Maternal nutrient restriction at specific gestational stages compromises fetal growth and development, in particular, fetal adipose tissue deposition. The extent to which nutritional supplementation can promote growth and development of specific fetal organs is unknown. This study aimed to determine whether protein supplementation of the maternal diet at defined stages of gestation promoted the abundance of the key mitochondrial proteins; uncoupling protein 1 (UCP1), cytochrome c and the voltage dependent anion channel (VDAC) in fetal adipose tissue.
Twenty-nine twin-bearing ewes of similar body weight and parity were randomly allocated to 4 feeding groups from 10d gestation. All ewes received a control diet, which was supplemented with fishmeal in 3 of the groups during early i.e. 10d-40d, mid i.e. 40d-70d or late i.e. 110d-140d gestation. Each ewe was then humanely euthanased with an overdose of barbiturate (100 mg/kg pentobarbital sodium: Euthanal) at 140d gestation to enable sampling of perirenal adipose tissue. Protein abundance was determined by immunoblotting using fully validated antibodies. Results, in arbitrary units (means plus/minus s.e.m) are expressed as a percentage of a reference sample present on all gels. Significant differences between groups were assessed by GLM.
UCP1 abundance was significantly increased in fetus born to ewes supplemented in during mid gestation (mid, 125.6 plus/minus 13.6; control, 79.0 plus/minus 10.2 (P=0.02)), despite a reduction in total mitochondrial protein (mid, 85.2 plus/minus 9.7; control, 129.8 plus/minus 13.5 (P=0.013)). The abundance of VDAC and cytochrome c which were not significantly affected by supplementation.
In conclusion, feeding a protein supplement during mid gestation, the period of maximal placental growth results in a significant increase in the abundance of UCP1, which is likely to improve thermoregulation in the newborn.
DD was supported by a Wellcome Trust Vacation Scholarship.
03 - 05 Nov 2003
Society for Endocrinology