Biology subjects

Suess, S. C.

Publications and source records attributed to Suess, S. C..

3 recordsLinked to original sources

bioRxiv2023

Nociception in chicken embryos, Part III: Analysis of movements before and after application of a noxious stimulus

Many potentially noxious interventions are performed on chicken embryos in research and in the poultry industry. It is therefore in the interest of animal welfare to define the point at which a chicken embryo is capable of nociception. The present part III of a comprehensive study examined the movements of developing chicken embryos with the aim of identifying behavioral responses to aww noxious stimulus. For this purpose, a noxious mechanical stimulus and a control stimulus were applied. The recorded movements of the embryos were evaluated using the markerless pose estimation software DeepLabCut and manual observations. After the application of the noxious stimulus, a significant increase in beak movement was identified in 15- to 18-day-old embryos. In younger embryos, no behavioral changes related to the noxious stimulus were observed. The results indicate that noxious stimuli at the beak base evoke a nocifensive reaction in chicken embryos starting at embryonic day 15.

animal behavior and cognition↗

bioRxiv2023

Nociception in chicken embryos, Part I: Analysis of cardiovascular responses to a mechanical noxious stimulus

While it is assumed that chicken embryos acquire the ability for nociception during the developmental period in the egg, an exact time point has not yet been specified. This study aimed to determine the onset of nociception during embryonic development in chicken. Changes in blood pressure and heart rate (HR) in response to a mechanical noxious stimulus at the base of the beak versus a light touch on the beak in chicken embryos between embryonic days (EDs) 7 and 18 were examined. Mean arterial pressure (MAP) was the most sensitive parameter for assessing cardiovascular responses. Significant changes in MAP in response to a noxious stimulus were detected in embryos at ED16 to ED18, while significant changes in HR were observed on ED17 and ED18. Infiltration anesthesia with the local anesthetic lidocaine significantly reduced reactions in MAP on ED18, so the cardiovascular changes can be assumed to be nociceptive responses.

physiology↗

bioRxiv2023

Nociception in chicken embryos, Part II: Embryonal development of electroencephalic neuronal activity in ovo as a prerequisite for nociception

Chicken culling is forbidden in Germany since 2022, male/female selection and male elimination must be brought to an embryonic status prior to the onset of nociception. The present study evaluated the ontogenetic point when noxious stimuli potentially could be perceived/processed in the brain in ovo. EEG-recordings from randomized hyperpallial brain sites were recorded in ovo and noxious stimuli were applied. Temporal and spectral analyses of the EEG were performed. The onset of physiological neuronal signals could be determined at developmental day 13. ERP/ERSP/ITC analysis did not reveal phase-locked nociceptive responses. Although no central nociceptive responses were documented, adequate EEG-responses to noxious stimuli from other brain areas cannot be excluded. The extreme stress impact on the embryo during the recording may overwrite the perception of noniceptive stimuli. The results suggest developmental day 13 as the earliest embryonal stage being able to receive and process nociceptive stimuli.

neuroscience↗