MLT groups, while the concentration of LP increased (p ≤ .05) in the LC-HD or control groups. Furthermore, supplementing buck sperm medium with 4 μL/mL of MLT or LC improved (p < .05) the sperm characteristics and decreased (p < .05) DNA fragmentation index after thawing.

Discriminant Analysis and Data Mining CHAID Decision Tree as Tools to Evaluate the Buffering Effect of Hydroxytyrosol on Reactive Oxygen Species in Rooster Sperm Cryopreservation

Sperm cryopreservation is effective in safeguarding genetic biodiversity in avian species. However, during this process, spermatozoa are very susceptible to plasma membrane peroxidation in the presence of high concentrations of reactive oxygen species (ROS). To mitigate this effect, the addition of exogenous antioxidants, such as hydroxytyrosol (3,4-dihydroxyphenylethanol; HT), an antioxidant derived from olive oil, to the cryopreservation sperm diluent, could be useful. To verify this, a cryopreservation diluent was supplemented with different concentrations (0 μg/mL, 50 μg/mL, 100 μg/mL, and 150 μg/mL) of HT. For this, semen was collected in 10 replicates from 16 roosters of the Utrerana avian breed, and a pool was prepared with the optimum quality ejaculates in each replicate. After cryopreservation, spermatozoa were thawed and different in vitro semen quality parameters were evaluated. A discriminant canonical analysis (DCA) was carried out and revealed that total motility (TM; Lambda = 0.301, F = 26,173), hypo-osmotic swelling test (HOST; Lambda = 0.338, F = 22,065), and amplitude of lateral head displacement (ALH, Lambda = 0.442; F = 14,180) were the variables with the highest discriminant power. Finally, a chi-squared automatic interaction detection (CHAID) decision tree (DT) was performed excluding fresh semen samples and ROS was found to be the most valuable variable to discriminate between the different established freezing groups. Samples in the absence of HT or with low concentrations of this antioxidant showed less desirable ROS values in cryopreserved rooster semen. The present study could lead to the improvement of cryopreservation techniques for the genetic material of local poultry breeds and optimize the conservation programs of endangered native avian breeds.

Combined addition of L-carnitine and L-proline improves cryopreservation of dairy goat semen

Cryopreservation of semen renders artificial insemination easier and cheaper compared to use of fresh semen. However, the cellular oxidative stress, toxicity of cryoprotectants, and osmotic imbalance may lead to a decline in semen quality and fertilization ability during the process of cryopreservation. L-carnitine and L-proline have been demonstrated to possess effective antioxidant properties in cryopreservation, with the latter also exhibiting excellent permeability and thus being utilized as a permeable cryoprotectant in the field. The aim of this study was to investigate the effects of LC and LP on cryopreservation of semen of dairy goats. After thawing, sperm motility, membrane integrity, and acrosome integrity rate of cryopreserved semen treated with LC (50 mM) were significantly higher compared to the untreated control samples. Based on this premise, we conducted experiments to assess the cryoprotective efficacy of different concentrations of LP. The findings demonstrated that the inclusion of 50 mM LP resulted in improved sperm motility compared to other concentrations. Furthermore, the levels of damaging reactive oxygen species and the malonyldialdehyde marker for oxidative stress were significantly lower in goat semen treated with these concentrations of LC and LP compared to semen exposed to other treatments. Semen treated with LC and LP also exhibited good fertilization ability during both in vitro fertilization and artificial insemination. Thus, LC (50 mM) and LP (50 mM) improve cryoprotection of dairy goat sperm which suggests that addition of these compounds will be highly beneficial to the development of dairy goat breeding.

Advances in storage of poultry semen

Semen cryopreservation is a key biotechnological strategy used to preserve and protect genetic resources, which are subject to increasingly serious reductions in some species, and to protect animal biodiversity. Assisted reproductive techniques, however, are still not utilized to the same extent in avian species to the extent that occurs in mammals. The reasons for this situation are described in this review. The content of this paper is focused on current poultry preservation systems, published since 2010, and new strategies that are very promising for preserving avian genetic resources. Two major types of storage technologies which are utilized for avian sperm preservation, liquid storage and cryopreservation, are emphasized. The issues on which there is a focus includes supplementation of avian extenders with various compounds prior to the preservation period, use of cryoprotectants and fertility results when there were in vitro sperm evaluations. Results from recent studies indicate there are opportunities to improve the quality of bird semen after preservation. It is obvious that cryo-diluent composition may be the most important factor for development of efficacious cryopreservation methods for avian semen.

Poultry genetic heritage cryopreservation and reconstruction: advancement and future challenges

Poultry genetics resources, including commercial selected lines, indigenous breeds, and experimental lines, are now being irreversibly lost at an alarming rate due to multiple reasons, which further threats the future livelihood and academic purpose. Collections of germplasm may reduce the risk of catastrophic loss of genetic diversity by guaranteeing that a pool of genetic variability is available to ensure the reintroduction and replenishment of the genetic stocks. The setting up of biobanks for poultry is challenging because the high sensitiveness of spermatozoa to freezing–thawing process, inability to cryopreserve the egg or embryo, coupled with the females being heterogametic sex. The progress in cryobiology and biotechnologies have made possible the extension of the range of germplasm for poultry species available in cryobanks, including semen, primordial germ cells, somatic cells and gonads. In this review, we introduce the state-of-the-art technologies for avian genetic resource conservation and breed reconstruction, and discuss the potential challenges for future study and further extending of these technologies to ongoing and future conservation efforts.

