The influence of maternal exercise on gene expression in the liver of porcine offspring

Kallie Blaine Foust, Purdue University

Abstract

Cardiovascular and metabolic diseases have been thought to be the result of diet and inactivity in adulthood; however, evidence suggests that these diseases may be programmed in utero. It has been shown that the effect of maternal nutrition during pregnancy has an effect on metabolic programming of offspring in utero that leads to an increased susceptibility of the offspring to develop obesity, cardiovascular disease, and diabetes mellitus in adulthood. However, little is known about what happens to the developing fetus under other environmental conditions, such as maternal exercise. The objective of the study was to determine the impact of maternal exercise on metabolic function in offspring. It was hypothesized that maternal exercise during pregnancy would alter postnatal metabolism and hepatic gene expression as a result of fetal programming in utero. To test this hypothesis, eight, six month old pubertal gilts were artificially inseminated at estrus and randomly assigned to either an exercise or sedentary protocol for fifteen weeks of gestation. Animals in the exercise group were loaded onto a treadmill and exercised five days a week for 30 to 45 minutes per session. Animals concluded the exercise protocol one week prior to their expected farrow date (week 15). The average weight gain between the exercise and sedentary gilts was significantly different at the end of the 15 week trial. There were no significant differences in the number of piglets born per litter or piglet birth weight between the sedentary and exercise groups. Piglets were euthanized from each litter at 48 hours, 3, 5, and 9 months after parturition; liver samples were collected. The transcript abundance of nine genes involved in gluconeogenesis, fatty acid synthesis, and PPAR signaling were quantified from mRNA isolated from liver tissue. The absolute transcript abundance of acetyl-CoA carboxylase alpha (ACACA), acyl-CoA synthetase long-chain family member (ACSL3), carnitine palmitoyltransferase 1A (CPT1), glucocorticoid receptor (gR), fructose-1,6-bisphosphatase 1 (FBPASE), fatty acid synthase (FASN), peroxisome proliferator activated receptor gamma, coactivator 1 alpha (PGC1), peroxisome proliferator-activated receptor alpha (PPARα), and phosphoenolpyruvate carboxykinase 1(PEPCK) was found to not differ significantly between the two treatments at any of the ages tested. However, these results do not conclude that there is a metatabolic advantage or disadvantage of maternal exercise on offspring. Therefore, RNA from liver samples of 48 hour offspring were purified and quantified for microarray analysis. The RNA samples were grouped and pooled based on treatment and sex; each pool consisted of four animals. Each RNA sample was hybridized to an Affymetrix Porcine Genome Expression Array. Upon evaluating 11341 probe sets, no transcripts present on the microarray were found to be present in significantly different amounts between the two treatments. The results suggest that there is no metabolic advantage in offspring of exercised-trained gilts over offspring of sedentary gilts at 48 hours of age. These studies are the first to demonstrate that exercise during pregnancy does not alter expression of hepatic genes. These results give justification for further studies probing the effects that a sedentary or active lifestyle during pregnancy might have on fetal programming.

Degree

M.S.

Advisors

Cabot, Purdue University.

Subject Area

Animal sciences

COinS