Abstract # 21:

Scheduled for Thursday, June 19, 2008 03:20 PM-03:35 PM: Session 3 (Meeting Room 2DEF) Symposium

Lactational programming? Mother’s milk energy predicts infant behavior and temperament

K. Hinde1,2,3 and J. P. Capitanio3,4
1Dept. of Anthropology, UCLA, Los Angeles, CA, USA, 2Nutrition Laboratory, Dept. of Conservation Biology, Smithsonian National Zoological Park, 3California National Primate Research Center, 4Dept. of Psychology, UC Davis, California
     For mammals, fetal programming has well-established impacts on the long-term growth, metabolism, and health of infants. Additionally, postnatal maternal factors may provide information to the infant about environmental conditions during critical periods of development. One essential element of maternal care involves the quantity and quality of milk that mothers produce for their infants, but little is known about individual variation in milk production and infant outcome. Mother’s milk provides the energetic foundation for infant growth as well as behavioral development, and the effect of milk on infant behavior is likely mediated by its contribution to brain development and to the development of response dispositions (temperament). We therefore examined the relationship between available milk energy and infant behavioral adaptation and temperament in a large sample of rhesus macaques (Macaca mulatta, N=59). Hierarchical multiple regression analyses [a=0.05] controlling for maternal rank, weight, parity, infant age and sex revealed that infants that had higher available milk energy at one month of age were characterized by significantly higher activity levels and greater confidence in a stressful setting at 3.5 months of age. We also showed that this infant activity measure, reflecting better adaptation to the stressful setting, was associated with significantly earlier reproduction in adulthood. Our results suggest that the milk energy available soon after birth may be a nutritional cue that calibrates the infant’s behavior to environmental and/or maternal conditions and this calibration has consequences for fitness.