An automated home cage observation system as a model of feeding behaviour in mice
Lianne Robinson, Susan McKillop-Smith, and Gernot Riedel
School of Medical Science, College of Life Science and Medicine, University of Aberdeen, Aberdeen, Scotland, UK, Introduction
both the light and dark phases of the experimental days. In addition to these parameters the body weight of each animal,
Obesity is characterised by an increase in consumption of food
weight of food hopper (food intake) and weight of water bottle
containing high levels of sugar and saturated fats combined
(water intake) were recorded on a daily basis immediately
with a reduction in physical activity. The increased prevalence
prior to drug injection and also post drug treatment (between
of obesity and childhood obesity in western countries has
the hours of 10.00 – 11.00 am of the light cycle).
highlighted the need for anorectic agents which are effective in weight management.
The Cannabinoid (CB1) antagonist SR141716A
Acute treatment with AM251 induced a suppression of food
(Rimonabant/Acomplia) has previously been shown to
intake and a reduction in body weight compared to vehicle
suppress food intake [1, 2]. However, in addition to drug
treated animals. AM251 treated animals also spent less in the
induced effects on food intake and body weight, drug
areas of the arena associated with food and water. In addition
treatment can also affect activity levels [3, 4]. An increase in
a reduction in locomotor activity was also observed although
activity may lead to hyperactivity which could explain a
this was only apparent for the first few hours of the dark
reduction in body weight which is independent of any
phase. Repeated dosing with AM251 also produced a
reduction in food consumption. Therefore, a more detailed
significant suppression in body weight and food intake relative
assessment of drug-related effects on activity in conjunction
to controls, with animals spending less time in the food zone
with drug-induced hypophagic properties is required.
on all nights following treatment. Similar to acute treatment a decrease in overall locomotor activity was also evident.
The aim of this study was to develop a novel method which
Conclusions
would combine these two approaches and allow us to assess
These findings suggest that the home cage observation system
both the feeding behaviour and locomotor activity of free-
‘phenotyper’ is a sensitive and effective method to assess the
feeding mice. The cannabinoid antagonist AM251 was used to
hypophagic effects of possible anti-obesity drugs as it allows
the long-term continuous monitoring of both food intake and behavioural activity.
Male and female C57BL6 mice (25-32g) were used in this
study. The automated home cage video-based observation system ‘phenotyper’ was used to allow long-term continuous
References
monitoring of behavioural activity of the mice. During testing
Colombo, G, Agabio, R, Diaz, G, Lobina, C, Reali, R, Gessa,
the mice were maintained on a 12 hr light/dark cycle (lights
GL (1998). Appetite suppression and weight loss after the
off 7pm) with free access to food (food hopper) and water
cannabinoid antagonist SR 141716. Life Science63: PL113-117
Vickers, SP, Webster, LJ, Wyatt, A, Dourish, CT, Kennett, GA
(water bottle). Animals were given 3-4 days of habituation in
(2003). Preferential effects of the cannabinoid CB1 receptor
the phenotyper prior to drug administration in order to attain a
antagonist, SR141716, on food intake and body weight gain of
baseline level of performance and were matched for body
obese (fa/fa) compared to lean Zucker rats.
weight before being assigned to drug groups of AM251 (10
Psychopharmacology167: 103-111
mg/kg) or Tween 80, with all drugs injected intraperitoneally
Compton, DR, Aceto, MD, Lowe, J, Martin, BR (1996). In vivo
1-2 hours prior to the start of the dark phase of the circadian
characterization of a specific cannabinoid receptor antagonist
cycle. A single acute treatment or repeated dosing regime was
(SR141716A): Inhibition of Delta (9)- tetrahydrocannabinol-
employed with the drug administered daily for 4 consecutive
induced responses and apparent agonist activity. Journal of
days. The behaviour of the animals was monitored using the
Pharmacology and Experimental Therapeutics277 (2): 586-594
computer based tracking software Ethovision (version 3.0,
Bass, CE, Griffin, G, Grier, M, Mahadevan, A, Razdan, RK, Martin, BR (2002). SR141716A induced stimulation of
Noldus, Netherlands). The parameters recorded included total
locomotor activity: a structure-activity relationship study.
locomotor activity, time spent in the area in front of the food
Pharmacology Biochemistry and Behavior74: 31-40
hopper and time spent in the area close to the water bottle. These parameters were analysed in hourly intervals during
roceedings of Measuring Behavior 2008 (Maastricht, The Netherlands, August 26-29, 2008)
Eds. A.J. Spink, M.R. Ballintijn, N.D. Bogers, F. Grieco, L.W.S. Loijens, L.P.J.J. Noldus, G. Smit, and P.H. Zimmerman
Antibiotic Residues Although most countries have banned the antibiotics chloramphenicol and nitrofurans from animal food production due to their toxicity to humans, traces of the drugs have been detected in shrimp and other aquaculture products. Chloramphenicol can cause potentially fatal aplastic anemia and leukemia, and nitrofurans are carcinogenic. Therefore, the seafood industry fully