Effect of Different Media and Protein Source on Equine Gametes: Potential Impact During In Vitro Fertilization

Area of Science:

• Reproductive Biology
• Animal Science
• Cell Biology

Background:

• Equine in vitro fertilization (IVF) success rates remain variable.
• Optimizing culture media is crucial for improving equine gamete quality and fertilization outcomes.

Purpose of the Study:

• To evaluate the impact of two culture media, modified Whitten's (MW) and Tissue Culture Medium 199 (TCM), supplemented with either Foetal Bovine Serum (FBS) or Bovine Serum Albumin (BSA), on equine oocyte maturation and sperm capacitation for IVF.

Main Methods:

• Equine oocytes (compact and expanded) were matured in TCM or MW with FBS or BSA.
• Sperm capacitation was assessed by evaluating motility and protein tyrosine phosphorylation (PY).
• IVF trials were conducted using selected media and supplements.

Main Results:

• TCM with FBS or BSA significantly increased metaphase II (MII) rates in expanded equine oocytes compared to MW.
• FBS supplementation in both TCM and MW enhanced sperm protein tyrosine phosphorylation (PY) compared to BSA.
• Despite improved gamete parameters, no fertilization was achieved in the IVF trials.

Conclusions:

• TCM supplemented with FBS demonstrates superior performance in enhancing the meiotic competence of expanded equine oocytes.
• FBS effectively induces sperm capacitation, indicated by PY, in both TCM and MW media.
• Further research is needed to identify the specific block to fertilization in equine IVF under these conditions.