Interleukin-6 supplementation improves post-transfer embryonic and fetal development of in vitro-produced bovine embryos

The use of in vitro produced embryos dairy and beef cattle has increased recent years, but compromised post-transfer pregnancy success prevents producers from capturing all the benefits this technology can provide. This study explored whether supplementing interleukin-6 (IL6) during embryo development influences embryo-proper, fetus placenta early gestation cattle. Slaughterhouse-derived cumulus oocyte complexes underwent IVM (day −1) IVF 0). On day 5 post-fertilization, were treated with either 0 (CONT) or 100 ng/mL recombinant bovine IL6. No difference blastocyst formation was detected on 7.5 an increase (P < 0.05) inner cell mass numbers tendency for = 0.08) trophectoderm IL6-treated blastocysts. A subset blastocysts loaded individually into transfer straws, (ET) completed using estrous cycle stage-matched, nonlactating commercial cows. cows each group timed artificial insemination (TAI). Pregnancy rates similar among three treatment groups at 28 70. differences crown-rump length (CRL), crown nose (CNL), abdominal diameter (AD), placental fluid volume (PFV) between TAI ET-IL6 groups. Reductions CRL AD 56 a reduction PFV 35 when comparing ET-CONT group. CNL as well contrasting ET-IL6. Circulating plasma pregnancy-associated glycoprotein concentrations In summary, IL6 to IVP before ET pregnancies that more closely resembled TAI-generated than generated conventionally cultured embryos. These findings failed find any adverse effects supplementation embryo-proper activity. Rather, these observations suggest may normalize developmental trajectory