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Macronutritional composition of Swedish moose rumen samples collected 2014/15

Citation

Felton, Annika et al. (2022), Macronutritional composition of Swedish moose rumen samples collected 2014/15, Dryad, Dataset, https://doi.org/10.5061/dryad.9zw3r22fh

Abstract

At northern latitudes, large spatial and temporal variation in the nutritional composition of available foods poses challenges to wild herbivores trying to satisfy their nutrient requirements. Studies conducted in mostly captive settings have shown that animals from a variety of taxonomic groups deal with this challenge by adjusting the amounts and proportions of available food combinations to achieve a target nutrient balance. In this study, we used proportions-based nutritional geometry to analyse the nutritional composition of rumen samples collected in winter from 481 moose (Alces alces) in southern Sweden and examine whether free-ranging moose show comparable patterns of nutrient balancing. Our main hypothesis was that wild moose actively regulate their rumen nutrient composition to offset ecologically imposed variation in the nutritional composition of available foods. To test this, we assessed the macronutritional composition (protein, carbohydrates, and lipids) of rumen contents and commonly eaten foods, including supplementary feed, across populations with contrasting winter diets, spanning an area of approximately 10 000 km2. Our results suggest that moose balanced the macronutrient composition of their rumen, with the rumen contents having consistently similar proportional relationship between protein and non-structural carbohydrates, despite differences in available (and eaten) foods. Furthermore, we found that rumen macronutrient balance was tightly related to ingested levels of dietary fiber (cellulose and hemicellulose), such that the greater the fiber content, the less protein was present in the rumen compared to non-structural carbohydrates. Our results also suggest that moose benefit from access to a greater variety of trees, shrubs, herbs and grasses, which provides them with a larger nutritional space to manoeuvre within. Our findings provide novel theoretical insights into a model species for ungulate nutritional ecology, while also generating data of direct relevance to wildlife and forest management, such as silvicultural or supplementary feeding practices.

Methods

To obtain information about the nutritional composition of foods eaten, fresh rumen samples were collected immediately after harvest by filling a 1 litre plastic airtight container with rumen content. Hunters were instructed to mix contents and take material from throughout the rumen and to remove excess rumen liquid by squeezing each handful. Rumen samples were frozen shortly after sampling (normally 0.5-1 hour) and stored at -20 ˚C. Rumen samples were dried at 60 °C until the samples came to a constant mass, and then ground using a hammer mill (KAMAS© Slagy 200B; 1 mm sieve).
 
We obtained 481 rumen samples (collected between 13-Oct-2014 and 22-Feb-2015), all of which were used in our sample-based nutritional analyses (wet chemistry, near infrared spectroscopy (NIRS) and right-angle mixture triangles). We used NIRS to estimate the concentrations of nutritional constituents of rumen samples, with a subset of representative samples also analysed using wet chemistry for calibration purposes. For more information about field and laboratory procedures, please see the associated article.

Usage Notes

The Excel file contains one work sheet, on which you find data regarding the nutritional composition (and metadata) of moose rumen samples (n=481), used in the Right-angled Mixture Triangle in the article. The units are displayed in each column heading, as are explanations of abbreviations. 

Funding

The Swedish Environmental Protection Agency, Award: 13/274

The Swedish Council for Sustainable Development, Award: 2016-01140-3

The Södra Research Fund

The Swedish Environmental Protection Agency, Award: 13/274

The Swedish Council for Sustainable Development, Award: 2016-01140-3

The Södra Research Fund