Ca. Ernst et al., Effect of long-term selection for early postnatal growth rate on survival and prenatal development of transferred mouse embryos, J REPR FERT, 118(1), 2000, pp. 205-210
Reciprocal embryo transfer procedures were performed among mouse selection
lines to examine prenatal maternal effects on survival and development of t
ransferred embryos. Mice were from generations 28 and 29 of an experiment t
o select for (i) increased body weight gain from 0 to 10 days (E+); (ii) de
creased body weight gain from 0 to 10 days (E-); or (iii) a randomly bred c
ontrol line (C). A total of 118 embryo transfer procedures performed 12 h a
fter conception resulted in 983 progeny born to 89 litters. There was a 39%
overall embryo survival rate and 75% overall pregnancy success rate. Respo
nse to superovulation and oestrous synchronization was significantly lower
(P < 0.01) in the E+ Line. E+ individuals that did superovulate produced an
average of 37 oocytes per flush, which was significantly higher than in th
e control line mice (29 oocytes per flush; P < 0.01). The ability to comple
te pregnancy successfully was not influenced by uterine environment or embr
yo-uterine interaction. In contrast, embryo survival in successful pregnanc
ies was significantly affected by uterine environment. There were large mat
ernal effects for body weight and tail length at birth; E+ recipients produ
ced pups that were significantly larger than E- recipient pups (P < 0.01),
which in turn were significantly larger than pups gestated by control recip
ients (P < 0.01).