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Influence of Cellulose and Ambient Temperature on Feed Intake and Growth of Chicks
Influence of Cellulose and Ambient Temperature on Feed Intake and Growth of Chicks R. A. DVORAK and D. J. BRAY Department of Animal Science, University of Illinois, Urbana, Illinois 61801 (Received for publication December 12, 1977) ABSTRACT The effects of dietary cellulose level at various ambient temperatures on the voluntary feed intake of four-week-old chicks were studied. Cellulose (as Solka Floe) was added to a basal diet at levels of 10, 20, and 30% in trial 1 and 15, 30 and 45% in trial 2. The addition of graded increments of cellulose elicited a linear increase (P<.05) in feed intake and a linear depression (P<.05) in growth rate. Cellulose tended to lower (P<.05) gains per unit of basal consumed, indicating that the nondigestible material reduced the utilization of the basal portion of the diet. Feed intakes at 15.6 and 23.9 C were not significantly different in trial 1, but chicks consumed more (P<.05) feed at 7.2 C than at 23.9 C in trial 2.
INTRODUCTION Chicks t e n d t o eat t o m e e t their energy needs. It has been d e m o n s t r a t e d with broilers t h a t t h e addition of fiber t o t h e ration causes an elevated dry m a t t e r intake as t h e chick a t t e m p t s t o maintain a c o n s t a n t level of energy intake (Hill and Dansky, 1 9 5 4 ; Scott and Forbes, 1 9 5 8 ) . Fiber can be provided w i t h o u t altering t h e balance of n u t r i e n t s by adding purified cellulose t o a basal diet. Since cellulose c a n n o t be digested b y t h e chick (Tasaki and Kibe, 1 9 5 9 ) , it is assumed t o merely serve as a n u t r i e n t diluent. Fisher and Weiss ( 1 9 5 6 ) r e p o r t e d t h a t t h e m a x i m u m possible i n t a k e of cellulose-containing diets was regulated b y t h e e x t e n t t o which t h e digestive tract could be distended. In o t h e r studies (Peterson et al, 1 9 5 3 ; Hill and Dansky, 1 9 5 4 ; Scott and Forbes, 1 9 5 8 ) , t h e addition of increments of cellulose t o a basal diet up to a level of 24% elicited a linear increase in dry m a t t e r c o n s u m p t i o n after which t h e weight of feed c o n s u m e d per chick was depressed. Prince et al. ( 1 9 6 1 ) r e p o r t e d t h a t a m b i e n t t e m p e r a t u r e had a significant influence on feed intake. As t h e t e m p e r a t u r e was increased from 7.2 t o 23.9 C, feed i n t a k e decreased. Information is lacking concerning t h e feed i n t a k e responses of chicks t o lowered a m b i e n t temperatures when high fiber (bulky) diets are fed. It has n o t been d e m o n s t r a t e d w h e t h e r t h e capacity of t h e chick t o c o n s u m e bulky rations can be stimulated b y lowering t h e environmental temperature. A s t u d y was c o n d u c t e d t o d e t e r m i n e t h e 1978 Poultry Sci 57:1351-1354
effects of t h e level of dietary cellulose at different a m b i e n t t e m p e r a t u r e s u p o n t h e voluntary feed intake and growth rate of chicks. MATERIALS AND METHODS T h e s t u d y consisted of t w o three-week trials. Each was of a completely r a n d o m i z e d design with a factorial c o m b i n a t i o n of t r e a t m e n t s . In each trial four-week-old New Hampshire x Columbian P l y m o u t h R o c k female chicks were
TABLE 1 .—Composition of basal diet
% Ingredient
in diet
Ground yellow corn Dehulled soybean meal (48.5%) Corn gluten meal (47%) Alfalfa meal, dehydrated (20%) Corn oil Dicalcium phosphate Ground limestone Iodized salt Manganese sulfate Zinc carbonate DL-methionine Tylosin a Choline chloride Vitamin premix 0
53.95 37.00 2.00 1.00 2.00 2.20 1.00 .50 .05 + .05 .05 .10 .10
Supplies 11 mg per kg of ration. Supplies the following per kg of ration: 2990 IU vitamin A, 1000 ICU vitamin D 3 , 10 IU vitamin E, .5 mg menadione, 3.6 mg riboflavin, 27.0 mg niacin, 11.0 mg calcium pantothenate, 9 meg vitamin B I 2 , and .1 mgbiotin.
