Egg yolk enriched with polyunsaturated fatty acids (PUFAs) improves the shelf life of ram semen in liquid storage

Effects of different extenders, storage temperatures, and antioxidant supplementation on chilled semen quality: a review

The successful preservation of ram semen is essential to promote genetic variability, ensure semen transportation, and inseminate multiple ewes. Currently, either animal or plant-based lipoprotein-based extenders are used for semen preservation. Animal product-based extenders include milk and egg yolk, while soybean lecithin is a plant-based extender. Although extenders containing products of animal origin better preserve the quality of chilled semen, the in vivo efficacy after 24 h of storage is still of great concern. Storage temperature is another important and effective factor in preserving sperm quality, whereby different storage temperatures are adopted to enhance the storage life of sperm. Low temperatures (4-5 °C) better preserve sperm quality for a longer duration than high temperatures (15, 20, and 25 °C). Moreover, antioxidant supplementation has a positive impact on sperm quality during liquid storage. The current review summarizes the outcomes of various extenders, different storage temperatures, and antioxidant supplementation on the liquid storage of ram sperm.

Effect of olive, flaxseed, and grape seed nano-emulsion essential oils on semen buffalo freezability

The existing treatise targeted to compare the effects of adding different nano-emulsions essential oils (olive, flaxseed, and grapeseed oils) in freezing extender on semen quality and freezability in buffalo. Nano-emulsions were prepared from olive, flaxseed, and grapeseed oils and characterized for their sizes and shapes. Semen extended in four tubes were supplemented with 0 (control) and 3.5% nanoemulsion oils, including olive (NEO), flaxseed (NEFO) and grape seed oils (NEGSO) respectively. NEGSO resulted in the highest (p < 0.05) membrane integrity, vitality, progressive motility (P-motility) of sperm compared to the other groups in post-thawed buffalo bull semen (at 37 °C for 30 s). The addition of NEGSO had the best results for membrane integrity, progressive motility, and vitality of sperm after incubation (at 37 °C and 5% CO2 for 2 h). A superior (p < 0.05) value of total antioxidant capacity in frozen-thawed spermatozoa was monitored in all supplemented groups as relative to the control. The values of malondialdehyde (MDA) and nitric oxide (NO) were lower (p < 0.05) in NEGSO group compared with other groups. Both NEO and NEFO exhibited the same results for MDA, and NO levels (p > 0.05). All supplemented groups exhibited lower hydrogen peroxide levels (p < 0.05) as relative to the un-treated group. The lowest (p < 0.05) caspase 3 levels were verified in NEGSO treatment, followed by NEFO and NEO treatments. Post-thawed sperm showed ultrastructural damages in the control group, and theses damages were attenuated or resorted by the NEGSO, NEFO and NEO supplemented to freezing extender. In consequences with in vitro results regarding the sperm attribute, a greater pregnancy rate (92%) was observed in NEGSO group as compared with NEFO (88%), NEO (76%) and CON (68%) groups. Our findings demonstrate that NEGSO (3.5%) could be used as a new strategy in enhancing sperm functionality, potential fertility and reducing the oxidative damage and apoptosis markers. This could be significantly applicable for sperm physiology cryopreservation in the milieu of assisted reproduction systems.

Correlation between fatty acids levels in chicken, duck, goose, pigeon, quail and turkey egg yolks and post-thawed quality of ram semen

The comparison between adding egg yolks (EY) of chicken, duck, goose, pigeon, Japanese quail or turkey to the Tris glycerol extender on the quality of ram semen before freezing and post-thawing was evaluated. The correlation between fatty acids levels in egg yolks of different avian species and the post-thawed quality of ram semen was studied. The pooled ejaculates collected from five rams were extended with Tris EY glycerol extenders containing the EY of chicken, duck, goose, pigeon, quail or turkey and cryopreserved at -196°C. The straws were evaluated before freezing and post-thawing for sperm motility using a sperm cell analyser, vitality using a FluoVit kit and abnormality using a SpermBlue stain besides plasma-membrane and DNA integrities using a hypo-osmotic swelling test and a Halomax kit, respectively. The moisture, ash, protein and fatty acid (FA) contents of EY of chicken, duck, goose, pigeon, quail and turkey were analysed using a gas chromatograph. The chicken and quail EY extenders significantly improved the total progressive motility (32.05 ± 1.41 and 31.68 ± 1.43, respectively), vitality, plasma membrane and DNA integrities and abnormalities of post-thawing ram semen in comparison with other EY extenders. Pigeon EY had the lowest saturated fatty acids (SFAs) in comparison with the other types of EYs. The chicken and turkey EYs had the lowest percentage of (monounsaturated fatty acids) MUFAs in comparison with the other types of EYs. The highest percentage of polyunsaturated fatty acids (PUFAs) was observed in the turkey, pigeon and chicken EYs which were considered double or triple their percentage in duck and goose EYs, respectively. Significant positive correlations existed between SFAs levels and total motility, vitality, plasma membrane functionality and DNA integrity (0.77, 0.80, 0.67, 0.52, respectively). Significant negative correlations existed between gondoic EY levels and total motility, vitality, plasma membrane functionality and DNA integrity. In conclusion, the EYs of duck, goose, pigeon or turkey cannot substitute the chicken EY in ram semen extenders as they gave lower post-thawing quality. The quail EY can be used as a good replacer for chicken EY in the extender used for cryopreservation of ram semen. The EY composition of FAs can significantly affect the quality of ram semen post-thawing.

