Effects of monensin feeding and withdrawal on fat pad adipocyte size in female broilers

Abdominal fat pad adipocyte size was determined in two experiments to evaluate the effect of monensin feeding and withdrawal on female broilers. In Experiment 1 at 49 days of age mean adipocyte sizes were: 49.2 micron, unmedicated controls; 50.0 micron, medicated controls; 55.6 micron, medicated birds with 5-day withdrawal period; and 55.1 micron medicated birds with 10-day withdrawal period. In Experiment 2, adipocyte sizes of medicated controls were 62.5 and 63.5 micron at 44 and 51 days, respectively. All medicated birds received 120 ppm dietary monensin. In broilers subjected to drug withdrawal for 7 days, adipocyte size was 60.1 micron at 44 days and 68.8 micron at 51 days after the drug withdrawal period. There were no significant differences (P less than .05) in adipocyte size among treatments in either experiment.