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Schedule and quinine induced deprivation in feeding and refeeding
Physiology and Behavior, Vol. 6, pp. 87-90. Pergamon Prms, 1971. Printed in C.rreat Britain
BRIEF COMMUNICATION Schedule and Quinine Induced Deprivation in Feeding and Refeeding E L L E N R. B A U E R
The College of William and Mary, Williamsburg, Virginia 23185, U.S.A. (Received 11 M a y 1970)
BAUER, E. R. Schedule and quinine induced deprivation in feeding and refeeding. PHYSIOL.BEHAV. 6 (1) 87-90, 1971.Twenty female albino rats were adapted to either 0 or 23 hr of food deprivation. Half of each group was then fed 0.125 % quinine sulfate adulterated diet for seven days. Following the quinine feeding, ad lib feeding (refeeding) was instituted for 14 days. Several conclusions were drawn from the results: (1) rats on a deprivation schedule fail to show a predicted change to regulation on the basis of taste rather than calories; (2) rats on food deprivation actually increase their relative intake of water; (3) refeeding after a deprivation schedule does not lead to depression of initial intake below normal, but otherwise the process of recovery follows the same course as after total starvation. Food deprivation
Quinine tolerance
Finickiness
Palatability
Crmomc food deprivation induces a propensity toward a negative emotional state [7]. This may be exhibited as increased irritability or hyperreactivity to external stimulation resulting in exaggerated normal responses: unpalatable substances which in the ad lib animal produce mild aversion in the deprived produce vigorous rejection [2]. Jacobs and Sharma [5] proposed an alternative hypothesis: animals in caloric need regulate on the basis of the sensory aspects of the diet; animals not in need regulate solely on the basis of the caloric content. They predict that ad lib animals do not respond to taste and do not depress intake of quinine adulterated diet as do deprived animals. There is a fundamental difference between these two hypotheses. The Bauer and Bauer hypothesis [2] views deprived and nondeprived animals as exhibiting the same operating characteristics; i.e. they both respond to the taste properties of the diet but the deprived animals overreact. Thus the Bauer and Bauer hypothesis predicts that the deprived and nondeprived animals show only a quantitative difference in response whereas the Jacobs and Sharma hypothesis predicts a qualitative difference in response characteristics. After acute deprivation (total starvation for at least seven days), reinstitution of ad lib feeding results in poststarvation anorexia [6]. Animals eat less initially than prior to the fasting period. With continued ad lib feeding intake increases until it peaks in a few days (refeeding phenomenon). If this is a general deprivation related phenomenon then it ought to occur after chronic (deprivation schedule) as well as acute (total starvation) deprivation [4]. Further, anything such as quinine adulteration which increases deprivation prior to reinstatement of ad lib feeding ought to lengthen the time to reach maximum.
Refeeding
Food related thirst
METHOD
Twenty 80 day old female DUB/SDD albino rats (Flow Labs, Dublin, Va.) were randomly assigned to either a 0 or 23 hr food deprivation schedule (ten each). Food (Purina Laboratory Meal) was presented in the home cage in food cups (Wahmann L C 306-B) and ad lib tap water in inverted 100 ml graduated cylinders. Animals were kept under constant light at about 78°F. Fifteen days were allowed for adaptation. Ad lib animals always had food cups but deprived animals had them only during their daily one hour feeding time. Food, water and body weight were recorded daily. After the fifteenth day both groups were subdivided so that they had equal food intakes that day. One subgroup from each condition was then fed 0.125% quinine sulfate adulterated diet for the next seven days. The other subgroups were fed regular stock diet. After this period, ad lib feeding of stock diet was reinstituted for 14 days. RESULTS AND DISCUSSION
Because of body weight differences induced by deprivation schedule (F = 40.55 with 1 and 16 df)and by quinine adulteration (F = 6.52 with 1 and 16 dr) food intake was calculated as g of food ingested per g of weight. The same was done for refeeding (deprivation induced differences F = 15.31 with 1 and 16 dr). These differences are visible in Fig. 1. Average dally intakes per g weight for both periods are plotted in Fig. 2. The repeated measures analysis of variance done on the quinine feeding period showed a significant depressing effect of time restriction of feeding (F = 79.55 with 1 and 16 dr) and a further depressing effect of quinine in the diet (F : 23.42 with 1 and 16 dr) which decreased with time (F = 2.46 87
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FIG. 1. Average daiJy body weights in grams for all four groups throughout the experiment excluding the first fifteen days (adaptation to deprivation).
