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Responses of Broilers to Dietary Protein Levels and Amino Acid Supplementation to Low Protein Diets at Various Environmental Temperatures1
01997Applied Poultry Science, Inc
m S P O N S E S OF BROILERS TO DIETARY PROTEIN LEVELS AND AMINO ACID
THIM K. CHENG, MELVIN L. HAMRE, and CRAIG N. COON2 Depament of Animal Science, University of Minnesota, St. Paul, MN 55108 Phone: (612)624-6263 F M : (612)625-5789 ~~
~
~
Primary Audience: Nutritionists, Broiler Producers, Researchers
tal effect on weight gain and carcass composiDESCRIPTION OF PROBLEMtion as well as efficiency of feed, protein, and High ambient temperatures have been shown to reduce broiler feed consumption and growth rate [l,21. Research showing the effect of feeding increased dietary protein mncentrations or aminoacid levels to broilers housed in hot temperatures to compensate for the reduced feed intake has been limited. Cheng et al. [3]recently reported that feeding high CP diets to heat-stressed broilers had a detrimen-
energy utilization. The researchers suggested that broilers housed in hot environmentalconditions should not be fed increased concentrations of protein to provide the additional dietary amino acids suggested by Combs [4] and the updated Maryland amino acid requirements [5]. Previous studies have been divided some show a reduced protein requirement for chicks housed in hot temperatures
1 Published as Paper Number 971165802, the ScientificJournal Series, Minnesota Agricultural 2
Experiment Station. To whom correspondence should be addressed
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SUPPLEMENTATION TO Low PROTEIN DIETSAT VARlrOUS ENVIRONMENTAL TEMPERATURES'
Research Report CHENG et al.
treatment consisted of four replicates. Each pen weight of six broilers was adjusted to within 1SD of mean pen weights for all rooms. Experiment 1 investigated the effect of dietary CP and temperature on broiler performance. The design was identical to that of Chengetal. [3] except that only the high energy diet (3250 kcal ME/kg) was used. Diets were formulated in such a way that the five essential amino acid levels (Met, Lys, Arg, Thr, Trp) and TSAA would meet or exceed the 80,90, 100, 110, and 120% levels recommended by the NRC [16] for the 16, 18, 20, 22, and 24% CP diets, respectively (Table 1). Experiment 2 investigated the impact of amino acid supplementation of low protein diets (16 and 18%) to provide 90, 100, and 110% of NRC-recommended amino acid requirements on broiler performance at various temperatures. Synthetic amino acids were added to the 16 and 18% CP diets (Table 1) at two levels, so that the five essential amino acids equaled or exceeded the 100 and 110% levels specified by the NRC [16]. The 16% CP diet was also supplemented at the 90% level. Since the amino acids in the 18% CP diet used in Experiment 1 were already at the 90% levels, the data collected from this group were also used in Experiment 2. All treatments were randomized in the same block for both experiments. AU diets were pelleted and fed to the broilers on an ad libitum basis. The diets were analyzed for moisture, crude protein, and amino acids [3]. Feed intake and body weight were recorded weekly, and mortality was recorded daily. Feed intake values were adjusted for the mortality to the nearest day. Both experiments ended when the birds were 7 wk of age. ' h obuds from each replicate were fasted overnight and killed by C02 asphyxiation. Totalbody protein and fat were determined on feather-free uneviscerated carcasses to determine the protein efficiency ratio (PER), protein utilization (PU), energy efficiency ratio (EER), and energy utilization (EU) as described by Cheng et al. [3]. AU data were subjected to statistical analysis [lq.
MATERIALS AND METHODS A total of 1440 male Arbor Acre x Ross chicks were used in the present study. The nutrition and management procedures used tcr rear the birds from 1to 21 days have been described by Cheng et ul. [3]. The experiment began with birds at 21 days of age. Birds were evenly divided into six environmental rooms with temperatures set at 21.1, 23.9, 26.6, 29.4, 32.2, and 350°C. The mean relative humidity during the grower trial was 52%. There were 40 cages (76 x 66 cm) in each room and buds were housed at a density of six birds per cage. Half of the birds in each room were used in Experiment 1 and the other half in Experiment 2. In both experiments, each cage of six birds constituted a replicate and each
RESULTS AND DISCUSSION In Experiment 1, the effect of temperature and dietary CP, as well as the interaction between them were highly significant (P< .001) for weight gain, total feed intake,
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[6, 7, 81, and others are unable to find any interaction between dietary CP and temperature [9, 10, 111. Sinurat and Balnave [ll]reported no significant interaction for dietary CP and broiler performance in hot temperatures; however, they reported that heatstressed broilers obtained maximum growth by eating a hqh ME diet with a slight deficiency in lysine or a lower 1ysine:ME ratio. Harris et al. [12] reported that weight gain reduced maximum levels in heat-stressed birds (29°C) with a concentrated diet of 3410 kcaVkg ME and 110% of NRC-suggested amino acid levels. The data of Fuller and Mora [13] and Dale and M e r [8] also support the view that heat-stressed buds respond to increasing amino acid consumption. Teeter and Smith [14] also showed that broilers housed at 30°C and force-fed additional diet above ad libitum intake had increased weight gain. The research does not indicate whether the force-fed broilers responded to the additional dietary energy, amino acids, or both. Since heat-stressed broilers have been shown to select lower CP diets in choice feeding studies [15], it may be useful to feed heat-stressed birds low CP diets supplemented with higher levels of essential amino acids. This study seeks to determine the optimum dietary protein and amino acid levels for broilers housed in various environmental temperatures. The research was conducted with enough different controlled environmental temperatures, dietary protein, and amino acid levels to correlate specific diet and temperature relationships.
19
JAPR CP,AMINO ACIDS, AND TEMPERATURE
20
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*Diets 1,2,3,4,and 5 contained ~,90,100,110, and 120% NRGrecommended amino acid levels (methionine, lysin arginine, tryptophan, and threonine), respectively. %Tee new 16% CP diets were mixed b supplementing the five amino acids to Diet 1to attain 90,100, and 110 NRC levels, ctively. Two new 18% diets were mixed by supplementing the fne amino acids to Diet 2 to atta 100and llOY%C levels, respectively. These five new diets had a total slightly exceeding 100%.
&'
S u lied the following r kg of diet: vitamin A, 6,600 IU; vitamin D3,1,650 IUvitamin E, 3.3 IU; menadione sodiu 1 'bisugte, 4.9 mg; niacin,% mg; riboflavin, 6.6 m& folacin, 0.2 mg; pantothenic acid, 11mg; vitamin B12,O.Ol mg. DSupplied the following in mgkg of diet: Mn,100; Fe, 275; Zn,625; Cu, 3.3; I, 1.2.
Research Report 21
CHENG et al.
BODY WEIGHT GAIN
WEIGHT
g
feed conversion increased with temperatures up to 27 to 28"C, followed by a decrease as temperature was raised further. The maximum feed conversion reported by Hurwitz etal. [18] was in broilers fed a 19.4% CP diet, which is consistent with the maximum feed conversions reported herein with broilers fed lower CP (20%) diets. The maximum feed conversion would be at a lower temperature if the dietary CP was higher (Figure 1). Figure 2 reveals a deleterious effect of feeding high dietary protein and amino acids at high temperatures (26.7T) observed for the determination of PER. Maximum PER occurred at 28.1"C and the PER remained high for birds fed low CP diets (< 18.4%) at temperatures above 28.1"C. The maximum EER was located between 26.7 to 28.1"C and between 20 to 20.8% dietary CP (Figure 2). The deleterious effect of high CP diets
TOTAL
FEED TOTAL TOTAL CONVERSION~PROTEIN ME INTAKE INTAKE INTAKE g kcal
FEED
PER^
EER~
gain/100 kcal
16
2114b
lWb
3Wb
0.483b
566'
10280b
2.941'
14.86b
18
2150b
1561b
3248e
0.476b
Sab
10560'
2.SSOd
14.4gb
20
2140b
lSMb
3193be
0.47Sb
2.292'
14.39b
211P
UO?
3081'
0.469b
645' 682d
l0Wk
22
10010'
2.0Bb
14.4Sb
24
1942'
1330'
3022'
0.439'
me
9823'
1.m'
13.16'
Temperature (T)
40.001
<0.001
<0.001
4 0.001
40.001
40.001
<0.001
Dietary CP (CP)
rxCP
40.001
0.013
0.022
0.014
0.034
4 0.001
0.008
<0.011
<0.001
40.001
c 0.001
<0.001
<0.001
~0.001 40.001
0.017 40.001
DEER (energy efficiencyratio) = weight gain x 100/total ME intake &Means within each column and within each main effect with different superscripts are significantly different at 5% level.