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DVORAK AND BRAY
randomly assigned from within weight groups to experimental groups. Each group consisted of seven chicks, and all were housed in grower batteries. Four levels of cellulose were fed to two replicate groups at two environmental temperatures in each trial. Differences between treatment and means were tested by Fisher's least significant difference test (Steel and Torrie, 1960). The basal diet was a corn-soybean meal ration calculated to contain 23% crude protein
'Solka Floe, a 99.5% cellulose product purchased from Brown Paper Company, Berlin, NH.
and 3.01 kcal ME/g (Table 1). Graded levels of cellulose 1 were added to the basal ration. Feed intake was recorded daily, and body weights were recorded at the onset and termination of each trial. Trial 1. The chicks were subjected to temperatures of either 15.6 or 23.9 C. For the lower temperature group the temperature was reduced by successive daily 4.15 C decrements from 23.9 C to a level of 15.6 C on the third day of the trial. The dietary treatments were 1) basal, 2) basal + 10% cellulose, 3) basal + 20% cellulose, and 4) basal + 30% cellulose. Ration densities were determined to be .64, .57, .49, and .42 g/cc, respectively. Trial 2. The rations tested were 1) basal, 2)
TABLE 2.—Growth rate, feed intake, and feed utilization Temperature (C)
Trial 1
Feed intake g/chick/day g basal/chick/day cc/chick/day Gain g/chick/day Gain/feed Gain/basal
2
Feed intake g/chick/day g basal/chick/day cc/chick/day Gain g/chick/day Gain/feed Gain/basal
Percent added cellulose* 0
10
20
30
15.6 23.9 15.6 23.9 15.6 23.9
66.6 a 64.4 a 66.6 a b 64.4 a b 104.1 a 100.6 a
71.4 a b 72.6 b 65.0ab 66.0 a 125.3 b 127.4b
77.6 b 76.3 b 64.4 a b 63.4 a 158.4 C 155.7 C
78.1b 76.2 b 60.1ab 58.7 b 186.0 d 181.4 d
15.6 23.9 15.6 23.9 15.6 23.9
27.2 a 27.3 a .41 a .43 a .41 .43 a
26.4 a b 27.0 a .37 b .37b .41 a .41 a
25.0bc 24.8b .32C .32= .39 a .39 a
22.8 C 21.lc .29 d .28 d .38 a .37 a
0
15
30
45
7.2 23.9 7.2 23.9 7.2 23.9 7.2 23.9 7.2 23.9 7.2 23.9
83.4 a 69.3b 83.4 a 69.3 b 130.3 a 108.3 b 28.1 a 28.5 a .34 a .4lb .34 a .41b
89.5b 77.5 C 77.9 C 67.4 b 168.9b 146.2 C 23.0 b 26.6 a b .26 b .34 c .30 a ,40 b
88.7b 80.5 C 68.5 d 62.0 C 211.2 C 191.7 d 15.4 C 22.6 d .17C .28 d .23 b .36 d
80.1a 77.6 C 55.3 e 53.6 e 267.0 d e 258.7 e 9.4 d 17.0 e .12 d .22 e .17C .32 d
•Provided as Solka Floe. ' ' ' ' For each item, means in the same row or column not having a common superscript are significantly different (P<.05). 3 h c H f*
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INFLUENCE OF CELLULOSE AND TEMPERATURE ON CHICKS TABLE 3.—Average feed intake during the last four days of each trial relative to final body weight
Trial
Item
1
g/100 g BW/day g basal/100 g BW/day cc/lOOg BW/day
2
g/100 g BW/day g basal/100 g BW/day cc/100 g BW/day
Temperature (C)
0
10
20
30
15.6 23.9 15.6 23.9 15.6 23.9
8.4 a 7.8 a 8.4 a 7.8 a 13.1 a 12.2 a
9.3ab 9.2 b 8.4 a 8.4 a 16.3 b 16.lb
10.4C lO.obc 8.6 a 8.3 a 21.2 C 20.4 C
11.lc 10.5 C 8.5 a 8.1a 26.4 d 25.0 d
0
15
30
45
13.2 d 9.9 C 10.0 a 7.6 b 31.4C 23.6 d
14.2 d 11.4 e 9.5 a 7.6 b 47.3d 38.0^
7.2 23.9 7.2 23.9 7.2 23.9
Percent added cellulose
9.4 a 7.6b 9.4 a 7.6b 14.7 a 11.9 a
b
ll.l 9.1c 9.7 a 7.9 b 20.9 b 17.2 C
3. ti O (\ t?