Seasonal Variations in Semen Quality, Testosterone Levels, and Scrotal Size following Dietary Flaxseed Oil and Ascorbic Acid in South African Indigenous Rams

The purpose of this study was to determine the seasonal variations in semen quality, testosterone levels, and scrotal size, following dietary flaxseed oil and ascorbic acid in South African indigenous rams. A total of 22 South African indigenous rams were randomly distributed into five treatment diets from June 2021 to May 2022 (12 months). To allow for the spermatogenesis period, semen was collected after sixty days of dietary supplementation with treatment diets. Blood was collected twice a week using an 18-gauge needle and vacutainer tubes and sent to the laboratory for testosterone analysis. Semen and blood collection were repeated eight times each season. The scrotal size (circumference, length, and width) was measured using a flexible measuring tape. Data was subjected to the General Linear Model (GLM) in Minitab® 2017. Treatment means were separated using Fisher’s t-test and considered significantly different when the p-value was less than 0.05. Seasons and diet had an effect on progression, total motility, and testosterone levels. For instance, NC during the spring season had the lowest progressive motility (42.84 ± 5.32), followed by the summer (49.38 ± 4.49), winter (62.46 ± 4.35), and autumn (63.26 ± 3.58). Notably, when treatment diets were introduced, improvements were realized, and there were significant differences (p < 0.05) among the seasons following supplementation of FLAX, ASCA, and FLAX + ASCA, except for FLAX in the autumn season (53.83 ± 4.16). Total motility did not differ significantly (p > 0.05) between the seasons when the NC and PC diets were supplemented; nevertheless, there was an improvement when FLAX, ASCA, and FLAX + ASCA were supplemented. Testosterone levels were significantly influenced by the seasons when negative and PC diets were supplemented. It is noteworthy that supplementing FLAX + ASCA can reverse the influence of the season on the testosterone levels (spring, 27.52 ± 4.42; summer, 20.23 ± 5.11; autumn, 25.24 ± 3.96; and winter, 25.92 ± 4.42). In conclusion, seasons do affect semen quality and testosterone levels of South African indigenous rams. However, flaxseed oil and ascorbic acid can reverse the seasonal variations in semen quality and testosterone levels.

Effects of adding mixed chicken and quail egg yolks to the cryodiluent on the quality of ram semen before and after cryopreservation

The effects of adding mixed chicken and Japanese quail egg yolks (EYs) to the cryodiluent on the quality of ram semen before freezing and post-thawing were evaluated. Additionally, the composition of chicken and quail egg EYs and their mixture were analyzed for results explanation. The semen was collected from rams (n = 5) and extended with cryodiluent containing the EY of chicken, quail or their mixture (1:1). The extended semen was chilled slowly to 5 °C within 2 h and equilibrated for 2 h, before frozen on the liquid nitrogen vapor and cryopreserved at -196 °C. The straws were evaluated before freezing and post-thawing for sperm motility, vitality and abnormality besides plasma-membrane and DNA integrities. The moisture, ash, protein, and fatty acid (FA) contents of chicken EY, quail EY and their mixture were analyzed. Sperm vitality, plasma membrane integrity and DNA integrity before freezing were significantly (P < 0.05) higher in quail EY than chicken EY and mixed EYs cryodiluent. The chicken EY extender significantly improved the vitality, plasma membrane and DNA integrities of post-thawed ram semen in comparison with quail EY or mixed EYs extenders. While, the post-thawing sperm abnormalities was lower (P ≤ 0.05) in quail EY than chicken EY and mixed EYs cryodiluent. The post-thawing sperm motion kinetics parameters were higher in quail EY than chicken EY and mixed EYs cryodiluent. The highest percentages of moisture, ash, saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) were detected in quail EY had. While, the highest percentages of fat, protein and polyunsaturated fatty acids (PUFAs) were detected in chicken EY. In conclusion, using of chicken EY can improve total motility, vitality, plasma membrane integrity and DNA integrity of cryopreserved ram semen. While, using of quail EY can improve sperm abnormalities and kinetic motion parameters of cryopreserved ram semen. Mixing chicken and quail EYs added no value for post-thawing ram semen parameters.

