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In vitro development of early sheep embryos is superior in medium supplemented with human serum compared with sheep serum or human serum albumin

1992; Elsevier BV; Volume: 29; Issue: 1-2 Linguagem: Inglês

10.1016/0378-4320(92)90020-e

1873-2232

Jeremy G. Thompson, A. C. Simpson, P.A. Pugh, H.R. Tervit,

Assisted Reproductive Technology and Twin Pregnancy

Two experiments were performed to assess the effect of supplemental protein source on sheep embryo development in vitro when incubated in synthetic oviduct fluid medium (SOF). In Experiment 1, a 2 × 3 factorial (N = 215) design examined two serum sources (20% v/v human serum (HS) vs. sheep serum (SS)) and three incubation vessels (multiwells, containing 500 μl media (MW); microwells, containing 50 μl media (μW); microdrops under paraffin oil, containing 50 μl media (μD)). One-cell embryos were incubated for approximately 144 h at 39°C under humidified 5% CO2, 5% O2, 90% N2. Incubation in medium containing HS resulted in more blastocysts (81 vs. 60%, P<0.001), expanded blastocysts (79 vs. 45%, P<0.001) and hatched blastocysts (51 vs. 22%, P<0.001), and more cells were present in blastocysts (P<0.01). More blastocysts had hatched (P<0.05) when incubated in MW compared with μW or μD. In Experiment 2, a 2 × 2 × 2 (+1) factorial (N = 135) design examined two macromolecules (human serum albumin (HSA) or polyvinyl alcohol) and the presence or absence of two medium additives (minimal essential medium (MEM) non-essential amino acids (NEAA) and MEM essential amino acids plus MEM vitamins (EAA&V)). An additional group, comprising SOF supplemented with 20% HS, was included. Polyvinyl alcohol supplemented media supported limited development with only four out of 61 embryos reaching the 16-cell stage. Human serum albumin supplemented medium supported development, especially if further supplemented with NEAA (P<0.05). There was no difference for the proportion of embryos developing to blastocyst stage between HS supplemented SOF and HSA + NEAA supplemented SOF, but blastocysts in HS had significantly more cells (P<0.001) and a greater proportion had hatched (41 vs. 0%). The addition of EAA&V inhibited development beyond the 16-cell stage (P<0.05). The results demonstrate that human serum is a very effective supplement for sheep embryo culture and that factor(s) in the serum, other than albumin, promote development.