Macronutrient composition of milk from two captive African elephant (Loxodonta africana) cows.

We assayed 31 milk samples collected from two African elephant cows housed at the Indianapolis Zoo across lactation (birth to calf age 973 days) for macronutrient composition (water, fat, protein, sugar, gross energy [GE], ash, calcium, and phosphorus). All assays were performed at the Smithsonian National Zoological Park Nutrition Laboratory, Washington, DC (SNZP) using standard methods developed at SNZP. Milk constituents are expressed on a weight-per-weight basis (%) and as a proportion each constituent contributes to milk energy. Calf weights were recorded, and growth rate calculated. The macronutrient composition of the African elephant milk samples was compared to previously published results for Asian elephants using analysis of covariance. African elephant milk is similar to Asian elephant milk, being moderately high in fat and energy and low in sugar. The mean values across lactation (excluding colostrum; n = 28) are 5.6 ± 0.3% crude protein, 3.1 ± 0.3% sugar, 13.0 ± 1.0% fat, and GE of 1.63 ± 0.10 kcal/g. Milk composition did not differ between cows. Milk composition significantly changed over lactation; fat and protein increased, and sugar decreased with calf age, comparable to previously reported data for African and Asian elephant milk. The proportion of milk energy from fat increased and that from sugar decreased over lactation, but the energy from protein was relatively constant. Protein contributed a higher proportion of energy to African elephant milk compared to Asian elephant milk (20.6% vs. 17.0%, p = .001). Despite this, calf growth rate was similar between the species, with the calves in this study gaining about 0.8 kg/day for the first 6 months.

Diversity and temporal dynamics of primate milk microbiomes.

Milk is inhabited by a community of bacteria and is one of the first postnatal sources of microbial exposure for mammalian young. Bacteria in breast milk may enhance immune development, improve intestinal health, and stimulate the gut-brain axis for infants. Variation in milk microbiome structure (e.g., operational taxonomic unit [OTU] diversity, community composition) may lead to different infant developmental outcomes. Milk microbiome structure may depend on evolutionary processes acting at the host species level and ecological processes occurring over lactation time, among others. We quantified milk microbiomes using 16S rRNA high-throughput sequencing for nine primate species and for six primate mothers sampled over lactation. Our data set included humans (Homo sapiens, Philippines and USA) and eight nonhuman primate species living in captivity (bonobo [Pan paniscus], chimpanzee [Pan troglodytes], western lowland gorilla [Gorilla gorilla gorilla], Bornean orangutan [Pongo pygmaeus], Sumatran orangutan [Pongo abelii], rhesus macaque [Macaca mulatta], owl monkey [Aotus nancymaae]) and in the wild (mantled howler monkey [Alouatta palliata]). For a subset of the data, we paired microbiome data with nutrient and hormone assay results to quantify the effect of milk chemistry on milk microbiomes. We detected a core primate milk microbiome of seven bacterial OTUs indicating a robust relationship between these bacteria and primate species. Milk microbiomes differed among primate species with rhesus macaques, humans and mantled howler monkeys having notably distinct milk microbiomes. Gross energy in milk from protein and fat explained some of the variations in microbiome composition among species. Microbiome composition changed in a predictable manner for three primate mothers over lactation time, suggesting that different bacterial communities may be selected for as the infant ages. Our results contribute to understanding ecological and evolutionary relationships between bacteria and primate hosts, which can have applied benefits for humans and endangered primates in our care.

Macronutrient composition of longitudinal milk samples from captive aardvarks (Orycteropus afer).

