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Johns Hopkins Bloomberg School of Public HealthCAAT

Animal Welfare Enhancement Awards - 2004 Recipients

The Use of a Conditioning Technique to Reduce the Physiological and Behavioural Stress Associated with Repeated Intra-peritoneal Injections in Rats
Sylvie Cloutier, PhD
 Washington State University

I hypothesized that using a conditioning technique to pair a stressful procedure such as intra-peritoneal injection with a rewarding experience decreases the stress associated with repeated exposure to the procedure in rats. Three different reward types (Food (F), Petting (P) and Tickling (T)) were compared to two control conditions (Handling (CH) and Injected (CI)) (N=8 rats/treatment). Rats were handled and/or injected daily for 10 days with 1ml/kg of saline. Chromodacryorrhea was recorded daily during injection period. Body weight and behaviour were measured before and after injection period. Behaviour was assessed using the Anticipatory Reaction to Handling (ARH), the Human Approach (HA) and the Elevated Plus Maze (EPM) tests. Body weight was not affected by treatment. Rats of all conditions had higher chromodacryorrhea scores on all, but two, treatment days compared to baseline (p<0.0001). P rats had higher chromodacryorrhea scores (p=0.02) and showed significant positive changes in behaviour toward a human hand (p=0.008) in a familiar environment (ARH test) but they took longer to approach a human hand, and made less visits and contact with the hand after treatment (p<0.02) in an unfamiliar environment (HA test). T rats took longer than CH, CI and P to walk with a curved back (normal posture) in the open arms (p=0.04) (EPM test). By refining the methods, Food, Petting and Tickling rewards could be used to reduce the stress of laboratory procedures and improve the relationship between