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Energy Utilization in Laying Hens1
Energy Utilization in Laying Hens.1 III. Effect of Dietary Protein Level at 21 and 32 C M. E. VALENCIA,2 P. M. MAIORINO, and B. L. REID Departments of Animal Sciences and Nutrition and Food Science, University of Arizona, Tucson, Arizona 85721 (Received for publication September 4, 1979)
1980 Poultry Science 59:2508-2513 INTRODUCTION
As early as 1935, Forbes et al. reported the effects of dietary protein level on energy utilization and heat production. These workers found that at extremely high or very low protein intakes heat production was increased and that it reached a minimum near the requirement for dietary protein. Since that time, additional studies by Guillaume and Summers (1970) on the effects of dietary amino acid excesses on the utilization of metabolizable energy (ME) in chicks failed to support the theory that an improved balance of dietary amino acids resulted in an improved utilization of ME. Direct oxygen consumption measurements in these studies suggested that differences in energy utilization
'Arizona Agricultural Experiment Station Journal Article No. 2838. 2 Present address: Institute de Investigacion y Estudios Superiores del Noreste, Hermosillo, Sonora, Mexico.
were mainly due to differences in the heat increment of the respective diets employed. Burlacu (1969) has also investigated the effects of individual amino acid excesses on the specific dynamic action (SDA) in hens. In these studies only alanine, asparagine, and phenylalanine were found to increase the SDA (heat increment). The feeding of casein or an amino acid mixture based on casein in these studies produced heat increment values equivalent to 16% of the ingested ME. The results of these studies and others would suggest that the alterations in heat increment associated with protein intake could be employed to decrease the requirements of ME for maintenance of hens fed diets containing an optimal amino acid balance. Reid (1976) fed six experimental diets varying in protein content from 10 to 19.5% to laying hens housed in colony cages and reported that the daily protein needs for egg production were in the range of 17.0 to 17.8 g/day during the early portion of the laying year. The protein requirements were reduced to 14.9 g during the last phase when egg production had dropped to 69.3%.
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ABSTRACT White Leghorn pullets housed at eitiier 21 or 32 C were used to investigate the effects of dietary protein level on energy utilization. Protein levels of 12, 14, 16, 18, and 20% were employed in this study with three feeding levels of each (two restricted levels and ad lib.). All diets were isocaloric, and the duration of the study was 21 days. Maintenance metabolizable energy (ME) was estimated as 134 and 121 kcal/kg physiological body weight (BW- 75 ) at 21 and 32 C, respectively. Fasting heat production/BW- 75 was 21% higher at the lower temperature (89 vs. 70 kcal). Estimates of energetic efficiencies at 21 C varied from 60.9% for the 12% protein diet to 72.4% for the 18% protein diets. At 32 C, similar diets showed lower energetic efficiencies for ME conversion to net energy (50.6% for the 12% protein diet and 70.6% at 20% protein) due to lower feed intakes. Egg weights were significantly higher at the lower environmental temperature, and at each temperature they were increased with the feeding of the higher protein diets. The average feed efficiency (g egg/g feed) was significantly better at the higher environmental temperature (.46 vs. .53). Calculations of heat increment (HI) plus activity values from a parabolic regression developed in relation to protein intakes showed higher (HI plus activity) values with either low or high protein intakes. Thus, the feeding of dietary protein levels which result in intakes commensurate with needs should result in maximum energetic efficiencies and dietary net energy. (Key words: energy utilization, protein, temperature stress, laying hens, metabolizable energy)
ENERGY UTILIZATION
The above studies led to our evaluation of the effects of dietary protein level on the utilization of ME by laying hens at constant temperatures of 21 and 32 C.
