Manganese exposure and iron deficiency result in home cage behavior alterations in the developing rat

Abstract

Both manganese (Mn) exposure and iron deficiency (ID) have been linked to alterations in behavior, such as anxiety and locomotion, due to neurochemical disturbances. To date, no study has looked at the longitudinal behavioral alterations in the unaltered home cage of animals exposed to Mn or ID. Therefore, we sought to examine the effects of ID and Mn exposure over a three‐week period to determine time and dose‐dependent behavioral changes. Twenty one day old male rats were randomly placed into one of four dietary treatment groups: control, iron‐deficient, control with Mn exposure (via the drinking water), and iron‐deficient with Mn exposure. Rats were monitored for 24 hours during weeks four, five, and six of the dietary protocol using the Clever Systems Home Cage Scan video surveillance system. Several novel findings emerged from this study. For example, although ID was associated with a decrease in total distance traveled over time as previously reported, Mn exposure was related to an increase in total distance traveled over time which is contrary to prior reports of reduced locomotor activity in Mn exposed animals. While studies have examined effects of either Mn exposure or ID over short observational periods, this is the first to examine these effects on exploratory, locomotor, and autonomic behaviors longitudinally over a 24‐hour period in the home cage environment.