Effect of sperm pooling with seminal plasma collected in breeding or nonbreeding season on Saanen goat sperm cryosurvival

Does Rainbow Trout Seminal Plasma-Cysteine Combination Affect the Cryo-Survivability and Post-Thaw Incubation Resilience of Ram Semen?

The aim of this study was to evaluate the effect of both pure rainbow trout seminal plasma (RTSP) supplementation and RTSP-cysteine combination on cryopreservation success and post-thaw incubation resilience of ram semen in the nonbreeding season. For this purpose, different doses of RTSP (0%, 1%, 10%, and 15%) with or without cysteine supplementation were used for experiments. Ejaculates chosen for experiments were pooled and then divided into eight equal volumes for grouping (Control-ControlC, RTSP1-RTSP1C, RTSP10-RTSP10C, and RTSP15-RTSP15C). After cryopreservation, frozen-thawed semen samples were incubated for 5 hours at 37°C for determination of post-thaw incubation resistance. Motility, HOST, TUNEL, Rh123-PI, and CTC tests were performed at 0 hour and 3rd and 5th hours of post-thaw incubation to evaluate the efficacy of all experimental groups. The RTSP10 and RTSP10C groups were noted to provide the best protection on motility, plasma membrane integrity, DNA integrity, and mitochondrial function of cryopreserved ram semen. On the other hand, the best protection against cryo-capacitation was observed in RTSP15 and RTSP15C groups. The addition of cysteine was found to be effective when the higher (15%) or lower (1%) doses of RTSP were used, as well as for no use of RTSP.

The Combined Effect of Melatonin Implant and Removal of Buck Seminal Plasma on Cryopreservation During the Nonbreeding Season

This study aimed to determine how melatonin (MT) and seminal plasma affected the freezability of buck sperm during the nonbreeding season. Semen was collected from eight bucks before (pre-MT) and after (post-MT) MT application in the nonbreeding season. Individual ejaculates were collected from the bucks, split into two equal groups according to the removal of seminal plasma (SP) (-) or nonremoval of SP (+). For washing, the groups of ejaculates were centrifuged, and the supernatant was separated, SP (-) and SP (+) ejaculates were diluted, then frozen. Semen samples were examined for sperm motility, plasma membrane integrity, defective acrosomes, DNA fragmentation, and mitochondrial membrane function at the native and post-thaw stages. When the general average post-thaw motility (p < 0.01), plasma membrane (p < 0.05), acrosome (p < 0.05), and DNA integrity rates (p < 0.05) and mitochondrial membrane potential (MMP) (p < 0.01) were evaluated, it was seen that MT administration caused a statistically significant improvement. The dramatic effect of nonremoval of seminal plasma on motility and plasma membrane integrity is more clearly observed in individual semen samples frozen in the pre-MT group (p < 0.05). Also, it was observed that removing seminal plasma in the post-MT group caused even milder post-thaw acrosome damage compared with the SP (+) group (p < 0.05). The effect of removing seminal plasma was not observed in terms of DNA integrity and MMP rates in pre- and post-MT groups. As a result, it was concluded that MT application and removal of seminal plasma in the nonbreeding season result in improvement in the freezability of buck semen.

Methionine, cysteine, and butylated hydroxytoluene enhance cryosurvival of ram semen on post-thaw and post-incubation time points

Despite there have been many experiments conducted about antioxidants, the best sole or combination use of antioxidants to include as a standard ingredient to freezing extenders is yet to be found. This study was designed to investigate the different doses of methionine (2.5 and 5 mM), cysteine (1 and 2 mM), and butylated hydroxytoluene (BHT) (1 and 2 mM) for ram semen cryopreservation on post-thaw and post-incubation (6 h) time points over spermatological parameters. Semen samples were collected from Kivircik rams via electro-ejaculator in breeding season. After essential spermatological evaluations, appropriate samples were pooled then split into 7 equal aliquots to create study groups (antioxidant free control, 2.5 mM methionine, 5 mM methionine, 1 mM cysteine, 2 mM cysteine, 1 mM BHT, and 2 mM BHT). Semen samples were put into French straws (0.25 mL), and freezing procedure (two-step) was conducted via a programmable gamete freezer. At both time points, motility, HOST, PSA-FITC, and TUNEL assays were made to discover the impacts of cryopreservation and incubation process over sperm cells. Antioxidant supplemented groups yielded better results compared to the control groups in terms of various spermatological parameters not only at post-thaw time point but after incubation for 6 h of time. The study demonstrated that supplementing sperm freezing extenders with previous antioxidants may create new approaches to cryopreservation procedures, and through increasing success rate of freezing, fertility results may increase to better results in near future.

Changes in histology, protein expression, and autophagy in dairy goat testes during nonbreeding season†

Seasonal reproduction contributes to increased chances of offspring survival in some animals. Dairy goats are seasonal breeding mammals. In this study, adult male Guanzhong dairy goats (10-12 months old) were used. Testis size, semen quality, hormone level, apoptosis of germ cells, and autophagy of Sertoli cells were analyzed in dairy goats during the breeding (October) and nonbreeding (April) seasons. We found that, during the nonbreeding season for dairy goats, semen quality, follicle-stimulating hormone (FSH) levels, and testosterone levels were reduced, and the number of apoptotic germ cells increased. The proliferation with decrease activity of germ cells in dairy goat during the nonbreeding season was significantly affected. However, the testis size did not change seasonally. Interestingly, Sertoli cell autophagy was more active during the nonbreeding season. The expression levels of FSH receptor, wilms tumor 1, androgen binding protein, glial cell derived neurotrophic factor, and stem cell factor decreased in dairy goats during the nonbreeding season. In summary, our results indicate that spermatogenesis in dairy goats during the nonbreeding season was not completely arrested. In addition, germ cell apoptosis and the morphology of Sertoli cells considerably changed in dairy goats during the nonbreeding season. Sertoli cell autophagy is involved in the seasonal regulation of spermatogenesis in dairy goats. These findings provide key insights into the fertility and spermatogenesis of seasonal breeding animals.