Using Deuterium Oxide as a Non-Invasive, Non-Lethal Tool for Assessing Body Composition and Water Consumption in Mammals

Summary

This article describes the deuterium oxide dilution technique in two mammals, an insectivore and carnivore, to determine total body water, lean body mass, body fat mass, and water consumption.

Abstract

Body condition scoring systems and body condition indices are common techniques used for assessing the health status or fitness of a species. Body condition scoring systems are evaluator dependent and have the potential to be highly subjective. Body condition indices can be confounded by foraging, the effects of body weight, as well as statistical and inferential problems. An alternative to body condition scoring systems and body condition indices is using a stable isotope such as deuterium oxide to determine body composition. The deuterium oxide dilution method is a repeatable, quantitative technique used to estimate body composition in humans, wildlife, and domestic species. Additionally, the deuterium oxide dilution technique can be used to determine the water consumption of an individual animal. Here, we describe the adaption of the deuterium oxide dilution technique for assessing body composition in big brown bats (Eptesicus fuscus) and for assessing water consumption in cats (Felis catis).

Introduction

Body condition scoring systems and body condition indices are common techniques used for assessing the health status or fitness of a species^1,2. Many domestic and zoological species have unique body condition scoring (BCS) systems that are used to assess an animal's muscle and superficial fatty tissue³. However, BCS assessment relies upon the evaluator—meaning that BCS is an objective or semiquantitative measurement when assessed by a trained evaluator. In wildlife species, body condition indices are commonly used rather than BCS and are based upon a ratio of body mass to body....

Protocol

All experiments described here were approved by the University of Missouri Animal Care and Use Committee and conducted under the Missouri Department of Conservation (MDC) Wildlife Scientific Collection permit (Permit #16409 and #17649).

1. Preparation of sterile, isotonic, salinated D₂O stock solution

1. Make a 50 mL stock solution of 9.0 g/L salinated D₂O.
   1. Weigh 450 mg of pharmaceutical grade NaCl and transfer all NaCl into a 100 mL, sterilized beake.......

Discussion

The use of deuterium oxide to determine TBW has been used since the 1940s¹⁷ and is used in humans and a variety of domestic and wildlife species^4,6,7. Other non-destructive techniques have been developed including bioelectrical impedance analysis (BIA), DXA, and quantitative magnetic resonance (QMR). Each method has advantages and disadvantages that should be considered before selecting a particular metho.......

Materials

Name	Company	Catalog Number	Comments
0.2 micron non-pyrogenic disk filter	Argos Technologies	FN32S	nylon, 30mm diameter, 0.22um, sterile
1.5 mL conical microcentrifuge tubes	USA Scientific	1415-9701	1.5 ml self-standing microcentrifuge tube, natural with blue cap
10 mL sterile glass vial for injection	Mountainside Medical Equipment	MS-SEV10	clear, sterile glass injection unit
10 mL syringe	Becton Dickinson	305219	sterile 10 mL syringe individually wrapped
100 mL sterile glass vial for injection	Mountainside Medical Equipment	AL-SV10020	clear, sterile glass injection unit
20 gauge needle	Exel	26417	needles hypodermic 20g x 1" plastic hub (yellow) / regular bevel
22 gauge needle	Exel	26411	needles hypodermic 22g x 1" plastic hub (black) / regular bevel
deuterium oxide	Sigma-Aldrich	151882-25G	99.9 atom % D
isofluorane	Vetone	3060	fluriso isoflurane, USP
OMNIC Spectra Software	ThermoFisher Scientific	833-036200	FT-IR standard software
petroleum jelly	Vaseline	305212311006	Vaseline, 100% pure petroleum jelly, original, skin protectant
plastic capillary tubes	Innovative Med Tech	100050	sodium heparin anticoagulant, 50 μL capacity, 30 mm length
Sealed liquid spectrophotometer SL-3 FTIR CAF2 Cell	International Crystal Laboratory	0005D-875	0.05 mm Pathlength
sodium chloride	EMD Millipore	1.37017	suitable for biopharmaceutical production
Thermo Electron Nicolet 380 FT-IR Spectrometer	ThermoFisher Scientific	269-169400	discontinued model, newer models available