Abstract # 3132 LPS-induced sickness behavior during lactation induces predatory behavior instead of maternal behavior in rats

This study analyzed the effects of lipopolysaccharide (LPS)-induced sickness behavior on selection between maternal behavior and predatory behavior in lactating rats. We also evaluated general maternal activity and TNF-alpha levels to confirm that LPS-induced sickness behavior. Lactating rats received 100 μg/kg LPS or saline solution on day 5 or 6 of lactation 2 h before the behavioral tests. Five pups and five cockroaches were introduced to the experimental cage at the same time, and maternal, predatory, and general activity behaviors were observed for 30 min. Maternal behavior was measured by the time of pup contact, pup grouping, pup grooming, and nursing. Predatory behavior was measured by the time of insect contact, foraging, and insect eating. General maternal activity was measured by the time of exploration and immobility. Immediately after the observations, blood was collected to measure the plasma TNF-alpha levels. LPS administration reduced the pup contact, pup grouping, and pup grooming, i.e., LPS impaired maternal behavior. LPS increased foraging and the insect eating, i.e., LPS increased predatory behavior. LPS also decreased exploration, increased immobility and TNF-alpha levels, i.e., LPS induced sickness behavior. Thus, LPS-induced sickness behavior during lactation induced predatory behavior instead of maternal behavior in rats.