Flock differences in the impact of maternal dietary restriction on offspring growth and glucose tolerance in female offspring.

Variable impacts of in-utero programming stimuli on postnatal offspring development suggest that genotype may play a role in this response. In this study, ewes from two flocks of similar breeding but adapted for 6-8 generations to one of two markedly different production environments were utilized (Baggs ewes--nomadic lifestyle and limited nutrition; UW ewes--sedentary lifestyle and adequate nutrition). Ewes from each flock were fed 50% (nutrient restricted) or 100% (control) National Research Council (NRC) requirements between day 28 and 78 of gestation; some ewes in each dietary group were then necropsied. Remaining ewes were fed 100% NRC requirements from day 79 to term. Weights of singleton female fetuses were reduced (P < 0.05) in nutrient restricted UW ewes compared to control UW ewes on day 78. Two month old ewe lambs from nutrient restricted UW ewes had greater (P < 0.05) baseline glucose concentrations, and exhibited greater (P < 0.05) glucose and insulin concentrations to an intravenous glucose bolus than lambs from control UW ewes. From 4 to 12 months of age, ewe lambs from nutrient restricted UW ewes were heavier (P < 0.05) than lambs from control UW ewes. In contrast, no differences in fetal weight, baseline glucose, glucose and insulin concentration to an intravenous glucose bolus, or body weight were observed for nutrient restricted and control Baggs ewes. These data suggest that a multigenerational adaptation of ewes to different production systems impacts their ability to protect their fetus against a bout of early to mid-gestational nutrient restriction.