Research reportAnxiety-like behaviour in adult rats perinatally exposed to maternal calorie restriction

Environmental stimuli such as caloric availability during the perinatal period exert a profound influence on the development of an organism. Studies in this domain have focused on the effects of under- and malnutrition while the effects of more mild levels of restriction have not been delineated. Rat dams and their offspring were subjected to one of five dietary regimens: control, CR50% for 3 days preconception, CR25% during gestation, CR25% during lactation, and CR25% during gestation, lactation, and post-weaning (lifelong). The pup retrieval test and maternal observations were conducted during lactation to quantify maternal care. In the pup retrieval test, dams that were concurrently experiencing CR (i.e., from the lactation and lifelong groups) displayed shorter latencies to retrieve all pups than the control and preconception groups and the lactation group constructed better nests than all groups. Adult offspring were tested in three tests of anxiety: the elevated plus maze, open field, and emergence test. No differences were observed in the elevated plus maze; however, in the open field preconception animals made fewer entries and spent more time in the central zone than controls. In addition, preconception offspring exhibited longer latencies to full body emergence, spent less time fully emerged, and spent more time engaged in risk assessment behaviours than all other groups. Offspring from the preconception group were also on average 11% heavier than control rats throughout life and displayed 37% higher serum leptin concentrations than controls. A potential role for leptin in the anxiogenic effect of preconception CR is discussed.