with 6 and 96 df for days and F : 5.24 with 6 and 96 df for the interaction). The quinine strength was aversive but quinine and deprivation did not interact significantly (F = 3.19 with 1 and 16 dr). The Jacobs and Sharma [5]hypothesis was not substantiated: thenonde_prived animals did depress. Neither was the Bauer and Bauer [2] hypothesis confirmed: deprived animals showed less depression of intake at least on the first day than ad lib animals. The quinine induced depression was not made up: both ad lib and deprived groups increased intake of quinine adulterated diet over days until eating about the same amount as animals eating stock but never more. Further, introduction of quinine into the food reduced both the ad lib and deprived animals intake to the same level below that of stock intake by deprived animals. Thus, initially, quinine produced the same depression of intake without regard to prior state of deprivation. After quinine feeding all animals were given ad lib stock diet. Initially, the quinine fed groups should be slightly more deprived due to failure to make up their deficit. Figure 2 shows that poststarvation anorexia was not obtained; all groups ate more than the ad lib stock group. Further, having had quinine had to effect on refeeding (F : 0.06 with l a n d 16 dr) except as an interaction with deprivation over days (F : 2.26 with 6 and 96 dr). This is probably du¢ to the very first day of rcfeeding, the ad lib animals ~ up their loss by overeating, consuming as much as the previously deprived. The deprived animals who had been eating the quinine diet, however, ate little more than ad lib animals eating stock. Prior time restriction of feeding also produced a s i g n e t increase in intake during refeeding (F = 61.21 with 1 and 16
DAY OF D E P R I V A T I O N
FIG. 2. Average relative food intake (g intake/g body weight) for all four groups throughout the experiment excluding the first fifteen days (adaptation to deprivation).
dr) which declined with time (F - - 4.34 with 6 and 96 d[ for interaction with days, F : 20.24 with 1 and 16 d f f o r interaction with weeks, F - - 9.12 with 9 and 96 d f f o r interaction with days over weeks). Further, as expected, time measures showed significance: with passage of time average intakes declined (F - - 53.18 with 1 and 16 d f f o r week, and F - - 12.30 with 6 and 96 d f f o r days). Thus, unlike after acute deprivation (starvation) the refeeding phenomenon occurs in only a limited sense after chronic (schedule induced) deprivation. Instead of initial intake upon refeeding starting out at a level below normal, it starts above, but still builds to a maximum in a few days. Slight deficits, such as that produced by addition of quinine to the diet of ad lib animals, serve only to increase initial intake when quinine is removed. However, the addition of such a slight deficit to already deficient animals further slows down the process of reaching maximal intake and further depresses initial intake. Again, due to body weight differences, water intake per g weight was used as the measure of fluid intake. Average daily intake for both the quinine period and the refeeding period are presented in Fig. 3. The repeated measures analysis of variance for the quinine feeding period showed only a significant effect of deprivation (F - - 9.37 with 1 and 16 df). The deprived animals drank more water per g weight than nondeprived. The additional restriction o f food intake induced by quinine adulteration of the diet did not additionally increase water intake. Thus, this experiment finds evidence for an increase in relative fluid intake with a decrease in
FOOD DEPRIVATION AND QUININE TOLERANCE
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DAY OF DEPRIVATION FIG. 3. Average relative water intake (cma intake/g body weight) for all four ~'oups throughout the experiment excluding the first fifteen days (adaptation to deprivation).
