Looking at the world through rose colored cages: Lighting and cage color preferences in rats
Brianna N. Gaskill, PhD
Assistant Professor of Animal Welfare
Purdue University
Frequency or wavelength
Rat vision
400
500
Wavelength (nm)
600
Jacobs et al, 2001
Light intensity
• Luminous flux: measure of the perceived power of light (weighted toward what the eye can see)
• How strong is the light? = Lumens
• Illuminance: luminous flux incident on a surface
• How well is something lit? = Lux
Light intensity
Example
Office lighting
Overcast day
Illuminance (lux)
320-500
1000
Full daylight
10,000-25,000
Light intensity
Location in a vivarium
Intensity (Lux)
A
183.5
B
107.6
C
10.8
D
19.7
Open room
328.0
Lights out
0
Inside a nest
0
Under igloo
32
Natural conditions
Intensity (Lux)
Twilight
1 ‐ 10
Full Moon
0.27
No Moon
0.001
A
B
C
D
Previous preference
Morning
Afternoon
Schlingman et al, 1993
Bright lighting is stressful
Basis of behavioral tests
Physiological effects
Ader et al, 1991
Do rats seek out red environments?
Amber
Red
Amber Top/Red bottom (AT/RB)
Red Top/Amber bottom (RT/AB)
Cage Location
Caging Type
Bottom Rear
Bottom Front Top Rear
Amber
72 lux ± 15 lux
132 ± 30lux
77 lux ± 13 lux
Red
19 lux ± 5 lux
25 lux ± 15 lux
13lux± 5 lux
AT/RB
37 lux ± 10 lux
97 lux ± 20 lux
58 lux ± 10 lux
RT/AB
24 lux ± 6 lux
44 lux ± 10 lux
15 lux± 5 lux
Red tinted cages change environments
Spectral makeup
Hormones
Dauchy et al, 2013; 200 Lux
25 Lux
Breeding environment
Breeding environment
Assessing affect in rats
Negative Affect
22 kHz
• Exposure to predators, electric shock, fighting
• Anticipation of negative events
Positive Affect
Positive Affect – 50 kHz
• Exploration, copulation, food reward, amphetamine injection, social play
• Anticipation of positive events
Knutson and Panksepp, 2002; Burman et al., 2007; Burgdorf et al., 2011
Eliciting Positive Affect in rats‐ Rat Social Play
2 Main Components
Dorsal contact
Pin
200 Lux
Weaning environment
25 Lux
Weaning environment
Breeding environment
Cage color vs Lighting intensity
Strain vs Cage color
Strain vs Lighting intensity
200 Lux
Breeding environment
Weaning environment
25 Lux
Tested at 4‐6, 7‐9, and 10‐12 weeks of age
Weaning environment
Tested at 4‐6, 7‐9, and 10‐12 weeks of age
Nesting data
Thank you!
Collaborators:
Sponsors:
Deb Hickman
ACLAM Foundation
Melissa Swan
www.labanimalwelfare.com
Megan LaFollette
Becca Smith
Roya Ball
Scores of undergraduates