Minerals in the Foods Eaten by Mountain Gorillas (Gorilla beringei)

Minerals are critical to an individual’s health and fitness, and yet little is known about mineral nutrition and requirements in free-ranging primates. We estimated the mineral content of foods consumed by mountain gorillas (Gorilla beringei beringei) in the Bwindi Impenetrable National Park, Uganda. Mountain gorillas acquire the majority of their minerals from herbaceous leaves, which constitute the bulk of their diet. However, less commonly eaten foods were sometimes found to be higher in specific minerals, suggesting their potential importance. A principal component analysis demonstrated little correlation among minerals in food items, which further suggests that mountain gorillas might increase dietary diversity to obtain a full complement of minerals in their diet. Future work is needed to examine the bioavailability of minerals to mountain gorillas in order to better understand their intake in relation to estimated needs and the consequences of suboptimal mineral balance in gorilla foods

Dietary Development and Nutritional Ontogeny in \u3ci\u3e Gorilla beringei \u3c/i\u3e: A Multi-layered, -Omics Approach

In species who consume folivorous diets, immature individuals must contend with the challenges of extracting nutrients from fibrous foods before dietary adaptations and strategies are fully developed. Additionally, immatures have distinct nutritional needs to support their stage-specific metabolic and biophysiological requirements. To meet these stage-specific needs, while constrained by underdeveloped feeding strategies and digestive capacities, immatures may adopt distinct diets better suited to their specific developmental context. However, where dietary modification is constrained by low dietary diversity or landscape homogeneity, it is unclear how immature individuals compensate through alternative strategies. In turn, little is known about the nutritional and life history implications of restrictions in alternative foraging strategies. This dissertation is divided into three main studies. Firstly, a comprehensive literature review examines the theoretical framework and provides context for the importance and relevance of this topic to the broader study of life history patterning and developmental outcomes. Following this, the diet of mountain gorillas across development is characterized through a combination of four hour focal follows and nutritional biochemical analysis of consumed food items. The results of this study suggest that mountain gorillas self-select their diets to age- and stage-specific nutrient targets, occupying unique nutritional niches within the species’ overall nutritional landscape. To meet these age-specific nutritional needs within their relatively constrained ecological environment, immature mountain gorillas engage in three principle behavioral strategies: 1) differential reliance on food items, including increased consumption of highly digestibly foods as well as self-selection of a balance of nutrients higher in non-protein energy intake relative to protein intake, 2) compensatory foraging and increased overall foraging effort to compensate for biophysiological limitations (i.e. gut size) and behavioral limitations (feeding/foraging competency), and 3) extended use of mother’s milk as a nutritional ‘buffer’ during periods of preferred food scarcity. Next, this dissertation considers the one of the most complex and dynamic systems involved in the regulation and utilization of nutrients: the gastrointestinal microbiome. The gastrointestinal microbiome is first characterized using a large library of mountain gorilla samples, spanning all members of three social groups. This characterization confirms previous work on the microbiome of mountain gorillas, and further establishes that the microbiome of mountain gorillas is relatively aseasonal, but can be differentiated based on age-class. Contrary to expectations of diversity, the infant mountain gorilla microbiome is broadly less diverse than those of juvenile and adult individuals, with higher abundance of key hydrogenotrophic taxa and sulfate-reducing bacteria. These taxa may play a role in preventing hydrogen accumulation in the gut during development. Additionally, this study shows that there are differences in the abundance of major phyletic groups (specifically, Actinobacteria, Firmicutes, and Bacteroidetes), suggesting that immature individuals may house microbiomes with greater capacity for energy harvest, potentially as an adaptation to maximize nutrient availability during periods of growth and development where individuals are sensitive to environmental perturbation and dietary shortfalls. Lastly, this dissertation considers the dietary metabolome of mountain gorillas through characterization of the fecal metabolome, in a pivotal step to bridge the gap between observed diet/nutrient intake and individuals’ capacity to use ingested nutrients (including through microbiome-mediated nutrient pathways). Mountain gorillas demonstrate distinct metabolomes throughout development, especially with respect to the relative concentration of lipid and lipid-derived molecules and organic acids/phenolic compounds and their derivatives. Additionally, this study explicitly considered the potential influence of observed diet and nutrient intake as drivers of differentiation among age groups; it is found that protein intake is a primary driver of infant microbiome differentiation, and non-digestible fibers are a primary driver in differentiating both the adult microbiome and metabolome. Through these studies, this dissertation provides the first comprehensive examination of nutritional ontogeny through a multi-layered ecological approach, by examining these complex relationships in immature mountain gorillas (Gorilla beringei). This dissertation significantly contributes to our understanding of nutritional ontogeny and compensatory nutritional strategies among great apes living at the extreme end of their known ecologies, and, in turn, provides a lens towards the potential evolutionary basis of these behaviors and adaptations

Mean ratios of minerals in staple foods eaten by Bwindi Mountain gorillas, weighted by daily intake (measured in g) [40].

