Restricted temporal access to food and anorexia in mice: Microstructure of eating within feeding opportunities

Restricted Temporal Access to Food and Anorexia: Modelling Systems

“…At low FUP (5), the temporal evolution of responding and intake at FO 2 (usually the largest) were similar to those in rats, with a marked reduction in pellets earned in successive 10-min segments (Fig. 3, right panel; full analysis in Rowland et al 2016). In contrast, the maximum number of pellets obtained in the first 10 min by mice was only~35% of the corresponding number in rats at corresponding FUPs, and the response rate was correspondingly lower.…”

“…All of our subsequent work in both rats and mice thus has used 4 FOs, each of 40 min duration. In both rats (unpublished data) and mice (Atalayer and Rowland 2012;Rowland et al 2016), daily food intakes were 80-90% of those in the 23-h protocols at each corresponding FUP, so the shapes of the daily food demand curves in 4 FO protocols are similar to those for continuous access shown in Fig. 2.…”

“…By the end of the FUP 100 segment in the 4 FO protocol, rats had lost an average of 22 g body weight (~7% of initial weights) with most of that loss during FUP 50 and 100 segments. In mice, weight loss was~8% of initial at the end of FUP 25, but 50% of animals did not complete FUP 50 due to weight loss >15% (Rowland et al 2016). Importantly, during rapid weight loss at FUP 25 or 50, intake did not change across successive days.…”

“…Individuals that ate the least day after day were the first to be removed due to weight loss. For completeness, we should note that while sex differences are sometimes evident (Minervini et al 2015;Rowland et al 2016), they have been omitted to simplify the foregoing section since they do not alter the main conclusions.…”

“…In the foregoing section using the 4 FO protocol, we described how intake at FO 4, which occurred at or near the time of lights on ("dawn"), was less than half the intake at the first three (nocturnal) FOs (Atalayer and Rowland 2012;Rowland et al 2016). It is possible that light and/or an endogenous circadian oscillator has an important inhibitory effect at FO 4.…”