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feed conversion, PER, and EER (Table 2). Weight gain and feed intake declined as temperature increased (Figure 1). At temperatures below 25.3"C, weight gainwasresponsive to increasing dietary CP until it reached a plateau at 22.4% CI?However, at housing temperatures between 26.7 to 32.2"C, diets containing more than 20% CP depressed weight gain in broilers. Feed conversion improved with increasing dietary CP at low temperatures (< 24.0"C) but at high temperatures ( > 28.1"C) the conversion was better with low protein (< 18%) diets (Figure 1).The maximum feed conversionwas obtained by broilers housed between 26.0 to 28.l0C, and fed a diet containing 20.0 to 20.8% dietary C€! The temperature and diet needed for maximum weight gain and feed conversion were very similar to those reported by Cheng et al. [3]. Hurwitz et al. [18] also reported that
JAPR CP, AMINO ACIDS, AND TEMPERATURE
22
8 2089 Xi
3
9
E 1535
d
Ern
.-
980
E 426
.oo
30.37
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r
.-C
25.74
Temperature (c)
X-
3
3 0.526 .-a C
0) v
35.00
I
30.37
I
25.74
Temperature (q
21.1 1
-IGURE 1, Response surface of weight gain, feed intake, and feed mnversion for broilers housed at differe :emperaturesand fed various protein levels
Research Report 23
CHENG et al.
14.87
12.65
10.44 \
24.00
-1GURE2. Response surface of protein efficiency ratio and energy efficiency ratio for broilers housedat differen emperatures and fed various protein levels
(> 20%) on EER was detectable at 22.5"C but the effect was more profound at temperatures greater than 28.1"C.The temperatures at which maximum feed conversion, PER, and EER occurred in the present study (26 to 28°C) were supportive of the findings of Hurwitz et al. [18]which found that the maintenance requirement for energy reached a minimum at 27°C and the requirement would
increase if temperature was either increased or decreased from 27°C. The data from Figures 1 and 2 clearly demonstrate that a high protein diet had a detrimental effect on broiler performance at constant temperaturesequal to or greater than 267°C. The research indicates that the practice of increasing dietary CP to increase the amino acid content for heat-stressed buds is
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17.08
24
caused a switch in their priority in metabolic fuel selection, thereby causing an increase in body fat. Geraert et al. [23] recently reported that broilers housed at 32°C from day 28 to day 42 had a significantly increased percent of abdominal fat because the broilers bad an increased insulin sensitivity, less "3 and T4, and increased plasma corticosteronelevels. The percent total body fat decreased as dietary CP (or CP:ME ratio) was increased at temperatures below 28.1"C (Figure 3). However, at temperatures above 28.l0C, the percent total body fat was minimum when birds were fed 19.2 to 20.0% CP diets. The data indicated that when temperatures were greater than 28.1"C the birds' percent total body fat would increase if dietary CP deviated from optimum CP levels. Bartov [24] reported that the percentage of body fat can be reduced for broilers fed diets containing an increased percentage of dietary protein or amino acids
TABLE 3. Effect of temperature and dietary CP on carcass compositionA,protein, and metabolizable energy utilization of broilers (Experiment 1 )
BCalculatedas percentage of total body protein to total (49 day) protein consumption. 'Calculated asgercentay of carcass energy to total (49 day) ME intake. Body fat and protein were assumed to contain 5.66 an 9.35 kca per dried gram tissue, respectively. 84 Means within each column and within each main effect with different superscripts are significantly different at 5% level.
I
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clearly not recommended. Several studies [6,7,8, 131 have also reported that growth of broilers housed in hot temperatures improved when the protein level in the diet was lowered. The total body composition as well as PU and EU were significantly (P < .001) affected by temperature, dietary CP, and their interaction (Bble 3). The percent total body fat increased as temperature increased from 21 to 35°C (Figure 3). The increase in percent body fat withincreasing environmentaltemperature is consistent with the results of Kubena et al. [9], Howlider and Rose [19], and Cheng et al. [3]. Since the percent total body fat was still increasing in conditions beyond B'C, where the energy requirement for maintenance has been shown to increase [MI, the increase in body fat could not be due to the decline in maintenance energy alone. The changes in various hormonal equilibria in heat-stressed domestic animals [ZO, 21, 221 might have
CP, AMINO ACIDS, A N D TEMPERATURE
Research Report CHENGetul.
25
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:IGURE 3. Response surface of percentage total body fat, total body protein, and fat-free protein dry matter Dr broilers housed at different temperatures and fed various protein levels
JAPR CP, AMINO ACIDS, A N D TEMPERATURE
26
but high dietary CP at high temperatures caused a detrimental effect. The percent fatfree protein (consisting primarily of body protein and ash) was similar for broilers between 21°C and 32°C; however, the percentage of fat-free protein dropped sharply for broilers housed in temperatures above 32°C. Cheng et al. [3] also reported a decrease in the percent fat-free protein and an increase in the percent ash in broilers housed in temperatures above 32°C. The constant percentage of fat-free protein found in broilers housed in temperatures of 21 to 32°C (Figure 3) is similar to the report of Hakansson et al. [28] which suggests the protein to ash ratio of growing birds remains constant during normal growth. The reduction of percent fat-free protein of the whole broiler at temperatures above 32°C indirectly shows the protein:ash ratio has changed (Figure 3). Protein deposition in the present study was therefore more severely impaired than bone mineralization at high temperatures (> 32.2"C). This severe reduction in protein deposition compared to bone mineralization of the heat stressed broilers may be related to areport by Beitz [29] that showed animal bone growth has priority over protein deposition. Figure 4 showed that maximum PU occurred between 26.7 to 29.4"C. The severe decrease in PU for broilers housed in temper-
49.51
42.87
-IGURE 4. Response surface of protein utilization for broilers housed at different temperatures and fed various ,rotein levels
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with the same dietary energy concentration, or fed diets containing the same percent protein with lower dietary energy. Bartov [24] did not report an interaction of diet and temperature as having an effect on percent carcass fat. Recently, Gous et al. [25] suggested that broilers would deposit fat above a minimum level only when faced with a nutrient deficiency. Since most current market broilers consistently have body fat above this minimum level, the researchers suggested that nutritional deficiencies were a widely occurring phenomenon. Amino acid imbalance, which is usually correctable by adding the second limiting amino acid, could be considered a special form of amino acid deficiency [%I. The increase in total body fat as dietary CP and amino acids depart from the optimum levels at high temperatures could therefore be explained in terms of protein as well as amino acid deficiency and imbalance. Although March and Beily [27j conducted research with 16-day-old White Leghorn cockerels instead of fast-growing broilers, the researchers reported that amino acid imbalances affecting feed conversions and weight gain were greatly aggravated at hot environmental temperatures. The percent dry matter body protein increased as dietary CP increased (Figure 3),
Research Report CHENGetal.
27 version for broilers occurs because the broilers fed 16% CP diets gain slightly more weight and have a higher feed conversion at 35°C compared to broilers fed the 18% diet. The broilers fed the 16% protein diet also had a higher feed conversion at 26.6"C. The maximum EER occurred at 26.6 and 29.4"C for the 16 and 18%CP diets, respectively (Figure 5). Broilers fed the 18% CP diet showed a deleterious effect on PER and EER at temperatures higher than 32.2"C. The interactions between amino acid level and temperature for weight gain, feed conver-
BODY WEIGHT TOTAL FEED TOTAL TOTAL GAIN FEED CONVERSION~PROTEIN ME INTAKE INTAKE INTAKE
WEIGHT
kcal
0.475'
549'
10680b
2.697b
14.86a
0.458'
643b
10530'
2.289'
14.48'
04743b
549'
lO68Ob
2.76?
14.35'
613a
10630b
2.471b
14Ma
10290'
2.240a
14.08'
16
21178
1529'
3242'
18
2121'
1535'
32478
90
2 1 f ~ 3 ~ 1550b
100 110
2134b
1550b
3272b
0.4689ab
2060'
1496'
316.5'
0.4581'
3287b
I
EER~
g
g
I
PER^
gain/100 kcal
'Feed conversion = weight gaidtotal feed intake
LPER@rotein efficiency ratio) = weight gain/totalprotein intake DEER (energy efficiency ratio) = weight gain x 100/total ME intake a 4
Means within each column and within each main effect with different superscripts are significantly different at 5% level.