Effect of tempol and straw size on rooster sperm quality and fertility after post-thawing

The aim of the present study was to investigate the effects of tempol and straw size on rooster sperm post-thaw quality and fertility. Rooster semen was cryopreserved in Lake extender containing 0 (control), 5, 10, 15 and 20 μM tempol (in two different straw size, 0.25 and 0.5). The percentage of total and progressive sperm motility, VAP and VSL increased in the 10 µM tempol group. Moreover, 10 µM tempol led to lower ROS compared to other groups. The lowest percentage of apoptotic-like changes was detected when the extender was treated with 10 µM of tempol. The minimum ROS was observed in the group treated with 0.5 straw size. Straw size did not have any significantly effect on GPx and SOD activities and TAC of frozen-thawed sperm. The highest significant percentage of fertility and hatching rate were observed in 10 µM of tempol. The results of the present study showed that supplementation of the Lake cryopreservation medium with 10 µM tempol improved cryo-survival. Also, the results of the present study suggested that Lake cryopreservation medium with 0.5-ml straw may perhaps be an appropriate method to improve the quality and fertility post-thawed rooster sperm.

Sperm flow cytometric parameters, antioxidant status, and testicular histomorphology in roosters fed diets supplemented with camphor

Genetic selection based on the high growth rate and consequently high slaughter weight in broiler chickens has caused many problems in broiler breeders. A negative correlation between growth and reproductive traits has declined semen quality and fertility in roosters. The present study aimed to evaluate the effects of camphor levels on some reproductive parameters included semen parameters, antioxidant status, and testicular development in broiler breeder roosters. Thirty-five ROSS 308 broiler breeder roosters were divided into 5 groups to receive camphor (C) levels: C0, C50, C250, C750, and C1000 ppm for 12 consecutive weeks (31–43 wk). Body weight, seminal volume, sperm concentration, and percentage of live and morphologically normal sperm were not affected by diets (P > 0.05), however, significantly were changed by bird age over the experiment (P < 0.05). Semen quality factor (SQF) significantly was affected by both diets and age (P < 0.05). Mitochondrial activity, apoptotic-like changes, and DNA fragmentation were improved in the groups fed camphor levels compared to the control group (P < 0.05). Testes weight (left, right, and combined weights) and gonadosomatic index were increased linearly by the camphor supplementation (P < 0.05). The serum activity of glutathione peroxidase (GP_X) was not affected by treatments, however, superoxide dismutase (SOD) activity, ferric ion reducing antioxidant power (FRAP), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity were significantly higher in C50, C250, and C750, respectively (P < 0.05). The lower malondialdehyde (MDA) content in the testes and liver samples was observed in C750 (P < 0.05). Excluding the number of Sertoli cells and blood vessels, other histomorphological traits of testes showed one of the linear or quadratic responses to the camphor levels (P < 0.05). It can be concluded that camphor as an antioxidant source may improve reproduction performance in roosters.

Addition of l-carnitine to the freezing extender improves post-thaw sperm quality of Okinawan native Agu pig

The objective of the present study was to establish whether the addition of l-carnitine (LC), which exhibits antioxidant activity, to the freezing extender improves the quality of cryopreserved Okinawan native Agu pig sperm. Ejaculated sperm frozen in an extender supplemented with 0, 1, 2.5, or 5 mM LC was thawed, and the integrities of mitochondria and the plasmalemma and other sperm characteristics were evaluated. The treatment with different concentrations of LC effectively improved sperm motility, mitochondrial and plasmalemmal integrities, and the proteolytic activity of acrosomal contents after freeze-thawing (P < 0.05). The proportion of post-thaw sperm possessing intact mitochondria and plasmalemma and higher proteolytic activity of acrosomal contents was markedly higher among sperm frozen in the presence of 2.5 mM LC than among sperm frozen in the extender without LC (P < 0.05). Furthermore, although the addition of LC to the freezing extender had no effect on disturbance of DNA damage and caspase activity, sperm treated with 2.5 mM LC during freezing exhibited significantly higher penetrability into matured oocytes in vitro than untreated sperm. Collectively, these results indicate that the addition of LC to the freezing extender effectively improved the post-thaw quality of Agu pig sperm by preventing mitochondrial dysfunction caused by oxidative stress during cryopreservation.

Improving Gander Reproductive Efficacy in the Context of Globally Sustainable Goose Production

The goose is a popular poultry species, and in the past two decades the goose industry has become highly profitable across the globe. Ganders low reproductive performance remains a barrier to achieving high fertility and hatchability in subsequent flocks. To address the global demand for cheaper animal protein, various methodologies for improving avian (re)production should be explored. A large amount of literature is available on reproduction traits and techniques for commercial chicken breeder flocks, while research on improved reproduction in ganders has been carried out to a lesser extent. The present review aims to provide a comprehensive literature overview focusing on recent advancements/techniques used in improving gander reproductive efficacy in the context of ensuring a globally sustainable goose industry.

The antioxidant roles of L-carnitine and N-acetyl cysteine against oxidative stress on human sperm functional parameters during vitrification

Objective

Amino acids can protect sperm structure in cryopreservation due to their antioxidant properties. Therefore, the present study aimed to investigate the protective effect of L-carnitine (LC) and N-acetyl cysteine (NAC) on motility parameters, plasma membrane integrity (PMI), mitochondrial membrane potential (MMP), DNA damage, and human sperm intracellular reactive oxygen species (ROS) during vitrification.

Methods

Twenty normal human sperm samples were examined. Each sample was divided into six equal groups: LC (1 and 10 mM), NAC (5 and 10 mM), and cryopreserved and fresh control groups.