' ' ' < For each item, means in the same row or column not having a common superscript are significantly different (P<.05). basal + 15% cellulose, 3) basal + 30% cellulose, and 4) basal + 45% cellulose. Their densities were .64, .53, .42, and .30 g/cc, respectively. Temperature treatments were 7.2 and 24.9 C. The temperature was decreased from 23.9 C by 2.4 C decrements for seven days to reach a level of 7.2 C on the eighth day of the trial for the lower temperature group. RESULTS AND DISCUSSION
Cellulose. The additions of cellulose in trial 1 increased the total weight of feed consumed (P<.05) with the level of intake plateauing at 10% cellulose (Table 2). A similar trend was observed in trial 2, although the addition of 45% cellulose appeared to reduce the chick's intake capacity at the 7.2 C temperature. The increase in the volume of feed consumed was even more dramatic. As the density of the diets progressively decreased with successive increments of cellulose, the volume of feed consumed in both trials increased accordingly (P<.05). The data demonstrate the capacity of the chick to accommodate large volumes of feed in an attempt to maintain a static level of nutrient intake, at all temperatures. The basal portion of the diet provided the nutrients. In trial 1, basal intake remained relatively constant until the highest level of cellulose was fed. A linear decrease (P<.05) in basal intake was observed in trial 2 with a more
pronounced effect at 7.2 C than at 23.9 C. It is important to note that although no significant differences in basal intake were observed for the first three dietary treatments in trial 1, the growth rates of the chicks decreased linearly (P<.05). A reduction in the utilization of the basal portion for growth is also indicated by a trend towards lower gain/basal values. Similar responses in bird performance occurred in trial 2. When feed intake is expressed on a per chick basis for the total assay period, no allowance is made for the differences in body mass that have developed during the assay. Therefore, feed intake in Table 3 is expressed in terms of mass or volume of feed per day per 100 g of final body weight. The data summarized are for the last four days of each trial. In both trials the total mass and volume of feed consumed relative to body weight increased linearly (P<.05) with successive increments of cellulose. Apparently the maximum capacity for feed consumption relative to body mass was not reached even though volume consumption had increased by as much as 320% above that for the basal ration in trial 2. Basal intake per unit of body mass was not affected by the level of cellulose, supporting the concept that with time chicks are able to adjust their level of feed intake to maintain an equivalent energy intake per unit of body mass. This observation is not compatible, however,
1354
DVORAK AND BRAY
with the reduction in weight gain shown in Table 2. Lower efficiencies of converting basal to gain with progressively increasing additions of cellulose indicate that there was a reduction in the utilization of the basal portion. The lowered utilization may have been due in part to an increased rate of passage of the feed through the digestive tract, thereby reducing the time of ingesta exposure to enzymatic degradation and the time of nutrient contact with the absorptive membranes. The inert material (cellulose) may have sufficiently distended the digestive tract, thereby limiting the mixing of ingesta with digestive secretions and reducing the proportion of the total ingesta making contact with the absorptive surfaces to the extent