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atures above 29°C and fed high protein diets has been previously reported by Cheng et al. [31. Weight gain, feed intake, energy intake, and EER in Experiment 2 were not affected by dietary protein (Table 4). However, the effect of temperature, amino acid level, temperature x dietary protein, and temperature x amino acid level were significant. The interactions between dietary CP and temperature for weight gain and feed conversion are shown in Figure 5. The interaction of temperature x dietary protein for weight gain and feed con-
JAPR CP, AMINO ACIDS, AND TEMPERATURE
28 0 Gain +Gain 6 FC 16%CP 18%CP 16%CP
* FC
3000 j
I O 55
,
01 I 1 I 1025 182 2 1 0 238 266 294 322 350 37.8
50
+ Fat 18%CP
+PER 18%CP
aEER 16%CP
+ Protein
16%CP
18%CP
I
40, 182
I
, 21 0
, 23.8
266
294
322
350
65
I35 378
k
Temperature ("C)
Temperature ("C)
+PER 16%CP
+ Protein
+EER 18%CP
j
Q P U 16%CP
+PU 18%CP
+EU 16%CP
*EU 18%CP
75
50
C
m
$--;
n 18 2
21 0
238
266
294
322
350
Temperature ("C)
182
21 0
238
266
294
322
350
378
Temperature ("C)
flGURE 5. The effect of dietary CP (16 and 18%)and environmental temperature on broiler weight gain, feed conversion, protein efficiency ratio, energy efficiency ratio, percent total body fat, total body protein, protein utilization,and energy utilization
sion, PER, and EER are shown in Figures 6 and 7. The research shows that broiler performance declines with increasinglevels of amino acid supplementation, similar to the reduction in performance for broilersfed higher levels of dietary CP in Experiment 1. The dietary CP xamino acid interactionfor EER is caused by an increased energy retention in broilers fed the 16% CP diets compared to the 18% diets at 26.6"C.Broilers fed the 100 and 110% NRC amino acid diets at this temperature were more efficient in energy retention than broilers fed the 90% NRC amino acid diets. The 18% CP diets or protein diets supplemented with 100 and 110% NRC amino acid levels increased the EER for broilers housed at 29.4"C. In Experiment 2, the temperature that produced m d u m feed conversion (26.6"C) and the decreasingweight gainwithincreasing temperature were consistent with the results of Experiment 1. Supplementation of the essential amino acids to the low CP diets used in Experiment 2 should have minimized the excess nitrogen in the diets, lowering the po-
tential heat production from digestion and metabolism of the nitrogen. The lack of a weight gain response in Experiment 2 for heatstressed broilers fed the 16 and 18% protein diets supplemented with synthetic amino acids to provide 100% NRC amino acid levels differs from the positive response reported by Waldroup et al. [6] and Harris et al. [12]. Waldroup et al. [6] conducted four broiler trials during different times of the year and utilized diets containing different levels of excess amino acid nitrogen and energy. The research indicated broilers could be fed diets with minimum essential amino acids without regard to CP levels. The researchers suggested that the minimum dietary protein levels created an advantage for broilers reared in heatstressed conditionsand significantlyimproved efficiency of protein and calorie utilization. The dietary energy levels used by these researchers varied with each trial; however, the energy levels utilized for the heat stress broiler trial were 3080 kcal MEkg in the starter diet and 3190 kcal MEkg in the finisher diet. The optimum heat stress diet utilized during the
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,
4 Fat 16%CP
18%CP
Research Report 29
CHENG et al. 4 9O%NRC
h
100%NRC
+ llO%NRC
1800 -
m
.s
v
1400 -
c1
E m
.-
600-
I
200 18.2
5 4
21.0
I
I
23.8
26.6
I
29.4
I
I
32.2
35.0 37.8
Temperature ("C)
+- 9O%NRC
0.30 1 18.2
, 21.0
-0- 100YoNAC
,
1
23.8
+ IlO%NRC
I
I
26.6 29.4
32.2
I
I
35.0 37.8
Temperature ("C) 4 9O%NRC
-ct 100%NRC
+ 11OYNRC I
51 .OO1
lTJ 43.5
2
ot
41 .O1 I 018.2 21.0
1
I
23.8 26.6
I
29.4
I
32.2
1
I
35.0 37.8
Temperature ("C)
FIGURE 6. The effect of amino acid supplementation at 90, 100, and 110% NRCrecommended levels on weight gain, feed conversion, and percent total body fat for broilers housed at various temperatures
finishing period of 4 8 wk contained 18% protein with 1.0% lysine and 0.77% TSAA (100% NRC amino acid levels). The dietary levels of amino acids, CP, and g amino acid/kcal ME were comparable to levels utilized in Experiment 2. Waldroup et al. [6] indicated the second best performance of heat-stressed broilers was for broilers fed 110% minimum amino acid levels provided by
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2
1000-
increasing the dietary CP levels (20.5% CP frnisher diets compared to 18%). This good performance contradicts the performance of broilers housed in temperatures above 32"C, as shown in Figure 6. McNaughton and Reece [30] reported a maximum statistical body weight response of heat-stressed male broilers reared at 267°C when feeding a higher dietary lysine level (0.322% 1ysineMcal ME compared to a 0.308% lysine/Mcal ME) using 3250 kcal ME diets. The broilers reared at 26.7"C in Experiments 1 and 2 had significantly lower body weights than broilers at 21.0 and 23.8"C; however, the broilers reared at 267°C had the highest feed conversion for all groups. The problem with comparing optimum protein or amino acid levels for heatstressed broilers from different laboratories is the inability to correlate optimum energy, protein, and amino acid levels across a series of controlled increasing environmental temperatures. The effect of temperature and diet on body composition, PU, and EU in Experiment 2 is given in Table 5. The interactions between temperature and dietary CP as well as amino acid level were significant (P c .001) for all responses except fat-free body protein (P>.70). Figure 5 shows that with increasing temperatures, total body fat increased but total body protein decreased. This was also consistent with the data discussed in Experiment 1. The advantage of feeding higher dietary CP (Figure 5 ) and higher levels of added synthetic amino acids (110% NRC, Figure 6) to diets to decrease body fat was not seen in broilers housed at temperatures above 29.4"C. Similar trends were also seen for PU and EU (Figures 5 and 7). This again illustrates the extra sensitivity of heat-stressed broilers to dietary amino acid levels [3,6]. In Experiment 2, the weight gains of broilers housed at temperatures from 25.3 to 32.2 decreased, but the weight gain response to the 16 or 18% CP diets or amino acid levels was similar (Figures 5 and 6). In Experiment 1,the same range of hot temperatures showed that the 20.8% CP diet produced maximum weight gains (Figure 1). The lack of a weight gain response for broilers housed in hot temperatures and fed low protein diets with added amino acids may be caused by other limiting amino acids than methionine, TSAA, arginine, lysine, tryptophan, and threonine. These data
CP, AMINO ACIDS, AND TEMPERATURE
30 + 90%NRC
+ 9O%NRC
+ IIO%NRC
0 100%NRC
4
* 11O%NRC
IOOXNRC
&
; I
I
I
210
238
7
I
266
294
322
350
378
7
182
210
238
@32
* llO%NRC
0 100%NRC
I
I
I
21.0
238
266
322
+ 9O%NRC
I
1
294
294
322
350
3 8
Temperature ("C)
Temperature ("C)
+ 9O%NRC
266
350
378
Temperature ('C)
21
1082
0 100%NRC
I
1
21 0
238
4
lIO%NRC
I
266
294
322
350
3 3
Temperature ("C)
FIGURE7. The effect of amino acid supplementation at 90,100, and 110% NRCrecommended levels on energy efficiency ratio, energy utilization, protein efficiencyratio, and protein utilization for broilers housed at various temperatures
indicate that the lower CP levels with added synthetic amino acids in Experiment 2 were not providing the same nutrients as in the 20% CP diets of Experiment 1. Recently, Fancher and Jensen [31, 321 reported that optimum growth and feed efficiency could not be attained when broilers were fed low CP diets (e18%) supplemented with several essential amino acids. Mortality was low (e0.8%) and was not significantly different among treatment groups. Also, some of the mortality was not related to treatment effect (e.g. legs trapped in the floor wire of the cage). Since dietary formulation changes have been shown to provide a limited success in improvingweight gain at temperaturesgreater than 29.4"C, dietary manipulation may be better utilized for improving carcass composition and efficiency of nutrient utilization. Feeding heat-stressed birds a high ME diet slightly deficient in lysine to stimulate feed intake as
suggested by Sinurat and Balnave [lo] has been reported by Boorman [27] to be a technique that does not usually improve weight gain and/or feed conversion. Balnave and Oliva 1331 have also reported that although general amino acid digestibility is decreased at 30°C compared to 21"C, the broiler requirement for methionine expressed as g methioninern ME is decreased in hot temperatures [MI. The researchers observed that lower levels of abdominal fat and improved feed conversions resulted when broilers were housed at hot temperatures and fed the higher methionine levels determined to be optimum for weight gain for broilers reared at 21°C [%I. Cheng et al. [3] showed that broilers reared in temperaturesabove 29.4"Chad the lowest carcass fat content when fed diets containing approximately 100% NRC amino acid levels. Austic [35l has also reported that a marginal deficiency in.methioninewill increase fat deposition of broilers.
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182
Research Report 31
CHENG et al.
BODYDRY
MATIER
TOTAL BODYFAT
%
TOTAL BODY PROTEIN
% DM
FAT-FREE
BODY
ENERGY
PROTEIN
UTILIZATION^ UTILIZATIONC
PROTEIN %
%
36.7"
465'
45.4de
84.9d
41.13'
37Mb
37.3'
45.4'
45.9e
84.1"
45.88=
39.12"
26.6
36.8'
46.9bc
45.1'
84.9d
43ad
40.30'
29.4
36.8'
48.8'
43.9c
85.Sd
43.17d
41.71'
32.2
36.8'
485'
42.F
3753b
35.79
35.0
358
479
39.4'
83.Sb 75.1'
31.64'
34.49'
IDIETARY CP. %
I
=Means within each column and within each main effect with different superscripts are significantlydifferent at 5% level.
