The study that this data supports aimed to evaluate the stunning effectiveness of various stunning attempts on Nile tilapia by measuring brain activity to assess neurological indicators of conscioussness/unconsciousness. Thus, this data set contains raw data from measurements of brain activity using electroencephalography in Nile tilapia. Data were collected before and after stunning attempts using the following stunning methods: Live chilling, mechanical stunning (percussion), electrical stunning and a combinational approach consisting of electrical stunning followed by direct throat cutting and chilling. The data is extracted from Labchart, where data was collected using a Powerlab and a Bioamp. The data contains the mean amplitude during 20-80 s during the 200 ms long light and dark phases. The data set also contains the mean amplitude during 10 s before short electrical exposure as well as the mean amplitude of the signal during the time that the epileptic-like seizure lasted after electrical exposure (i.e., 9-27 s). The data also include information on the time that visually evoked respon

Data contains personal data

Language

English

Method and outcome

Unit of analysis

Animal

Population

Nile tilapia (Oreochromis niloticus)

Study design

Observational study

Experimental study

Description of study design

Brain activity was measured using needle electrodes that were placed near the brain by penetrating the skin and underlying tissues. Electroencephalography (EEG) was used as a method to study how the fish responded to different stunning methods. That is, the baseline EEG of the fish was collected before any stunning was applied, and the fish then underwent one of four different stunning protocols. These were i) mechanical stunning by shooting the fish on the head with a non-penetrating bolt gun driven by pressurized air, ii) electrical stunning where both short electrical stunning (1 s) and longer electrical stunning (30 s) were tested, iii) live chilling where the fish was rapidly cooled down by adding ice cold water to tank, replacing the warm water immersing the fish iv) a combinational approach where electrical stunning for 30 s was followed by direct throat cutting and cooling. Before, during and after the stunning procedure, the fish were observed to note differences and/or deviations in behavior and physiological expressions (for example ventilation) and the EEG was measured.

Time period(s) investigated

2021-01-31 – 2021-04-30

Data format / data structure

Numeric

Text

Species and taxons

Oreochromis niloticus (linnaeus, 1758)

Data collection

Mode of collection: Laboratory experiment
Description of the mode of collection: The EEG was collected using electrodes that picked up the electrical activity in the brain. By stimulating the fish with a repetitive visual stimulus, responses to the visual stimulus were evoked if the fish was conscious, while these responses were absent if the fish was unconscious. The repetitive stimuli used here was a light that was turned on and off at a frequency of 2 Hz whose duration (i.e., the time the light was turned on) was 5 ms per event. In order to provide the right conditions for being stimulated by the lamp, the room was otherwise kept dark. Multiple measurements (between xx-yy measurements) were overlapped to generate the average response over a period of time. The response during this time was in turn divided into two parts, each 200 ms long: the 200 ms long light phase (which revolved around the 5 ms of light turned on) and the 200 ms long dark phase, which followed the 200 ms light phase (and thus occurred before the lamp was lit for 5 ms). Data were collected using a Powerlab and the signal was amplified by a BioAmp. The data was extracted from Labchart and transferred to excel for further analyses and calculations.
Time period(s) for data collection: 2021-01-31 – 2021-04-30
Data collector: Swedish University of Agricultural Sciences
Instrument: Electrodes - Electrodes to pic up the electrical actviity in the brain was made from 1.5 mm shielded silver wires, also from AD instruments, soldered onto 21 gauge needles.
Instrument: PowerLab - A 16 SP Powerlab from AD instruments was used to collect the EEG signals, as well as the signals from the solar panel every time the light was turned on
Instrument: Stunning machine for electrical stunning in water - A stunning machine for in water electrical stunning made by Ace Aquatec was used. The stunner had the ability to deliver 50 Hz AC current.
Instrument: Bio amplifier - An amplifier from AD instruments was used to amplify the signal

Geographic coverage

Administrative information

Responsible department/unit

Departement of Applied Animal Science and Welfare

Contributor(s)

Albin Gräns - Swedish University of Agricultural Sciences, Departement of Applied Animal Science and Welfare

Jeroen Brijs - Swedish University of Agricultural Sciences, Department of Applied Animal Science and Welfare

Commissioning organisation

Institutionen för Biologi och miljövetenskap - Institutionen för Biologi och miljövetenskap

Funding 1

Funding agency: Swedish Research Council for Environment Agricultural Sciences and Spatial Planning
Funding agency's reference number: 2021-01556

Funding 2

Funding agency: Swedish Board of Agriculture

Funding 3

Funding agency: Swedish Research Council for Environment Agricultural Sciences and Spatial Planning
Funding agency's reference number: 2021-02303

Ethics Review

Gothenburg - Ref. 5.8.18-12466/2018

Topic and keywords

Research area

Zoology (Standard för svensk indelning av forskningsämnen 2011)

Behavioural sciences biology (Standard för svensk indelning av forskningsämnen 2011)

Fish and aquacultural science (Standard för svensk indelning av forskningsämnen 2011)

Keywords

Agricultural and aquaculture facilities, Electroencephalography, Percussive stunning, Electrical stunning, Live chilling, Visually evoked responses, Brain activity, Consciousness, Unconsciousness, Stunning, Grand mal, Nile tilapia

Publications

Sundell, Erika & Brijs, Jeroen & Gräns, Albin. (2024). The quest for a humane protocol for stunning and killing Nile tilapia (Oreochromis niloticus). Aquaculture. 593. 741317.
DOI: https://doi.org/10.1016/j.aquaculture.2024.741317

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