390 - Young Scholar Award Talk: The Effect of Chronic Maternal Lipopolysaccharide Exposure during Late Gestation on Offspring Muscle Development

Abstract: The objective of this study was to determine the effect of chronic inflammation during late gestation on offspring muscle development. Starting at gestational day (GD) 70, first-parity gilts were administered either lipopolysaccharide (LPS, n=7) or saline (CON, n=8) via jugular venipuncture every other day until GD 84. LPS was initially given at 10 µg/kg BW and was increased by 12% each instance of administration. Volume of PBS was increased accordingly. Rectal temperatures of gilts were collected at 0, 2, 3, and 4-h post injection. Gilts farrowed naturally at GD 114 (±2). At postnatal day (PND) 3, the pig closest to the average litter weight was euthanized, and the longissimus dorsi, psoas major, semitendinosus, heart, lungs, liver, and kidneys dissected and weighed. The semitendinosus was frozen in liquid N cooled-methylbutane and sectioned for muscle fiber typing analysis. Data were analyzed as a one-way ANOVA with cohort as a random effect and significance considered at (P ≤ 0.05). Gilts exposed to LPS had a 1.3°C increase in rectal temperature at 3 and 4-h post injection (P < 0.05), indicating successful induction of an inflammatory response. LPS exposure reduced (P = 0.04) the weight of piglets born alive and tended to reduce (P =0.09) the weight of piglets weaned, but did not alter the percent of pigs born alive or survival during the suckling period (P ≥ 0.29). Semitendinosus weight was also reduced (P < 0.01) in LPS pigs, and tended to be reduced (P =0.09) as a percentage of whole-body weight. However, there were no differences between treatments in any other tissues. Further, maternal LPS exposure did not alter fiber type proportions, average fiber area, or estimated number of fibers (P ≥ 0.17). Overall, these data indicate that chronic maternal LPS exposure during late gestation did not reduce offspring muscle fiber formation.