# Comparative developmental competence and gene expression in laparoscopically retrieved- and abattoir-derived goat oocytes

## TL;DR

LOPU-retrieved goat oocytes develop better and have more favorable gene expression than abattoir-derived ones, making them better for embryo production.

## Contribution

Demonstrates that laparoscopic ovum pick-up yields superior oocytes for in-vitro embryo development in goats.

## Key findings

- LOPU-derived oocytes showed higher cleavage, morula, and blastocyst formation rates compared to abattoir-derived oocytes.
- LOPU oocytes exhibited enriched ZAR1 and MFN2 expression and favorable BAX/BCL2 ratios, indicating better developmental competence.

## Abstract

Advancing in-vitro embryo production in goats requires identification of optimal oocyte sources and retrieval methods. While abattoir-derived ovaries provide abundant material for routine research, laparoscopic ovum pick-up from hormonally synchronized goats yields physiologically staged oocytes that may better support embryo development and advanced reproductive applications.

We compared the developmental competence and gene expression in bakerwal goat oocytes obtained via LOPU and from abattoir-sourced ovaries. A total of 528 cumulus oocyte complexes (COCs) were collected from 12 live donors across three LOPU sessions, while 1,517 COCs were retrieved from 338 abattoir ovaries. All oocytes underwent in vitro maturation, fertilization, and culture under similar conditions. Developmental competence was evaluated by cleavage, morula, blastocyst formation, and blastocyst morphology. Expression of competence-associated genes (ZAR1, MFN2, BAX, and BCL2) was quantified at immature oocyte, mature oocyte, and early blastocyst stages.

LOPU-derived oocytes demonstrated significantly higher developmental performance, including cleavage (54.9% vs. 45.2%), morula (45.9% vs. 34.9%), and blastocyst rates (29.5% vs. 19.0%; p < 0.05). Nuclear maturation did not differ significantly between groups (81.1% vs. 76.3%; p > 0.05). Gene expression analysis revealed enrichment of ZAR1 at GV and MII stages (up to 5.79-fold), progressive upregulation of MFN2 at the blastocyst stage (5.98-fold), downregulation of pro-apoptotic BAX (0.26–0.57 fold), and upregulation of pro-survival BCL2 (up to 1.85-fold) in LOPU-derived samples.

In goats, oocytes retrieved via LOPU show superior developmental competence and more favorable molecular signatures than those obtained from abattoir-derived ovaries. LOPU-derived oocytes provide a more reliable option for achieving higher -quality embryos and may be more suitable for application in advanced reproductive biotechnologies.