Early embryonic survival and embryo development in two lines of rabbits divergently selected for uterine capacity.
The aim of this work is to study early embryo survival and development in 2 lines divergently selected for high and low uterine capacity throughout 10 generations. A total of 162 female rabbits from the high line and 133 from the low line were slaughtered at 25, 48, or 62 h of gestation. There were no differences in ovulation rate and fertilization rate between lines in any of the 3 stages of gestation. Embryo survival, estimated as the number of normal embryos recovered at a constant ovulation rate, was similar in both lines at 25 and 48 h. Embryo survival was greater in the high line [D (posterior mean of the difference between the high and low lines) = 0.57 embryos] at 62 h of gestation. There was no difference in embryonic stage of development at 25 h, but at 48 and 62 h of gestation, the high line, compared with the low line, had a greater percentage of early morulae (83 vs. 72%) and compacted morulae (55 vs. 38%). Divergent selection for uterine capacity appeared to modify embryo development, at least from 48 h of gestation, and embryo survival from 62 h.
Peiró
R
R
Departamento de Ciencia Animal, Universidad Politécnica de Valencia, Valencia, Spain. ropeibar@dca.upv.es
Santacreu
M A
MA
Climent
A
A
Blasco
A
A
D000818:Animals; D047108:Embryonic Development / Q000235:genetics*; D005260:Female; D005328:Fetal Viability / Q000235:genetics / Q000502:physiology*; D008098:Litter Size; D010060:Ovulation / Q000235:genetics / Q000502:physiology; D011247:Pregnancy; D011817:Rabbits / Q000196:embryology / Q000235:genetics; D012641:Selection, Genetic; D014599:Uterus / Q000502:physiology*