Behaviors associated with formalin-induced pain in the Japanese quail (Coturnix coturnix japonica )

The present study aimed to investigate behaviors associated with formalin-induced nociception in the Japanese quail (Coturnix japonica ). The tarsometatarsus region of the male quail's foot (shank) was in-jected with 40 mu l of formalin (0.3, 0.6, and 0.9%) solutions or normal saline. Two distinct nociceptive be-haviors that is injected foot lifting and flinching/shaking behaviors were recorded over 45 minutes. Also, unstimulated preening, eye closing, and chamber wall pecking behaviors were recorded during the ob-servation period. Subcutaneous injection of formalin 0.6 and 0.9% significantly increased the foot lifting activity in the 0-5 minutes (acute phase) and 15-45 minutes (inflammatory phase) after administration. But the injection of formalin 0.3% significantly increased foot lifting activity only in the acute phase. In the other recorded behaviors, we did not find this biphasic time course pattern. All formalin concentra-tions induced significant foot flinching/shaking activity only in the acute phase. Subcutaneous injection of formalin 0.9% but not 0.6 and 0.3% significantly increased the duration of eye closure behavior be-tween 20-45 minutes after administration. Injection of all formalin concentrations caused a significant decrease in the unstimulated preening activity between the period of 10 to 45 minutes after adminis-tration. Injection of all formalin concentrations caused a significant decrease in the observation chamber wall pecking activity between the period 30 to 45 minutes after administration. These results suggest that the quail formalin test can be considered a relevant, sensitive, and specific technique that helps re-searchers to use it in the determination of the neurobiology and pharmacology of nociception in the avian species.(c) 2022 Elsevier Inc. All rights reserved.