MATERIALS AND METHODS
Single Comb White Leghorn pullets of 1.75 to 1.90 kg body weight were housed in individual laying cages in two houses and were maintained at constant temperatures of 21 ± 1 and 32 ± 1 C. The birds were acclimated at these temperatures for a 2-week pre-experimental period and were fed the experimental diets for the subsequent 3 weeks. The experimental diets employed in this study are shown in Table 1. Dietary protein levels of 12, 14, 16, 18, and 20% were employed in isocaloric diets formulated by linear programming techniques. Each of the experimental diets was fed ad lib. and at two restricted levels in order to provide data for regression analyses. Within each dietary treatment at 21 C, birds were fed ad lib. 90 and 70 g of feed/bird/day. Restriction levels of 60 and 40 g of feed/bird/day were fed in addition to the ad lib. level at 32 C. A total of 5 birds were fed each of the levels for each diet at each temperature. The chromium oxide marker technique of Edwards and Gillis (1959) was employed for die determination of apparent ME values calculated from gross energy data on feed and fecal samples collected during the last week of the 21-day study. The birds were fed individually each day and feed consumption records main-
tained. Tap water was supplied ad lib. throughout the experiment, and data on egg weight and egg production were recorded daily. Energy output calculations were based on 1.6 kcal/g whole egg (Brody, 1945; Romanoff and Romanoff, 1949; Tasaki and Sasa, 1970; Grimbergen, 1970; Hoffman and Schiemann, 1973) and 5 kcal/g change in body weight (Davis et al., 1972, 1973; Reid et al, 1978). Energy balance, determined as the algebraic sum of energy output in eggs and body weight gain or loss, was employed as the dependent variable in regression analyses in order to arrive at an evaluation of the treatment effects. The regression technique employed in these studies was that of Farrell (1974), in which ME consumption/BW-75 as the independent variable was regressed on energy balance/BW- 7 5 ; the resulting equation predicts the maintenance energy requirement as the intercept on the x-axis and the fasting heat production (FHP) as the intercept on the y-axis. The slope of the regression line estimates the efficiency of ME conversion to NE. Similar regression calculations employing feed consumption as the independent variable provide an estimate of the NE content of the diet as the slope of the regression line.
RESULTS AND DISCUSSION
The feeding of isocaloric diets varying in total protein level from 12 to 20% resulted in maintenance ME estimates of 127 to 144 kcal/BW-7 5 at 21 C in comparison with values of 113 to 135 at 3 2 C (Table 2). The average maintenance ME at 21 C was 134 kcal/BW-75 and 121 at 32 C. Although not significantly different within housing temperature, the birds fed the lower protein diets had higher maintenance ME requirements at each temperature (Table 2). These findings show that the birds fed the protein deficient diets at each temperature had higher heat increments and activities than birds fed more adequate protein levels. The FHP values obtained in the present study were quite constant within each housing temperature and were not affected by dietary protein level (Table 2). The average FHP was 27% higher at 21 C than at 32 C in this study. Morrison and Leeson (1978) measured the FHP of "efficient" and "inefficient" hens. These differences were investigated further by measurements of activity, and the inefficient hens were found to spend more time eating, although the results were quite variable.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on February 28, 2015
Evaluations of energy utilization by laying hens have been reported by a number of workers employing either energy balance trials or calorimetric techniques (Waring and Brown, 1965; van Es et al, 1970, Burlacu and Baltac, 1971; Grimbergen, 1970; Davis et al, 1972, 1973). The studies employing energy balance techniques have estimated energetic efficiencies of ME conversion to net energy (NE) as 60 to 74%, depending on the diet employed. Davidson et al. (1968), in a comparison between die techniques found less heat production in calorimetry studies than with the balance technique, but differences between the two methods were in the order of 3 to 12%. Employing the balance technique with young cockerels, the mean rate of heat loss was 223 kcal/kg physiological body weight (BW 7 5 ) when 19.3% protein was fed and 239 kcal/BW 75 at 16.9% dietary protein.
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VALENCIA ET AL. TABLE 1. Experimental diets (% composition) Protein (%)
Ingredients
12
14
16
Milo Soybean meal Meat scraps Dehydrated alfalfa meal Animal fat Calcium carbonate Dicalcium phosphate Salt Trace mineral mix 1 Vitamin mix 2 DL-Methionine
75.25 6.25 3.00 5.00 1.25 7.00 .75 .40 .10 1.00
67.50 12.50 3.00 5.00 2.75 7.00
61.00 18.25 3.00 5.00 3.50 7.00
54.50 24.00 3.00 5.00 4.25 7.00
48.00 29.75 3.00 5.00 5.00 7.00
.75 .40 .10
.75 .40 .10
.75 .40 .10
.75 .40 .10
1.00
1.00
.06
.08
.02
1.00 .025
3
Nutrient levels % Protein (N X 6.25) %Ca % P (total) % Lysine % M+ C ME (kcal/g), determined 1
12.13 3.26 .58 .52 .42 2.91
14.19 3.27
16.14 3.28
18.09 3.29
20.04 3.30
.60 .67 .49
.62 .82 .55
.64 .96 .63
1.10
2.95
2.96
2.98
2.98
.66 .70
Supplied the following (ppm): 20 Fe, 60 Zn, 60 Mn, 4 Cu, and 1 Mo.
