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Abstract Background The intricate interplay of gene expression within ovarian granulosa cells (GCs) is not fully understood. This study aimed to investigate the miRNA regulatory mechanisms of ferroptosis during the process of follicle development in lamb GCs. Methods Employing transcriptome sequencing, we compared differentially expressed mRNAs (DE-mRNAs) and miRNAs (DE-miRNAs) in GCs from lambs treated with follicle-stimulating hormone (FL) to untreated controls (CL). We further screened differentially expressed ferroptosis-related genes and identified potential miRNA regulatory factors. The expression patterns of HMOX1 and miRNAs in GCs were validated using qRT‒PCR and Western blotting. Additionally, we investigated the regulatory effect of oar-miR-134-3p on HMOX1 and its function in ferroptosis through cell transfection and erastin treatment. Results We identified a total of 4,184 DE-mRNAs and 304 DE-miRNAs. The DE-mRNAs were mainly enriched in ferroptosis, insulin resistance, and the cell cycle. Specifically, we focused on the differential expression of ferroptosis-related genes. Notably, the ferroptosis-related genes HMOX1 and SLC3A2, modulated by DE-miRNAs, were markedly suppressed in FLs. Experimental validation revealed that HMOX1 was significantly downregulated in FL and large follicles, while oar-miR-134-3p was significantly upregulated compared to that in the CLs. HMOX1 expression was regulated by the targeting effect of oar-miR-134-3p. Functional assays further revealed that modulation of oar-miR-134-3p influenced HMOX1 expression and altered cellular responses to ferroptosis induction by erastin. Conclusion This study suggested that oar-miR-134-3p and HMOX1 may be one of the pathways regulating ferroptosis in GCs. This finding provides new clues to understanding the development and regulatory process of follicles.

The application of laparoscopic ovum pick-up (LOPU) and in vitro production of embryos (IVEP) technologies has opened up a new path for purebred breeding and breed improvement in goats. However, due to the complexity of the procedures and multiple influencing factors, these technologies have not been widely adopted in goat production. This study explores factors affecting the efficiency of LOPU in goats by comparing the use of controlled internal drug release (CIDR) for estrus synchronization, conventional FSH versus long-acting recombinant ovine FSH (R-FSH) for superovulation, and the timing of LOPU at 48 h, 60 h, and 72 h of follicular development. The metrics evaluated included the recovery rate of cumulus–oocyte complexes (COCs), the average number of ovarian follicles, the average number of COCs, and the average number of available COCs. The results demonstrated that the efficiency of LOPU was significantly higher with two doses of R-FSH compared to the conventional FSH superovulation protocol and the control group (p < 0.05), with two doses of R-FSH providing a higher LOPU efficiency than one dose (p < 0.05). Using CIDR for estrus synchronization showed no significant difference in LOPU efficiency compared to the non-CIDR group. Similarly, the efficiency of LOPU showed no significant difference between the hormone treatments at 48 h, 60 h, and 72 h. By exploring and optimizing the factors influencing LOPU, we ultimately established a LOPU technology system for goats that meets the production needs of small ruminants.