Results

The groups treated with LC and NAC showed favorable findings in terms of motility parameters, DNA damage, and MMP. Significantly higher levels of intracellular ROS were observed in all cryopreserved groups than in the fresh group (p≤0.05). The presence of LC and NAC at both concentrations caused an increase in PMI, MMP, and progressive motility parameters, as well as a significant reduction in intracellular ROS compared to the control group (p≤0.05). The concentrations of the amino acids did not show any significant effect.

Conclusion

LC and NAC are promising as potential additives in sperm cryopreservation.

The effects of glutathione supplementation on post-thawed Turkey semen quality and oxidative stress parameters and fertilization, and hatching potential

This study was conducted to investigate the effect of semen extenders enriched with glutathione (GSH) on in vitro quality parameters and fertility of post-thawed turkey. In experiment 1, pools of semen diluted in glucose-based extender containing 0.5, 1, and 2 mM of GSH were cryopreserved. During the next step, a different variable such as motility and motion parameters, plasma membrane integrity (PMI) and functionality (PMF), DNA integrity, lipid peroxidation (MDA), total antioxidant capacity (TAC), catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity were determined in the post-thawed samples. In the second experiment, artificial insemination was used to evaluate the fertility and hatchability performances of the post-thawed semen. The results of the first experiment showed that the extenders supplemented with 2, 1 and 0.5 mM of GSH had higher levels (p ≤ 0.05) of motility and motion parameters, PMI, PMF, TAC, CAT and SOD activity and lower abnormal morphology, DNA damage, and lipid peroxidation respectively in comparison to the control group (only extender with semen). Notably, the second experiment showed a higher rate of fertility (p ≤ 0.05) in 2 mM of GSH compared to the control group. It can be concluded that adding 2, 1 and 0.5 mM of glutathione leads to an improvement in the survival of the post-thawed turkey, while 2 mM of GSH can increase the fertility strength of the turkey sperm; hence it can be used to improve fertility and hatchability performance.

Impacts of different antioxidants sources on semen quality and sperm fertilizing ability of Muscovy ducks under high ambient temperature

The potentiality of coenzyme Q10 (CoQ10), D-Aspartic acids (D-Asp), Maca or vitamin C, as antioxidant agents, to reduce negative impacts of high ambient temperature on semen quality, oxidative capacity and fertility of Muscovy ducks was investigated. Seventy-five Muscovy males (34-wk of age) were distributed randomly into five experimental groups of fifteen ducks each. The first group was fed a basal diet without supplementation and served as a control. The other four groups were fed a basal diet supplemented with 400 mg CoQ10, 400 mg D-Asp, 500 mg Maca and 200 mg vitamin C (ascorbic acid) per kg diet for 17 consecutive weeks under high ambient temperature conditions. The dietary inclusion of antioxidants significantly maintains better semen variables and a higher fertility rate either for fresh or preserved semen. Among the tested antioxidants, the Maca group showed the best status and outperformed the others in terms of motility, viability, sperm cell concentration, intact acrosome and membrane integrity percentages, total proteins, total antioxidants capacity, glutathione peroxidase, superoxide dismutase (SOD), malondialdehyde (MDA), testosterone, and the fertility rate for the fresh semen, as well as, forward motility, SOD and MDA for the preserved semen. The CoQ10 showed similar results to Maca in some measurements. Conversely, the basal diet had the poorest performance in all examined variables. The dietary incorporation of antioxidants (Maca or CoQ10) enhances fresh and preserved semen quantity and quality, as well as the fertility rate of Muscovy males under high ambient temperature conditions.

Dietary supplementation of pumpkin seed oil and sunflower oil along with vitamin E improves sperm characteristics and reproductive hormones in roosters

This study evaluates the effects of pumpkin seed oil and sunflower oil along with vitamin E on the reproductive characteristics of aged roosters. Thirty Ross breeder roosters (45-wk-old) were assigned into 6 groups (5 birds/group) with the following diets: 1) control group (basal diet), 2) basal diet with 2% pumpkin seed oil as omega-3 fatty acid (PSO group), 3) basal diet with 2% sunflower oil as omega-6 fatty acid (SFO group), 4) basal diet with 200 mg/kg vitamin E (Control + vitE group), 5) basal diet and 2% pumpkin seed oil along with 200 mg/kg vitamin E (PSO + vitE group) and 6) basal diet and 2% sunflower oil along with 200 mg/kg vitamin E (SFO + vitE group). Roosters were fed on the experimental diets for 60 d and different characteristics of sperm characteristics including routine semen analysis and several sperm functional tests in every 20 d were examined. Reproductive hormones were also evaluated in 0 d and at the end of the trial. Semen volume and morphology were not affected by any of the diets. The roosters fed with pumpkin seed oil + vitE showed the higher percentage of sperm concentration, total motility, progressive motility, viability and membrane integrity and the lower lipid peroxidation (P ≤ 0.05). The group 5 (PSO + vitE) had numerically the lowest sperm with fragmented DNA (DNA Fr⁺) at 0 of the experiment and sperm with non-fragmented DNA (DNA Fr⁻) was lowest in group 6 (SFO + vitE) on da 40 the experiment. Testosterone level was not affected by the experimental diets (P > 0.05), however other hormones (LH and FSH) were affected. Based on the results, the supplementation of aged roosters’ diet with pumpkin seed oil + vitE improves reproductive performance which can be an appropriate strategy to preserve the reproductive performance of aged roosters.

