Michael L. Power

Maternal stress and high-fat diet effect on maternal behavior, milk composition, and pup ingestive behavior

Chronic variable prenatal stress or maternal high-fat diet results in offspring that are significantly heavier by the end of the first postnatal week with increased adiposity by weaning. It is unclear, however, what role maternal care and diet play in the ontogenesis of this phenotype and what contributions come from differences already established in the rat pups. In the present studies, we examined maternal behavior and milk composition as well as offspring ingestive behavior. Our aim was to better understand the development of the obese phenotype in offspring from dams subjected to prenatal stress and/or fed a high-fat (HF) diet during gestation and lactation. We found that dams maintained on a HF diet through gestation and lactation spent significantly more time nursing their pups during the first postnatal week. In addition, offspring of prenatal stress dams consumed more milk at postnatal day (PND) 3 and offspring of HF dams consume more milk on PND 7 in an independent ingestion test. Milk from HF dams showed a significant increase in fat content from PND 10-21. Together these results suggest that gestational dietary or stress manipulations can alter the rat offsprings developmental environment, evidence of which is apparent by PND 3. Alterations in maternal care, milk composition, and pup consumption during the early postnatal period may contribute to long-term changes in body weight and adiposity induced by maternal prenatal stress or high-fat diet.

Predictors of breast milk macronutrient composition in filipino mothers

There is increasing evidence that breastfeeding has long‐term effects on offspring biology and health, which has heightened interest in understanding the extent of variation in breast milk composition and its underlying determinants. Here, we report variation in milk macronutrient composition in a well‐characterized cohort of young Filipino mothers and test underlying maternal predictors of this variation.

Nutritional Composition of Actual and Potential Insect Prey for the Kasekela Chimpanzees of Gombe National Park, Tanzania

Humans, all great ape species, and some lesser apes consume insects. Insects can provide comparable nutritional yields to meat on a gram-for-gram basis and may serve as an important source of energy, fat, protein, minerals, and vitamins for hominoids. Although potential insect prey are abundant in ape habitats, patterns of insectivory are not consistent across species or populations. Efforts to understand these patterns are complicated by a lack of nutritional data. We collected samples of insects consumed by the Kasekela chimpanzee community of Gombe National Park, Tanzania, as well as of some insects found within the community range and ignored by these chimpanzees but known to be preyed upon by Pan elsewhere. We determined the gross energy (GE), estimated metabolizable energy (ME), fat, protein, fiber, and ash content of these samples following standard methodologies. We use these data to test the hypothesis that Kasekela chimpanzees choose insect prey (at least in part) based on energy and/or macronutrient content. On a fresh-weight, per-gram basis, the insect prey consumed by Kasekela chimpanzees had significantly higher fat and lower ash content than other assayed insects, and on a fresh-weight, per-foraging-unit (per-insect, per-dip, or per-nest) basis were significantly higher in GE, fat, and protein. On a per-gram basis, the assayed insects were generally comparable in energy and macronutrients to wild vertebrate meat. We conclude that Kasekela chimpanzees do favor insects that are high in energy, fat, and protein, and that the potential macronutrient yields from some forms of insectivory are not trivial.