CONCLUSIONS ANDAPPLICATIONS 1. Heat-stressed broilers from 3 to 6 wk of age are highly sensitive to dietary CP and amino acid levels and should not be fed a diet greater than 20% CP (100% NRC amino acid levels) with a 3250 kcal ME diet. 2. Supplementing 16 and 18% CP diets with methionine, lysine, threonine, tryptophan, and arginine to provide a minimum of 100% and 110%NRC levels did not improve weight gain of heat-stressed broilers compared to providing only a 90% NRC level. 3. Increasing dietary CP levels above 20% or supplementing 16 and 18% CP diets with methionine, lysine, threonine, tryptophan, and arginine to provide 100% NRC amino acid levels in a corn-soy diet produced deleterious effects on feed conversion and body fat deposition at temperatures above 29.4"C. 4. There appears to be no advantage in attempting to overcome the effects of heat stress through increased protein or amino acid levels. Such practices with broilers from 3 to 6 wk of age might lead to even more deleterious results.
=-
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21.1 23.9
JAPR CP, AMINO ACIDS, AND TEMPERATURE
32 ~~~~~~
~
REFERENCES AND NOTES 1. Cemigua, G.L, J.A. Herbert, and AB. Watts, 1983. The effect of constant ambient temperature and ration on the performance of sexed broilers. Poultry S i . 62746-
7%. 2. Reece, F.N. and B.D. Ldt, 1983. The effect of temperature and age on body wei t and feed efficiency of broilers. Poultry Sci. 621906-1 .
&
3. Cheng, T.K., M.L Hamrt, and CN. Coon, 19%.
4.Combs, J.F., 1970.Feed ingredientcomposition and amino acid standards for broilers. Pages 81-89 in: Proc. Maryland Nutr. Conf., College Park, MD. 5. Thomas,O.P., M. Farran, and CB. Tamplin, 1992. Broiler nutrition update. Pa es45-53 in: Proc. Maryland Nutr. Conf., College Park, d D .
6. Waldroup, P.W., RJ.Mitchell, J.R Payue, and KR Hazen, 1976.Performance of chicks fed diets formulated to minimize excess levels of essential amino acids. Poultry sci. 55:243-253.
7.McNaughton, J.L, LF. Kubena, J.W. Dcaton, and F.N. R N ~ ,1978.Influence of dietay rotein and energy on the performance of commerciaf egg-type ullets reared under summer conditions. Poultry Sa.5~?13911398. 8. Dale,N.M. and H.L F&r, 1979. Effect of diet composition on feed intake and growth of chicks under heat stress. I. Dietary fat levels. Poultry Sci. 591434-1441. 9.Kubena, LF., J.W. Dealon, F.N. Reeee, J.D. May, and T.H.VardPman, 1972.The influence of temperature and sex on the amino acid requirement of the broiler. Poultry Sci. 51:1391-1396. 10. Cowan, PJ. and W. Mitchie, 1978.Environmental temperature and broiler performance: The use of diets containing increased amount of protein. Br. Poultry Sci.
19601605. 11. Sinurat, A.P. and D. Balnave, 1985. Effect of dietary amino acids and metabolible energy on the rformance of broilers kept at high temperatures. Br. oultry Sci. 26A17-128.
g.
12.Harris, G. C,Jr., P.W. WpMroup, RL S a y , and G.S. Nelsoa 1974.The influence of humiditv. enerw. and amino acid status on the performanceof bkiiers. l%ultry Sci. 531933 (Abs). 13. Fuller, H.L and G. Mora, 1973. Effect of diet com sition on heat increment, feed intake, and of c g k s subjected to heat stress. Poultry Sci. (Abs). 14. Smith, M.O.and RG. Teeter,1987.Influence of feed intake and ambient temperature stress on the relative yield of broiler parts. Nutr. Rep. Intl. 35299-306. 15. Cheng, T. K,1991.Selfelection of diets varyin in protein content by broilers under heat stress. Cha ter in: Ph.D. Dissertation, University of Minnesota, St.$aul,
f
MN. 16. National Research Counc4 1994. Nutrient Reuirements of Poult 9th Rev. Edition. Natl. Acad. #res, Washington, D Z
.
17.The data were analyzed as a lit-plot design with h z the sub-plot contemperature as the whole plot w
%
18. FIUnvikq S., M. Welselbcrg, U. Eisner, I. Bartov, G. Rlesenfeld, M. Sharvit, A Nhr, and S. Bornstein, 1980. The energy requirements and performance of growing chickens and turkeys as affected environmental temperature. Poultry Sci. 5922XL222 19.HonUder, M A R and S.P. Rose,1987.Temperature and h for broilers. World's Poultry Sci. J. 43228-23r 20. Himms-Hagen, J., 1967.Sympathetic regulation of metabolism. Pharmac. Rev. 19367-461.
21. Mobcrg, G.P., 1976. Effects of environment and management stress on reproduction in dairy cows. J. Dairy Sci. 591618-1624. 22.De Andrade, AN.,J.C. Rogler, W.R Featherston, and C.W. Wston, 1977.Interrelationships between diet and elevated tem ratures ( clical and constant) on egg production and sgll qualily%oultry Sci. 561178-1188. 23. Ge~ncrt,PA,J.C. F. PadIJha, € Ain I.BazLz, and S.CulUaumln, 1994. Heat-induced changes in energy metabolism in broilers. Pages 375-378 in: Proc. 13th Symium of Energy Metabolism of Farm Animals, EAAP ub. No. 76,Mojacar, Spain.
$"
24.Bartov, I., 1979.Nutritional factors affecting uantity and quality of carcass fat in chickens. Fed. %roc. 3832627-2630. 25. Cons, RM., G.C. Emmans, LA Broadbent, and C. Fisher, 1990. Nutritional effects on the wth and fatness of broilers. Br. Poultry Sci. 31:495-50r 26. Boorman, KN., 1979.Regulation of protein and amino acid intake. Pa es 87 126 in: Food Intake Regulation in Poultry. K.N. %oox&an and B.M. Freeman, eds. Br. Poultry Sci. Ltd., Edinburgh, U K 27.Marc4 BE and J. Blely, 1972.The effect of energy supplied from the diet and from environmental heat on the response of chicks to different levels of dietary lysine. Poultry Sci. 51665-668. 28. H.kaasson, J., S. Erikson, and S. Skensson, 1978. Reports 57 and 59,Dept. of Anim. Husbandry, Swedish University of Agricultural Science, Uppsala, Sweden.
29.Bel& D.C, 1985.Physiological and metabolic syst e m im rtant to animal growth: An overview. J. h i m . Sci. 61(r uppl. 2):1-20. 30. McNaughbn, J.L and F.N. Retce, 1984.Response of broiler chickens to dietaryener and lysine levels in a warm environment. Poultry Sci. 68170-1174.
31.Fancher, B.I. and LS. Jensen, 1989a.Influence of varying dietary protein content while satisfying essential amino acid requirements upon broiler rformance from three to six week of age. Poultry Sci. gl13-123.
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Effect of environmental temperature, dietary protein, and ener levels on broiler performance. J. Appl.Poultry Res. 61--7.
sisted of the five dietary CP levels in Experiment 1, and the two(dietary CP) x three (amino acid supplementation levels) factorial arrangement in nment 2 using a Statistix software pro m Statistx, Analytical SoftWBIC, Minneapolis, $55614). ANOVA P-values were given for all main effects and interactions.Multiple mean comparisonsweredone by the method of least significant difference with significance set at 5% level. Regression models were checked b the residual plots and the Mallows' Cpvalues [36].d e three dimensional graphs of smoothed response surface (SRS)using temperature and dietary CP as the two horizontal axes were done by the smoothing technique of SAWGRAPH [37J.
Research Report CHENGetal.
33 35.Austic, RE,1985.Amino acid interrelationships rformance. Pages 158-168 in: Proc. Mary-
32. Fancher, B.I. and LS.Jeosmn, 198%. Dietary protein level and essential amino acid content: Influence upon female broiler rformance during grmvingperiod. Poultry Sci. 68:897-&.
Ed%::t?&f.,
33. B a h v e , D. and AG. olive, 1991.The influence of sodium bicarbonate and sulfur amino acids on the performance of broilers at moderate and high temperatures. Aust. J. Agric. Res. 421385-1397.
37.SAS Institute, 1985.SAS User’s Guide. 1985 mition.SAS Institute, Inc., Raleigh, NC.
A.
36. Weisberg, S., 1985. A plied Linear Re ession. 2nd Edition. John Wiley and %ns, New York,
ACKNOWLEDGEMENT This research was partiallysu ported b research gifts from Heartland Lysine, Inc., 8hicago, I)t and Gold’n Plump, Inc., St. Cloud, MN.
Downloaded from http://japr.oxfordjournals.org/ at H.E.C. Bibliotheque Myriam & J. Robert Ouimet on June 8, 2015
34. Balnavc, D. and A Oliva, 1990. R e m n s e s of finishing broilers at h i p temperatures to d i e t 6 methionine source and supp ementation levels. Aust. J. Agric. Res. 41557-564.