New semen freezing method for chicken and drake using dimethylacetamide as the cryoprotectant

The aim is to optimize the dimethylacetamide (DMA) straw freezing technology of Black silkies rooster semen through the handy patent equipment, screening the formula of freezing basic extender and optimizing the DMA addition method, and then by comparing the fertility of DMA straw frozen semen with the pellet frozen semen. After the DMA straw freezing technology is optimized, it is extended to the Youxian Partridge drake semen. The result showed that the frozen sperm motility of Lake and Ravie (LR) group is 64%, the fertility 49.57% and the hatchability 91.52%, all of which are superior to those of FEB, Beltsville Poultry Semen Extender (BPSE) and Lake (P < 0.05). The sperm motility of adding DMA stock solution is 59%, which is superior to adding DMA directly into diluted semen (P > 0.05). The fertility and hatchability of DMA straw group are 77.61% and 92.30%, respectively, and it is significantly higher than those in the pellet group (P < 0.01; P < 0.05). The fresh drake sperm motility of induction collection method is 71%, the massage collection method 61% and the frozen drake sperm motility of induction 33% while the massage 19%. The fertility of frozen drake semen group is 85.93%, while that of the fresh semen group is 88.17%. The frozen drake semen fertility of the highest batch is 93.8%. In conclusion, the world's advanced fertility of frozen semen can be obtained both in the chicken and drake through the optimized DMA straw freezing technology and the method of screening freeze-resistant individuals.

The effect of methyl-beta-cyclodextrin on DNA absorption and quality of posttransfected sperm

Sperm can be selected as a natural vector for the production of transgenic animals. Methyl-beta-cyclodextrin (MBCD) removes cholesterol from the phospholipid membrane of sperm and improves the efficiency of DNA uptake by sperm. In experiment 1, fresh sperm was treated with various concentrations of MBCD. The direct effects of MBCD on sperm parameters were monitored. In experiment 2, different concentrations of MBCD (0, 1, 2, and 4 mmol) were assessed for the transfection of genetically exogenous construction to rooster sperm. Washed semen was divided into 5 equal groups for the incubation and transfection with a pcDNA3.1+/hG-CSF vector (exogenous DNA) as follows; Treatment I-Control (washed semen without DNA); Treatment II-Control (washed semen with DNA); Treatment III-(washed semen incubated with DNA and 1 mmol MBCD); Treatment IV-(washed semen incubated with DNA and 2 mmol MBCD); and Treatment V-(washed semen incubated with DNA and 4 mmol MBCD). We demonstrated that rooster spermatozoa spontaneously can uptake exogenous DNA; this was assessed using exogenous DNA amplification (sperm genomic DNA used as a template for PCR reaction) after DNase I treatment. In addition, total motility (TM), progressive motility (PM), velocity parameters [curvilinear velocity (VCL), straight linear velocity (VSL), sperm track straightness (STR), linearity (LIN)], membrane integrity (MI), and membrane functionality were posttransfectionally evaluated. The concentrations of 1 and 2 mmol MBCD significantly (P < 0.05) improved the motion characteristics and membrane integrity of fresh sperm. The presence of hG-CSF in rooster sperm was detected by PCR and based on sperm analyses MBCD (1 mmol) improved the percentage of motility (98.9 ± 0.81), membrane functionality (64 ± 1.64), and MI (76.2 ± 1.65) after transfection when compared with the other groups (P < 0.05). For the production of transgenic chicken, hens were inseminated (AI) by transfected sperm treated with 1 and 0 mmol MBCD. A PCR analysis of the blood samples and dead embryo tissues of chicks did not reveal the transgene integration.

Improving seminal quality and reproductive performance in male broiler breeder by supplementation of camphor

The current study was conducted to evaluate the effect of dietary camphor levels as a medicinal feed additive to improve semen quality, antioxidant capacity, reproductive hormones, and reproduction performance in roosters. For this purpose, thirty-five 29-wk-old Ross 308 broiler breeder roosters randomly were assigned to five experimental groups (seven birds/group) and received five doses of camphor containing 0, 50, 250, 750, and 1000 mg camphor/kg of feed for 12 wk consecutive. Semen quality parameters and motion characteristics of sperm were evaluated every 28 days and semen antioxidant capacity and plasma reproductive hormones concentration were tested at the end of the experiment. Also, at the end of the experiment, reproductive performance was assessed using artificial insemination. Among seminal quality parameters, sperm forward motility (88.96 vs 82.56%) and percentage of abnormal sperm (14.75 vs 15.86%) were improved in roosters fed 50 mg camphor/kg of feed compared to the control group (P < 0.05). Overall percentage of live sperm and plasma membrane integrity exhibited the quadratic responses to the levels of camphor (P < 0.08). The motion characteristics of sperm including progressive motility (28.81 vs 21.77%), average path velocity (VAP, 33.35 vs 26.83 μm/s), progressive velocity (VSL, 19.78 vs 16.48 μm/s), curvilinear line velocity (VCL, 52.87 vs 44.38 μm/s), the amplitude of lateral head displacement (ALH, 2.92 vs 2.46 μm) were improved in roosters fed 50 mg camphor/kg of feed compared to the control group (P < 0.05). However, dietary camphor levels linearly increased the percentage of linearity (LIN) and straightness (STR) (P < 0.05). A significant decrease in seminal plasma concentration of malondialdehyde (MDA) and an increase in superoxide dismutase (SOD) activity were observed in birds fed 1000 mg camphor/kg of feed (P < 0.05). Testosterone concentration was considerably increased by doses of 50 and 250 mg camphor/kg of feed compared to control (4.68, 4.79 vs 3.88 ng/mL) (P < 0.05). FSH and LH concentrations were not affected by camphor supplementation (P > 0.05). In the artificial insemination, fertility rate from both 50 mg camphor/kg of feed (88%) and 250 mg camphor/kg of feed (84%) was higher than control (75%) (P < 0.05). In conclusion, low levels of camphor, especially 50 mg camphor/kg of feed, improved seminal characteristics and, reproductive performance of roosters. Further researches are needed on the effect of higher levels of camphor and divulge of underlying mechanism on male's reproductive function.

