Rabbit Resilience Selection Alters Embryo Development and Modifies Metabolic Profiles of Organic Acid and Glucose

A divergent selection for resilience was carried out in rabbits over 12 generations. The selection criterion was increased (the HO line) and decreased litter size variability at birth (the HE line). The HO line (more resilient) shows higher litter size than the HE line (less resilient). The HO line sows higher litter size and embryo development than the HE line. The aim of this work is to investigate the plasma organic acid profile in both lines at mating and early gestation in order to analyze the effect of selection by resilience in the ovulation rate and early gestation. A total of 19 and 18 nonlactating multiparous females from the HE and HO lines were used. The ovulation rate, normal embryos, and percentage of compacted morulae at 72 h post-coitum (hpc) were studied, and blood samples were obtained at mating and 72 hpc. The organic profile was determined by HPLC. Bayesian methodology was used for statistical analysis. The HE line had 1.5% fewer normal embryos and 12.3% fewer compacted morulae than the HO line. The ovulation rate was similar in both lines. α-ketoglutaric acid and cis-aconitic acid were higher in the HE line than in the HO line. Citric acid, lactic acid, and pyruvic acid were higher at mating than at early gestation. In conclusion, the lower efficiency in the utilization of energy sources in the HE line could explain the reduced embryo production observed. The organic profile varies depending on the reproductive state in the female.