title: Telemetric assessment of social and single housing: Evaluation of electrocardiographic intervals in jacketed cynomolgus monkeys.
abstract: BACKGROUND
  Proactive efforts to socially house laboratory animals are a contemporary, important focus for enhancing animal welfare. Jacketing cynomolgus monkeys has been traditionally considered an exclusionary criterion for social housing based on unsubstantiated concerns that study conduct or telemetry equipment might be compromised. Our objective was to evaluate the effects of jacketing naïve, adolescent cynomolgus monkeys in different single and social housing types based on parallel comparisons of heart rate.
  
  
  METHODS
  Eight naive cynomolgus monkeys were randomized into pairs and ECG data were collected for 24h from each animal in each housing condition using a crossover design. Caging paradigms consisted of standard individual, standard pair, quaternary pair (4 linked cages), and European-style pair housing in non-sequential order varied by pair to control for possible time bias. Dosing and blood collection procedures were performed to characterize any effects of housing on ECG data during study conduct.
  
  
  RESULTS
  There was no increase in the incidence of equipment damage in pair vs. individually housed animals. Further, animals in all 4 housing paradigms showed similar acclimation assessed as heart rate (mean 139-154 beats per minute), and maintained similar diurnal rhythms, with an expected slowing of the heart rate at night (aggregate lights out HR 110±4bpm compared to daytime 146±7bpm).
  
  
  CONCLUSIONS
  This study demonstrates the effects of different social access and housing types on the study-naïve cynomolgus monkeys during jacketed cardiovascular telemetry data collection in a repeat-dose toxicology study design. There were no discernible effects of social housing on baseline ECG parameters collected via jacketed telemetry, and all animals maintained expected diurnal rhythms in all housing settings tested. These data demonstrate that cynomolgus monkeys can be socially housed during data collection as a standard practice, consistent with global efforts to improve study animal welfare.
authors.affiliation: Charles River Laboratories, 6995 Longley Lane, Reno, NV 89511, United States.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Kaiser
authors.affiliation: Charles River Laboratories, 6995 Longley Lane, Reno, NV 89511, United States.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Tichenor
authors.affiliation: Charles River Laboratories, 6995 Longley Lane, Reno, NV 89511, United States.
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Regalia
authors.affiliation: Charles River Laboratories, 6995 Longley Lane, Reno, NV 89511, United States.
authors.forename: Kristina
authors.initials: K
authors.lastname: York
authors.affiliation: Charles River Laboratories, 6995 Longley Lane, Reno, NV 89511, United States.
authors.forename: Henry H
authors.initials: HH
authors.lastname: Holzgrefe
mesh_terms: D000827:Animal Welfare; D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D018592:Cross-Over Studies; D004562:Electrocardiography / Q000379:methods; D006339:Heart Rate / Q000502:physiology*; D006799:Housing, Animal; D008252:Macaca fascicularis; D008297:Male; D013686:Telemetry / Q000379:methods*; D018675:Toxicity Tests / Q000379:methods
keywords: Cardiovascular safety pharmacology; Cynomolgus monkey; ECG; Heart rate; Jacketed external telemetry; Methods; Social housing