Food Intake, Water Intake and Body Water Regulation

Food Intake, Water Intake and Body Water Regulation S. LEPKOVSKY, AVIVA CHARI-BITRON,* R. L. LYMAN** AND M. K. DIMICK

The Laboratory oj the University of California, Department of Poultry Husbandry, Berkeley 4, California (Received for publication July 20, 1959)

I

EXPERIMENTAL

Chickens, trained-fed to eat their 24-hour ration in 2 hours of continuous feeding, were used. In this way the mechanisms involved were exaggerated. Such chickens were fed with and without water. They were sacrificed (nembutal) before feeding (22hour fast) and at 2, 4, 7, and 11 hours thereafter. The contents of the crop, gizzard, intestine and ceca were collected and dried for moisture determinations. When the intestinal contents were used for the determination of proteolytic enzymes, they were dried from the frozen state. U. C. Stock mash (Lepkovsky and Furuta, 1960) was used in these studies. Chickens weighing over 600 grams in weight were Present Addresses: * Israeli Institute for Biological Research, NessZiona, Israel. ** Department of Nutrition and Home Economics, University of California, Berkeley, California.

RESULTS

In Table 1 are shown the effect of water with meals upon the food intake, crop contents and the rate of the removal of the food from the crop 2 hours after eating. The birds eating without water ate more food. The crop contents of the birds eating without water contained about 48 percent water while the contents of those eating with water contained about 67 percent. There was no regulation of the water of the crop contents at any fixed level. The rate of digestion as measured by the rate of the removal of the food from the crop was slower in the birds eating without water. In two other experiments (Tables 2 and 3) more extensive measurements were made. The crop contents of the birds also were not closely regulated with respect to their water content. The chickens eating with water had crop contents varying from 57 to 73 percent of water with an average of about 65 percent. The crop contents of the water-deprived chickens varied with the time after eating. Two hours after eating, the water of the crop contents was about 41 percent. After 4 hours it was 43 and after 7 to 11 hours it rose to 50 to 59 percent. Either food passed out of the crop faster than the water or else water absorbed from the intestinal tract during digestion circulated back to the crop where it was

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used since chickens weighing less could not easily be trained to eat their food in 2 hours. The proteolytic activity was determined by Anson's method (1938) and the glycogen by the method of Pfliiger (190S) as modified by Good et al. (1933).

INTRODUCTION

T HAS been shown that regulation of food intake is part of the overall regulation of body water. Rats eating without water will decrease their food intake to such levels that the food in the stomach can be diluted with water from the tissues to make its water content approximately 48 percent. (Lepkovsky et al, 1957). The chicken has no stomach as such but it seemed worth-while to study its regulation of food intake in relation to the availability of water. Along with food intake, digestion and glycogen synthesis were also studied.

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FOOD AND WATER INTAKE AND BODY WATER TABLE 1.—Eject of water with meals upon food intake, water content of crop contents and rate of removal of food from crop. Measurements were made Z hours after the commencement of eating Percent water in crop contents

Dry crop contents gm.

Food removed from crop gm.

Percent removed from crop

Without water

72.0 64.8 61.2 54.0 54.0 44.1 57.6 54.0 61.2

44.5 48.3 49.1 51.0 47.9 49.3 43.3 47.1 48.8

48.6 46.0 41.8 42.9 30.3 27.8 42.3 39.6 47.2

23.4 18.8 19.4 11.1 23.7 16.3 15.3 14.4 14.0

32.5 29.0 31.6 20.5 43.8 36.9 26.5 26.6 22.8

Average

58.1

47.7

40.7

17.4

30.0

With water

46.8 42.3 42.3 53.1 22.5 39.6 63.0 42.3 51.3

68.8 69.0 68.2 61.7 72.7 67.3 64.5 63.3 64.8

25.7 22.0 25.6 38.8 12.7 23.0 39.7 13.2 33.3

21.1 20.3 16.7 14.3 9.8 16.6 23.3 29.1 17.0

45.0 47.9 39.4 26.9 43.5 41.9 36.9 68.7 33.1

Average

44.8

66.7

26.0

18.7

42.6

absorbed from the blood and diluted the crop contents. Closer regulation of water began with the gizzard contents. Little difference is seen (Table 2) between the water of the gizzard contents of the birds fed with or without

water, and the same was the case for the intestinal contents. There seemed to be a little less water in the cecal contents of the water-deprived chickens. In both of these experiments (Table 3), the birds eating with water ate more than

