---

Background: Heat stress reduces reproductive performance in farm animals. The aim of this study was to determine the effect of heat stress and different concentrations of melatonin on nuclear maturation of ovine oocytes. Materials and Methods: In this experimental study, ovary collection and oocyte recovery were carried out by standard methods. Oocytes culture was in A: TCM199+10% FBS, 5µg/ml FSH, 0.01IU/ml LH, 100 IU/ml penicillin, and 100 IU/ml streptomycin, B: A+heat stress at 40 C0, and C and D:B+1 and 10 µM melatonin, respectively. Results: Heat stress significantly (P<0.05) decreased nuclear maturation in the treatment group in comparison with the control group (60.60 vs. 84.89). Also, 1 and 10 µM melatonin could improve oocytes to reach metaphase-II stage (60.60 vs. 76.92, 78.82, respectively). However, increasing the melatonin dose from 1 to 10 µM did not alter oocytes maturation. Conclusion: Overall, this study showed that melatonin improves ovine immature oocytes maturation during heat stress.

---

Background: Maturation of oocytes and fertilization in vitro can be considered as one of the most important steps to treat infertility. In this study maturation medium was enriched with Platelet extraction (PL) which has high concentration of growth factors. Meiosis resumption and maturation was monitored after 18 hours of maturation.

Materials and Methods: In this experimental study, oocytes at germinal vesicle stage were obtained from mature NMRI female mice. Maturation medium was &alphaMEM and the control groups had 5-10% FBS and the medium in the experimental groups was enriched by 5, 10% PL and the combination of 5% PL and 5% FBS. Meiosis resumption and maturation were observed after 18 hours.

Results: The rate of matured oocytes in the experimental group 5% PL for both COC and DO group was significantly higher than the control groups (P<0.05). The maturation rate for 5% PL was 61% for the COC group and 72% for the DO group while this rate for 5% FBS control group was 53% and 50% respectively.

Conclusion: PL had a significant effect on meiosis resumption and maturation of oocyte at germinal vesicle stage. Based on these results, PL could be used as a maturation promoting factor.

---

Introduction: Glyphosate is the most popular broad-spectrum herbicide globally due to the growing demand for glyphosate-resistant crops. Glyphosate exhibits harmful properties, including cytotoxicity, neurotoxicity, and reproductive toxicity. This study aimed to investigate the detrimental effects of glyphosate on ovarian histopathology in mice and the in vitro maturation (IVM) of oocytes following superovulation.
Methods: In this study, thirty-two female NMRI mice were randomly divided into the following groups: control, glyphosate, superovulation, and superovulation-glyphosate. Animals received glyphosate (0.5%) continuously through drinking water for three weeks. HMG and HCG were used to induce superovulation. Oocytes were collected from the ampulla, and the quantity and quality of oocytes were analyzed. Then, in vitro maturation (IVM) of oocytes was performed. At the end of the study, ovarian histopathology was analyzed.
Results: Compared to the control group, the glyphosate-treated group exhibited a significant decrease in secondary and Graafian follicles while demonstrating a concomitant increase in atretic follicles (P < 0.05). Additionally, the superovulation-glyphosate group showed fewer germinal vesicle breakdown (GVBD) and MII oocytes than the superovulation group. In the superovulation-glyphosate group, there was a notable reduction in GVBD and MII oocytes following in vitro maturation (IVM).
Conclusions: Glyphosate has the potential to damage ovarian tissue and adversely affect IVM and oogenesis.