Antioxidant enrichment of rooster semen extenders - A systematic review

The purpose of this systematic review was to evaluate the potential benefits of antioxidant enrichment of semen extenders. These substances are used to combat oxidative stress during processing and conservation of rooster semen. A literature search was performed in June 2020 using the keywords rooster AND (semen OR spermatozoa OR sperm OR ejaculate OR ejaculation). This report followed the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) guidelines. The PICO (population intervention comparison outcome) question was defined to compare roosters (Population) which had added antioxidants in the semen (Intervention) compared to the no-antioxidant group (Control); the outcome was semen quality (Outcome). Only articles investigating rooster cooled or frozen enriched semen with antioxidant extenders (Gallus Gallus domesticus) were selected by reading the title and abstract, totalizing 38 articles. After full text reading, we found that only 13 studies carried out sperm characteristics and fertility assays. To assess article quality, 15 items related to rooster breeding conditions, seminal collection methodology, and analyzed variables (seminal characteristics and fertility test) were established. There were positive effects of antioxidants on the preservation of seminal characteristics (motility, viability, membrane integrity, antioxidant activity, and lipid peroxidation) and on semen fertility after the conservation process. We conclude that the antioxidants reduce the oxidative stress and improve fertilizing capacity. The most used substances for cooled semen are glutathione, CoQ10, and l-carnitine; whereas for frozen semen, resveratrol, lycopene, and quercitin are most frequently used.

Nutritional modulation of fertility in male poultry

The increased consumption of protein derived from poultry demands greater poultry production, but increased poultry production (meat and eggs) is dependent on the fertility of the parent flocks. Clearly, the fertility of poultry flocks is associated with the fertility of both males and females, but the low numbers of males used for natural or artificial insemination mean that their role is more important. Thus, enhancing the semen volume, sperm concentration, viability, forward motility, and polyunsaturated fatty acids in sperm, as well as protecting against oxidative damage, could help to optimize the sperm membrane functionality, mitochondrial activity, and sperm-egg penetration, and thus fertility. Therefore, this review summarizes the nutritional factors that could improve the fertility of poultry males as well as their associated mechanisms to allow poultry producers to overcome low-fertility problems, especially in aging poultry males, thereby obtaining beneficial impacts on the poultry production industry.

Effects of k-carrageenan supplementation or in combination with cholesterol-loaded cyclodextrin following freezing-thawing process of rooster spermatozoa

This experimental research purposely seeks to explore the effect of supplementing k-carrageenan (k-CRG) or CLC (cholesterol-loaded cyclodextrins) or the combined effect of k-CRG and CLC as supplements of antioxidants to an extender for rooster semen freezing. A total of 75 neat pooled ejaculates were collected twice a week from twenty-five (25) commercial line arbor acres broiler roosters (30 wks) during the experimental period. In each replicate, semen samples (n= 15, three ejaculates per rooster) were pooled and divided into nine equal aliquots, and each aliquot was diluted with one of the following extender supplemented with k-CRG, CLC, and k-CRG + CLC after which it was subjected to cryopreservation process using the "pellet" method. In study I, the supplementation of extenders with k-CRG was in five equal aliquots as follows; (0.2, 0.4, 0.6, 0.8) mg/mL and control group (k-CRG 0) mg/mL while in Study II, there was a combination of both k-CRG + CLC (0.4 mg/mL + 1.5 mg/mL, respectively), 0.4 mg/mL k-CRG, 1.5 mg/mL CLC and control group. Sperm quality parameters, endogenous antioxidant enzymes, lipid peroxidation (MDA) and ROS were all assessed after the freeze-thaw process. Our findings in study I indicated that at post-thaw, an optimum 0.4 mg/mL k-CRG supplementation in the extender improved semen quality parameters, endogenous enzymes, MDA and ROS in comparison to the control group. Interestingly prior to the freeze-thaw process, it was depicted in study II that combined k-CRG + CLC (0.4 mg/mL+1.5 mg/mL) inclusion in the extender provided maximum protection to sperm quality parameters, endogenous enzymes, MDA and ROS in comparison to 1.5 mg/mL CLC and control group at post-thaw. Besides, there was also a significant difference observed in the extenders supplemented with combined k-CRG + CLC (0.4 mg/mL +1.5 mg/mL) when compared to 0.4 mg/mL k-CRG for semen quality parameters and endogenous antioxidant enzymes (SOD, CAT, and GPx) but no significant difference was observed for MDA and ROS. Also, there was a significant difference observed in the extender supplemented with 1.5 mg/mL CLC when compared to the control group for semen quality parameters, SOD, CAT, and MDA but no significant difference for GPx and ROS at post-thaw. In conclusion, k-CRG at an optimal dosage of 0.4 mg/mL proved effective for improving post-thaw sperm quality but its combined addition k-CRG + CLC at an optimal concentration of (0.4 + 1.5) mg/mL in the extender provided greater protection to the rooster spermatozoa at post-thaw.