<p>Staple foods considered accounted for 80% of total diet <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112117#pone.0112117-Reiner1" target="_blank">[40]</a>.</p><p>Mean ratios of minerals in staple foods eaten by Bwindi Mountain gorillas, weighted by daily intake (measured in g) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112117#pone.0112117-Reiner1" target="_blank">[40]</a>.</p

Biplot showing the first two loadings of the principal component analysis of all mineral values in samples analyzed.

<p>Food items grouped by color.</p

Comparisons of mean mineral composition in gorilla food items at Bwindi Impenetrable National Park.

<p>Comparisons of mean mineral composition in gorilla food items at Bwindi Impenetrable National Park.</p

Mineral content of leaves consumed by gorillas at BINP compared to leaves consumed by wild primates at other research sites.

<p>Mineral content of leaves consumed by gorillas at BINP compared to leaves consumed by wild primates at other research sites.</p

Comparison of mineral composition of food items between <i>Gorilla beringei</i> and <i>Gorilla gorilla</i>[16]¹.

1<p>*, denotes significantly higher values (<i>P<0.05</i>) as determined by Mann-Whitney U tests of significance. Samples with an n<2 were excluded from analysis.</p><p>Comparison of mineral composition of food items between <i>Gorilla beringei</i> and <i>Gorilla gorilla</i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112117#pone.0112117-Calvert1" target="_blank">[16]</a>^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112117#nt104" target="_blank">1</a>}.</p

"Delirium Day": A nationwide point prevalence study of delirium in older hospitalized patients using an easy standardized diagnostic tool

Background: To date, delirium prevalence in adult acute hospital populations has been estimated generally from pooled findings of single-center studies and/or among specific patient populations. Furthermore, the number of participants in these studies has not exceeded a few hundred. To overcome these limitations, we have determined, in a multicenter study, the prevalence of delirium over a single day among a large population of patients admitted to acute and rehabilitation hospital wards in Italy. Methods: This is a point prevalence study (called "Delirium Day") including 1867 older patients (aged 65 years or more) across 108 acute and 12 rehabilitation wards in Italian hospitals. Delirium was assessed on the same day in all patients using the 4AT, a validated and briefly administered tool which does not require training. We also collected data regarding motoric subtypes of delirium, functional and nutritional status, dementia, comorbidity, medications, feeding tubes, peripheral venous and urinary catheters, and physical restraints. Results: The mean sample age was 82.0 ± 7.5 years (58 % female). Overall, 429 patients (22.9 %) had delirium. Hypoactive was the commonest subtype (132/344 patients, 38.5 %), followed by mixed, hyperactive, and nonmotoric delirium. The prevalence was highest in Neurology (28.5 %) and Geriatrics (24.7 %), lowest in Rehabilitation (14.0 %), and intermediate in Orthopedic (20.6 %) and Internal Medicine wards (21.4 %). In a multivariable logistic regression, age (odds ratio [OR] 1.03, 95 % confidence interval [CI] 1.01-1.05), Activities of Daily Living dependence (OR 1.19, 95 % CI 1.12-1.27), dementia (OR 3.25, 95 % CI 2.41-4.38), malnutrition (OR 2.01, 95 % CI 1.29-3.14), and use of antipsychotics (OR 2.03, 95 % CI 1.45-2.82), feeding tubes (OR 2.51, 95 % CI 1.11-5.66), peripheral venous catheters (OR 1.41, 95 % CI 1.06-1.87), urinary catheters (OR 1.73, 95 % CI 1.30-2.29), and physical restraints (OR 1.84, 95 % CI 1.40-2.40) were associated with delirium. Admission to Neurology wards was also associated with delirium (OR 2.00, 95 % CI 1.29-3.14), while admission to other settings was not. Conclusions: Delirium occurred in more than one out of five patients in acute and rehabilitation hospital wards. Prevalence was highest in Neurology and lowest in Rehabilitation divisions. The "Delirium Day" project might become a useful method to assess delirium across hospital settings and a benchmarking platform for future surveys