- Department of Clinical Sciences, Swedish University of Agricultural Sciences
Does breeding of laboratory rats in larger cages affect behaviour, corticosterone and blood pressure?
Cvek, Katarina; Arborelius, Lotta
This study aimed at investigating effects of housing laboratory rats in larger cages on behaviour and physiology during the lactation period, in both dams and pups. Telemetric transmitters for registration of blood pressure, heart rate and activity were surgically placed in female Wistar rats, subcutaneously on the flank with the femoral artery catheterized. When fully recovered, the rats were mated and randomly placed singly in standard cages (ST; 2240 cm2, height 20 cm; n=8) or standard cage bottoms with raised tops (RT; height 50 cm; n=7) fitted with a shelf. Black plastic tubes and nesting material was placed in all cages. Maternal behaviour was studied through direct observations once per minute for 90 minutes at five different occasions during the lactation period. Blood pressure, heart rate and activity were measured telemetrically at postnatal day (PND) 12. At weaning, urine samples were collected by placing the animals in empty cages. The urine was analysed for creatinine/corticosterone ratio. Preliminary results indicate no differences in the amount of time the dams spent with their pups, but the ST dams displayed more arched-back nursing and licking/grooming of the pups than dams in RT cages (data from all animals not yet analysed). This may imply that RT dams had not adjusted fully to the new cages. No differences in blood pressure, heart rate or activity of the dams could be detected during PND 12 between cage types or between day and night. Nor could any differences in creatinine/corticosterone ratio be detected between the dams (RT=75±47SEM, ST=145±89, t-test p=0.157). All pups were very active during the second half of the lactation period. However, the pups in the RT cages had more space and opportunities to climb and perform physical activity and also had significantly lower creatinine/corticosterone ratio than the pups in the ST cages (RT=416±61SEM, ST=638±53SEM, Mann-Whitney Rank Sum Test, p<0.001) indicating a lower stress level
42nd Congress of the International Society for Applied Ethology
UKÄ Subject classification
Animal and Dairy Science
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