Quercetin supplemented casein-based extender improves the post-thaw quality of rooster semen

The advantageous influence of quercetin (Q) supplementation in an extender has not yet been evaluated for rooster semen cryopreservation. This research was purposely conducted in order to assess the effect of different quercetin concentrations added into an extender on the sperm quality of the rooster subsequent to a freezing-thawing process. After the freezing-thawing process, spermatozoa quality parameters (membrane functionality, acrosome integrity, motility, viability, and abnormal morphology), endogenous enzymes (SOD, CAT, and GPx), mitochondrial activity, DNA fragmentation index, lipid peroxidation (MDA), and ROS were all evaluated. A total of 75 neat pooled ejaculates (3 ejaculates/rooster) were collected from 25 arbor acres roosters (24 wks) twice a week using abdominal massage technique, then divided into five equal aliquots and diluted with an extender containing different doses of Q (CS-Q) as follows: casein extender without Q (control only), casein extender containing 0.040 mg/mL quercetin (CS-Q 0.040), 0.020 mg/mL quercetin (CS-Q 0.020), 0.010 mg/mL quercetin (CS-Q 0.010), and 0.005 mg/mL quercetin (CS-Q 0.005). Our results depicted that adding to the extender with a 0.010 mg/mL Q enhanced (P < 0.01) sperm motility, membrane function, viability, mitochondrial activity, intact acrosome (P < 0.05), SOD (P < 0.001), CAT, and GPx (P < 0.01) compared to the control group at post-thaw. Compared to the control group and other treatment groups after the freeze-thawing process, the addition of 0.005 mg/mL Q into the extender also showed higher (P < 0.05) improvement in the quality of sperm parameters and a higher (P < 0.01) SOD and CAT but did not improve mitochondrial activity and sperm viability. In addition, there was a lower degree of DNA fragmentation index, lower (P < 0.05) lipid peroxidation and ROS in frozen-thawed sperm treated with 0.010 mg/mL and 0.005 mg/mL Q than in control and the other treatment groups. In addition, 0.020 mg/mL Q supplementation into the extender also reduced DNA fragmentation and improved GPx activity compared to the control group at post-thaw. Different concentrations of Q 0.010 and 0.005 mg/mL added to the extender reduced the percentage of abnormal spermatozoa compared to the other groups. The results of this study showed for the first time that the inclusion of an extender with a suitable quercetin concentration of 0.010 mg/mL improved the post-thawed quality of rooster semen.

Acrosome and chromatin integrity, oxidative stress, and expression of apoptosis-related genes in cryopreserved mouse epididymal spermatozoa treated with L-Carnitine

Oxidative stress is believed to be an important cause of sperm damage during freezing. l-Carnitine (LC) may have the potential to improve sperm quality after frozen-thawed process. The present study aimed to investigate the effect of LC supplementation in cryoprotectant media of mouse epididymal sperm on post-thaw sperm quality and expression of apoptosis-related genes. Male BALB/cJ mice spermatozoa were cryopreserved in a cryoprotectant medium containing 2.5 or 5 mM LC. The untreated group was cryopreserved with the cryoprotectant medium only. Six months following cryopreservation, the samples were thawed and sperm quality parameters, chromatin and acrosome integrity, reactive oxygen species (ROS) and glutathione (GSH) levels, mitochondrial activity, and mRNA expression of Bax and Bcl-2 were assessed. The results demonstrated that the concentration of 5 mM LC in cryoprotectant media exhibited higher values for the sperm quality parameters and integrity of chromatin and acrosome in post-thaw spermatozoa than those of the untreated group. Furthermore, sperm ROS levels decreased while GSH and mitochondrial activity levels increased in 5 mM LC group compared to those in the untreated group (P < 0.01). In 5 mM LC-treated group, Bax was down-regulated (P < 0.05) while Bcl-2 was up-regulated (P < 0.001) compared to the untreated group. Collectively, LC supplementation of cryoprotectant medium improved the quality of frozen-thawed mouse epididymal spermatozoa, as showed reduced ROS level and Bax expression as well as increased GSH, mitochondrial activity, and Bcl-2 expression.

Effect of astaxanthin nanoparticles in protecting the post-thawing quality of rooster sperm challenged by cadmium administration

The protective role of astaxanthin nanoparticles (Ast NPs, 25 mg/kg p.o) against cadmium (Cd, 1 mg/100 g b.w. SC), a known inductor of lipid peroxidation and changes in the antioxidant defense system in the Ross 308 breeder roosters sperm, was examined. Sperm motility (computer-assisted sperm motility analysis), membrane integrity (hypoosmotic swelling test), viability, total abnormality, and enzymatic parameters were assessed after thawing. The testis/body weight (mg/kg) ratio and HE staining results of testis were also performed. The obtained results showed that Cd induced detrimental effects on testis and sperm, while Cd treated by Ast NPs (Cd Ast) diminished this change compared to the Cd group. Cd-treated group resulted in significantly (P < 0.05) lowest total (37.29 ± 2.46) and progressive (5.84 ± 0.47) motility and decreased antioxidant enzyme activity (CAT, TAC, and GPx), as well as producing a significant (P < 0.05) decrease in testis weight (mg) compared to the control group. Treatment with Ast NPs (Ast NPs + Cd) had reversed Cd-induced changes in the antioxidant defense system and significantly prevented Cd-induced testis damage. In conclusion, the results of our work suggest that Ast NPs at 25 mg/kg act as a potent antioxidant in protecting rooster testes against oxidative stress induced by Cd.

