Effect of acute heat stress on cognitive performance of chickens in a feed-related discriminant task

• Published in: Journal of thermal biology 2021-05, Vol.98, p.102914-102914, Article 102914
• Main Authors: Iyasere, Oluwaseun S., Oyetunji, Damilola E., Wheto, Mathew, Durosaro, Samuel O., Adigun, Taiwo T., Muraina, Habeeb A., Akinyemi, Olaoluwa O., Daramola, James O.
• Format: Article
• Language: English
• Subjects: Animal welfare; Body temperatures; Cognitive ability; Discriminant task; FUNAAB Alpha chickens; Heat stress; Latency; Motivation; Thermal suffering
• ISSN: 0306-4565; 1879-0992
• DOI: 10.1016/j.jtherbio.2021.102914

Little is known about immediate and long-lasting effect of acute heat stress on chicken cognition. Thirty-five, 9-week-old birds were trained to differentiate two cone colours; white (rewarded, R; with feed underneath) and black (unrewarded, UR; empty). The sixteen birds that learnt the task were randomly assigned to three temperature regimens (TR: 22–24 °C (control), 30–32 and 36–38 °C for 3h/day) for three consecutive days during which rectal (RT), wing (WT) and eye (ET) temperatures were monitored. After the 3 h of exposure, birds were allowed to rest for 1 h before the commencement of the discriminant task. The latencies to open the cones (R and UR) and proportion of cones opened were recorded. A long-lasting effect was tested a week after exposure to TR. TR had a significant effect on RT, WT and ET. The motivation to turn over R cones was weaker in birds exposed to 36–38 °C than birds exposed to 22–24 °C. Also, the proportion of R cones opened were fewer in birds that experienced TR of 36–38 °C compared to birds exposed to 22–24 °C and 30–32 °C specifically on two out of the three cognitive test days (Days 1 and 3). Latency and proportion of UR cones opened was not affected by TR. RT, WT and ET were all negatively and significantly correlated with latency to open the UR cones. Previous exposure of birds to three TR had no effect on the latency to open both cones but the proportion of R cones opened was greater in birds exposed to 30–32 °C compared to the 22–24 °C birds. In conclusion, an immediate (36–38 °C) and long-lasting effect (30–32 °C) of acute heat stress was associated with a weak motivation to perform feed related discrimination task. •Temperature regimen (TR) had a significant effect on rectal, wing and eye temperatures of FUNAAB Alpha chickens.•The motivation to turn over rewarded cones was weaker in birds exposed to 36-38oC than birds exposed to 22-24oC.•Fewer rewarded cones were opened by birds that experienced TR of 36-38oC than those exposed to 22-24oC and 30-32oC.•An immediate (36-38oC) and long-lasting effect (30-32oC) of acute heat stress towards the rewarded cones was observed.