Exploring the use of sodium nitrite as a humane method for mass euthanasia of poultry.

Authors: Lay Jr, Donald; Enneking, Stacey

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/12/2020
Publication Date: N/A
Citation: N/A

Interpretive Summary: When disease outbreaks that threaten the poultry industry require mass euthanasia, it is imperative to ensure humane methods of euthanasia. Current methods are not practical on a large scale. Sodium nitrite ingested at high concentrations prevents the transport of oxygen in the blood and thereby renders the animal unconscious and then dead. Laying hens (n=8 per treatment, 18 wk of age) were subjected to 1 of 4 treatments: A, 75 mg/kg BW; B, 150 mg/kg BW; C, 300 mg/kg BW; or D, 600 mg/kg BW of sodium nitrite in feed. Behavior was recorded via direct observation and video recording. The D hens spent more time lying/sitting, less time standing, and more time inactive alert then C hens (P < 0.03), but not A and B hens. However, A, B, and C hens spent more time standing compared to lying/sitting (P < 0.01), whereas D hens spent equal time in both behaviors. The D hens spent less time eating and drinking, and had fewer drinking events compared to the A, B, and C hens (P < 0.04). Only 1 hen, a D hen, died. She stopped eating 1 min after eating, was lying on her side by 2 min, had total loss of posture and feather erection at 2.5 min, and tremors and wing flapping 5 s later, with subsequent (1 s later) lack of a palpebral reflex. The greatest dose of sodium nitrite caused hens to be lethargic and eat and drink less. This could be due to sedation and aversion to the taste of sodium nitrite. The hen that died did so in an apparently humane manner. However, with only 1 hen dying it is not possible to say if sodium nitrite is a humane method of euthanasia and future research should investigate feeding in an encapsulated form.

Technical Abstract: When disease outbreaks that threaten the poultry industry require mass euthanasia, it is imperative to ensure humane methods of euthanasia. Current methods are not practical on a large scale. Sodium nitrite ingested at high concentrations prevents the transport of oxygen in the blood and thereby renders the animal unconscious and then dead. Laying hens (n=8 per treatment, 18 wk of age) were subjected to 1 of 4 treatments: A, 75 mg/kg BW; B, 150 mg/kg BW; C, 300 mg/kg BW; or D, 600 mg/kg BW of sodium nitrite in feed. Behavior was recorded via direct observation and video recording. The D hens spent more time lying/sitting, less time standing, and more time inactive alert then C hens (P < 0.03), but not A and B hens. However, A, B, and C hens spent more time standing compared to lying/sitting (P < 0.01), whereas D hens spent equal time in both behaviors. The D hens spent less time eating and drinking, and had fewer drinking events compared to the A, B, and C hens (P < 0.04). Only 1 hen, a D hen, died. She stopped eating 1 min after eating, was lying on her side by 2 min, had total loss of posture and feather erection at 2.5 min, and tremors and wing flapping 5 s later, with subsequent (1 s later) lack of a palpebral reflex. The greatest dose of sodium nitrite caused hens to be lethargic and eat and drink less. This could be due to sedation and aversion to the taste of sodium nitrite. The hen that died did so in an apparently humane manner. However, with only 1 hen dying it is not possible to say if sodium nitrite is a humane method of euthanasia and future research should investigate feeding in an encapsulated form.