Changes in seminal parameters and hormonal profile with use of aromatase inhibitor in management of aging broiler breeder roosters

An excessive amount of aromatase enzyme reduces reproductive performance in aging roosters. Testosterone metabolism by aromatase enzyme is one of the reasons for reduced testosterone and lower fertility of aging roosters. The purpose of this study was to determine the effects of Exemestane (EX), as a steroidal aromatase inhibitor, on the seminal parameters and reproductive hormones of aging roosters. A total of 20 roosters (45 wk of age) were housed in individual cages and received a standard basal diet and oral EX capsules for 60 D at the daily doses per rooster (mg/rooster) in the following experimental groups: 0 mg (CTRL), 0.25 mg (Ex-0.25), 0.5 mg (Ex-0.5), and 1.5 mg (Ex-1.5). Sperm samples were obtained on days 1, 20, 40, and 60 of experiment. Blood samples were taken on days 1 and 60. The results indicated that different EX dosages affected semen parameters (P < 0.05) other than semen volume, morphology, apoptosis, and acrosome integrity. Various semen characteristics were significant (P < 0.05) during different times of the experiment, with the exception of semen volume, total motility, membrane integrity, morphology, apoptosis, and acrosome integrity. Roosters that received 0.5 mg of EX had higher percentages of sperm concentration, total motility, progressive motility, membrane integrity, viability, and mitochondrial activity (P < 0.05). There were lower concentrations of malondialdehyde in the CTRL (0 mg) and Ex-0.25 groups (P < 0.05). Although there was no significant difference in hormones at day 0 of the experiment (P > 0.05), roosters in the Ex-0.5 had higher concentration of testosterone as well as lower of aromatase activity at day 60 (P < 0.05). It can be concluded that EX improved semen parameters and testosterone, which ultimately can increase fertility in the aging broiler breeder roosters.

Improving the quality of rooster semen frozen in straws by screening the glycerol concentration and freezing rate

1. This study examined different glycerol concentrations (GC) and freezing rates to improve the quality of rooster spermatozoa frozen in straws, and to determine the effect of varying GC on post-thawed spermatozoa quality, as evaluated by fertility and hatchability.2.The experiment included two tests. In test 1, rooster semen straws containing 2, 4, 6, 8 and 11% glycerol were put in a rack (nine tiers with a 1 cm interval between every two tiers, 1 to 9 cm above liquid nitrogen (LN) source), and gradually frozen. The semen straws located in different tiers experienced different temperatures and freezing rates. The straws were then thawed and live sperm numbers determined. In test 2, rooster semen straws containing 2, 4, 6, 8 and 11% glycerol were put on optimal tiers (identified in test 1) for freezing, and stored at -196°C. Hens were inseminated with the frozen semen (post-thawed and glycerol removed, about 4.0 × 10⁸ sperm per hen), and eggs incubated.3. The numbers of live sperm in the 11% glycerol group was higher than that in 2, 4 or 6% glycerol group (P < 0.05) for the semen straws on tiers 1 to 9, while that on tiers 1 to 5 was lower than that on tier 6 to 8 (P < 0.05). GC, freezing rate and the interaction between GC and freezing rate had a significant effect on live sperm numbers (P < 0.01). The highest fertility was in the 6% glycerol group and occurred on day 5 after insemination. The lowest fertility occurred in the 2% glycerol group on day 10 after insemination.4. The optimal combination was 11% glycerol in straws located 6 cm above the LN surface (on tier 6). The 6% glycerol group achieved the highest fertility (77.6%), which surpassed that reported in recent years.

Effect of different concentrations of l-carnitine in extender for semen cryopreservation in sheep

This study assessed the effect of l-carnitine (LC) in sheep semen extenders containing or not egg yolk for cryopreservation in sheep. Two extenders (TRIS-egg yolk or the commercial optiXcell™ IMV medium) were used, totaling six groups: IMV - (0, 5 and 10 mM LC) and TRIS - (0, 5 and 10 mM LC). After the freezing-thawing process and throughout incubation at 38 °C for up to 3 h, several parameters were evaluated: sperm kinetics, hypoosmotic, plasma membrane integrity, capacitation status and lipid peroxidation level. The supplementation of either 5 or 10 mM LC randomly affected some parameters and, overall, TRIS was superior (P < 0.05) than IMV extender. In the LC-groups, IMV had greater (P < 0.05) oxidative stress than TRIS. In conclusion, although LC affected isolated parameters, its supplementation in semen extender had no consistently beneficial effect on freezing-thawing ram sperm.

Dietary supplementation with linseed oil improves semen quality, reproductive hormone, gene and protein expression related to testosterone synthesis in aging layer breeder roosters

Omega-3/n-3 polyunsaturated fatty acids (ω-3/n-3 PUFAs) play an important role in male reproductive function. The present study was designed to evaluate the effects of linseed oil (LO) as a source of α-linolenic acid (ALA, n-3 PUFA) on semen quality, plasma reproductive hormone and expression of key enzyme and protein related to steroidogenesis in aging layer breeder roosters. Ninety-six 57-wk-old Nongda No.3 layer breeder roosters were randomly assigned into one of four dietary treatments. All birds were fed a basal diet for 1wk and then assigned to a corn-soybean meal-based diet containing 0, 1, 2, 4% LO for 4 wk. After feeding trial, the roosters were slaughtered and investigated. The results showed that semen volume was dramatically increased relative to the other treatments in 2% LO group (P < 0.05). With an increase in dietary LO, semen concentration, sperm viability, sperm motility and total sperm count increased linearly (P < 0.05). Plasma follicle-stimulating hormone (FSH) level increased gradually and reached a maximum when 4% LO was fed (P < 0.01). Plasma luteinizing hormone (LH) levels in 1% and 2% LO group were improved significantly (P < 0.05) relative to the control group. Plasma testosterone (T) levels were remarkably improved compared with the control when birds were fed 2% and 4% LO (P < 0.05). A significant increase of steroidogenic acute regulatory protein (StAR) mRNA expression in 2% and 4% LO group was observed relative to the control group (P < 0.05). An increase in dietary LO supplementation from 1% to 4% markedly enhanced (P < 0.05) the mRNA expression of cholesterol side-chain cleavage enzyme (P450scc) compared to the control. A significant increase (P < 0.05) in the Steroidogenic Factor 1 (SF-1) mRNA levels was observed in the 2% and 4% LO-added groups. SF-1 protein expression was markedly increased by adding LO in diets (P < 0.05), and reached a maximum in 2% LO group. In conclusion, the results above suggest that dietary LO may improve semen quality by increasing the T hormone secretion, which may be related to higher StAR and P450scc mRNA expression and SF-1 expression. These findings provide a potential for using LO to attenuate the age-related sub-fertility in commercial layer breeder roosters.

