Four behavioral tests associated with fear and aggressiveness in Japanese quail

Abstract

Japanese quail were evaluated in 4 tests, performed aproximately 30 days appart from each other. Partial mechanical restraint test , Social Interaction, Tonic Inmovility and Welfare assesment. Partial mechanical restraint test was performed at 40 days of age. This test consists in restricting the movement of the animal between two walls of a melamine box of 20 x 10 cm (height per width, respectively) with the characteristic that the front wall was made of glass, and the back wall was adjustable to induce immobility in such a way that the animal cannot open the wings, but can move the head and legs (Jones et al 2000). The experimenters retreated out of the birds' sight, and the test was during 5 minutes recorded with a video camera place in front of the box. All the birds were tested in 31 batches of 4 animals each, where the birds had no visual or physical contact between each other. The video was analyzed manually, and the following variables were recorded: the latency to struggle considered as time between the initiation of restraint until the first struggling episode (defined as the movement of the legs of the animal trying to escape) and the number of struggles during the observation period. The struggle episodes were considered different if they were separated by 5 s or more. The immobility of the animal during the test has been widely considered in the literature as an indicator of intense fear. Social interaction (SI) test was performed between 70 days of age. This test is described in detail in Caliva et al (2017, Poult Sci9 6(12):4140-4150). Briefly, the SI test consists in a 5 min encounter between an unfamiliar test adult bird and a photocastrated stimulus adult male, in the presence of the test bird’s cagemate (audience). A video-camera was positioned 1 m above the apparatus and connected to a computer that allowed constant monitoring and recording during the test while out of the sight of the birds. Using behavioral tracking software (Any-maze, 2015) the following aggressive behaviors were recorded: Pecks: when one bird raises its head and vigorously pecks the other bird’s body (usually on the head). Grabs: when a male catches (“grabs”) with their beak the neck or head region of the female. Mounts: while performing a grab, the male approaches a female from behind, and places both feet on the dorsal surface of its torso, stepping over the females’ tail. Cloacal contacts: during mounting, the male lifts his tail and tilts his pelvis underneath the other bird and briefly presses its cloaca against the female. Threats: one bird stands with its neck and head raised in front of the other bird that usually has itshead at a lower level than the first. Chase: a bird runs after another that is escaping. Attack with claws. Tonic immobility (IT) test was performed at 100 days of age, the individual was place in the left lateral decubitus and hold for 15 seconds, holding him with both hands against a support base (one hand on the head and another in the body). We recorded the number of inductions to achieve an immobility of at least 10 seconds and the duration of the immobility (IT). A long duration of IT and a smaller number of necessary inductions is indicative of a high level of fear as opposed to a short response 41. If IT was not attained after 5 successive attempts, the bird was considered not to be susceptible and scores of 0 were given for TI duration. Welfare assessment. At 96 and 108 days of age female skin lesions and plumage status were evaluated using an adapted version of the protocol proposed by Welfare Quality ® consortium 42. Head, neck and back skin lesions were determined using a score scale from 0 to 2 where "0" represents no lesions (punctiform damage <0.25 cm diameter) or scratches, "1" represents less than 3 lesion or scratches, and "2" reflects 3 or more lesion or scratches. Head, neck and back plumage damage was also determined using a score scale from 0 to 2 as follows: "0" represents individuals with no plumage damage or slight wear (only single feathers lacking), "1" represent individuals with one or more body parts that have moderate wear (i.e. damaged feathers worn or deformed) or one or more featherless areas < 1.5 cm in diameter at the larger extent and "2" corresponded to individuals that have at least one featherless area > 1.5 cm in diameter at the largest extent (Pellegrini et al 2017, Poult. Sci. 96(E-Suppl. 1):133 )