title: Resting energy expenditure per lean body mass determined by indirect calorimetry and bioelectrical impedance analysis in cats.
abstract: BACKGROUND
  Resting energy expenditure (REE) approximates ≥60% of daily energy expenditure (DEE). Accurate REE determination could facilitate sequential comparisons among patients and diseases if normalized against lean body mass (LBM).
  
  
  OBJECTIVE
  (1) Validate open-flow indirect calorimetry (IC) system and multifrequency bioelectrical impedance analysis (MF-BIA) to determine REE and LBM, respectively, in healthy nonsedated cats of varied body conditions; (2) normalize REE against LBM.
  
  
  METHODS
  Fifty-seven adult neutered domestic short-haired cats with stable BW.
  
  
  METHODS
  Continuous (45-min) IC-measurements determined least observed metabolism REE. Cage gas flow regulated with mass flow controllers was verified using nitrogen dilution; span gases calibrated gas measurements. Respiratory quotient accuracy was verified using alcohol combustion. IC-REE was compared to DEE, determined using doubly labeled water. MF-BIA LBM was validated against criterion references (deuterium, sodium bromide). Intra- and interassay variation was determined for IC and MF-BIA.
  
  
  RESULTS
  Mean IC-REE (175 ± 38.7 kcal; 1.5-14% intra- and interassay CV%) represented 61 ± 14.3% of DEE. Best MF-BIA measurements were collected in sternal recumbency and with electrodes in neck-tail configuration. MF-BIA LBM was not significantly different from criterion references and generated LBM interassay CV% of 6.6-10.1%. Over- and underconditioned cats had significantly (P ≤ .05) lower and higher IC-REE (kcal/kg) respectively, compared with normal-conditioned cats. However, differences resolved with REE/LBM (approximating 53 ± 10.3 kcal/LBM [kg]).
  
  
  CONCLUSIONS
  IC and MF-BIA validated herein reasonably estimate REE and LBM in cats. REE/LBM(kg) may permit comparison of energy utilization in sequential studies or among different cats.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA. sac6@cornell.edu
authors.forename: S A
authors.initials: SA
authors.lastname: Center
authors.forename: K L
authors.initials: KL
authors.lastname: Warner
authors.forename: J F
authors.initials: JF
authors.lastname: Randolph
authors.forename: J J
authors.initials: JJ
authors.lastname: Wakshlag
authors.forename: G D
authors.initials: GD
authors.lastname: Sunvold
mesh_terms: D000818:Animals; D001823:Body Composition; D001835:Body Weight / Q000502:physiology*; D002153:Calorimetry, Indirect / Q000662:veterinary*; D002415:Cats; D017097:Electric Impedance; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D008297:Male