The energetic and nutritional yields from insectivory for Kasekela chimpanzees

Insectivory is hypothesized to be an important source of macronutrients, minerals, and vitamins for chimpanzees (Pan troglodytes), yet nutritional data based on actual intake are lacking. Drawing on observations from 2008 to 2010 and recently published nutritional assays, we determined the energy, macronutrient and mineral yields for termite-fishing (Macrotermes), ant-dipping (Dorylus), and ant-fishing (Camponotus) by the Kasekela chimpanzees of Gombe National Park, Tanzania. We also estimated the yields from consumption of weaver ants (Oecophylla) and termite alates (Macrotermes and Pseudacanthotermes). On days when chimpanzees were observed to prey on insects, the time spent in insectivorous behavior ranged from <1 min to over 4 h. After excluding partial bouts and those of <1 min duration, ant-dipping bouts were of significantly shorter duration than the other two forms of tool-assisted insectivory but provided the highest mass intake rate. Termite-fishing bouts were of significantly longer duration than ant-dipping and had a lower mass intake rate, but provided higher mean and maximum mass yields. Ant-fishing bouts were comparable to termite-fishing bouts in duration but had significantly lower mass intake rates. Mean and maximum all-day yields from termite-fishing and ant-dipping contributed to or met estimated recommended intake (ERI) values for a broad array of minerals. The mean and maximum all-day yields of other insects consistently contributed to the ERI only for manganese. All forms of insectivory provided small but probably non-trivial amounts of fat and protein. We conclude that different forms of insectivory have the potential to address different nutritional needs for Kasekela chimpanzees. Other than honeybees, insects have received little attention as potential foods for hominins. Our results suggest that ants and (on a seasonal basis) termites would have been viable sources of fat, high-quality protein and minerals for extinct hominins employing Pan-like subsistence technology in East African woodlands.

The human obesity epidemic, the mismatch paradigm, and our modern “captive” environment

In the distant past obesity in humans was rare and likely caused by metabolic dysregulation due to genetic or disease‐related pathology. External factors precluded the ability of most people to overeat or under exert. Socio‐cultural obesity came about due to the rareness of obesity and its difficulty to achieve. What is rare becomes valuable and what is difficult to achieve becomes a badge of prestige. The modern human obesity epidemic would appear to represent a third class of obesity: environmental obesity. Much like the captive environments which humans construct for the captive/companion animals in our care, the modern human environment has greatly decreased the challenges of life that would restrict food intake and enforce exertion. And like us, our captive/companion animal populations are also experiencing obesity epidemics. A further concern is that maternal obesity alters maternal signaling to offspring, in utero through the placenta and after birth through breast milk, in ways that perpetuate an enhanced vulnerability to obesity. Molecules such as leptin, produced by adipose tissue and placenta, have significant developmental effects on brain areas associated with feeding behavior. Leptin and other cytokines and growth factors are found in breast milk. These molecules have positive effects on gut maturation; their effects on metabolism and brain development are unclear. Placenta and brain also are hotspots for epigenetic regulation, and epigenetic changes may play significant roles in the later vulnerability to obesity and to the development of a diverse array of diseases, including heart disease, hypertension, and noninsulin‐dependent diabetes. Am. J. Hum. Biol., 2012.

Proximate composition of milk of the bongo (Tragelaphus eurycerus) in comparison to other African bovids and to hand‐rearing formulas

African bovids represent a highly diverse group with divergent neonatal care strategies. The extent to which their milks reflect this diversity is poorly understood. We analyzed milk of the bongo (Tragelaphus eurycerus) to compare its composition to milks of other African bovids and to evaluate bongo milk replacement formulas. Milk samples from three individuals (0 through 300 days postpartum, nu2009=u200928) were assayed for dry matter (total solids), crude fat, crude protein, total sugar, ash, calcium, and phosphorus; gross energy was assayed on a subset of samples and compared to calculated values. Nutrient composition changed very little over the lactation period except for day 0 (colostrum) and the last sample (day 300). Bongo milk (days 6-286) contained (meanu2009±u2009SEM): 28.1u2009±u20090.7% dry matter (71.9u2009±u20090.7% water), 12.3u2009±u20090.6% fat, 10.6u2009±u20090.3% crude protein, 3.6u2009±u20090.1% sugar, 1.05u2009±u20090.03% ash, 0.26u2009±u20090.01% calcium, 0.16u2009±u20090.01% phosphorus, and a GE of 1.88u2009±u20090.06u2009kcal/g. The protein content of bongo milk accounts for 33% of energy. High protein energy appears to be typical of Tragelaphines and of African bovids that utilize a hider system of postnatal care. The stability of milk composition until day 300 suggests complete weaning may not occur until 9 months rather than at 6 months of age, as commonly assumed. None of the milk replacement formulas previously used for bongos was well matched to bongo milk composition; therefore, a new milk replacement formula is proposed.