that digestion and absorption were reduced. In addition, greater abrasive action of the added fiber may have contributed to higher maintenance costs for gut epithelial replacement. Temperature. Feed intakes were similar at 15.6 and 23.9 C. Lowering the temperature to 7.2 C, however, did stimulate (P<.05) consumption at all levels of cellulose above the level of the control group. Although it may appear in Table 2 that the differences in intake in trial 2 were smaller as the level of cellulose was increased, this reflects the differences in body weights that developed with time during the assay. This trend was not observed when intake was related to body weight during the last four days of the assay (Table 3). At the lower temperature, basal intake was considerably greater as the chick attempted to eat
enough to meet the energy demands for both growth and body temperature maintenance. The increased energy requirements for body temperature maintenance resulted in greater use of the basal nutrients for heat production, as evidenced by the lower gain/basal ratios compared to the 23.9 C environment. The ultimate result was a lower rate of gain. The capacity of the growing chick to consume feed (volume) relative to body mass, when bulky ingredients are fed for an extended period, remains to be determined.
REFERENCES Fisher, Hans, and H. S. Weiss, 1956. Feed consumption in relation to dietary bulk and energy level: The effect of surgical removal of the crop. Poultry Sci. 35:418-423. Hill, F. W., and L. M. Dansky, 1954. Studies of the energy requirements of chickens. 1. The effect of dietary energy level on growth and feed consumption. Poultry Sci. 33:112-119. Peterson, D. W., C. R. Grau, and N. F. Peek, 1953. Growth and food consumption in relation to dietary levels of protein and fibrous bulk. J. Nutr. 52:241-257. Prince, R. P., L. M. Potter and W. W. Irish, 1961. Response of chickens to temperature and ventilation environments. Poultry Sci. 40:102—108. Scott, H. M., and R. M. Forbes, 1958. The arginine requirement of chicks in relation to diet consumption. Poultry Sci. 37:1347-1349. Steel, R. G. D., and J. H. Torrie, 1960. Page 106-107 in Principles and procedures of statistics. McGrawHill Book Co., Inc. Tasaki, Iwao, and Kyuei Kibe, 1959. A study on the digestion of cellulose in poultry. Poultry Sci. 38:376-379.
INTRODUCTION Chicks t e n d t o eat t o m e e t their energy needs. It has been d e m o n s t r a t e d with broilers t h a t t h e addition of fiber t o t h e ration causes an elevated dry m a t t e r intake as t h e chick a t t e m p t s t o maintain a c o n s t a n t level of energy intake (Hill and Dansky, 1 9 5 4 ; Scott and Forbes, 1 9 5 8 ) . Fiber can be provided w i t h o u t altering t h e balance of n u t r i e n t s by adding purified cellulose t o a basal diet. Since cellulose c a n n o t be digested b y t h e chick (Tasaki and Kibe, 1 9 5 9 ) , it is assumed t o merely serve as a n u t r i e n t diluent. Fisher and Weiss ( 1 9 5 6 ) r e p o r t e d t h a t t h e m a x i m u m possible i n t a k e of cellulose-containing diets was regulated b y t h e e x t e n t t o which t h e digestive tract could be distended. In o t h e r studies (Peterson et al, 1 9 5 3 ; Hill and Dansky, 1 9 5 4 ; Scott and Forbes, 1 9 5 8 ) , t h e addition of increments of cellulose t o a basal diet up to a level of 24% elicited a linear increase in dry m a t t e r c o n s u m p t i o n after which t h e weight of feed c o n s u m e d per chick was depressed. Prince et al. ( 1 9 6 1 ) r e p o r t e d t h a t a m b i e n t t e m p e r a t u r e had a significant influence on feed intake. As t h e t e m p e r a t u r e was increased from 7.2 t o 23.9 C, feed i n t a k e decreased. Information is lacking concerning t h e feed i n t a k e responses of chicks t o lowered a m b i e n t temperatures when high fiber (bulky) diets are fed. It has n o t been d e m o n s t r a t e d w h e t h e r t h e capacity of t h e chick t o c o n s u m e bulky rations can be stimulated b y lowering t h e environmental temperature. A s t u d y was c o n d u c t e d t o d e t e r m i n e t h e 1978 Poultry Sci 57:1351-1354