Dietary supplementation with flaxseed oil as source of Omega-3 fatty acids improves seminal quality and reproductive performance in aged broiler breeder roosters

Reproductive performance in aged broiler breeder roosters is not desirable. The purpose of this study was to assess the effects of dietary flaxseed oil and vitamin E on the semen parameters, hormonal profiles, fatty acid analysis of sperm, and fertility performance of aged roosters. Twenty four roosters were assigned into four treatments and received their diets as following: 1) basal diet as control group (CTRL), 2) basal diet supplemented with 200 mg/kg vitamin E (CTRL + VITE), 3) basal diet supplemented with 2% flaxseed oil (FLAX) and 4) basal diet supplemented with 2% flaxseed oil plus 200 mg/kg vitamin E (FLAX + VITE). Roosters were fed their diets for 60 days and then, different characteristics of reproduction in the roosters were examined during experiment. Different diets affected semen parameters (P ≤ 0.05) except semen volume and morphology. Various characteristics of semen were significant (P ≤ 0.05) during different times of experiment excluding the total motility, membrane integrity and morphology. The higher percentage of sperm concentration, total motility, progressive motility, viability and membrane integrity accorded with a lower lipid peroxidation were observed in the roosters fed diet of FLAX + VITE (P ≤ 0.05). A higher concentration of testosterone was detected in roosters fed FALX + VITE at day 60 (P ≤ 0.05). Moreover, the percentage docosapantaenoic acid (DPA), docosahexaenoic acid (DHA) of sperm were increased in the diet of FLAX (P ≤ 0.05). Finally, rate of fertility after artificial insemination was significantly higher in the diet of FLAX + VITE. It seems that supplementation of aged roosters' diet with flaxseed oil and VITE improves the semen performance and fertility potential that can be a suitable strategy to preserve the reproductive performance of aged rooters.

Improvement of post-thawed sperm quality in broiler breeder roosters by ellagic acid-loaded liposomes

Liposomes could improve the delivery of substances to sperm. This study was conducted to investigate the effect of the antioxidant ellagic acid and ellagic acid-loaded liposomes on post-thawed sperm quality in broiler breeder roosters. Semen was diluted in Beltsville extender containing ellagic acid or ellagic acid-loaded liposomes (ellagic acid at 0 (control), 0.5, 1, and 2 mM) and cryopreserved. Sperm quality was evaluated post-thawing: motility characteristics (Computer-Assisted Semen Analysis), membrane functionality (HOS test), abnormal morphology, mitochondrial activity (Rhodamine 123), apoptotic status (Annexin V/Propidium iodide), malondialdehyde, and antioxidant activities (glutathione peroxidase (GPx), superoxide dismutase (SOD), and total antioxidant capacity (TAC)). The results showed that 1 mM ellagic acid-loaded liposomes improved total motility, membrane functionality, and viability comparing to 0.5 and 2 mM ellagic acid, 2 mM ellagic acid-loaded liposomes, and control group. Mitochondrial activity was significantly higher for 1 mM ellagic acid-loaded liposomes compared to the rest of the treatments, except 1 mM ellagic acid. Ellagic acid at 1 mM in both forms significantly increased GPx and TAC after freeze-thawing (no significant variation for SOD), and also yielded the lower proportion of apoptotic and dead cells. In conclusion, ellagic acid improved post-thawed sperm quality in broiler breeder roosters. The use of liposomes could further enhance the effects of ellagic acid.

Sperm quality characteristics and fertilization capacity after cryopreservation of rooster semen in extender exposed to a magnetic field

There has not been as much success in the effectiveness of avian semen cryopreservation as that of mammalian semen cryopreservation. This has been attributed to the unique characteristics of poultry sperm. In the area of mammalian semen, the use of magnetized extenders has enhanced the cryo-resistance of sperm in some species. The applicability of this strategy to avian semen has not yet been evaluated. The purpose of this study was to evaluate the effects on sperm quality and fertility after magnetization of extenders and use of these extenders for cryopreservation of rooster semen. Extenders were passed between two neodymium magnets that produced different magnetic induction values (0, 2000, 4000 and 6000 G). Physicochemical properties of the extenders were assessed and then semen samples were cryopreserved in the magnetized extenders. The smallest cluster sizes and zeta potentials in the extenders were observed in the extender magnetized at 2000 gauss (G). There were greater percentages of sperm total motility, viability and mitochondrial membrane potential in semen treated with the extender magnetized at 2000 G A greater percentage of sperm with enhanced membrane functionality was observed when sperm were stored in extenders magnetized with 2000 G and 4000 G. In a field trial, there were greater percentages of fertility and hatching rates of eggs using semen treated with extenders magnetized at 2000 G and 4000 G. Cryopreservation of rooster semen with magnetized extenders at 2000-4000 G resulted in enhanced quality indices of thawed sperm as well as the fertility capacity of the cryopreserved semen.