^Supplied the following per kilogram of diet: 3,690 IU vitamin A, 615 ICU vitamin D , , 1.76 mg riboflavin, 11 mg niacin, 4.4 mg calcium pantothenate, 5.3 Mg vitamin B 1 2 , 2.2 IU d-alpha-tocopheryl acetate, .9 mgmenadione sodium bisulfite, 175 choline chloride, and 50 mg ethoxyquin. 3
Percent protein determined by the Kjeldahl method; other nutrients were calculated.
Dietary NE values, measured as the slope of die regression employing ME consumed/BW-75/ day as the independent variable and energy balance/BW-75/day as the dependent variable, ranged from 1.72 kcal/g feed for the 12% protein diet at 21 C to 2.09 when a protein level of 18% was fed at this temperature. At the higher environmental temperature (32 C), the 12% protein diet had a NE value of 1.51 kcal/g, while a value comparable to the maximum values obtained at 21 C was attained only when 20% protein was fed. This interaction of NE, protein level, and temperature can be explained on the basis of protein consumption at the different temperatures. Although a significant difference in NE was obtained between the 12% protein diets at the two temperatures, the intake of protein was only 10.3 g at 32 C, while at 21 C the protein intake was 13.3 g. Increases in dietary NE with increasing dietary protein were to be expected in view of the decreased maintenance requirements noted above. Forbes et al. (1935) also reported decreased heat loss (heat increment) with the feeding of higher dietary protein levels to rats. As shown in Table 2, energetic efficiencies
of ME conversion to NE were significantly improved by increasing the dietary protein level from 12 to 18% at 21 C and from 12 to 20% at 32 C. These improved energetic efficiencies were related to protein intake and were not affected by temperature. Calculations of heat increment plus activity, as dietary ME X (1 - energetic efficiency), suggest a minimum at or near the protein intake requirement for the hens in this study. A parabolic curve, which showed a significantly lower variance than the linear regression, was fitted to these data in the form HI + activity (kcal/g diet) = A (g protein/day) 2 + B (g protein/day) + C with a correlation coefficient of .939 where A = .004, B = .179, and C = 2.80. The summary of the performance data for the ad lib. fed groups is shown in Table 3. Due to the small number of birds employed and the short duration of the experiment, no significant differences were obtained among the dietary protein levels with regard to egg production at either 21 or 32 C. However, a significant decrease in average egg production was observed for those birds housed at the higher environmental temperature. Feed efficiency measured as grams of egg per grams of feed consumed
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1.00
20
ENERGY UTILIZATION
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TABLE 2. Effect of dietary protein and ambient temperature on energy utilization % Dietary protein Criteria
12
14
16
18
20
Mean ± SD
Maintenance ME, kcal/BW-75 21 C 32 C
144Y i35xy
139Y 125 x y
130y 118 x
i27y 114 x
130y 113 x
134 a ± 7 121b ± 9
88y 69x
89y 71x
89y 71*
87y 69x
9iy 72 x
89a± 1 70b+ 1
Fasting heat production, kcal/BW-75 21 C 32 C
1.72b 1.51 a
Energetic efficiency, % 21 C 32 C
60.9 C 50.6 a
Heat increment + activity, kcal/g feed 21 C 32C
2.03 d 1.90c
1.85c 1.68b 64.2 d 56.8b
68.5 e 64.8 d
1.06b 1.27c
1.14c 1.44 d
2.09 d 2.09 d
2.09 d 1.94c 72.4 f 65.ld
.93ab 1.04 b
70.ief 70.6 e f .89 a .88 a
.82a 1.04b
sbodpfxv 1 > 1 1 . . -/Means not having common letter superscripts within each criteria are significantly different (P<.05).
TABLE 3. Dietary protein and temperature effects on performance of ad lib fed bens % Dietary protein Criteria
12
% Production 21 C 32C
16
20
18
Mean ± SD
90.5 X 80.0 X
92.6 X 87.lx
86.3 X 85.0 X
94.7 X 83.0 X
93.7 X 89.0 X
91.6 a ± 84.8 b +
.44 .51
.45 .54
.46 .55
.48 .57
.48 .48
.46 a ± .53 b +
Feed efficiency, g egg/g feed 21 C 32C Feed consumption, g/bird/day 21 C 32 C
14
111 86
120 89
116 84
119 81
119 110
117 90
3.3 3.5 .02 .04
±
3.7 11.6
+
Egg weight, g 21C 32C
53.8 X 54.9 X
58.5 x y 54.9 X
60.9y 54.6 X
60.4y 60.8y 55.3 x y 59.9y
59.1 a ± 55.9b ±
3.2 2.2
Egg output, g egg/day 21 C 32C
48.7y 43.9 X
54.2y 47.8 x y
53.4y 46.4 x y
57.2y 57.oy 45.9 x y 53.3y
54.1 a ± 47.5b ±
3.5 3.6
Body weight change, g/day 21 C 32C
-4.5y -7.8Z
-2.6xy -6.5Z
27w -4.3y
40w -2.2X
ME consumed above maintenance, kcal/day 21 C 32 C
85.3 X 115.4y 52.2™ 73.7 X
a
.C>,w,x,y,z^ eans (P<.05).
