title: Patterns of milk macronutrients and bioactive molecules across lactation in a western lowland gorilla (Gorilla gorilla) and a Sumatran orangutan (Pongo abelii).
abstract: In addition to nutrients, milk contains signaling molecules that influence offspring development. Human milk is similar in nutrient composition to that of apes, but appears to differ in other aspects such as immune function. We examine the longitudinal patterns across lactation of macronutrients, the metabolic hormone adiponectin, the growth factors epidermal growth factor (EGF) and transforming growth factor β2 (TGF-β2), and two receptors for these growth factors (EGF-R and TGF-β2-RIII) in milk samples collected between days 175 and 313 postpartum from a Sumatran orangutan (Pongo abelii) and between days 3 and 1,276 from a western lowland gorilla (Gorilla gorilla), and compare the results with human data from the literature. Milk macronutrients and hormones were measured using standard nutritional assays and commercially available enzyme immunoassay kits. Ape milk fat content was lower than human milk values, but protein and sugar were similar. Concentrations of all bioactive molecules were consistently detectable except for TGF-β2 in orangutan milk. Concentrations of adiponectin, EGF, and TGF-β2 in both ape milks were lower than found in human breast milk. Concentrations declined with infant age in orangutan milk; in gorilla milk concentrations were high in the first months, and then declined to stable levels until 2-3 years after birth when they increased. However, when expressed on a per energy basis milk constituent values did not differ with age for orangutan and the variation was reduced at all ages in gorilla. In orangutan milk, the ratio of EGF-R to EGF was constant, with EGF-R at 7.7% of EGF; in gorilla milk the EGF-R concentration was 4.4 ± 0.2% of the EGF concentration through 3 years and then increased. These data indicate that potent signaling molecules such as EGF and adiponectin are present in ape milk at physiological concentrations. However, human breast milk on average contains higher concentrations.
authors: Smithsonian Conservation Biology Institute, Conservation Ecology Center, Nutrition, Laboratory, National Zoological Park, Washington, District of Columbia.|Research Department, American College of Obstetricians and Gynecologists, Washington, District of Columbia.
authors: Michael L
authors: ML
authors: Power
authors: Research Department, American College of Obstetricians and Gynecologists, Washington, District of Columbia.|Department of Neuroscience, Georgetown University, Washington, District of Columbia.
authors: Jay
authors: J
authors: Schulkin
authors: Department of Anthropology, The George Washington University, Washington, District of Columbia.
authors: Heather
authors: H
authors: Drought
authors: Smithsonian Conservation Biology Institute, Conservation Ecology Center, Nutrition, Laboratory, National Zoological Park, Washington, District of Columbia.|Anthropology Department, Mira Costa College, Oceanside, California.
authors: Lauren A
authors: LA
authors: Milligan
authors: Smithsonian Conservation Biology Institute, Conservation Ecology Center, Nutrition, Laboratory, National Zoological Park, Washington, District of Columbia.|College of Computer, Mathematical, and Natural Sciences, University of Maryland, College Park, Maryland.
authors: Katie L
authors: KL
authors: Murtough
authors: Department of Anthropology, University of Colorado Boulder, Boulder, Colorado.|Health and Society Program, Institute of Behavioral Science, University of Colorado Boulder, Boulder, Colorado.
authors: Robin M
authors: RM
authors: Bernstein
mesh_terms: D000818:Animals; D005260:Female; D006071:Gorilla gorilla / Q000502:physiology*; D006801:Humans; D007774:Lactation; D008892:Milk / Q000737:chemistry*; D008895:Milk, Human / Q000737:chemistry; D009752:Nutritional Status; D057080:Pongo abelii / Q000502:physiology*; D011148:Pongo pygmaeus
keywords: great ape; growth factor; hormones; milk; nutrition; primate