TABLE 2.—Percent water in the contents of the various portions of the gastrointestinal tract of chickens fed with and without water Each run represented the average of 2 birds

Time*

No. of run

+H20 Fasting (22 hrs.)

Gizzard

Crop -H20

+H20

-H20

+H20

-H20

Lower intestine +H2O

-H2O

81.0 79.0

79.5 78.9

75.6 78.6

1 2

Upper intestine

Ceca +H20

-B.0

79.3 71.5

2 hours

1 2

56.8 72.7

40.8 42.1

71.9 74.5

71.0 68.4

84.1 77.4

83.4 78.4

78.9 75.7

77.3 80.8

80.5 76.2

77.7 77.8

4 hours

1 2

64.2 66.4

43.8 43.9

74.0 73.1

72.6 68.4

84.3 77.5

84.9 76.0

81.2 80.3

80.2 77.2

81.4 81.4

78.0 70.9

7 hours

1 2

62.7 67.6

50.4 58.3

75.3 71.7

73.3 70.5

86.4 79.3

82.5 78.5

82.6 78.9

79.6 83.1

85.1 79.9

77.5 75.6

11 hours

1 2

67.4 71.7

50.4 59.9

73.7 72.1

69.3 70.8

78.2 79.6

77.6 81.2

80.2 80.3

81.4 80.7

84.0 75.7

76.1 76.0

* Hours after initiation of feeding (2 hr. feeding period).

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Food eaten gm.

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S. LEPKOVSKY, A. CHARI-BITRON, R. L. LYMAN AND M. K. DIMICK TABLE 3.—Eject of the availability of water during feeding upon the food intake and the contents (dry) of the crop, gizzard, intestine and ceca Crop

Time*

No. of run

Av. food consumed

Solids removed from crop

Solids +H20 -HsO +H20 - H 2 0

Gizzard

Upper and lower intestine

Ceca

Solids

Solids

Solids

+H20 - H 2 0 +H20 -HsO +H20 - H 2 0 +H20 - H 2 0

grams grams grams grams percent percent grams grams grams grams grams grams 1.60 .86 0 2.23 1.35 .29 0 1.33

1 2

2 hours

1 2

86 41

42 30

28.3 11.5

11.8 16.3

67.0 71.9

71.9 45.6

4.1 2.94

4.4 2.7

2.26 3.64

3.26 2.29

.57 .31

.62 .24

4 hours

1 2

76 39

55 32

18.9 12.5

15.2 18.3

75.1 67.9

72.3 42.8

4.0 3.16

4.0 2.3

3.42 3.20

2.12 2.92

.92 .50

.57 .40

7 hours

1 2

68 33

41 30

10.9 2.6

3.42 7.52

83.9 92.1

91.7 75.0

4.3 2.32

2.8 2.3

2.25 2.14

2.25 1.50

.56 .80

.70 .65

11 hours

1 2

90 46

30 32

10.0 .36

3.98 7.87

88.8 99.1

86.6 75.4

4.3 2.4

3.2 3.0

4.10 1.03

1.80 1.12

1.04 .55

.92 .65

* Hours after initiation of feeding (2 hr. feeding period).

zymes, there was in all probability little disturbance in the other digestive enzymes. In Table 5 are given the data on the glycogen content of the various tissues of chickens fed with and without water at the time intervals studied. There seemed to be more glycogen in the livers and the leg muscles of the chickens fed with water compared to those fed without water, but no differences were found in the glycogen contents of the other tissues. No great significance can be given to such differences because only 6 birds were used.