effects of t h e level of dietary cellulose at different a m b i e n t t e m p e r a t u r e s u p o n t h e voluntary feed intake and growth rate of chicks. MATERIALS AND METHODS T h e s t u d y consisted of t w o three-week trials. Each was of a completely r a n d o m i z e d design with a factorial c o m b i n a t i o n of t r e a t m e n t s . In each trial four-week-old New Hampshire x Columbian P l y m o u t h R o c k female chicks were
TABLE 1 .—Composition of basal diet
% Ingredient
in diet
Ground yellow corn Dehulled soybean meal (48.5%) Corn gluten meal (47%) Alfalfa meal, dehydrated (20%) Corn oil Dicalcium phosphate Ground limestone Iodized salt Manganese sulfate Zinc carbonate DL-methionine Tylosin a Choline chloride Vitamin premix 0
53.95 37.00 2.00 1.00 2.00 2.20 1.00 .50 .05 + .05 .05 .10 .10
Supplies 11 mg per kg of ration. Supplies the following per kg of ration: 2990 IU vitamin A, 1000 ICU vitamin D 3 , 10 IU vitamin E, .5 mg menadione, 3.6 mg riboflavin, 27.0 mg niacin, 11.0 mg calcium pantothenate, 9 meg vitamin B I 2 , and .1 mgbiotin.
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DVORAK AND BRAY
randomly assigned from within weight groups to experimental groups. Each group consisted of seven chicks, and all were housed in grower batteries. Four levels of cellulose were fed to two replicate groups at two environmental temperatures in each trial. Differences between treatment and means were tested by Fisher's least significant difference test (Steel and Torrie, 1960). The basal diet was a corn-soybean meal ration calculated to contain 23% crude protein
'Solka Floe, a 99.5% cellulose product purchased from Brown Paper Company, Berlin, NH.
and 3.01 kcal ME/g (Table 1). Graded levels of cellulose 1 were added to the basal ration. Feed intake was recorded daily, and body weights were recorded at the onset and termination of each trial. Trial 1. The chicks were subjected to temperatures of either 15.6 or 23.9 C. For the lower temperature group the temperature was reduced by successive daily 4.15 C decrements from 23.9 C to a level of 15.6 C on the third day of the trial. The dietary treatments were 1) basal, 2) basal + 10% cellulose, 3) basal + 20% cellulose, and 4) basal + 30% cellulose. Ration densities were determined to be .64, .57, .49, and .42 g/cc, respectively. Trial 2. The rations tested were 1) basal, 2)
TABLE 2.—Growth rate, feed intake, and feed utilization Temperature (C)
Trial 1
Feed intake g/chick/day g basal/chick/day cc/chick/day Gain g/chick/day Gain/feed Gain/basal
2
Feed intake g/chick/day g basal/chick/day cc/chick/day Gain g/chick/day Gain/feed Gain/basal
Percent added cellulose* 0
10
20
30
15.6 23.9 15.6 23.9 15.6 23.9
66.6 a 64.4 a 66.6 a b 64.4 a b 104.1 a 100.6 a
71.4 a b 72.6 b 65.0ab 66.0 a 125.3 b 127.4b
77.6 b 76.3 b 64.4 a b 63.4 a 158.4 C 155.7 C
78.1b 76.2 b 60.1ab 58.7 b 186.0 d 181.4 d
15.6 23.9 15.6 23.9 15.6 23.9
27.2 a 27.3 a .41 a .43 a .41 .43 a
26.4 a b 27.0 a .37 b .37b .41 a .41 a
25.0bc 24.8b .32C .32= .39 a .39 a
22.8 C 21.lc .29 d .28 d .38 a .37 a
0
15
30
45
