Food deprivation- and palatability-induced microstructural changes in ingestive behavior.

The effects of 17 h food deprivation and stimulation by five concentrations (0.05-0.8 M) of sucrose solutions on the licking behavior of rats were investigated. Food deprivation increased the intake of the three lowest concentrations (0.05, 0.1, and 0.2 M) but had no effect on the volume ingested of the two highest concentrations (0.4 and 0.8 M). Food deprivation had no significant effect on the duration of the meals of any of the sucrose solutions; rather it affected the rate of ingestion. In those cases where food deprivation did affect volume intake, it did so by increasing the initial rate of ingestion. Although food deprivation had no effect on the volume ingested of the two strongest concentrations of sucrose, it nevertheless affected the ingestive behavior by increasing the duration of the sustained periods of bursts of licking and decreasing their number. Deprivation also significantly decreased the rate of licking within these sustained bouts of licking. The results indicate that food deprivation can affect the ingestive behavior of rats in ways that are not revealed by measuring volumetric intake alone. The data also support the view that food deprivation increases the palatability of the test solutions.