The Effect of Different Extenders on the Quality Characteristics of European Red Deer Epididymal Sperm Stored at 5 °C

The aim of this study was to evaluate the effect of different extenders on the quality of European red deer epididymal sperm stored at 5 °C. Epididymal spermatozoa were collected post mortem from 10 stags and diluted with three extenders (Bovidyl®, BoviFree®, and BioXcell®) and stored at 5 °C. Sperm motility (TMOT), motility parameters (system CASA), plasma membrane integrity (SYBR-14+/PI−), acrosomal membrane integrity (FITC-PNA−/PI−), mitochondrial activity (JC-1/PI), viability, and apoptotic-like changes (YOPRO/PI) were evaluated. The analyses were conducted on the first and successive days of storage (D1−D7). The applied extender, storage time, and the interactions between these factors significantly (p < 0.001) affected most of the analyzed parameters whose values were highest in sperm samples stored in Bovidyl®, regardless of storage time. In Bovidyl®, BoviFree®, and BioXcell® extenders, TMOT values were estimated at 83%, 63%, and 59%, respectively, on D3. The extenders significantly influenced DNA integrity on D7. The percentage of dead sperm increased from D3. The quality of stored sperm cells was significantly influenced by the extenders’ biochemical composition. BoviFree® and BioXcell® contain glycerol which could contribute to deteriorating the quality of spermatozoa stored at 5 °C. Sperm cells stored in the egg yolk-based extender (Bovidyl®) were characterized by the highest viability and functionality.

Effects of dietary supplementation of different oils and conjugated linoleic acid on the reproductive and metabolic aspects of male mice

The present study was carried out to examine first, if diets enriched with 320 g of the base diet with common dietary oils including fish oil, olive oil, hydrogenated sunflower seed (H-SFS) oil, flaxseed oil and sunflower seed oil (SFS) could induce weight gain and alter reproductive and metabolic characteristics of male mice. Second, whether the addition of conjugated linoleic acid (CLA, 10% of the diet) could ameliorate any negative effects. In this cross-sectional study, 90 four-week-old male NMRI mice were used in two consecutive experiments. A high level of dietary oils negatively affected some reproductive and metabolic characteristics of male mice (p < 0.05), specifically, sunflower seed oil enrichment resulted in higher HDL levels and apoptosis of germinal epithelial cells. An olive oil-enriched diet caused an increase in plasma triglyceride concentrations and germinal cell apoptosis, as well as a decrease in sperm concentration and perturbed spermatogenesis. When CLA was fed in conjunction with dietary oils it successfully mitigated some of the negative reproductive and metabolic characteristics. We conclude that male reproductive processes are affected by high dietary oils, even before signs of obesity are evident. Inclusion of dietary CLA may provide some benefit to offset negative effects, although further studies are required.

Reproductive performance and luteal function of Santa Ines ewes inseminated by cervical retraction with fresh or frozen semen

SUMMARY The artificial insemination (AI) by cervical retraction using fresh or commercially available frozen semen was evaluated. Santa Inês ewes (n=151) were assigned in five groups. Natural mating (NM) composed the control group. Four groups were submitted to hormonal treatment and timed insemination by cervical retraction (CRI) or laparoscopy (LAI), using fresh or frozen semen. To perform CRI, the ewes were kept in standing position. The time required to penetrate the cervical canal and to perform CRI were recorded; local deposition of semen and the reaction intensity of the ewe (weak, moderate or strong) were measured. Blood samples were collected to perform the progesterone dosage at days 0, 3, 5, 12 and 17 (day 0 = AI/NM). Non-return to estrus rate (NRE), pregnancy (at D35) and fertility (birth / mated ewes) were evaluated. Mean time for cervical penetration and CRI were 52.8 ± 21.2s and 3:26min ± 47s, respectively. Reaction intensity to CRI was weak or moderate in 92.3% of the ewes. Serum levels of progesterone after CRI, LAI or NM were similar. NRE of the inseminated ewes were similar, except for CRI with frozen semen, which was lower (P<0.05). Fertility rates were similar between CRI and LAI (35.4% and 42.2%, respectively). Artificial insemination by cervical retraction with ewes in a standing position is practical, and does not change the progesterone profile, providing reproductive rates similar to laparoscopy. However, the use of this technique along with commercial frozen semen presents low fertility rate.