Hand-rearing and assisted-rearing aardvarks in captivity has become commonplace and has led to success in breeding the species. However, the macronutrient content of aardvark milk past 1 month of age is unknown. A better understanding of aardvark milk composition would enhance captive management efforts. Here, we assayed milk samples from two captive individuals from 2 to 114 days postpartum (N = 21) for dry matter, fat, crude protein, total sugar, ash (total minerals), calcium (Ca), phosphorus (P), and gross energy. The body weight of one calf was measured from birth to weaning. Milk macronutrient composition was compared to that of other Afrotherian species and Xenarthra species with similar diets. Average protein, fat, and sugar concentrations of aardvark milk across lactation were 12.3%, 13.6%, and 2.5%, respectively. Ash averaged 1.9%, with Ca (0.50%) and P (0.35%) accounting for about 45% of total minerals. All measured nutrients increased over lactation except sugar, which decreased. Aardvark milk is high in energy (2.12 kcal/g) mostly derived from fat and protein and little energy from sugar. Calf growth was linear (r2 = 0.995) with a mean gain of 159 g/day, achieving almost 30% of adult weight at weaning. Within Afrotheria, aardvark milk is higher in fat and protein and lower in sugar than elephant milk and more closely resembles the milk of its fellow insectivore, the elephant shrew. Aardvark milk is also similar in composition to milk of insectivorous Xenarthra species (nine-banded armadillo and giant anteater). Aardvark milk composition is consistent with the species' high-protein diet, fast growth, and nursing pattern.

Neisseria arctica sp. nov., isolated from nonviable eggs of greater white-fronted geese (Anser albifrons) in Arctic Alaska.

During the summers of 2013 and 2014, isolates of a novel Gram-stain-negative coccus in the genus Neisseriawere obtained from the contents of nonviable greater white-fronted goose (Anseralbifrons) eggs on the Arctic Coastal Plain of Alaska. We used a polyphasic approach to determine whether these isolates represent a novel species. 16S rRNA gene sequences, 23S rRNA gene sequences, and chaperonin 60 gene sequences suggested that these Alaskan isolates are members of a distinct species that is most closely related to Neisseria canis, Neisseriaanimaloris and Neisseriashayeganii. Analysis of the rplF gene additionally showed that the isolates are unique and most closely related to Neisseriaweaveri. Average nucleotide identity of the whole genome sequence of the type strain was between 71.5 and 74.6 % compared to close relatives, further supporting designation as a novel species. Fatty acid methyl ester analysis showed a predominance of C14 : 0, C16 : 0 and C16 : 1ω7c fatty acids. Finally, biochemical characteristics distinguished the isolates from other species of the genus Neisseria. On the basis of these combined data, the isolates are proposed to represent a novel species of the genus Neisseria, with the name Neisseria arctica sp. nov. The type strain is KH1503T (=ATCC TSD-57T=DSM 103136T).

Population structure of two rabies hosts relative to the known distribution of rabies virus variants in Alaska.

For pathogens that infect multiple species, the distinction between reservoir hosts and spillover hosts is often difficult. In Alaska, three variants of the arctic rabies virus exist with distinct spatial distributions. We tested the hypothesis that rabies virus variant distribution corresponds to the population structure of the primary rabies hosts in Alaska, arctic foxes (Vulpes lagopus) and red foxes (Vulpes vulpes) to possibly distinguish reservoir and spillover hosts. We used mitochondrial DNA (mtDNA) sequence and nine microsatellites to assess population structure in those two species. mtDNA structure did not correspond to rabies virus variant structure in either species. Microsatellite analyses gave varying results. Bayesian clustering found two groups of arctic foxes in the coastal tundra region, but for red foxes it identified tundra and boreal types. Spatial Bayesian clustering and spatial principal components analysis identified 3 and 4 groups of arctic foxes, respectively, closely matching the distribution of rabies virus variants in the state. Red foxes, conversely, showed eight clusters comprising two regions (boreal and tundra) with much admixture. These results run contrary to previous beliefs that arctic fox show no fine-scale spatial population structure. While we cannot rule out that the red fox is part of the maintenance host community for rabies in Alaska, the distribution of virus variants appears to be driven primarily by the arctic fox. Therefore, we show that host population genetics can be utilized to distinguish between maintenance and spillover hosts when used in conjunction with other approaches.