Rate of fat compensation and growth efficiency of lipectomized Sprague Dawley rats

The objective of this experiment was to measure changes in food efficiency and to determine the rate of fat compensation following the surgical removal of adipose tissue in Sprague Dawley rats. The right inguinal fat pad and both epididymal pads were surgically removed from 375 g male castrate rats that were then paired with sham-operated controls. Pairs were evenly distributed into one of five groups. The rats were killed when they reached their group designated weight: immediate post surgery, 375, 405, 435 and 465 g. Dissected fat weight was significantly less in lipectomized animals at all body weights except 465 g. Gradual fat compensation up to 465 g was due to partial regeneration of the right inguinal fat pad as well as compensatory growth of other (intact) fat depots. Epididymal fat pads showed no signs of regeneration. Lipectomized animals had similar food intake but gained weight more rapidly than shams. Lipectomized rats had more food available for production when calculated maintenance energy requirements were subtracted from total food intake. Efficiency of utilization of production food did not differ significantly between treatments. Compensatory weight gain seen in lipectomized rats was therefore due to greater ad-libitum food consumption above maintenance requirements.