The effect of dividing walls, a tunnel, and restricted feeding on cardiovascular responses to cage change and gavage in rats (Rattus norvegicus).

Cage change and gavage are routine procedures in animal facilities, yet little is known about whether housing modifications change responses to these procedures. Telemetric activity and cardiovascular parameters were assessed in this experiment. BN and F344 male rats were housed in open or individually ventilated cages, each containing 3 rats, 1 of which had a transponder. A crossover design was used, in which 2 groups were given dividers made of 2 intersecting boards (1 form contained holes loaded with food pellets; the other did not) and 1 group was given a rectangular tunnel. On day 8 of each 2-wk period, the cages were changed; on day 11, rats were gavaged. The parameters were evaluated for the first hour and for the following 17 h. Baseline values for each rat were subtracted from the corresponding response values. The presence of objects did not affect the responses of F344 rats to cage changing or gavage. In BN rats with IVCs, the presence of the plain divider modified the response to both procedures. Responses to procedures appeared to be dependent on both the strain and the cage object, thus complicating the establishment of valid general recommendations.