relative food intake although the relationship is not perfect. Furthermore, this relationship seems reversed in refeeding: increased food intake leads to increased water intake. Time restriction on feeding results in increased water intake during refeeding (F = 19.79 with 1 and 16 df) which declines with time (F ----78.94 with 1 and 16 d f f o r deprivation over weeks, F = 5.54 with 16 and 96 df for deprivation over days, F = 3.79 with 6 and 96 df for deprivation over days within weeks). There is also a significant overall decline of water intake over time (F for week = 84.79 with 1 and 16 d f a n d F for day -----6.46 with 6 and 96 dr) and a significant interation between measures of time (F : 7.26 with 6 and 96 dr). Several conclusions can be drawn. Rats partially deprived of food fail to show the change in preference behavior predicted by either the Jacobs and Sharma [5] hypothesis or the Bauer and Bauer [2] hypothesis. Quinine sulphate (0.125 %) added to the diet produced a depression of food intake per unit body weight regardless of deprivation condition. The ad lib animals showed a greater absolute decrease relative to their stock controls than did the deprived animals relative to their stock controls. The deficit decreased over days. As the animals became hungrier they ate more of the bitter tasting foodstuff, On the first few days ad lib rats given quinine ate only about
as much as deprived. Both groups overcame the bitter taste and r ~ u m e d almost normal consumption but they never overate to make up their deficit. Thus a commonsense view of regulation seems to be correct: the hungrier the animal is, the more willing he will be to eat anything that is edible. As a corollary, the hungrier an animals is, the more he prefers sweets which generally indicate higher caloric value. Adding sugar to food should increase intake by hungry animals and decrease intake of normal satiated animals. F o r water deprivation, adding sodium saccharin to water has been shown to initially decrease fluid intake [1]. But additives in water signal increased salts. The slight additional food deprivation caused by quinine did not affect the increase in water consumption produced by food deprivation. This increased intake was a result of the animal's maintaining a constant intake of water with a decreased body weight. Withholding of food generally has been shown to reduce water intake [3]. Kutscher [8], however, found a slight increase in water intake of rats on a 22 hr food deprivation schedule. At the same time, he found that restriction of amount of food produced a decrease in water consumption. Thus two factors are involved: [1] lessened water need due to weight loss and [2] type of deprivation procedure. Reintroduction of ad lib feeding after adaptation to a feeding schedule did not result in poststarvation anorexia. The food intake of the previously deprived rats was not initially below that of the continuously ad lib group. However, their initial intake was not the largest daily intake achieved during refeeding, even though presumably hungrier on the first day than on any subsequent day. This increase to maximum is similar to the process of recovery from total deprivation. Thus, chronic deprivation (feeding schedule) produces refeeding behavior slightly different from that produced by acute deprivation (total starvation): for chronic deprived animals the level of feeding on the first day is above that of a nondeprived control. Otherwise, the process seems similar. The only effect of increased deprivation due to quinine occured on the first day. The addition of the slight increase in deprivation on top of the schedule-induced deprivation caused lower initial intake. After the first day the recovery process returned to normal. F o r the ad lib rats, the quinine induced deprivation caused an initial increase in feeding with a prompt return to normal feeding. If the quinine feeding period had been longer the effect might have been greater. In general, mild prior deprivation produced an increase in initialrefeeding. This increase declined with increasing severity of deprivation. Thus, there may exist an inverted U-shaped relation between severity of deprivation and initial refeeding. There may also be a positive relation between day of maximal intake and severity of deprivation. In this experiment the mildest deprivation (quinine induced only) produced a maximal refeeding intake on day one, the next level (schedule induced only) on day two and the third level (quinine and schedule induced) on day four. Increased severity of deprivation produced an increased latency to maximal refeeding intake.
REFERENCES 1. Bauer, E. R. Deprivation changes initial affective value of sodium saccharin. Psychonom. ScL 16: 275, 1969. 2. Bauer, E. R. and F. S. Bauer. Effects of social isolation on quinine tolerance. Physiol. Behav. 4: 435--437, 1969.
3. Bolles, R.C. Theoryof Motivation. New York: Harper & Row, 1967. 4. Gold, R. M. Discussion of the paper by C. L. Hamilton: Problems of refeeding after starvation in the rat. Ann. N.Y. Acad. Sci. 157: 1017, 1969.
90 5. Jacobs, H. L. and K. N. Sharma. Taste versus calories: sensory and metabolic signals in the control of food intake. Ann. N.Y. ,4cad. Sci. 157: 1084--1112, 1969. 6. Hamilton, C. L. Problems of refeeding after starvation in the rat. Ann. N. Y. Acad. Sci. 157: 1005-1017, 1969.
BA U I R 7. Keys, A., J. Brozek, A. Henschel, O. Mickelsen and H. I_ Taylor. The Biology o f Human Starvation. Minneapolis, Minn. : University of Minnesota Press, 1950. 8. Kutscher, C. L. Species differences in the interaction of feeding and drinking. Ann. N.Y. Acad. Sci. 157: 539-551, 1969.