7.2 23.9 7.2 23.9 7.2 23.9 7.2 23.9 7.2 23.9 7.2 23.9
83.4 a 69.3b 83.4 a 69.3 b 130.3 a 108.3 b 28.1 a 28.5 a .34 a .4lb .34 a .41b
89.5b 77.5 C 77.9 C 67.4 b 168.9b 146.2 C 23.0 b 26.6 a b .26 b .34 c .30 a ,40 b
88.7b 80.5 C 68.5 d 62.0 C 211.2 C 191.7 d 15.4 C 22.6 d .17C .28 d .23 b .36 d
80.1a 77.6 C 55.3 e 53.6 e 267.0 d e 258.7 e 9.4 d 17.0 e .12 d .22 e .17C .32 d
•Provided as Solka Floe. ' ' ' ' For each item, means in the same row or column not having a common superscript are significantly different (P<.05). 3 h c H f*
1353
INFLUENCE OF CELLULOSE AND TEMPERATURE ON CHICKS TABLE 3.—Average feed intake during the last four days of each trial relative to final body weight
Trial
Item
1
g/100 g BW/day g basal/100 g BW/day cc/lOOg BW/day
2
g/100 g BW/day g basal/100 g BW/day cc/100 g BW/day
Temperature (C)
0
10
20
30
15.6 23.9 15.6 23.9 15.6 23.9
8.4 a 7.8 a 8.4 a 7.8 a 13.1 a 12.2 a
9.3ab 9.2 b 8.4 a 8.4 a 16.3 b 16.lb
10.4C lO.obc 8.6 a 8.3 a 21.2 C 20.4 C
11.lc 10.5 C 8.5 a 8.1a 26.4 d 25.0 d
0
15
30
45
13.2 d 9.9 C 10.0 a 7.6 b 31.4C 23.6 d
14.2 d 11.4 e 9.5 a 7.6 b 47.3d 38.0^
7.2 23.9 7.2 23.9 7.2 23.9
Percent added cellulose
9.4 a 7.6b 9.4 a 7.6b 14.7 a 11.9 a
b
ll.l 9.1c 9.7 a 7.9 b 20.9 b 17.2 C
3. ti O (\ t?
' ' ' < For each item, means in the same row or column not having a common superscript are significantly different (P<.05). basal + 15% cellulose, 3) basal + 30% cellulose, and 4) basal + 45% cellulose. Their densities were .64, .53, .42, and .30 g/cc, respectively. Temperature treatments were 7.2 and 24.9 C. The temperature was decreased from 23.9 C by 2.4 C decrements for seven days to reach a level of 7.2 C on the eighth day of the trial for the lower temperature group. RESULTS AND DISCUSSION
Cellulose. The additions of cellulose in trial 1 increased the total weight of feed consumed (P<.05) with the level of intake plateauing at 10% cellulose (Table 2). A similar trend was observed in trial 2, although the addition of 45% cellulose appeared to reduce the chick's intake capacity at the 7.2 C temperature. The increase in the volume of feed consumed was even more dramatic. As the density of the diets progressively decreased with successive increments of cellulose, the volume of feed consumed in both trials increased accordingly (P<.05). The data demonstrate the capacity of the chick to accommodate large volumes of feed in an attempt to maintain a static level of nutrient intake, at all temperatures. The basal portion of the diet provided the nutrients. In trial 1, basal intake remained relatively constant until the highest level of cellulose was fed. A linear decrease (P<.05) in basal intake was observed in trial 2 with a more
pronounced effect at 7.2 C than at 23.9 C. It is important to note that although no significant differences in basal intake were observed for the first three dietary treatments in trial 1, the growth rates of the chicks decreased linearly (P<.05). A reduction in the utilization of the basal portion for growth is also indicated by a trend towards lower gain/basal values. Similar responses in bird performance occurred in trial 2. When feed intake is expressed on a per chick basis for the total assay period, no allowance is made for the differences in body mass that have developed during the assay. Therefore, feed intake in Table 3 is expressed in terms of mass or volume of feed per day per 100 g of final body weight. The data summarized are for the last four days of each trial. In both trials the total mass and volume of feed consumed relative to body weight increased linearly (P<.05) with successive increments of cellulose. Apparently the maximum capacity for feed consumption relative to body mass was not reached even though volume consumption had increased by as much as 320% above that for the basal ration in trial 2. Basal intake per unit of body mass was not affected by the level of cellulose, supporting the concept that with time chicks are able to adjust their level of feed intake to maintain an equivalent energy intake per unit of body mass. This observation is not compatible, however,