College Park, MD.
m S P O N S E S OF BROILERS TO DIETARY PROTEIN LEVELS AND AMINO ACID
THIM K. CHENG, MELVIN L. HAMRE, and CRAIG N. COON2 Depament of Animal Science, University of Minnesota, St. Paul, MN 55108 Phone: (612)624-6263 F M : (612)625-5789 ~~
~
~
Primary Audience: Nutritionists, Broiler Producers, Researchers
tal effect on weight gain and carcass composiDESCRIPTION OF PROBLEMtion as well as efficiency of feed, protein, and High ambient temperatures have been shown to reduce broiler feed consumption and growth rate [l,21. Research showing the effect of feeding increased dietary protein mncentrations or aminoacid levels to broilers housed in hot temperatures to compensate for the reduced feed intake has been limited. Cheng et al. [3]recently reported that feeding high CP diets to heat-stressed broilers had a detrimen-
energy utilization. The researchers suggested that broilers housed in hot environmentalconditions should not be fed increased concentrations of protein to provide the additional dietary amino acids suggested by Combs [4] and the updated Maryland amino acid requirements [5]. Previous studies have been divided some show a reduced protein requirement for chicks housed in hot temperatures
1 Published as Paper Number 971165802, the ScientificJournal Series, Minnesota Agricultural 2
Experiment Station. To whom correspondence should be addressed
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SUPPLEMENTATION TO Low PROTEIN DIETSAT VARlrOUS ENVIRONMENTAL TEMPERATURES'
Research Report CHENG et al.
treatment consisted of four replicates. Each pen weight of six broilers was adjusted to within 1SD of mean pen weights for all rooms. Experiment 1 investigated the effect of dietary CP and temperature on broiler performance. The design was identical to that of Chengetal. [3] except that only the high energy diet (3250 kcal ME/kg) was used. Diets were formulated in such a way that the five essential amino acid levels (Met, Lys, Arg, Thr, Trp) and TSAA would meet or exceed the 80,90, 100, 110, and 120% levels recommended by the NRC [16] for the 16, 18, 20, 22, and 24% CP diets, respectively (Table 1). Experiment 2 investigated the impact of amino acid supplementation of low protein diets (16 and 18%) to provide 90, 100, and 110% of NRC-recommended amino acid requirements on broiler performance at various temperatures. Synthetic amino acids were added to the 16 and 18% CP diets (Table 1) at two levels, so that the five essential amino acids equaled or exceeded the 100 and 110% levels specified by the NRC [16]. The 16% CP diet was also supplemented at the 90% level. Since the amino acids in the 18% CP diet used in Experiment 1 were already at the 90% levels, the data collected from this group were also used in Experiment 2. All treatments were randomized in the same block for both experiments. AU diets were pelleted and fed to the broilers on an ad libitum basis. The diets were analyzed for moisture, crude protein, and amino acids [3]. Feed intake and body weight were recorded weekly, and mortality was recorded daily. Feed intake values were adjusted for the mortality to the nearest day. Both experiments ended when the birds were 7 wk of age. ' h obuds from each replicate were fasted overnight and killed by C02 asphyxiation. Totalbody protein and fat were determined on feather-free uneviscerated carcasses to determine the protein efficiency ratio (PER), protein utilization (PU), energy efficiency ratio (EER), and energy utilization (EU) as described by Cheng et al. [3]. AU data were subjected to statistical analysis [lq.
MATERIALS AND METHODS A total of 1440 male Arbor Acre x Ross chicks were used in the present study. The nutrition and management procedures used tcr rear the birds from 1to 21 days have been described by Cheng et ul. [3]. The experiment began with birds at 21 days of age. Birds were evenly divided into six environmental rooms with temperatures set at 21.1, 23.9, 26.6, 29.4, 32.2, and 350°C. The mean relative humidity during the grower trial was 52%. There were 40 cages (76 x 66 cm) in each room and buds were housed at a density of six birds per cage. Half of the birds in each room were used in Experiment 1 and the other half in Experiment 2. In both experiments, each cage of six birds constituted a replicate and each
RESULTS AND DISCUSSION In Experiment 1, the effect of temperature and dietary CP, as well as the interaction between them were highly significant (P< .001) for weight gain, total feed intake,
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[6, 7, 81, and others are unable to find any interaction between dietary CP and temperature [9, 10, 111. Sinurat and Balnave [ll]reported no significant interaction for dietary CP and broiler performance in hot temperatures; however, they reported that heatstressed broilers obtained maximum growth by eating a hqh ME diet with a slight deficiency in lysine or a lower 1ysine:ME ratio. Harris et al. [12] reported that weight gain reduced maximum levels in heat-stressed birds (29°C) with a concentrated diet of 3410 kcaVkg ME and 110% of NRC-suggested amino acid levels. The data of Fuller and Mora [13] and Dale and M e r [8] also support the view that heat-stressed buds respond to increasing amino acid consumption. Teeter and Smith [14] also showed that broilers housed at 30°C and force-fed additional diet above ad libitum intake had increased weight gain. The research does not indicate whether the force-fed broilers responded to the additional dietary energy, amino acids, or both. Since heat-stressed broilers have been shown to select lower CP diets in choice feeding studies [15], it may be useful to feed heat-stressed birds low CP diets supplemented with higher levels of essential amino acids. This study seeks to determine the optimum dietary protein and amino acid levels for broilers housed in various environmental temperatures. The research was conducted with enough different controlled environmental temperatures, dietary protein, and amino acid levels to correlate specific diet and temperature relationships.
19
JAPR CP,AMINO ACIDS, AND TEMPERATURE
20
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*Diets 1,2,3,4,and 5 contained ~,90,100,110, and 120% NRGrecommended amino acid levels (methionine, lysin arginine, tryptophan, and threonine), respectively. %Tee new 16% CP diets were mixed b supplementing the five amino acids to Diet 1to attain 90,100, and 110 NRC levels, ctively. Two new 18% diets were mixed by supplementing the fne amino acids to Diet 2 to atta 100and llOY%C levels, respectively. These five new diets had a total slightly exceeding 100%.
&'
S u lied the following r kg of diet: vitamin A, 6,600 IU; vitamin D3,1,650 IUvitamin E, 3.3 IU; menadione sodiu 1 'bisugte, 4.9 mg; niacin,% mg; riboflavin, 6.6 m& folacin, 0.2 mg; pantothenic acid, 11mg; vitamin B12,O.Ol mg. DSupplied the following in mgkg of diet: Mn,100; Fe, 275; Zn,625; Cu, 3.3; I, 1.2.
Research Report 21
CHENG et al.
BODY WEIGHT GAIN
WEIGHT
g
feed conversion increased with temperatures up to 27 to 28"C, followed by a decrease as temperature was raised further. The maximum feed conversion reported by Hurwitz etal. [18] was in broilers fed a 19.4% CP diet, which is consistent with the maximum feed conversions reported herein with broilers fed lower CP (20%) diets. The maximum feed conversion would be at a lower temperature if the dietary CP was higher (Figure 1). Figure 2 reveals a deleterious effect of feeding high dietary protein and amino acids at high temperatures (26.7T) observed for the determination of PER. Maximum PER occurred at 28.1"C and the PER remained high for birds fed low CP diets (< 18.4%) at temperatures above 28.1"C. The maximum EER was located between 26.7 to 28.1"C and between 20 to 20.8% dietary CP (Figure 2). The deleterious effect of high CP diets
TOTAL
FEED TOTAL TOTAL CONVERSION~PROTEIN ME INTAKE INTAKE INTAKE g kcal
FEED
PER^
EER~
gain/100 kcal
16
2114b
lWb
3Wb
0.483b
566'
10280b
2.941'
14.86b
18
2150b
1561b
3248e
0.476b
Sab
10560'
2.SSOd
14.4gb
20
2140b
lSMb
3193be
0.47Sb
2.292'
14.39b
211P
UO?
3081'
0.469b
645' 682d
l0Wk
22
10010'
2.0Bb
14.4Sb
24
1942'
1330'
3022'
0.439'
me
9823'
1.m'
13.16'
Temperature (T)
40.001
<0.001
<0.001
4 0.001
40.001
40.001
<0.001
Dietary CP (CP)
rxCP
40.001
0.013
0.022
0.014
0.034
4 0.001
0.008
<0.011
<0.001
40.001
c 0.001
<0.001
<0.001
~0.001 40.001
0.017 40.001
DEER (energy efficiencyratio) = weight gain x 100/total ME intake &Means within each column and within each main effect with different superscripts are significantly different at 5% level.
