Recent approaches in the use of antioxidants and proteomic modifications in ram semen preservation.

Sperm preservation is a well-established technique in reproductive biotechnology that is widely used to maintain the genetic quality of male individuals. However, there are several factors during the preservation process that can affect the vitality, functionality, and quality of sperm, thereby reducing their fertility potential after thawing. One of these factors is the synthesis of high levels of oxidative stress (OS) during semen preservation, which can have detrimental effects on sperm health and functionality. To counter the negative impact of OS on sperm, researchers have explored the supplementation of several exogenous antioxidants in the extenders used to preserve ram sperm. This approach has shown promising results in improving sperm health, functionality, and fertility potential in ram. Additionally, the preservation process can induce modifications in the ram sperm proteome. By employing targeted proteomics techniques, researchers have been able to identify and modify specific proteins in cryopreserved ram sperm, potentially offering further improvements in the quality of the cryopreserved ram sperm. In summary, this review provides a comprehensive overview of the antioxidants and targeted proteomics modifications that have been investigated for enhancing ram sperm preservation. These advancements aim to mitigate the negative effects of OS and optimize the techniques used in preserving ram sperm.

The Supplementation of Bee Bread Methanolic Extract to Egg Yolk or Soybean Lecithin Extenders Can Improve the Quality of Cryopreserved Ram Semen.

Bee bread has numerous nutritional benefits and bioactive compounds. Other bee byproducts have been used as extender additives to improve semen cryopreservation. Here, we examined the effects of supplementing egg yolk extender (EYE) or soybean lecithin extender (SBLE) with bee bread extract (BBE) on the quality of cryopreserved ram semen. Semen was collected from five adult Rahmani rams once a week for 7 weeks. EYE and SBLE were supplemented with BBE. Antioxidant capacity and total phenolic compound, total flavonoid compound, and total soluble carbohydrate levels of BBE were measured. Sperm characteristics, including progressive motility, viability, abnormalities, membrane integrity, and acrosome integrity, were analyzed after equilibration, thawing, and thawing followed by a 2-h incubation. The total antioxidant capacity and malondialdehyde, hydrogen peroxide, aspartate transaminase, alanine transaminase, alkaline phosphatase, and total acid phosphatase levels in extenders were determined after thawing. Sperm apoptosis was analyzed using annexin V assays. SBLE was more effective than EYE for cryopreserving ram semen. Extender supplementation with BBE improved ram semen quality during freezing in a concentration-dependent pattern. Motility, vitality, and membrane integrity were particularly enhanced in BBE-treated semen. Additionally, BBE promoted antioxidant and enzymatic activities and reduced apoptosis in semen. Thus, extender supplementation with BBE improved sperm cryopreservation.

The possibility of using citric phosphate dextrose in chilling ram semen instead of egg yolk and soybean lecithin to improve fertility.

Semen chilling has some harmful effects on sperm characteristics. Modification of extenders by using conventional and non-conventional chilling substances can affect sperm characteristics and fertility. One of the important substances using to chilling human blood cells is citric phosphate dextrose (CPD); therefore, it can be used to store ram semen. This study aimed to assay the ability of CPD instead of egg yolk (EGD) and soybean lecithin (SLD)-based extenders to store ram semen at 5°C. This trial was carried on pooling semen samples that were collected from five rams using a standard artificial vagina and an oestrous restrained ewe. Immediately after semen collection, semen was divided into four portions. The EGD, SLD and citric phosphate dextrose with an antibiotic (CPDA) and without antibiotic (CPD) were extender in the first, second, third and fourth portions of semen, respectively. Sperm characteristics were evaluated after dilution and cooling up to 7 days. Also, conception rate and fertility potential were assayed by 48 ewes (12 each) after 2 days of store ram semen extenders. Data clearly indicated that higher (p > .05) sperm characteristics in EGD, SLD and CPDA than CPD at 0 day of storage. Whilst, sperm characteristics from 1 day up to 7 days of storage were higher (p < .05) in EGD, SLD, CPDA extenders than CPD. Moreover amongst extender types, the advancing of chilling days reduced sperm characteristics. Also, the results showed an acceptable conception rate and the fertility rate of dilution ram semen, which stored 2 days in EGD, SLD and CPDA than CPD. Using of CPD substances with antibiotic in chilling extension ram semen has benefits as well as EGD- and SLD-based extenders. The future work should be conducted to validate these results in frozen ram semen.