Dual‐Energy X‐Ray Absorptiometry (DXA) Can Accurately and Nondestructively Measure the Body Composition of Small, Free‐Living Rodents

Abstract

Dual-energy x-ray absorptiometry (DXA) is a nondestructive technique that can potentially measure specific components of whole-body composition in free-living and lab-raised animals. Our aim was to test the ability of DXA to measure the composition of a common arvicoline rodent, the northern red-backed vole (Clethrionomys rutilus). We used a DXA apparatus to obtain measurements of fat mass (FM), lean mass (LM),bone mineral content, bone mineral density, and fat-free mass(FFM) in carcasses of free-living and lab-raised voles. We then used chemical carcass analysis to derive predictive algorithms for actual values of FM, total body water, total protein, total mineral, LM, and FFM. Unexplained error in the equations for all voles grouped collectively ranged from R(2) = 0.82 to R(2) = 0.98. The DXA FM measurement had the highest coefficient of variation, and it was higher for free-living voles than for lab-raised voles. However, FM can be determined by difference with excellent precision by using the FFM equation (R(2) = 0.98). We also derived corrective terms for passive integrated transponder-tagged animals. Thus, DXA is a nonlethal, nondestructive tool capable of precisely and accurately measuring many specific parameters of whole-body composition in small free-living and lab-raised rodents.

Validation of Dual‐energy X‐ray Absorptiometry to Predict Body Composition of Channel Catfish, Ictalurus punctatus

“…These precision values of 1-2% for lean and bone mass were similar to those observed for lemmings (Hunter and Nagy 2002), voles (Stevenson and van Tets 2008), water snakes (Secor and Nagy 2003), small birds (Korine et al 2004), chickens (Swennen et al 2004), and mice (Nagy and Clair 2000). The precision for FM in catfish (5.5%) was better than the 9.2% observed in water snakes (Secor and Nagy 2003), and 7% in voles (Stevenson and van Tets 2008), similar to chickens (6%; Swennen et al 2004), small birds (4%; Korine et al 2004), and lemmings (4%; Hunter and Nagy 2002), but not as good as the DXA fat precision for mice (2.2%; Nagy and Clair 2000). Although there has been one previous validation of DXA in fish (Wood 2004), the study only looked at accuracy and not precision in hybrid striped bass.…”

The effect of implantation on scaffoldless three-dimensional engineered bone constructs

“…Dual-energy X-ray absorptiometry (DEXA) and microcomputed tomography (micro-CT) are two methods commonly used to measure bone mineralization (Stevenson and van Tets 2008). The extent of mineralization can be accurately assessed by the amount of bone mineral content (BMC) using both methodologies.…”

Making no Bones About it: Bone Mineral Density Changes Seasonally in a Nonhibernating Alaskan Rodent

“…The length of each bone was determined using digital calipers accurate to the nearest 0.01 mm. Bone densities were determined using a PIXImus2 dual-energy X-ray apparatus (Lunar/GE, Madison, Wisconsin) that was known to accurately predict bone measurements in rodents (Nagy and Clair 2000) and that had previously been validated for use in determining the body composition of M. rutilus (Stevenson and van Tets 2008). Up to 16 bones were scanned at 1 time, and each was individually measured using the PIXImus2 software.…”