nQt
nav;ng
126.8 Z 101.4y
1.1™ 3.1w
152.8 Z 141.9 Z 95.3y 147.6 Z
common letter superscript within each criteria are significantly different
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Net energy, kcal/g feed 21 C 32 C
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VALENCIA ET AL.
At the lower housing temperature birds fed the 12 and 14% protein diets lost body weight during the experiment, while birds fed 16% dietary protein and above gained from 1.1 to 4.0 g/bird/day (Table 3). At the higher environmental temperature, only those birds fed the 20% protein diet showed a positive change in body weight while birds fed the lower protein diets lost weight during the experiment. Consumption of ME, calculated as kilocalories per day, above maintenance ranged from 85 to 153 kcal at 21 C. The energy available above maintenance was higher in diets containing 16% protein and above. Differences in energy consumption above maintenance for the 16, 18, and 20% protein diets at 21 C were not significant (Table 3). Birds housed at 32 C showed energy consumptions above maintenance ranging from 52.2 kcal/day with the feeding of the 12% protein diet to 147.6 with the feeding of the 20% protein diet. Only the 20% dietary protein level supported energy intakes comparable to the maximum levels obtained at the lower environmental temperature. Earlier work (Reid and Weber, 1973) has indicated that energy consumption became first limiting at high temperatures and that increased protein intakes only partially overcame the adverse temperature effects.
Data collected in this study support these relationships. REFERENCES Brody, S., 1945. Bioenergetics and growth. Reinhold, New York, NY. Burlacu, G., 1969. The specific dynamic action of amino acids in hens. Page 149—157 in Energy metabolism of farm animals. K. L. Blaxter, J. Kielanowski, and G. Thorbek, ed. Oriel Press, Newcastle upon Tyne. Burlacu, G., and M. Baltac, 1971. Efficiency of the utilization of the energy of food in laying hens. J. Agr. Sci. Camb. 77:405-411. Davidson, J., W. R. Hepburn, J. Mathieson, and J. D. Pullar, 1968. Comparisons of heat loss from young cockerels by direct measurement and by indirect assessment involving body analysis. Brit. Poultry Sci. 9:93-109. Davis, R. H., O.E.M. Hassan, and A. H. Sykes, 1972. The adaptation of energy utilization in the laying hen to warm and cool ambient temperatures. J. Agr. Sci. Camb. 79:363-369. Davis, R. H., O.E.M. Hassan, and A. H. Sykes, 1973. Energy utilization in the laying hen in relation to ambient temperature. J. Agr. Sci. Camb. 80: 173-177. Edwards, H. M., and M. B. Gillis, 1959. A chromic oxide balance method for determining phosphate availability. Poultry Sci. 38:569-574. Farrell, D. J., 1974. General principles and assumptions of calorimetry. Page 1—24/M Energy requirements of poultry. T. R. Morris and B. M. Freeman, ed. Brit. Poultry Sci. Ltd., Edinburgh. Forbes, E. B., R. W. Swift, A. Black, and O. J. Kahlenberg, 1935. The utilization of energy producing nutriment and protein as affected by individual nutrient deficiencies. III. The effects of the plane of protein intake. J. Nutr. 10:461-479. Grimbergen, A.H.M., 1970. The energy requirement for maintenance and production of laying hens. Netherlands J. Agr. Sci. 18:195-206. Guillaume, J., and J. D. Summers, 1970. Influence of amino acid excess on energy utilization in the growing chick. Can. J. Anim. Sci. 50:355—362. Hoffman, L., and R. Schiemann, 1973. Die Verwertung der Futterenergie durch die Legende Henne. Arch. Tierernahr 23:105-132. Morrison, W. D., and S. Leeson, 1978. Relationship of feed efficiency to carcass composition and metabolic rate in laying birds. Poultry Sci. 57:735-739. Reid, B. L., 1976. Estimated daily protein requirements of laying hens. Poultry Sci. 55:1641—1645. Reid, B. L., M. E. Valencia, and P. M. Maiorino, 1978. Energy utilization by laying hens. I. Energetic efficiencies of maintenance and production. Poultry Sci. 57:461-465. Reid, B. L., and C. W. Weber, 1973. Dietary protein and sulfur amino acid levels for laying hens during heat stress. Poultry Sci. 52:1335-1343. Romanoff, A. L., and A. J. Romanoff, 1949. The avian egg. John Wiley and Sons, New York, NY. Tasaki, I., and Y. Sasa, 1970. Energy metabolism in laying hens. Page 197—200 in Energy metabolism
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on February 28, 2015
