Prenatal exposure to different diets influences programming of glucose and insulin metabolism in dairy ewes

摘要

Nutrition in fetal and postnatal life can influence thedevelopment of several biological systems, with permanenteffects in adult life. The aim of this work was toinvestigate in dairy sheep whether diets rich in starch orfiber during intrauterine life (75 d before lambing) andpostnatal life (from weaning to first pregnancy; growthphase) program glucose and insulin metabolism in thefemale offspring during their first pregnancy. Startingfrom intrauterine life, 20 nulliparous Sarda ewes wereexposed to 4 dietary regimens (n = 5 per group) basedon different dietary carbohydrates during their intrauterinelife and their subsequent growth phase: (1) thefiber (FI) diet during both intrauterine and growth life,(2) the starch (ST) diet during both intrauterine andgrowth life, (3) the FI diet in intrauterine life followedby the ST diet in the growth phase, and (4) the ST dietin intrauterine life followed by the FI diet in the growthphase. After the end of the growth phase, all growingewes were fed the same diet and naturally mated. Whenewes were pregnant, on average at 124 ± 2 d of gestationthey were challenged with an intravenous glucosetolerance test, and peripheral concentrations of glucoseand insulin were determined. Basal insulin concentrationswere higher in ewes exposed to the ST diet (0.97μg/L) than in ewes exposed to the FI diet (0.52 μg/L)in intrauterine life. After glucose infusion, glucose andinsulin concentrations were not affected by intrauterinediet. Insulin resistance, determined by the homeostasismodel assessment, was affected by the intrauterine ×growth phases interaction. Insulin sensitivity, assessedby the quantitative insulin check index, was lower inewes exposed to the ST diet than in those exposed tothe FI diet in intrauterine life (ST = 0.28; FI = 0.30).Diet in growth life had no effect on glucose and insulinmetabolism. In conclusion, starchy diets offered duringintrauterine life but not during postnatal life increasedbasal insulin level and lowered insulin sensitivity duringthe first pregnancy. Nutritional strategies of metabolicprogramming should consider that exposure to starchydiets in late fetal life might favor the programming ofdietary nutrient partitioning toward organs with highrequirements, such as the gravid uterus or the mammarygland.