Lead induced alterations in maternal behavior and offspring development in the rat

The study was designed to determine whether lead ingestion by nursing rats would affect dam-pup interaction. Dams were exposed to diets with 0.0, 0.2, 0.4 or 1.0 percent by weight metallic lead. Mean blood-lead levels of pups at weaning were 3, 19, 40 and 57 micrograms/100 ml of blood respectively. Maternal behavior was assessed by videotaping behavior for complete 24 hour periods on alternate days from birth to weaning. Analysis of data revealed that lead affected dams nursed for longer periods than normal and offspring were slower to explore their environment. It was concluded that altered maternal behavior was related to delays in pup development and the functional isolation of experimental pups from their environment may be the antecedent to altered behavior later in maturity.