BRIEF COMMUNICATION Schedule and Quinine Induced Deprivation in Feeding and Refeeding E L L E N R. B A U E R
The College of William and Mary, Williamsburg, Virginia 23185, U.S.A. (Received 11 M a y 1970)
BAUER, E. R. Schedule and quinine induced deprivation in feeding and refeeding. PHYSIOL.BEHAV. 6 (1) 87-90, 1971.Twenty female albino rats were adapted to either 0 or 23 hr of food deprivation. Half of each group was then fed 0.125 % quinine sulfate adulterated diet for seven days. Following the quinine feeding, ad lib feeding (refeeding) was instituted for 14 days. Several conclusions were drawn from the results: (1) rats on a deprivation schedule fail to show a predicted change to regulation on the basis of taste rather than calories; (2) rats on food deprivation actually increase their relative intake of water; (3) refeeding after a deprivation schedule does not lead to depression of initial intake below normal, but otherwise the process of recovery follows the same course as after total starvation. Food deprivation
Quinine tolerance
Finickiness
Palatability
Crmomc food deprivation induces a propensity toward a negative emotional state [7]. This may be exhibited as increased irritability or hyperreactivity to external stimulation resulting in exaggerated normal responses: unpalatable substances which in the ad lib animal produce mild aversion in the deprived produce vigorous rejection [2]. Jacobs and Sharma [5] proposed an alternative hypothesis: animals in caloric need regulate on the basis of the sensory aspects of the diet; animals not in need regulate solely on the basis of the caloric content. They predict that ad lib animals do not respond to taste and do not depress intake of quinine adulterated diet as do deprived animals. There is a fundamental difference between these two hypotheses. The Bauer and Bauer hypothesis [2] views deprived and nondeprived animals as exhibiting the same operating characteristics; i.e. they both respond to the taste properties of the diet but the deprived animals overreact. Thus the Bauer and Bauer hypothesis predicts that the deprived and nondeprived animals show only a quantitative difference in response whereas the Jacobs and Sharma hypothesis predicts a qualitative difference in response characteristics. After acute deprivation (total starvation for at least seven days), reinstitution of ad lib feeding results in poststarvation anorexia [6]. Animals eat less initially than prior to the fasting period. With continued ad lib feeding intake increases until it peaks in a few days (refeeding phenomenon). If this is a general deprivation related phenomenon then it ought to occur after chronic (deprivation schedule) as well as acute (total starvation) deprivation [4]. Further, anything such as quinine adulteration which increases deprivation prior to reinstatement of ad lib feeding ought to lengthen the time to reach maximum.
Refeeding
Food related thirst
METHOD
Twenty 80 day old female DUB/SDD albino rats (Flow Labs, Dublin, Va.) were randomly assigned to either a 0 or 23 hr food deprivation schedule (ten each). Food (Purina Laboratory Meal) was presented in the home cage in food cups (Wahmann L C 306-B) and ad lib tap water in inverted 100 ml graduated cylinders. Animals were kept under constant light at about 78°F. Fifteen days were allowed for adaptation. Ad lib animals always had food cups but deprived animals had them only during their daily one hour feeding time. Food, water and body weight were recorded daily. After the fifteenth day both groups were subdivided so that they had equal food intakes that day. One subgroup from each condition was then fed 0.125% quinine sulfate adulterated diet for the next seven days. The other subgroups were fed regular stock diet. After this period, ad lib feeding of stock diet was reinstituted for 14 days. RESULTS AND DISCUSSION
Because of body weight differences induced by deprivation schedule (F = 40.55 with 1 and 16 df)and by quinine adulteration (F = 6.52 with 1 and 16 dr) food intake was calculated as g of food ingested per g of weight. The same was done for refeeding (deprivation induced differences F = 15.31 with 1 and 16 dr). These differences are visible in Fig. 1. Average dally intakes per g weight for both periods are plotted in Fig. 2. The repeated measures analysis of variance done on the quinine feeding period showed a significant depressing effect of time restriction of feeding (F = 79.55 with 1 and 16 dr) and a further depressing effect of quinine in the diet (F : 23.42 with 1 and 16 dr) which decreased with time (F = 2.46 87
88
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FIG. 1. Average daiJy body weights in grams for all four groups throughout the experiment excluding the first fifteen days (adaptation to deprivation).
