The impact of in utero heat stress and nutrient restriction on progeny body composition

• Published in: Journal of thermal biology Vol. 53; pp. 143 - 150
• Main Authors: Johnson, Jay S., Abuajamieh, Mohannad, Victoria Sanz Fernandez, M., Seibert, Jacob T., Stoakes, Sara K., Keating, Aileen F., Ross, Jason W., Selsby, Joshua T., Rhoads, Robert P., Baumgard, Lance H.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2015
• Subjects: Adiposity; Animals; Birth Weight; Caloric Restriction; Female; Heat-Shock Response; Intrauterine programming; Male; Maternal undernutrition; Pregnancy; Prenatal Exposure Delayed Effects - pathology; Prenatal Exposure Delayed Effects - physiopathology; Rats; Rats, Sprague-Dawley; Tissue accretion; Rats; Intrauterine programming; Tissue accretion; Maternal undernutrition
• ISSN: 0306-4565; 1879-0992
• DOI: 10.1016/j.jtherbio.2015.10.002

We recently demonstrated that in utero heat stress (IUHS) alters future tissue accretion in pigs, but whether this is a conserved response among species, is due to the direct effects of heat stress (HS) or mediated by reduced maternal feed intake (FI) is not clear. Study objectives were to compare the quantity and rate of tissue accretion in rats exposed to differing in utero thermal environments while eliminating the confounding effect of dissimilar maternal FI. On d3 of gestation, pregnant Sprague–Dawley rats (189.0±5.9g BW) were exposed to thermoneutral (TN; 22.2±0.1°C; n=8), or HS conditions (cyclical 30 to 34°C; n=8) until d18 of gestation. A third group was pair-fed to HS dams in TN conditions (PFTN; 22.2±0.1°C; n=8) from d4 to d19 of gestation. HS increased dam rectal temperature (p=0.01; 1.3°C) compared to TN and PFTN mothers, and reduced FI (p=0.01; 33%) compared to TN ad libitum fed controls. Although litter size was similar (p=0.97; 10.9 pups/litter), pup birth weight was reduced (p=0.03; 15.4%) in HS compared to PFTN and TN dams. Two male pups per dam [n=8 in utero TN (IUTN); n=8 IUHS; n=8 in utero PFTN (IUPFTN)] were selected from four dams per treatment based on similar gestation length, and body composition was determined using dual-energy x-ray absorptiometry (DXA) on d26, d46, and d66 of postnatal life. Whole-body fat content increased (p=0.01; 11.2%), and whole-body lean tissue decreased (p=0.01; 2.6%) in IUPFTN versus IUTN and IUHS offspring. Whole-body composition was similar between IUHS and IUTN offspring. Epididymal fat pad weight increased (p=0.03; 21.6%) in IUPFTN versus IUHS offspring. In summary and in contrast to pigs, IUHS did not impact rodent body composition during this stage of growth; however, IUPFTN altered the future hierarchy of tissue accretion. •Dams pair-fed in thermoneutral conditions gained less body weight compared to heat stress exposed mothers despite similar levels of nutrient restriction.•Despite a similar litter size and level of nutrient restriction, heat stress reduced offspring birth weight compared to dams pair-fed in thermoneutral conditions.•In utero undernutrition increased postnatal adipose tissue and reduced lean tissue compared to in utero heat stress exposure.•In utero undernutrition increased postnatal epididymal fat pad weight and adipocyte size compared to in utero thermoneutral and heat stress treatments.