Effects of feeding pattern and dietary regimen on growth and adipose tissue cellularity in polygenic obese mice

The effect of varying feed intake and feeding pattern during the early postweaning period on growth, body composition and adipose tissue cellularity was studied in polygenic obese and control normal mice. Male mice were assigned to the following dietary treatments at 4.5 wk of age: stock diet fed ad libitum(AL), four palatable foods cafeteria-fed(CF), stock diet fed every 2 h by automatic feeders adjusted for maximum intake(MI), fed same procedure as MI but restricted to produce 70% of the gain of mice fed ad libitum(RE), and stock diet fed one meal/d the same amount fed RE mice(PM). Mice were killed after 5 wk on treatment. Cafeteria-fed control mice were heavier (P less than .05) than RE control mice, but they were not different (P greater than .05) from AL, MI and PM control mice, while CF obese mice were heavier and RE obese mice were smaller than AL, MI and PM obese mice (P less than .05). Cafeteria-fed mice were fatter than mice from all other treatments in both the obese and control lines. Maximum intake, PM and RE mice were fatter than AL mice but this effect was only significant in the obese line. Alterations in feeding pattern can affect body composition even though body weight may not show a correlated response. Cafeteria-fed obese mice had larger fat pads and more small (less than 40 micron) and large (greater than 110 micron) adipocytes than other obese mice. Results indicate that the difference in the development of obesity on cafeteria diet was due primarily to genetic effects while the increase in percentage fat after restriction on MI, PM and RE treatments was due mainly to the acute change of feeding pattern.