Nutrient Requirements and Dietary Husbandry Principles for Captive Nonhuman Primates

Diets for captive nonhuman primates must be based on science. Although evidence regarding specific nutrient requirements for most primate species is quite limited, adequate levels of most nutrients can be estimated. Nutrient deficiencies in captive nonhuman primates are unlikely to occur due to poor understanding of requirements. Rather, other factors such as the manner in which the diet is given to animals, how it is stored, failing to account for the quantity and quality of enrichment and training foods, and the underlying health of the subjects may be more consequential. Accordingly, in addition to reviewing the evidence for nutrient requirements, this chapter will focus broadly on appropriate dietary management techniques for captive nonhuman primates. This chapter reviews general nutritional principles, gives an overview of nonhuman primate nutrient requirements and interactions among nutrients, and an overview of principles of modern manufactured diets. The National Research Council Second Revised Edition of the Nutrient Requirements of Nonhuman Primates (2003) contains a compilation of the best information on the nutrient requirements of primate species and should serve as a primary source of information regarding nutrition. The base diet provided to primates should comprise a food (commercial primate biscuit, canned primate food, primate gelled food, or home-made primate formula) that is nutritionally complete. Supplemental foods should have specific purposes (e.g. enrichment, training), but must be accounted for when evaluating the diet. Highly preferred foods may dilute the overall nutrient content of the diet, and should be rationed carefully.

Parabrachial lesions in rats disrupt sodium appetite induced by furosemide but not by calcium deprivation

An appetite for CaCl2 and NaCl occurs in young rats after they are fed a diet lacking Ca or Na, respectively. Bilateral lesions of the parabrachial nuclei (PBN) disrupt normal taste aversion learning and essentially eliminate the expression of sodium appetite. Here we tested whether similar lesions of the PBN would disrupt the calcium-deprivation-induced appetite for CaCl2 or NaCl. Controls and rats with PBN lesions failed to exhibit a calcium-deprivation-induced appetite for CaCl2. Nevertheless, both groups did exhibit a significant calcium-deprivation-induced appetite for 0.5M NaCl. Thus, while damage to the second central gustatory relay in the PBN disrupts the appetite for 0.5M NaCl induced by furosemide, deoxycorticosterone acetate, and polyethylene glycol, the sodium appetite induced by dietary CaCl2 depletion remains intact.

Macronutrient composition of milk of captive nine-banded armadillos (Dasypus novemcinctus)

Armadillo pups rapidly grow a bony carapace, suggesting a large transfer of calcium and phosphorus from mother to pups via milk. Because Ca and P in milk are bound in casein protein micelles, we predicted armadillo milk to be high in protein content. Milk samples (n = 25) from 10 lactating nine-banded armadillos (Dasypus novemcinctus) collected at days 1–6, 14–15, 33–38, and 49–51 after birth were assayed for macronutrient composition (water, fat, protein, sugar, ash, Ca, and P). Gross energy (GE) was calculated from protein, sugar, and fat. Protein concentration (8–11%) was the highest of the milk solids at all time points, and ash (total mineral) values increased from 1.6% to 3.6% and were higher than sugar values (2.4%) after 1 month. Calcium concentration increased from 0.4% to over 1.0% by 1 month of lactation. Calcium and phosphorus were strongly correlated with milk protein (r = 0.796 and 0.815, respectively; P < 0.001). Protein contributed the majority of milk GE over the first 2 weeks of lactation (51%) and was equal to fat after 1 month (both about 47% of GE). The proportion of GE from sugar declined from 14.5% to 6.6%. We suggest that a milk high in protein was an ancestral trait for armadillos that allowed the evolution of a bony carapace by enabling large amounts of Ca and P to be transferred via casein micelles. Based on data from giant anteater (Myrmecophaga tridactyla) milk, a highprotein milk may be ancestral to all Xenarthrans, but this suggestion awaits confirmation from data on the milk of sloths. We suggest that armadillo pups likely catabolize a significant amount of milk protein for metabolic energy.