Effect of asiatic acid supplementation in tris-extender on post-thaw functional competence, antioxidant enzyme activity and in vivo fertility of bull sperm

Reactive oxygen species at supra-physiological levels trigger oxidative stress during cryopreservation, which can be neutralised by incorporating suitable antioxidants into the semen extender medium. This study was intended to explore the effect of asiatic acid (AA) as an antioxidant in semen extender on frozen-thawed sperm quality and in vivo fertility of bull sperm. Semen was collected from Holstein Friesian bulls for 10 consecutive weeks (total ejaculates = 60). Semen was cryopreserved with a Tris citric acid egg yolk-based extender supplemented with 0 (control), 20, 40, 60, and 100 μM AA. The supplementation of the extender with 40 and 60 μM AA improved (p < 0.05) post-thaw motility kinematics, plasma membrane integrity, acrosome integrity, sperm viability, and DNA integrity of bull sperm. Mitochondrial membrane potential was high (p < 0.05) with 60 μM of AA concentration in extender media. The catalase activity in seminal plasma was maintained (p < 0.05) when semen was added with 20, 40, and 60 μM of AA. The in vivo fertility was found to be significantly high with the semen extended with 60 μM AA. Conclusively, this study showed that AA supplementation in semen extender significantly improved sperm motility kinematics and cell integrity, conserved antioxidant enzyme activity, and improved in vivo fertility.

54 Effect of clinical endometritis on the follicle growth dynamics, oocyte recovery, oocyte quality, and invitro developmental competence of oocytes using ovum pickup in Sahiwal cattle

Sahiwal cattle is the premium quality milk breed of cattle in Pakistan. Uterine infections often lead to culling of valuable animals from a herd, resulting in genetic drain. The genetic potential of problematic females could be reaped by invitro embryo production. The objective of the present study was to evaluate the effect of clinical endometritis on follicle growth dynamics, recovery, quality, and invitro developmental competence of oocytes using ovum pickup (OPU) in Sahiwal cattle. The animals, 5–7 years of age, third or fourth parity, and 160 to 170 days in milk (DIM), were inspected for any discharge at the vulva or inside the vagina. Then, B-mode ultrasonography was performed to measure the diameter of cervix and to examine the uterus for the presence of pus. The animals (n=12) were divided into 2 groups: (1) healthy (n=6), and (2) clinical endometritis (n=6), based on the presence or absence of pus at the vulva or in the vagina. The first OPU was performed after 7 days of dominant follicle puncture and subsequently repeated OPUs (54 and 50), after every 7 days over 9 OPU sessions, were performed in the healthy group and clinical endometritis group, respectively. Follicles were aspirated using transvaginal ultrasound–guided needle. Viable COCs were considered for further processing only and were placed in the 100-µL droplets of BO-IVM medium and incubated at 37°C, 5% CO2, and 95% humidity for 24h. Nuclear maturation was estimated by staining the oocytes with Hoechst 33342. Frozen semen from the same Sahiwal bull was thawed and processed for IVF throughout the study. Sperm were prepared using swim-up protocol. Sperm and COCs were co-incubated in 100-µL droplets of BO-IVF for 18h. Finally, presumptive zygotes were cultured in 100-µL drops of BO-IVC medium at 37°C, 5% CO2, 5% O2, and 95% humidity for a period of 7 days. Cleavage rate and blastocyst rate were recorded on Day 2 and 7 following IVF, respectively. The data were analysed using the GLIMMIX procedure of SAS (SAS Institute Inc.). The results revealed that the number of medium-sized follicle (1.32±0.11 vs. 0.56±0.11) and total follicles (9.14±0.70 vs. 6.58±0.72) were higher (P&lt;0.05) in the healthy group than in the clinical endometritis group, respectively. Similarly, the number of oocytes recovered (5.05±0.39 vs. 2.78±0.41), viable oocytes (2.87±0.25 vs. 1.46±0.26), COCs with grade AB, having minimum of 2 cumulus cell layers and homogeneous cytoplasm, (33 vs. 20%) and nuclear maturation (68 vs. 55%) were also higher (P&lt;0.05) in the healthy group than in the clinical endometritis group, respectively. However, cleavage rate (55 vs. 46%) and blastocyst rate (29 vs. 26%) did not differ (P&gt;0.05) between the groups. In conclusion, clinical endometritis has a negative effect on follicle growth dynamics, oocyte recovery, oocyte quality, and nuclear maturation; however, the developmental competence of COCs is not compromised by it.