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feed conversion, PER, and EER (Table 2). Weight gain and feed intake declined as temperature increased (Figure 1). At temperatures below 25.3"C, weight gainwasresponsive to increasing dietary CP until it reached a plateau at 22.4% CI?However, at housing temperatures between 26.7 to 32.2"C, diets containing more than 20% CP depressed weight gain in broilers. Feed conversion improved with increasing dietary CP at low temperatures (< 24.0"C) but at high temperatures ( > 28.1"C) the conversion was better with low protein (< 18%) diets (Figure 1).The maximum feed conversionwas obtained by broilers housed between 26.0 to 28.l0C, and fed a diet containing 20.0 to 20.8% dietary C€! The temperature and diet needed for maximum weight gain and feed conversion were very similar to those reported by Cheng et al. [3]. Hurwitz et al. [18] also reported that
JAPR CP, AMINO ACIDS, AND TEMPERATURE
22
8 2089 Xi
3
9
E 1535
d
Ern
.-
980
E 426
.oo
30.37
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r
.-C
25.74
Temperature (c)
X-
3
3 0.526 .-a C
0) v
35.00
I
30.37
I
25.74
Temperature (q
21.1 1
-IGURE 1, Response surface of weight gain, feed intake, and feed mnversion for broilers housed at differe :emperaturesand fed various protein levels
Research Report 23
CHENG et al.
14.87
12.65
10.44 \
24.00
-1GURE2. Response surface of protein efficiency ratio and energy efficiency ratio for broilers housedat differen emperatures and fed various protein levels
(> 20%) on EER was detectable at 22.5"C but the effect was more profound at temperatures greater than 28.1"C.The temperatures at which maximum feed conversion, PER, and EER occurred in the present study (26 to 28°C) were supportive of the findings of Hurwitz et al. [18]which found that the maintenance requirement for energy reached a minimum at 27°C and the requirement would
increase if temperature was either increased or decreased from 27°C. The data from Figures 1 and 2 clearly demonstrate that a high protein diet had a detrimental effect on broiler performance at constant temperaturesequal to or greater than 267°C. The research indicates that the practice of increasing dietary CP to increase the amino acid content for heat-stressed buds is
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17.08
24
caused a switch in their priority in metabolic fuel selection, thereby causing an increase in body fat. Geraert et al. [23] recently reported that broilers housed at 32°C from day 28 to day 42 had a significantly increased percent of abdominal fat because the broilers bad an increased insulin sensitivity, less "3 and T4, and increased plasma corticosteronelevels. The percent total body fat decreased as dietary CP (or CP:ME ratio) was increased at temperatures below 28.1"C (Figure 3). However, at temperatures above 28.l0C, the percent total body fat was minimum when birds were fed 19.2 to 20.0% CP diets. The data indicated that when temperatures were greater than 28.1"C the birds' percent total body fat would increase if dietary CP deviated from optimum CP levels. Bartov [24] reported that the percentage of body fat can be reduced for broilers fed diets containing an increased percentage of dietary protein or amino acids
TABLE 3. Effect of temperature and dietary CP on carcass compositionA,protein, and metabolizable energy utilization of broilers (Experiment 1 )
BCalculatedas percentage of total body protein to total (49 day) protein consumption. 'Calculated asgercentay of carcass energy to total (49 day) ME intake. Body fat and protein were assumed to contain 5.66 an 9.35 kca per dried gram tissue, respectively. 84 Means within each column and within each main effect with different superscripts are significantly different at 5% level.
I
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clearly not recommended. Several studies [6,7,8, 131 have also reported that growth of broilers housed in hot temperatures improved when the protein level in the diet was lowered. The total body composition as well as PU and EU were significantly (P < .001) affected by temperature, dietary CP, and their interaction (Bble 3). The percent total body fat increased as temperature increased from 21 to 35°C (Figure 3). The increase in percent body fat withincreasing environmentaltemperature is consistent with the results of Kubena et al. [9], Howlider and Rose [19], and Cheng et al. [3]. Since the percent total body fat was still increasing in conditions beyond B'C, where the energy requirement for maintenance has been shown to increase [MI, the increase in body fat could not be due to the decline in maintenance energy alone. The changes in various hormonal equilibria in heat-stressed domestic animals [ZO, 21, 221 might have
CP, AMINO ACIDS, A N D TEMPERATURE
Research Report CHENGetul.
25
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:IGURE 3. Response surface of percentage total body fat, total body protein, and fat-free protein dry matter Dr broilers housed at different temperatures and fed various protein levels
JAPR CP, AMINO ACIDS, A N D TEMPERATURE
26
but high dietary CP at high temperatures caused a detrimental effect. The percent fatfree protein (consisting primarily of body protein and ash) was similar for broilers between 21°C and 32°C; however, the percentage of fat-free protein dropped sharply for broilers housed in temperatures above 32°C. Cheng et al. [3] also reported a decrease in the percent fat-free protein and an increase in the percent ash in broilers housed in temperatures above 32°C. The constant percentage of fat-free protein found in broilers housed in temperatures of 21 to 32°C (Figure 3) is similar to the report of Hakansson et al. [28] which suggests the protein to ash ratio of growing birds remains constant during normal growth. The reduction of percent fat-free protein of the whole broiler at temperatures above 32°C indirectly shows the protein:ash ratio has changed (Figure 3). Protein deposition in the present study was therefore more severely impaired than bone mineralization at high temperatures (> 32.2"C). This severe reduction in protein deposition compared to bone mineralization of the heat stressed broilers may be related to areport by Beitz [29] that showed animal bone growth has priority over protein deposition. Figure 4 showed that maximum PU occurred between 26.7 to 29.4"C. The severe decrease in PU for broilers housed in temper-
49.51
42.87
-IGURE 4. Response surface of protein utilization for broilers housed at different temperatures and fed various ,rotein levels
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with the same dietary energy concentration, or fed diets containing the same percent protein with lower dietary energy. Bartov [24] did not report an interaction of diet and temperature as having an effect on percent carcass fat. Recently, Gous et al. [25] suggested that broilers would deposit fat above a minimum level only when faced with a nutrient deficiency. Since most current market broilers consistently have body fat above this minimum level, the researchers suggested that nutritional deficiencies were a widely occurring phenomenon. Amino acid imbalance, which is usually correctable by adding the second limiting amino acid, could be considered a special form of amino acid deficiency [%I. The increase in total body fat as dietary CP and amino acids depart from the optimum levels at high temperatures could therefore be explained in terms of protein as well as amino acid deficiency and imbalance. Although March and Beily [27j conducted research with 16-day-old White Leghorn cockerels instead of fast-growing broilers, the researchers reported that amino acid imbalances affecting feed conversions and weight gain were greatly aggravated at hot environmental temperatures. The percent dry matter body protein increased as dietary CP increased (Figure 3),
Research Report CHENGetal.
27 version for broilers occurs because the broilers fed 16% CP diets gain slightly more weight and have a higher feed conversion at 35°C compared to broilers fed the 18% diet. The broilers fed the 16% protein diet also had a higher feed conversion at 26.6"C. The maximum EER occurred at 26.6 and 29.4"C for the 16 and 18%CP diets, respectively (Figure 5). Broilers fed the 18% CP diet showed a deleterious effect on PER and EER at temperatures higher than 32.2"C. The interactions between amino acid level and temperature for weight gain, feed conver-
BODY WEIGHT TOTAL FEED TOTAL TOTAL GAIN FEED CONVERSION~PROTEIN ME INTAKE INTAKE INTAKE
WEIGHT
kcal
0.475'
549'
10680b
2.697b
14.86a
0.458'
643b
10530'
2.289'
14.48'
04743b
549'
lO68Ob
2.76?
14.35'
613a
10630b
2.471b
14Ma
10290'
2.240a
14.08'
16
21178
1529'
3242'
18
2121'
1535'
32478
90
2 1 f ~ 3 ~ 1550b
100 110
2134b
1550b
3272b
0.4689ab
2060'
1496'
316.5'
0.4581'
3287b
I
EER~
g
g
I
PER^
gain/100 kcal
'Feed conversion = weight gaidtotal feed intake
LPER@rotein efficiency ratio) = weight gain/totalprotein intake DEER (energy efficiency ratio) = weight gain x 100/total ME intake a 4
Means within each column and within each main effect with different superscripts are significantly different at 5% level.
