The 82nd Annual Meeting of the American Association of Physical Anthropologists (2013)

Bioactive factors in macaque milk: relationships with maternal physiology and infant growth


1Anthropology, The George Washington University, 2California National Primate Research Center, University of California Davis, 3Human Evolutionary Biology, Harvard University

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Mother’s milk contains nutrients, hormones, and growth factors that exert immediate and long-lasting physiological effects on infants. Several maternal factors are known or thought to have direct effects on relative concentrations and patterns of numerous milk constituents. We investigated 1) whether several bioactive factors, previously not measured in nonhuman primate milk, were detectable in the milk of rhesus macaques, and 2) whether concentrations of these constituents reflected maternal (age, mass, parity, rank) and infant characteristics (growth). We used 177 milk samples from 59 macaque mothers (each contributing samples from early, peak, and late lactation) housed in the outdoor breeding colony at the California National Primate Research Center. Using standard parallelism and recovery tests, we validated enzyme immunoassays (R&D Systems, Minneapolis) measuring epidermal growth factor (EGF), its receptor (EGF-R), adiponectin, transforming growth factor beta-2 (TGF-ß2), and insulin-like growth factor II receptor (IGF-IIR). Linear mixed models, controlling for total milk volume and repeated measures, show that adiponectin, EGF, and EGF-R all increased significantly from early to peak, and peak to late lactation. Increases from peak to late lactation were noted in TGF- ß2 and IGF-IIR. Younger mothers had higher milk adiponectin concentrations than prime or aged mothers. Adiponectin and EGF varied with rank in an inverted U-shape; mid-ranking mothers had higher concentrations than did high- or low-ranking mothers. Lastly, infant daily growth rate was positively correlated with the concentration of EGF in milk. These results illuminate new pathways for the investigation of early life programming through the transfer of bioactives in milk.

Support for milk analysis was provided by The George Washington University and the Smithsonian Institution (RB). Support for macaque data collection was provided by NSF BCS-0921978 (KH) and samples were made possible through the ARMMS program (Archive of Rhesus Macaque Milk Samples).

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