the water-deprived chickens. In run 1, the rate of the digestion (measured by removal of food from the crop) was the same in the chickens, irrespective of the availability of water during eating. In run 2, the rate of digestion was slower in the water-deprived birds. Otherwise, little difference was found in the solids of the gizzard, intestines, and ceca. Deprivation of water during eating caused little change in the proteolytic enzymes of the intestinal tract (Table 4). With no disturbance in the proteolytic en-

TABLE 4.—Proteolytic activity of the intestinal contents of chickens fed with and without water Fasting (22 hours)

Av. of 2 male chickens

Weight 600-750 gms. + H 2 0 Food consumed (gms.) Solids in intestinal contents (gms.) % Nitrogen in intestinal contents Proteolytic activity Meq Tyrosine activity

0

-H20

+H20 41

0

-H20 30

9 hours

4 hours

2 hours

+H20 39

-H20

+H20 - H 2 0 +H20 33

32

11 hours

30

31

-H20 32

.41

.41

3.05

1.61

2.45

1.33

1.59

.69

.53

.50

2.18

2.02

2.02

1.92

2.56

1.78

2.63

3.41

4.85

3.65

1.39

1.01

1.078

1.048

.441

.416

.918

.926

1.086

.605

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Fasting (22 hrs.)

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FOOD AND WATER INTAKE AND BODY WATER TABLE 5.—Percent glycogen found in various tissues of chickens fed with and without water Mg./lOO mg. wet tissue. Average of 6 chicks Liver

muscle

+H20I - H i O Fast 2 hours 4 hours 7 hours 11 hours

.66 1.29 3.10 3.52 2.11

.29 1.31 1.69 1.46 1.40

+H.0 .24 .37 .49 .56 .37

Breast muscle

Skin

Gizzard

- H 2 0 +H2O - H 2 0 +H2O - H 2 O + H 2 O .22 .18 .22 .28 .28

.51 .74 .84 .76 .71

.43 .62 .75 .97 .69

.03 .05 .03 .03 .01

.03 .03 .08 .02 .05

.06 .09 .04 .08 .02

-H 2 0 .06 .08 .08 .02 .03

Subcutaneous fat*

Abdominal

fat*

Mesenteric fat*

+H2O - H 2 O +H2O - H 2 O +H2O - H 2 O .01 .01 .02 .01 .03

.02 .01 .02 .01 .01

.01 .01 .01 .03 .02

.01 .01 .04 .02 .01

0 0 .01 .02 .01

.01 .01 .01 0 .03

* Average of 4 chicks. Gizzard fat, Cardiac fat and Bone Marrow showed no glycogen.

DISCUSSION

appears to make possible the progressive increase of the amount of water in the crop contents, indicating a cycle beginning with the mobilization of water from the body fluids to the crop, return of the water to the body fluids during absorption which make possible an additional mobilization of water by the crop leading to an increase in the water of the crop contents 7 to 11 hours after eating. Apparently some mechanism exists which limits the amount of water that can be mobilized by the crop at any one time. Further mobilization of water by the crop is possible only after some of the water mobilized during eating is returned to the body fluids during digestion. Presumably some mechanism limits the mobilizable water from the body fluids and the same mechanism may also limit food intake either directly or indirectly through the control of the mobilizable water. There appears to be a higher level of glycogen in the liver and in the leg muscle in birds fed with water. This seems to reflect the increased rate of digestion in these birds. The gizzard and skin have small amounts of glycogen. Many of the fats contain a little glycogen; others contain barely enough to measure. Once the feed enters the intestine normal digestion goes on in the birds fed with or without water. This is indicated by the proteolytic activity of the intestinal contents which differs little in chickens fed with or without water.