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atures above 29°C and fed high protein diets has been previously reported by Cheng et al. [31. Weight gain, feed intake, energy intake, and EER in Experiment 2 were not affected by dietary protein (Table 4). However, the effect of temperature, amino acid level, temperature x dietary protein, and temperature x amino acid level were significant. The interactions between dietary CP and temperature for weight gain and feed conversion are shown in Figure 5. The interaction of temperature x dietary protein for weight gain and feed con-
JAPR CP, AMINO ACIDS, AND TEMPERATURE
28 0 Gain +Gain 6 FC 16%CP 18%CP 16%CP
* FC
3000 j
I O 55
,
01 I 1 I 1025 182 2 1 0 238 266 294 322 350 37.8
50
+ Fat 18%CP
+PER 18%CP
aEER 16%CP
+ Protein
16%CP
18%CP
I
40, 182
I
, 21 0
, 23.8
266
294
322
350
65
I35 378
k
Temperature ("C)
Temperature ("C)
+PER 16%CP
+ Protein
+EER 18%CP
j
Q P U 16%CP
+PU 18%CP
+EU 16%CP
*EU 18%CP
75
50
C
m
$--;
n 18 2
21 0
238
266
294
322
350
Temperature ("C)
182
21 0
238
266
294
322
350
378
Temperature ("C)
flGURE 5. The effect of dietary CP (16 and 18%)and environmental temperature on broiler weight gain, feed conversion, protein efficiency ratio, energy efficiency ratio, percent total body fat, total body protein, protein utilization,and energy utilization
sion, PER, and EER are shown in Figures 6 and 7. The research shows that broiler performance declines with increasinglevels of amino acid supplementation, similar to the reduction in performance for broilersfed higher levels of dietary CP in Experiment 1. The dietary CP xamino acid interactionfor EER is caused by an increased energy retention in broilers fed the 16% CP diets compared to the 18% diets at 26.6"C.Broilers fed the 100 and 110% NRC amino acid diets at this temperature were more efficient in energy retention than broilers fed the 90% NRC amino acid diets. The 18% CP diets or protein diets supplemented with 100 and 110% NRC amino acid levels increased the EER for broilers housed at 29.4"C. In Experiment 2, the temperature that produced m d u m feed conversion (26.6"C) and the decreasingweight gainwithincreasing temperature were consistent with the results of Experiment 1. Supplementation of the essential amino acids to the low CP diets used in Experiment 2 should have minimized the excess nitrogen in the diets, lowering the po-
tential heat production from digestion and metabolism of the nitrogen. The lack of a weight gain response in Experiment 2 for heatstressed broilers fed the 16 and 18% protein diets supplemented with synthetic amino acids to provide 100% NRC amino acid levels differs from the positive response reported by Waldroup et al. [6] and Harris et al. [12]. Waldroup et al. [6] conducted four broiler trials during different times of the year and utilized diets containing different levels of excess amino acid nitrogen and energy. The research indicated broilers could be fed diets with minimum essential amino acids without regard to CP levels. The researchers suggested that the minimum dietary protein levels created an advantage for broilers reared in heatstressed conditionsand significantlyimproved efficiency of protein and calorie utilization. The dietary energy levels used by these researchers varied with each trial; however, the energy levels utilized for the heat stress broiler trial were 3080 kcal MEkg in the starter diet and 3190 kcal MEkg in the finisher diet. The optimum heat stress diet utilized during the
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,
4 Fat 16%CP
18%CP
Research Report 29
CHENG et al. 4 9O%NRC
h
100%NRC
+ llO%NRC
1800 -
m
.s
v
1400 -
c1
E m
.-
600-
I
200 18.2
5 4
21.0
I
I
23.8
26.6
I
29.4
I
I
32.2
35.0 37.8
Temperature ("C)
+- 9O%NRC
0.30 1 18.2
, 21.0
-0- 100YoNAC
,
1
23.8
+ IlO%NRC
I
I
26.6 29.4
32.2
I
I
35.0 37.8
Temperature ("C) 4 9O%NRC
-ct 100%NRC
+ 11OYNRC I
51 .OO1
lTJ 43.5
2
ot
41 .O1 I 018.2 21.0
1
I
23.8 26.6
I
29.4
I
32.2
1
I
35.0 37.8
Temperature ("C)
FIGURE 6. The effect of amino acid supplementation at 90, 100, and 110% NRCrecommended levels on weight gain, feed conversion, and percent total body fat for broilers housed at various temperatures
finishing period of 4 8 wk contained 18% protein with 1.0% lysine and 0.77% TSAA (100% NRC amino acid levels). The dietary levels of amino acids, CP, and g amino acid/kcal ME were comparable to levels utilized in Experiment 2. Waldroup et al. [6] indicated the second best performance of heat-stressed broilers was for broilers fed 110% minimum amino acid levels provided by
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2
1000-
increasing the dietary CP levels (20.5% CP frnisher diets compared to 18%). This good performance contradicts the performance of broilers housed in temperatures above 32"C, as shown in Figure 6. McNaughton and Reece [30] reported a maximum statistical body weight response of heat-stressed male broilers reared at 267°C when feeding a higher dietary lysine level (0.322% 1ysineMcal ME compared to a 0.308% lysine/Mcal ME) using 3250 kcal ME diets. The broilers reared at 26.7"C in Experiments 1 and 2 had significantly lower body weights than broilers at 21.0 and 23.8"C; however, the broilers reared at 267°C had the highest feed conversion for all groups. The problem with comparing optimum protein or amino acid levels for heatstressed broilers from different laboratories is the inability to correlate optimum energy, protein, and amino acid levels across a series of controlled increasing environmental temperatures. The effect of temperature and diet on body composition, PU, and EU in Experiment 2 is given in Table 5. The interactions between temperature and dietary CP as well as amino acid level were significant (P c .001) for all responses except fat-free body protein (P>.70). Figure 5 shows that with increasing temperatures, total body fat increased but total body protein decreased. This was also consistent with the data discussed in Experiment 1. The advantage of feeding higher dietary CP (Figure 5 ) and higher levels of added synthetic amino acids (110% NRC, Figure 6) to diets to decrease body fat was not seen in broilers housed at temperatures above 29.4"C. Similar trends were also seen for PU and EU (Figures 5 and 7). This again illustrates the extra sensitivity of heat-stressed broilers to dietary amino acid levels [3,6]. In Experiment 2, the weight gains of broilers housed at temperatures from 25.3 to 32.2 decreased, but the weight gain response to the 16 or 18% CP diets or amino acid levels was similar (Figures 5 and 6). In Experiment 1,the same range of hot temperatures showed that the 20.8% CP diet produced maximum weight gains (Figure 1). The lack of a weight gain response for broilers housed in hot temperatures and fed low protein diets with added amino acids may be caused by other limiting amino acids than methionine, TSAA, arginine, lysine, tryptophan, and threonine. These data
CP, AMINO ACIDS, AND TEMPERATURE
30 + 90%NRC
+ 9O%NRC
+ IIO%NRC
0 100%NRC
4
* 11O%NRC
IOOXNRC
&
; I
I
I
210
238
7
I
266
294
322
350
378
7
182
210
238
@32
* llO%NRC
0 100%NRC
I
I
I
21.0
238
266
322
+ 9O%NRC
I
1
294
294
322
350
3 8
Temperature ("C)
Temperature ("C)
+ 9O%NRC
266
350
378
Temperature ('C)
21
1082
0 100%NRC
I
1
21 0
238
4
lIO%NRC
I
266
294
322
350
3 3
Temperature ("C)
FIGURE7. The effect of amino acid supplementation at 90,100, and 110% NRCrecommended levels on energy efficiency ratio, energy utilization, protein efficiencyratio, and protein utilization for broilers housed at various temperatures
indicate that the lower CP levels with added synthetic amino acids in Experiment 2 were not providing the same nutrients as in the 20% CP diets of Experiment 1. Recently, Fancher and Jensen [31, 321 reported that optimum growth and feed efficiency could not be attained when broilers were fed low CP diets (e18%) supplemented with several essential amino acids. Mortality was low (e0.8%) and was not significantly different among treatment groups. Also, some of the mortality was not related to treatment effect (e.g. legs trapped in the floor wire of the cage). Since dietary formulation changes have been shown to provide a limited success in improvingweight gain at temperaturesgreater than 29.4"C, dietary manipulation may be better utilized for improving carcass composition and efficiency of nutrient utilization. Feeding heat-stressed birds a high ME diet slightly deficient in lysine to stimulate feed intake as
suggested by Sinurat and Balnave [lo] has been reported by Boorman [27] to be a technique that does not usually improve weight gain and/or feed conversion. Balnave and Oliva 1331 have also reported that although general amino acid digestibility is decreased at 30°C compared to 21"C, the broiler requirement for methionine expressed as g methioninern ME is decreased in hot temperatures [MI. The researchers observed that lower levels of abdominal fat and improved feed conversions resulted when broilers were housed at hot temperatures and fed the higher methionine levels determined to be optimum for weight gain for broilers reared at 21°C [%I. Cheng et al. [3] showed that broilers reared in temperaturesabove 29.4"Chad the lowest carcass fat content when fed diets containing approximately 100% NRC amino acid levels. Austic [35l has also reported that a marginal deficiency in.methioninewill increase fat deposition of broilers.
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182
Research Report 31
CHENG et al.
BODYDRY
MATIER
TOTAL BODYFAT
%
TOTAL BODY PROTEIN
% DM
FAT-FREE
BODY
ENERGY
PROTEIN
UTILIZATION^ UTILIZATIONC
PROTEIN %
%
36.7"
465'
45.4de
84.9d
41.13'
37Mb
37.3'
45.4'
45.9e
84.1"
45.88=
39.12"
26.6
36.8'
46.9bc
45.1'
84.9d
43ad
40.30'
29.4
36.8'
48.8'
43.9c
85.Sd
43.17d
41.71'
32.2
36.8'
485'
42.F
3753b
35.79
35.0
358
479
39.4'
83.Sb 75.1'
31.64'
34.49'
IDIETARY CP. %
I
=Means within each column and within each main effect with different superscripts are significantlydifferent at 5% level.
