Froot Loop consumption in food-deprived and non-food-deprived rats: Is there a difference?

Experiment conducted 30 May 2007 by GR Davis and Phillip Davis

Report written 18 June 2007 by GR Davis

Background:

Most of the sensory-specific satiety experiments conducted at WoffordCollege begin with an 18 hour food deprivation to assure that the rats are hungry and will eat to satiety on the first meal before being offered a second meal. We asked to what degree does hunger affect the consumption of a highly palatable food? In other words, do rats eat a large quantity of FL because they are hungry or to do the eat lots of FL because FL are highly palatable? In food-deprived rats, it is not possible to distinguish between these possibilities. To do so we measured FL intake at 30 minute intervals for two hours in rats that had been food deprived for 18 hours or not.

Purpose:

To determine to what extent hunger affects the intake FL.

Hypothesis:

Food deprived rats will consume more FL in a two hour period than non-food deprived rats.

Methods:

Twenty-four male S-D rats (previously used for a study of the effects of restricted access to FL during the spring of 2007) weighing 632 ± 70 g were used in this study. These animals had a prior history of exposure to Froot Loops. Animals were maintained on a 12 hour light cycle with lights on at 7 am, at which time animals were moved to lab 212 for one hour to acclimate to the new environment. Half of the rats (n=12) had been food deprived for 18 hours beginning at 2 pm the previous afternoon. Bedding was removed. For non-deprived rats, chow remained in the hopper during the experiment. At 8 am a plastic cup containing FL was placed into the center of each cage and FL consumption was calculated every thirty minutes for 120 minutes by weighing the remaining mass of FL.

Data were expressed as cumulative FL intake and as FL intake for each of the four 30 minute intervals.

Results:

All rats began to consume FL at short latency (data not shown) and ate vigorously during the first 30 minutes of the experiment. At the end of the 1st 30 minutes, food deprived rats had consumed nearly twice as much as their non-food-deprived counterparts (Table 1.) In the second 30 minute interval, food deprived rats consumed no FL at all whereas the non-deprived animals continued to eat a small quantity (more than half a gram) of FL. Over the last hour of the experiments, rats consumed very few FL.

Table 1

FL intake in 30 minute intervals for 2 hours.

0-30 min / 30-60 min / 60-90 min / 90-120 min
Non-deprived
n= 12 / 3.6 ± 0.6 / 0.7 ± 0.3 / 0.5 ± 0.3 / 0.2 ± 0.1
18 hr food
Deprived
n= 12 / 6.4 ± 0.8 (a) / 0.0 ± 0.0 (a) / 0.4 ± 0.3 / 0.1 ± 0.1

(a)= significantly different from value in same column.

By the end of the two hour experiment, the difference in FL intake for the two groups was not significantly different (Table 2, right column.)

Table 2

Cumulative FL intake

0-30 min / 0-120 min
Non-deprived n= 12 / 3.6 ± 0.6 / 4.9 ± 0.8
18 hr food Deprived n= 12 / 6.4 ± 0.8 (a) / 6.8 ± 0.8 (n.s.)

(a)= significantly different from value in same column.

(n.s.) = not different from value in same column

Conclusion:

An 18 hr food deprivation did not lead to a significantly larger intake of FL over two hours. However, food deprived rats consumed nearly twice as much FL in the 1st 30 minutes of the experiment. Thus hunger alters the rate of consumption but not the total amount consumed in this experiment.