with 6 and 96 df for days and F : 5.24 with 6 and 96 df for the interaction). The quinine strength was aversive but quinine and deprivation did not interact significantly (F = 3.19 with 1 and 16 dr). The Jacobs and Sharma [5]hypothesis was not substantiated: thenonde_prived animals did depress. Neither was the Bauer and Bauer [2] hypothesis confirmed: deprived animals showed less depression of intake at least on the first day than ad lib animals. The quinine induced depression was not made up: both ad lib and deprived groups increased intake of quinine adulterated diet over days until eating about the same amount as animals eating stock but never more. Further, introduction of quinine into the food reduced both the ad lib and deprived animals intake to the same level below that of stock intake by deprived animals. Thus, initially, quinine produced the same depression of intake without regard to prior state of deprivation. After quinine feeding all animals were given ad lib stock diet. Initially, the quinine fed groups should be slightly more deprived due to failure to make up their deficit. Figure 2 shows that poststarvation anorexia was not obtained; all groups ate more than the ad lib stock group. Further, having had quinine had to effect on refeeding (F : 0.06 with l a n d 16 dr) except as an interaction with deprivation over days (F : 2.26 with 6 and 96 dr). This is probably du¢ to the very first day of rcfeeding, the ad lib animals ~ up their loss by overeating, consuming as much as the previously deprived. The deprived animals who had been eating the quinine diet, however, ate little more than ad lib animals eating stock. Prior time restriction of feeding also produced a s i g n e t increase in intake during refeeding (F = 61.21 with 1 and 16
DAY OF D E P R I V A T I O N
FIG. 2. Average relative food intake (g intake/g body weight) for all four groups throughout the experiment excluding the first fifteen days (adaptation to deprivation).
dr) which declined with time (F - - 4.34 with 6 and 96 d[ for interaction with days, F : 20.24 with 1 and 16 d f f o r interaction with weeks, F - - 9.12 with 9 and 96 d f f o r interaction with days over weeks). Further, as expected, time measures showed significance: with passage of time average intakes declined (F - - 53.18 with 1 and 16 d f f o r week, and F - - 12.30 with 6 and 96 d f f o r days). Thus, unlike after acute deprivation (starvation) the refeeding phenomenon occurs in only a limited sense after chronic (schedule induced) deprivation. Instead of initial intake upon refeeding starting out at a level below normal, it starts above, but still builds to a maximum in a few days. Slight deficits, such as that produced by addition of quinine to the diet of ad lib animals, serve only to increase initial intake when quinine is removed. However, the addition of such a slight deficit to already deficient animals further slows down the process of reaching maximal intake and further depresses initial intake. Again, due to body weight differences, water intake per g weight was used as the measure of fluid intake. Average daily intake for both the quinine period and the refeeding period are presented in Fig. 3. The repeated measures analysis of variance for the quinine feeding period showed only a significant effect of deprivation (F - - 9.37 with 1 and 16 df). The deprived animals drank more water per g weight than nondeprived. The additional restriction o f food intake induced by quinine adulteration of the diet did not additionally increase water intake. Thus, this experiment finds evidence for an increase in relative fluid intake with a decrease in
FOOD DEPRIVATION AND QUININE TOLERANCE
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DAY OF DEPRIVATION FIG. 3. Average relative water intake (cma intake/g body weight) for all four ~'oups throughout the experiment excluding the first fifteen days (adaptation to deprivation).