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Like the rat (Lepkovsky et al., 1957), the chicken closely regulates the amount of the water in its intestinal contents and suggests that it is regulated as part of the internal environment. There is no fixed level at which the amount of water in the crop contents is regulated. Regulation begins with the gizzard contents and from there close regulation of the amount of water in the rest of the intestinal tract is evident. There is a suggestion that the amount of the water in the cecal contents may be regulated less well than in the intestinal contents. Chickens fed without water may eat less or more than those eating with water. The factors causing these differences are not obvious from these studies. Chickens may be less sensitive to water with meals than rats because chickens fed without water will regulate the water in their crop contents at lower levels without endangering the maintenance of the level of water in the intestinal contents. This may give chickens an advantage over the rat during eating when water is not available at this precise time. There appears to be a lower rate of digestion in chickens fed without water. This is shown by a delay in the movement of food from the crops of chickens fed without water. It seems that the amount of water in the crop contents exerts some influence upon the rate of the movement of the crop contents from the crop. Absorption of water from the intestinal tract during digestion

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S. LEPKOVSKY, A. CHARI-BITRON, R. L. LYMAN AND M. K. DIMICK

to decrease somewhat the accumulation of glycogen in the liver and leg muscles. ACKNOWLEDGMENTS

This investigation was supported in part by research grant No. A-498 from National Institutes of Health. REFERENCES Anson, M. L., 1938. Estimation of pepsin, trypsin, papain and cathepsin with hemoglobin. J. Gen. Physiol. 22: 79-89. Good, C. A., H. Kramer and M. Somogyi, 1933. The determination of glycogen. J. Biol. Chem. 100: 485-491. Lepkovsky, S., and F. Furuta, 1960. The effect of water treatment of feeds upon the nutritional values of feeds. Poultry Sci. 39: 394-398. Lepkovsky, S., R. Lyman, D. Fleming, M. Nagumo and M. K. Dimick, 1957. Gastrointestinal regulation of water and its effect on food intake and rate of digestion. Am. J. Physiol. 188: 327331. Pfliiger, E. F. W., 1905. Das Glykogen und seine Beziehungen zur Zuckerkrankheit. p. 53.

The Effect of Water Treatment of Feeds Upon the Nutritional Values of Feeds SAMUEL LEPKOVSKY AND FRED FURUTA Department of Poultry Husbandry, University of California, Berkeley, California (Received for publication July 20, 1959)

INTRODUCTION

T

REATMENT of dried whey with water (Kratzer et al., 1955) yielded a product which improved the growth of chicks beyond that of untreated dried whey. Treatment of the basal diet with water had little effect with perhaps a questionable improvement in the nutritive value of the feed. Treatment of barley, rye and wheat with water (Fry et al., 1957; 1958) improved the nutritional value of these grains, especially the barley. In this laboratory, we had occasion to feed dry feed as well as wet feed ad libitum

and for 2 hours daily. It was repeatedly noticed that birds fed for 2 hours grew better on wet feed than on the untreated dry feed. Treatment of feed with water did something to the feed which enhanced its nutritional value. EXPERIMENTAL Three different diets were used in these studies and the composition of these diets are listed in Table 1. The feeds were treated as follows before feeding: 1. Feed wetted with water in the ratio of 1 feed:l water, kept wet overnight and dried at about 70°C. (Table 2).

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SUMMARY 1. Feeding chickens with or without water does not greatly influence their food intake, since other factors had greater effects. 2. There is more water in the crop contents of chickens fed with water than in the crop contents of chickens fed without water. 3. The intestinal contents of chickens fed with or without water have approximately the same percentage of water. 4. Feeding with or without water does not affect the proteolytic activity of the intestinal contents. 5. The rate of digestion is slower in chickens fed without water. 6. During digestion, there is a progessive increase in the amount of water in the crop contents of the birds fed without water indicating the circulation of water absorbed from the intestinal tract during digestion to the crop. 7. Feeding chickens without water seems