Enhancing cryopreserved ram sperm quality at -80 °C with Spirulina platensis and Salvia verbenaca extracts.

This study was conducted in two steps to evaluate the influence of freezing methods and natural extracts on cryopreserved ram sperm quality. Initially, the research compared the effects of two freezing methods: liquid nitrogen (LN2) versus -80 °C, on post-thawed ram semen on total and progressive motilities and velocity parameters. Experiment I revealed no significant differences (P > 0.05) between the LN2 and -80 °C freezing methods, indicating similar effects on the analyzed parameters. Experiment II aimed to examine the influence of Spirulina platensis (SP) and Salvia verbenaca (SV) extracts added to egg yolk extender on cryopreserved sperm quality, utilizing the -80 °C freezing method. Various concentrations (1.25, 3.75, 6.25 and 8.75 µg*mL-1) of acetone (Ac-SP and Ac-SV) and hexanoic (Hex-SP), as well as methanolic (MeOH-SV) extracts, were added into the extender. A thorough assessment of post-thawed sperm quality parameters, encompassing motility, velocity parameters, viability, membrane integrity, abnormality and lipid peroxidation was conducted. The outcomes demonstrated that 1.25 and 3.75 g*mL-1 of Ac-SP and Hex-SP and 1.25 µg*mL-1 of AC-SV and MeOH-SV increased the post-thawed ram sperm quality. In conclusion, this study emphasizes the antioxidant properties of SP and SV extracts, highlighting their potential to protect cryopreserved sperm cells from oxidative stress at -80 °C.

Adjusting ram semen preservation: Exploring the impact of oxygen exposure during liquid storage.

This study investigated the effects of storage conditions on the quality of chilled ram semen stored at 4°C for 48 h, comparing aerobic and anaerobic conditions. Ejaculates from INRA180 rams were collected and stored under both conditions, with assessments at 0-, 24-, and 48-h intervals. Various sperm parameters were examined, including motility, velocity, viability, morphology, membrane integrity, and lipid peroxidation. Results showed that storage duration significantly impacted sperm quality, leading to a gradual decline from 0 to 24 h and 24 to 48 h. Notably, after the initial 24 h, progressive motility (PM) and membrane integrity (MI) demonstrated distinct responses to storage conditions. Anaerobic storage consistently improved PM and MI values compared to aerobic storage between 24 and 48 h. Anaerobic conditions also enhanced viability and reduced abnormality at the 48-h mark. Total motility remained stable throughout storage. Velocity parameters (VCL: curvilinear velocity; VSL: straight velocity and VAP: velocity average path) exhibited differences between the 24- and 48-h intervals, with anaerobic storage resulting in higher VAP and VSL values. Moreover, lipid peroxidation exhibited a progressive increase from 0 to 24 h and 24 to 48 h, independent of storage conditions. Remarkably, anaerobic storage consistently yielded lower lipid peroxidation levels compared to aerobic storage, regardless of storage duration. In conclusion, this study highlights that the anaerobic storage proved advantageous for chilled ram semen quality, particularly after the initial 24 h.

Heat stress and ram semen production and preservation: Exploring impacts and effective strategies.

As global warming persists, heat stress (HS) continues to affect animals, particularly those raised in extensive systems such as sheep. As a result, there is a growing body of research investigating the physiological and biological consequences of HS on these animals. Recent studies have specifically examined the effects of climate change, global warming, and HS on gametes. Heat stress has been shown to affect ram semen production, resulting in decreased sperm quality and volume in both fresh and stored samples. This is attributed to the effect of heat on hormone production in the testicles, which is critical for successful spermatogenesis. Such effects can have significant consequences on the fertility of female sheep, which could affect the farmers' revenue. Therefore, farmers and researchers are utilizing various strategies and laboratory techniques to mitigate these negative effects. This review aims to comprehensively evaluate the impact of HS on ram semen production and conservation and analyze the different mitigation strategies at various levels, including management and nutritional interventions. The findings of this review will serve as a critical foundation for the development of targeted interventions and sustainable practices in sheep farming, ensuring resilient and profitable operations in the face of ongoing global climate challenges.

Comparative evaluation of Duragen® and skim milk extenders to enhance ram semen quality and fertility: A promising alternative in ovine artificial insemination.

This study aimed to investigate the effectiveness of Duragen® and skimmed milk (SM) extenders on the quality parameters, bacterial load and fertilization ability of stored ram semen. A total of 50 ejaculates from Sardi rams (n = 5) aged 2.5-3 years, were collected and stored in Duragen® and SM at 15°C. The motilities and velocity parameters generated by the CASA system were then evaluated at 0, 8 and 24 h of storage. Afterward, bacterial loads of sperm extended in Duragen® and SM were determined at 0, 5 and 24 h of incubation. In addition, ewes (n = 100) aged 2 years, have been chosen in the same herd. The selected ewes were then synchronized and inseminated using semen extended in Duragen® and SM and stored for 5 h at 15°C. The results revealed that total and progressive motilities, straight velocity (VSL), straightness (SRT), lateral head displacement (ALH) and beat cross frequency (BCF) were not affected by the extender type after 24 h of storage (p > .05). However, curvilinear velocity (VCL), velocity average path (VAP), linearity (LIN) and wobble (WOB) showed higher values in Duragen® compared with SM extender after 24 h of storage (p < .05). Bacterial loads were observed mainly in sperm stored in SM at 5 h (183 UFC/mL) and at 24 h (357 UFC/mL) of incubation. However, the only case showing a bacterial load in Duragen® is when the storage time attains 24 h (199 UFC/mL). Concerning fertility, sperm diluted in both extenders resulting in high fertility rates which reaches 66% and 73% for Duragen® and SM, respectively, with no statistical difference (p > .05). In summary, Duragen® extender decreased bacterial load in stored semen and maintained high ram sperm quality and fertility. These findings suggest that Duragen® extender could be used as SM alternative in ovine artificial insemination (OAI).

Inclusion of Spirulina platensis and Salvia verbenaca extracts to boost semen quality and fertilization ability in sheep.

The aim of this study was to investigate the effect of Spirulina platensis (SP) and Salvia verbenaca (SV) extracts added to skimmed milk (SM) extender on ram sperm quality and fertility. Semen was collected using an artificial vagina, extended in SM to reach a final concentration of 0.8 × 109 spermatozoa/mL, stored at 4°C and evaluated at 0, 5 H and 24 H. The experiment has been performed in three steps. Firstly, from four extracts (methanol: MeOH, acetone: Ac, ethyl acetate: EtOAc and hexane: Hex) of SP and SV, only acetonic and hexanoic extracts of SP and acetonic and methanolic extracts of SV showed the highest in vitro antioxidant activities and were then selected for the following step. Thereafter, the effects of four concentrations (1.25, 3.75, 6.25, and 8.75 µg/mL) of each selected extract on stored sperm motility were evaluated. The output of this trial led to select the best concentrations having beneficial effects on sperm quality parameters (viability, abnormalities, membrane integrity, and lipid peroxidation) and fertility after insemination. The results showed that the same concentration (1.25 µg/mL) of both Ac-SP and Hex-SP, as well as 3.75 µg/mL of Ac-SV and 6.25 µg/mL of MeOH-SV, maintain all sperm quality parameters at 4°C during 24 H of storage. Besides, no difference was found in fertility between the selected extracts and the control. In conclusion, SP and SV extracts were shown to improve the quality of ram sperm and to maintain fertility rate after insemination as similar or competitive to many previous studies published in the field.