Abstract # 2183 Poster # 129:

Scheduled for Friday, June 22, 2007 05:00 PM-07:00 PM: Session 14 (South Main Hall) Poster Presentation

Housing Influences on Serotonin Metabolite Levels in Infant Rhesus Macaques (Macaca mulatta)

S. J. Unbehagen1, D. Kertes2, M. Schwandt3 and S. J. Suomi1
1Laboratory of Comparative Ethology, National Institute of Child Health & Human Development, National Institutes of Health, Poolesville, MD 20837, USA, 2Virginia Institute of Psychiatric & Behavioral Genetics, Virginia Commonwealth University, 3NIH/NIAAA, Laboratory of Clinical and Translational Studies
     Rearing conditions for nonhuman primates are known to influence serotonin metabolite levels, such that nursery-reared rhesus macaques have consistently lower metabolite levels than mother-reared animals throughout infancy. We examined the effect that housing clusters, or subgroups of infants housed in the same enclosure, had on serotonin metabolite levels for 98 mother-, 53 peer-, and 59 surrogate peer-reared animals. For the first six months of life, mother-reared animals interacted with a variety of adults and same-aged peers, peer-reared animals were housed continuously with three peers, and surrogate peer-reared animals were housed with a group of peers for a limited time each day (otherwise they were singly housed). CSF samples were collected on 14, 30, 60, 90, 120, and 150 days of age. Covariance structure of serotonin metabolite levels was modeled with and without housing clusters for mother-, peer-, and surrogate peer-reared animals in a growth curve model. Housing clusters improved model fit as indexed by reduced Aikike's Information Criterion values. The intraclass correlation (ICC) was greatest for peer-reared animals [ICC=45.0, p<0.05] compared to surrogate peer reared [ICC=22.8, p<0.05] or mother-reared [ICC=14.6 p=0.05] animals. This suggests infants who are housed with only a small group of peers develop more similar serotonin metabolite levels than infants housed in large social groups or those with only limited contact with other animals.