Submitted October 11, 2006
Returned for revision November 15, 2006
Accepted January 22, 2007
Embryo
Toward a Feline Optimized Culture Medium: Impact of Ions,
Carbohydrates, Essential Amino Acids, Vitamins, and Serum
on Development and Metabolism of In Vitro
Fertilization-Derived Feline Embryos Relative to Embryos
Grown In Vivo
Jason R. Herrick *,
Jennifer B. Bond ,
Genevieve M. Magarey ,
Helen L. Bateman ,
Rebecca L. Krisher ,
Susan A. Dunford ,
and
William F. Swanson
* To whom correspondence should be addressed. E-mail: jason.herrick{at}cincinnatizoo.org.
Abstract
The objective of this study was to define the
physiological needs of domestic cat embryos to facilitate
development of a feline specific culture medium. In a
series of factorial experiments, in vivo-matured oocytes
(n=2040) from gonadotropin-treated domestic cats were
inseminated in vitro to generate embryos (n=1464) for
culture. In the initial study, concentrations of NaCl
(100.0 vs. 120.0 mM), KCl (4.0 vs. 8.0 mM),
KH2PO4 (0.25 vs. 1.0 mM) and the
ratio of CaCl2 to
MgSO4-7H2O (1.0 mM:2.0 mM vs. 2.0
mM:1.0 mM) in the medium were evaluated during days 1 to 6
(day 0 = oocyte recovery and IVF) of culture. Subsequent
experiments assessed the effects of varying concentrations
of carbohydrate (glucose, 1.5, 3.0, or 6.0 mM; L-lactate,
3.0, 6.0, or 12.0 mM; and pyruvate, 0.1 or 1.0 mM) and
essential amino acids (EAA; 0, 0.5, or 1.0x) in the medium
during days 1 to 3 and days 3 to 6 of culture. Inclusion
of vitamins (0 vs. 1.0x) and fetal calf serum (FCS; 0 vs.
5% (v/v)) in the medium were also evaluated during days 3
to 6. Development and metabolism of IVF embryos on day 3
or 6 were compared to age-matched in vivo embryos
recovered from naturally-mated queens. Using a Feline
Optimized Culture Medium (FOCM) based on these results
(100.0 mM NaCl, 8.0 mM KCl, 1.0 mM
KH2PO4, 2.0 mM CaCl2, 1.0
mM MgSO4, 1.5 mM glucose, 6.0 mM L-lactate, 0.1
mM pyruvate, and 0x EAA with 25.0 mM NaHCO3,
1.0 mM alanyl-glutamine, 0.1 mM taurine, and 1.0x
nonessential amino acids) with 0.4% (w/v) BSA from day 0
to 3 and 5% FCS from day 3 to 6, ~70% of cleaved embryos
developed into blastocysts with similar profiles of
carbohydrate metabolism as in vivo embryos. Our results
suggest that feline embryos have stage-specific responses
to carbohydrates and are sensitive to EAA, but are still
reliant on one or more unidentified components of FCS for
optimal blastocyst development.
Key words:
Embryo •
Assisted Reproductive Technology •
Early development •
In vitro fertilization