relative food intake although the relationship is not perfect. Furthermore, this relationship seems reversed in refeeding: increased food intake leads to increased water intake. Time restriction on feeding results in increased water intake during refeeding (F = 19.79 with 1 and 16 df) which declines with time (F ----78.94 with 1 and 16 d f f o r deprivation over weeks, F = 5.54 with 16 and 96 df for deprivation over days, F = 3.79 with 6 and 96 df for deprivation over days within weeks). There is also a significant overall decline of water intake over time (F for week = 84.79 with 1 and 16 d f a n d F for day -----6.46 with 6 and 96 dr) and a significant interation between measures of time (F : 7.26 with 6 and 96 dr). Several conclusions can be drawn. Rats partially deprived of food fail to show the change in preference behavior predicted by either the Jacobs and Sharma [5] hypothesis or the Bauer and Bauer [2] hypothesis. Quinine sulphate (0.125 %) added to the diet produced a depression of food intake per unit body weight regardless of deprivation condition. The ad lib animals showed a greater absolute decrease relative to their stock controls than did the deprived animals relative to their stock controls. The deficit decreased over days. As the animals became hungrier they ate more of the bitter tasting foodstuff, On the first few days ad lib rats given quinine ate only about
as much as deprived. Both groups overcame the bitter taste and r ~ u m e d almost normal consumption but they never overate to make up their deficit. Thus a commonsense view of regulation seems to be correct: the hungrier the animal is, the more willing he will be to eat anything that is edible. As a corollary, the hungrier an animals is, the more he prefers sweets which generally indicate higher caloric value. Adding sugar to food should increase intake by hungry animals and decrease intake of normal satiated animals. F o r water deprivation, adding sodium saccharin to water has been shown to initially decrease fluid intake [1]. But additives in water signal increased salts. The slight additional food deprivation caused by quinine did not affect the increase in water consumption produced by food deprivation. This increased intake was a result of the animal's maintaining a constant intake of water with a decreased body weight. Withholding of food generally has been shown to reduce water intake [3]. Kutscher [8], however, found a slight increase in water intake of rats on a 22 hr food deprivation schedule. At the same time, he found that restriction of amount of food produced a decrease in water consumption. Thus two factors are involved: [1] lessened water need due to weight loss and [2] type of deprivation procedure. Reintroduction of ad lib feeding after adaptation to a feeding schedule did not result in poststarvation anorexia. The food intake of the previously deprived rats was not initially below that of the continuously ad lib group. However, their initial intake was not the largest daily intake achieved during refeeding, even though presumably hungrier on the first day than on any subsequent day. This increase to maximum is similar to the process of recovery from total deprivation. Thus, chronic deprivation (feeding schedule) produces refeeding behavior slightly different from that produced by acute deprivation (total starvation): for chronic deprived animals the level of feeding on the first day is above that of a nondeprived control. Otherwise, the process seems similar. The only effect of increased deprivation due to quinine occured on the first day. The addition of the slight increase in deprivation on top of the schedule-induced deprivation caused lower initial intake. After the first day the recovery process returned to normal. F o r the ad lib rats, the quinine induced deprivation caused an initial increase in feeding with a prompt return to normal feeding. If the quinine feeding period had been longer the effect might have been greater. In general, mild prior deprivation produced an increase in initialrefeeding. This increase declined with increasing severity of deprivation. Thus, there may exist an inverted U-shaped relation between severity of deprivation and initial refeeding. There may also be a positive relation between day of maximal intake and severity of deprivation. In this experiment the mildest deprivation (quinine induced only) produced a maximal refeeding intake on day one, the next level (schedule induced only) on day two and the third level (quinine and schedule induced) on day four. Increased severity of deprivation produced an increased latency to maximal refeeding intake.
REFERENCES 1. Bauer, E. R. Deprivation changes initial affective value of sodium saccharin. Psychonom. ScL 16: 275, 1969. 2. Bauer, E. R. and F. S. Bauer. Effects of social isolation on quinine tolerance. Physiol. Behav. 4: 435--437, 1969.
3. Bolles, R.C. Theoryof Motivation. New York: Harper & Row, 1967. 4. Gold, R. M. Discussion of the paper by C. L. Hamilton: Problems of refeeding after starvation in the rat. Ann. N.Y. Acad. Sci. 157: 1017, 1969.
90 5. Jacobs, H. L. and K. N. Sharma. Taste versus calories: sensory and metabolic signals in the control of food intake. Ann. N.Y. ,4cad. Sci. 157: 1084--1112, 1969. 6. Hamilton, C. L. Problems of refeeding after starvation in the rat. Ann. N. Y. Acad. Sci. 157: 1005-1017, 1969.
BA U I R 7. Keys, A., J. Brozek, A. Henschel, O. Mickelsen and H. I_ Taylor. The Biology o f Human Starvation. Minneapolis, Minn. : University of Minnesota Press, 1950. 8. Kutscher, C. L. Species differences in the interaction of feeding and drinking. Ann. N.Y. Acad. Sci. 157: 539-551, 1969.