CONCLUSIONS ANDAPPLICATIONS 1. Heat-stressed broilers from 3 to 6 wk of age are highly sensitive to dietary CP and amino acid levels and should not be fed a diet greater than 20% CP (100% NRC amino acid levels) with a 3250 kcal ME diet. 2. Supplementing 16 and 18% CP diets with methionine, lysine, threonine, tryptophan, and arginine to provide a minimum of 100% and 110%NRC levels did not improve weight gain of heat-stressed broilers compared to providing only a 90% NRC level. 3. Increasing dietary CP levels above 20% or supplementing 16 and 18% CP diets with methionine, lysine, threonine, tryptophan, and arginine to provide 100% NRC amino acid levels in a corn-soy diet produced deleterious effects on feed conversion and body fat deposition at temperatures above 29.4"C. 4. There appears to be no advantage in attempting to overcome the effects of heat stress through increased protein or amino acid levels. Such practices with broilers from 3 to 6 wk of age might lead to even more deleterious results.
=-
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21.1 23.9
JAPR CP, AMINO ACIDS, AND TEMPERATURE
32 ~~~~~~
~
REFERENCES AND NOTES 1. Cemigua, G.L, J.A. Herbert, and AB. Watts, 1983. The effect of constant ambient temperature and ration on the performance of sexed broilers. Poultry S i . 62746-
7%. 2. Reece, F.N. and B.D. Ldt, 1983. The effect of temperature and age on body wei t and feed efficiency of broilers. Poultry Sci. 621906-1 .
&
3. Cheng, T.K., M.L Hamrt, and CN. Coon, 19%.
4.Combs, J.F., 1970.Feed ingredientcomposition and amino acid standards for broilers. Pages 81-89 in: Proc. Maryland Nutr. Conf., College Park, MD. 5. Thomas,O.P., M. Farran, and CB. Tamplin, 1992. Broiler nutrition update. Pa es45-53 in: Proc. Maryland Nutr. Conf., College Park, d D .
6. Waldroup, P.W., RJ.Mitchell, J.R Payue, and KR Hazen, 1976.Performance of chicks fed diets formulated to minimize excess levels of essential amino acids. Poultry sci. 55:243-253.
7.McNaughton, J.L, LF. Kubena, J.W. Dcaton, and F.N. R N ~ ,1978.Influence of dietay rotein and energy on the performance of commerciaf egg-type ullets reared under summer conditions. Poultry Sa.5~?13911398. 8. Dale,N.M. and H.L F&r, 1979. Effect of diet composition on feed intake and growth of chicks under heat stress. I. Dietary fat levels. Poultry Sci. 591434-1441. 9.Kubena, LF., J.W. Dealon, F.N. Reeee, J.D. May, and T.H.VardPman, 1972.The influence of temperature and sex on the amino acid requirement of the broiler. Poultry Sci. 51:1391-1396. 10. Cowan, PJ. and W. Mitchie, 1978.Environmental temperature and broiler performance: The use of diets containing increased amount of protein. Br. Poultry Sci.
19601605. 11. Sinurat, A.P. and D. Balnave, 1985. Effect of dietary amino acids and metabolible energy on the rformance of broilers kept at high temperatures. Br. oultry Sci. 26A17-128.
g.
12.Harris, G. C,Jr., P.W. WpMroup, RL S a y , and G.S. Nelsoa 1974.The influence of humiditv. enerw. and amino acid status on the performanceof bkiiers. l%ultry Sci. 531933 (Abs). 13. Fuller, H.L and G. Mora, 1973. Effect of diet com sition on heat increment, feed intake, and of c g k s subjected to heat stress. Poultry Sci. (Abs). 14. Smith, M.O.and RG. Teeter,1987.Influence of feed intake and ambient temperature stress on the relative yield of broiler parts. Nutr. Rep. Intl. 35299-306. 15. Cheng, T. K,1991.Selfelection of diets varyin in protein content by broilers under heat stress. Cha ter in: Ph.D. Dissertation, University of Minnesota, St.$aul,
f
MN. 16. National Research Counc4 1994. Nutrient Reuirements of Poult 9th Rev. Edition. Natl. Acad. #res, Washington, D Z
.
17.The data were analyzed as a lit-plot design with h z the sub-plot contemperature as the whole plot w
%
18. FIUnvikq S., M. Welselbcrg, U. Eisner, I. Bartov, G. Rlesenfeld, M. Sharvit, A Nhr, and S. Bornstein, 1980. The energy requirements and performance of growing chickens and turkeys as affected environmental temperature. Poultry Sci. 5922XL222 19.HonUder, M A R and S.P. Rose,1987.Temperature and h for broilers. World's Poultry Sci. J. 43228-23r 20. Himms-Hagen, J., 1967.Sympathetic regulation of metabolism. Pharmac. Rev. 19367-461.
21. Mobcrg, G.P., 1976. Effects of environment and management stress on reproduction in dairy cows. J. Dairy Sci. 591618-1624. 22.De Andrade, AN.,J.C. Rogler, W.R Featherston, and C.W. Wston, 1977.Interrelationships between diet and elevated tem ratures ( clical and constant) on egg production and sgll qualily%oultry Sci. 561178-1188. 23. Ge~ncrt,PA,J.C. F. PadIJha, € Ain I.BazLz, and S.CulUaumln, 1994. Heat-induced changes in energy metabolism in broilers. Pages 375-378 in: Proc. 13th Symium of Energy Metabolism of Farm Animals, EAAP ub. No. 76,Mojacar, Spain.
$"
24.Bartov, I., 1979.Nutritional factors affecting uantity and quality of carcass fat in chickens. Fed. %roc. 3832627-2630. 25. Cons, RM., G.C. Emmans, LA Broadbent, and C. Fisher, 1990. Nutritional effects on the wth and fatness of broilers. Br. Poultry Sci. 31:495-50r 26. Boorman, KN., 1979.Regulation of protein and amino acid intake. Pa es 87 126 in: Food Intake Regulation in Poultry. K.N. %oox&an and B.M. Freeman, eds. Br. Poultry Sci. Ltd., Edinburgh, U K 27.Marc4 BE and J. Blely, 1972.The effect of energy supplied from the diet and from environmental heat on the response of chicks to different levels of dietary lysine. Poultry Sci. 51665-668. 28. H.kaasson, J., S. Erikson, and S. Skensson, 1978. Reports 57 and 59,Dept. of Anim. Husbandry, Swedish University of Agricultural Science, Uppsala, Sweden.
29.Bel& D.C, 1985.Physiological and metabolic syst e m im rtant to animal growth: An overview. J. h i m . Sci. 61(r uppl. 2):1-20. 30. McNaughbn, J.L and F.N. Retce, 1984.Response of broiler chickens to dietaryener and lysine levels in a warm environment. Poultry Sci. 68170-1174.
31.Fancher, B.I. and LS. Jensen, 1989a.Influence of varying dietary protein content while satisfying essential amino acid requirements upon broiler rformance from three to six week of age. Poultry Sci. gl13-123.
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Effect of environmental temperature, dietary protein, and ener levels on broiler performance. J. Appl.Poultry Res. 61--7.
sisted of the five dietary CP levels in Experiment 1, and the two(dietary CP) x three (amino acid supplementation levels) factorial arrangement in nment 2 using a Statistix software pro m Statistx, Analytical SoftWBIC, Minneapolis, $55614). ANOVA P-values were given for all main effects and interactions.Multiple mean comparisonsweredone by the method of least significant difference with significance set at 5% level. Regression models were checked b the residual plots and the Mallows' Cpvalues [36].d e three dimensional graphs of smoothed response surface (SRS)using temperature and dietary CP as the two horizontal axes were done by the smoothing technique of SAWGRAPH [37J.
Research Report CHENGetal.
33 35.Austic, RE,1985.Amino acid interrelationships rformance. Pages 158-168 in: Proc. Mary-
32. Fancher, B.I. and LS.Jeosmn, 198%. Dietary protein level and essential amino acid content: Influence upon female broiler rformance during grmvingperiod. Poultry Sci. 68:897-&.
Ed%::t?&f.,
33. B a h v e , D. and AG. olive, 1991.The influence of sodium bicarbonate and sulfur amino acids on the performance of broilers at moderate and high temperatures. Aust. J. Agric. Res. 421385-1397.
37.SAS Institute, 1985.SAS User’s Guide. 1985 mition.SAS Institute, Inc., Raleigh, NC.
A.
36. Weisberg, S., 1985. A plied Linear Re ession. 2nd Edition. John Wiley and %ns, New York,
ACKNOWLEDGEMENT This research was partiallysu ported b research gifts from Heartland Lysine, Inc., 8hicago, I)t and Gold’n Plump, Inc., St. Cloud, MN.
Downloaded from http://japr.oxfordjournals.org/ at H.E.C. Bibliotheque Myriam & J. Robert Ouimet on June 8, 2015
34. Balnavc, D. and A Oliva, 1990. R e m n s e s of finishing broilers at h i p temperatures to d i e t 6 methionine source and supp ementation levels. Aust. J. Agric. Res. 41557-564.
College Park, MD.