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DVORAK AND BRAY
with the reduction in weight gain shown in Table 2. Lower efficiencies of converting basal to gain with progressively increasing additions of cellulose indicate that there was a reduction in the utilization of the basal portion. The lowered utilization may have been due in part to an increased rate of passage of the feed through the digestive tract, thereby reducing the time of ingesta exposure to enzymatic degradation and the time of nutrient contact with the absorptive membranes. The inert material (cellulose) may have sufficiently distended the digestive tract, thereby limiting the mixing of ingesta with digestive secretions and reducing the proportion of the total ingesta making contact with the absorptive surfaces to the extent that digestion and absorption were reduced. In addition, greater abrasive action of the added fiber may have contributed to higher maintenance costs for gut epithelial replacement. Temperature. Feed intakes were similar at 15.6 and 23.9 C. Lowering the temperature to 7.2 C, however, did stimulate (P<.05) consumption at all levels of cellulose above the level of the control group. Although it may appear in Table 2 that the differences in intake in trial 2 were smaller as the level of cellulose was increased, this reflects the differences in body weights that developed with time during the assay. This trend was not observed when intake was related to body weight during the last four days of the assay (Table 3). At the lower temperature, basal intake was considerably greater as the chick attempted to eat
enough to meet the energy demands for both growth and body temperature maintenance. The increased energy requirements for body temperature maintenance resulted in greater use of the basal nutrients for heat production, as evidenced by the lower gain/basal ratios compared to the 23.9 C environment. The ultimate result was a lower rate of gain. The capacity of the growing chick to consume feed (volume) relative to body mass, when bulky ingredients are fed for an extended period, remains to be determined.
REFERENCES Fisher, Hans, and H. S. Weiss, 1956. Feed consumption in relation to dietary bulk and energy level: The effect of surgical removal of the crop. Poultry Sci. 35:418-423. Hill, F. W., and L. M. Dansky, 1954. Studies of the energy requirements of chickens. 1. The effect of dietary energy level on growth and feed consumption. Poultry Sci. 33:112-119. Peterson, D. W., C. R. Grau, and N. F. Peek, 1953. Growth and food consumption in relation to dietary levels of protein and fibrous bulk. J. Nutr. 52:241-257. Prince, R. P., L. M. Potter and W. W. Irish, 1961. Response of chickens to temperature and ventilation environments. Poultry Sci. 40:102—108. Scott, H. M., and R. M. Forbes, 1958. The arginine requirement of chicks in relation to diet consumption. Poultry Sci. 37:1347-1349. Steel, R. G. D., and J. H. Torrie, 1960. Page 106-107 in Principles and procedures of statistics. McGrawHill Book Co., Inc. Tasaki, Iwao, and Kyuei Kibe, 1959. A study on the digestion of cellulose in poultry. Poultry Sci. 38:376-379.