Voluntarily ingestion of a sedative prior to euthanasia with CO2 in mice

Published: 20 August 2021| Version 1 | DOI: 10.17632/zzzvwpzyvt.1
Raquel Rodriguez-Sanchez,


Our objective was to study if the voluntary ingestion of a sedative (tiletamine-zolazepam; Zoletil®) prior to euthanasia with CO2 reduces the aversiveness to this gas in female and male C57BL/6 mice. A total of 80 C57BL/6 mice (40 females, 40 males) were used in the study. Animals were housed in pairs of the same sex. The treatments differed in the dose of the sedative (tiletamine-zolazepam): Control (0 mg/kg), Z10 (10 mg/kg), Z20 (20 mg/kg), Z40 (40 mg/kg), Z80 (80 mg/kg), and Z100 (100 mg/kg). The data file contains two tabs. In both tabs, Columns A to E include: Cage_number: there were 40 cages in total. Sex: half of the cages were females and half males. MouseID: there were two mice/cage and to differentiate between them one was marked. Dosing Period: (1-5) A total of 5 dose escalation sessions were performed. At each dosage session, each treatment cage was randomly paired with a control cage containing mice of the same sex, resulting in a total of 16 mice from four male cages and four female cages per session. Type_of_treatment: Control, Z10, Z20, Z40, Z80 and Z100. 1) Pre-euthanasia Data Tab. Includes the behavioural data reported during 1200 s of observation after the voluntarily ingestion of the sedative and prior to euthanasia with CO2 (sedation period). Due to video loss for some mice, we standardised the behavioural reporting to the first 800 s of the sedation period. Under the column "Event_frequency" (Column K) are those behaviours coded as frequency (e.g., rearing and jumping), and under the column "Behaviour_duration" (Column L) are those behaviours coded as duration (e.g., walking on lid, ataxia). "CC In" and "CC Out" (Column I) indicates when the cream cheese +/- sedative was introduced and removed from the cage. "CC Out - End Obs" (Column J) is the total observation time. The duration for the behaviours or conditions appears under the column "Duration_Time" (00:00:00). The columns "Onset_Time" (Column F) and "Offset Time" (Column G) indicate the time when the behaviour or condition started and ended, respectively. 2) Euthanasia Data Tab. Includes the data about the voluntary intake of the cream cheese +/- sedative (Columns N to V); "z_dose" (Column U) is the planned tiletamine-zolazepam dose and "actual_z_dose" (Column V) is the real dose ingested. The behaviours recorded during the euthanasia with CO2 are also included (Columns F to K). Rearing (Column F) and jumping (Column G) were coded as frequency. The other behaviours were coded as durations (seconds). Under "Corrected_Latency_to_Ataxia" (Column H) appears the latency to ataxia from the onset of CO2 (seconds). The other latencies were coded from the previous behaviour as follows: "Latency to recumbency from ataxia" (Column I) "Latency to laboured breathing from recumbency" (Column J), and "Latency to last breath from laboured breathing" (Column K). The duration for which the CO2 was on is included in Column L.



AgResearch Ltd


Animal Behavior, Mouse, Animal Welfare, Sedation, Carbon Dioxide, Euthanasia