2026-04-17T11:28:05Zhttps://recercat.cat/oai/requestoai:recercat.cat:20.500.12327/29612025-10-22T11:31:00Zcom_2072_4428com_2072_4427col_2072_487898
RECERCAT
author
Llonch, P.
author
Rodríguez, P.
author
Jospin, M.
author
Dalmau, A.
author
Manteca, X.
author
Velarde, A.
other
Producció Animal
group
Benestar Animal
2025-10-22T11:31:00Z
2025-10-22T11:31:00Z
2012-10-26
Llonch, Pol, P. Rodríguez, M. Jospin, Antoni Dalmau, Xavier Manteca, and Antonio Velarde. 2013. “Assessment of Unconsciousness in Pigs During Exposure to Nitrogen and Carbon Dioxide Mixtures.” Animal 7 (3): 492–498. doi:10.1017/s1751731112001966
1751-7311
http://hdl.handle.net/20.500.12327/2961
https://doi.org/10.1017/S1751731112001966
The aim of this study was to assess unconsciousness in pigs during and after the exposure to gas mixtures of 70% nitrogen (N2)
and 30% carbon dioxide (CO2) (70N30C), 80% N2 and 20% CO2 (80N20C) and 85% N2 and 15% CO2 (85N15C) compared with
90% CO2 in air (90C) by means of the Index of Consciousness® R (IoC), their behaviour and the absence of brain stem reflexes.
The experiment included three trials of 24 pigs divided into four groups according to the number of treatments. Half of the group was
exposed for a short time and the other half for a long time (3 and 5 min for the N2/CO2 mixtures exposure and 2 and 3 min in 90C
exposure, respectively). During exposure, the IoC and the electroencephalography suppression rate (ESR) were assessed, as well as the
time to onset and percentage of gasping, loss of balance, vocalizations, muscular excitation and gagging. At the end of the exposure,
the corneal reflex, rhythmic breathing and sensitivity to pain were each assessed at 10 s intervals for 5 min. Brain activity decreased
significantly (P , 0.05) 37.60 s after the start of the exposure to 90% CO2, which was significantly earlier than in 70N30C, 80N20C and
85N15C exposure, (45.18 s, 46.92 s and 43.27 s, respectively). Before brain activity decreased, all pigs experienced gasping and loss of
balance and a 98% muscular excitation. The duration of the muscular excitation was longer in animals exposed to 70N30C, 80N20C
and 85N15C than 90C (P , 0.01). After a long exposure time, all animals exposed to 90C died, whereas the 30.4% of animals exposed
to N2/CO2 gas mixtures survived. Pigs exposed to 85N15C recovered corneal reflex and sensitivity to pain significantly earlier than when
exposed to 90C. Exposure to 90C causes a higher aversive reaction but a quicker loss of consciousness than N2/CO2 gas mixtures.
Exposure to N2/CO2 gas mixtures causes a lower percentage of deaths and an earlier recovery of the brain stem activity than 90C,
whereas the time to recover the cortical activity is similar. In conclusion, the inhalation of N2/CO2 gas mixtures reduces the aversion
compared with high concentrations of CO2; however, the period of exposure for inducing unconsciousness may be longer in N2/CO2 gas
mixtures, and the signs of recovery appear earlier, compared to CO2.
eng
Attribution-NonCommercial-NoDerivatives 4.0 International
Assessment of unconsciousness in pigs during exposure to nitrogen and carbon dioxide mixtures
info:eu-repo/semantics/article