In vitro fertilization of horse follicular oocytes matured in vitro

Abstract

In vitro fertilizing ability of stallion spermatozoa was assessed using horse follicular oocytes matured in vitro. After collection, stallion spermatozoa were either: 1) washed and incubated in TALP medium with 3 mg/ml bovine serum albumin (BSA) and 10 μg/ml heparin for 4 h, 2) washed and incubated in TALP with 3 mg/ml BSA for 3 h and cultured for a further 1 h with 1 mM caffeine and 5 mM dbcAMP, 3) washed and incubated in TALP medium with 3 mg/ml BSA at pH 7.9–8.2 for 2–4 h, or 4) diluted and incubated in TALP medium with 10 mg/ml BSA and 7.14 μM calcium ionophore A 23187 for 5–10 min followed by washing. After a given pretreatment, suspensions were diluted into B2 medium to a concentration of 5 × 10⁶ sperm/ml and co‐incubated with oocytes for 12 h or 24–48 h. In the ionophoretreated group, 18 of 54 oocytes (33%) were fertilized by 12 h, and 11 of 45 (24%) cleaved by 24–48 h. Evidence of fertilization was not found in the oocytes incubated with spermatozoa from other treatment procedures.