Meeting Abstract

30.5  Monday, Jan. 5  Evidence for a trade-off between immunity and reproduction in the pregnant Siberian hamster? CHESTER, E.M.*; FRENCH, S.S.; DEMAS, G.E.; Indiana University, Bloomington; Indiana University, Bloomington; Indiana University, Bloomington emcheste@indiana.edu

One assumption in life-history theory is that resources available for competing life functions (i.e., growth, reproduction and somatic maintenance) are limited, and resources allocated towards one function are unavailable for other functions. It is now well-established that immunity is energetically costly and immune activation can impair other energetically expensive responses such as reproduction in adult animals. Furthermore, mounting an immune response during pregnancy may result in long-term consequences for offspring due to a trade-off between investment in immune function and investment in reproductive effort. Here we test this hypothesis by examining Siberian hamsters (Phodopus sungorus) born to mothers injected with either lipopolysaccharide (LPS; 0.0625 mg/kg) or saline during pregnancy. LPS is the active fragment of the cell wall of Gram-negative bacteria that elicits an inflammatory response, providing a valid and reliable simulator of sickness in the absence of the actual pathogen. Preliminary results indicate that LPS induced a decrease in food intake but not mass in mothers following injection. Further, male growth rate was greater in LPS offspring. Additional offspring measurements, including a comprehensive immune profile, as well as behavioral responses to a resident-intruder interaction will be presented. Collectively, the results of this study contribute to our understanding of the epigenetic (i.e., maternal) effects of immune system activation on offspring physiology and behavior in vertebrates.