showed a significant improvement for those birds housed at 32 C compared to the birds at the lower temperature (.53 vs. .46). Feed consumptions were lower at the higher temperature by an average of 23%. There was higher than anticpated feed intake for birds fed the 20% protein diet at 32 C. Average egg weight was increased with increasing dietary protein levels at each of die environmental temperatures employed in this study. Those birds fed the 12% protein diet showed an average egg weight of 53.8 g, which was increased to 60.9 g with the feeding of 16% dietary protein. No additional increase in egg weight was noted with the higher protein diets for the birds housed at 21 C. The birds housed at 32 C showed increases in egg weight only at the highest protein level (20%). Average egg weight was significantly lower for birds housed at the higher temperature. A combination of the data for egg production and egg weight, calculated as egg output in grams egg per day, also failed to show a significant effect of dietary protein level. Egg output for -birds housed at 21 C was significantly improved over that for similar birds at 32 C.
ENERGY UTILIZATION
of farm animals. A. Schiirch and C. Wenk, ed. Juris Druck Verlag, Zurich. van Es, A.J.H., L. Vik-Mo, H. Janssen, A. Bosch, W. Spreenwenberg, J. E. Vogt, and H. J. Nijkamp, 1 9 7 0 . Balance trials with laying hens. Page 201—204 in Energy metabolism of farm animals.
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A. Schiirch and C. Wenk, ed. Juris D r u c k Verlag, Zurich. Waring, J. J., and W. O. Brown, 1 9 6 5 . A respiration c h a m b e r for t h e s t u d y of energy utilization for m a i n t e n a n c e and p r o d u c t i o n in t h e laying hen. J. Agr. Sci. C a m b . 6 5 : 1 3 9 - 1 4 6 .
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on February 28, 2015
1980 Poultry Science 59:2508-2513 INTRODUCTION
As early as 1935, Forbes et al. reported the effects of dietary protein level on energy utilization and heat production. These workers found that at extremely high or very low protein intakes heat production was increased and that it reached a minimum near the requirement for dietary protein. Since that time, additional studies by Guillaume and Summers (1970) on the effects of dietary amino acid excesses on the utilization of metabolizable energy (ME) in chicks failed to support the theory that an improved balance of dietary amino acids resulted in an improved utilization of ME. Direct oxygen consumption measurements in these studies suggested that differences in energy utilization
'Arizona Agricultural Experiment Station Journal Article No. 2838. 2 Present address: Institute de Investigacion y Estudios Superiores del Noreste, Hermosillo, Sonora, Mexico.
were mainly due to differences in the heat increment of the respective diets employed. Burlacu (1969) has also investigated the effects of individual amino acid excesses on the specific dynamic action (SDA) in hens. In these studies only alanine, asparagine, and phenylalanine were found to increase the SDA (heat increment). The feeding of casein or an amino acid mixture based on casein in these studies produced heat increment values equivalent to 16% of the ingested ME. The results of these studies and others would suggest that the alterations in heat increment associated with protein intake could be employed to decrease the requirements of ME for maintenance of hens fed diets containing an optimal amino acid balance. Reid (1976) fed six experimental diets varying in protein content from 10 to 19.5% to laying hens housed in colony cages and reported that the daily protein needs for egg production were in the range of 17.0 to 17.8 g/day during the early portion of the laying year. The protein requirements were reduced to 14.9 g during the last phase when egg production had dropped to 69.3%.
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Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on February 28, 2015
ABSTRACT White Leghorn pullets housed at eitiier 21 or 32 C were used to investigate the effects of dietary protein level on energy utilization. Protein levels of 12, 14, 16, 18, and 20% were employed in this study with three feeding levels of each (two restricted levels and ad lib.). All diets were isocaloric, and the duration of the study was 21 days. Maintenance metabolizable energy (ME) was estimated as 134 and 121 kcal/kg physiological body weight (BW- 75 ) at 21 and 32 C, respectively. Fasting heat production/BW- 75 was 21% higher at the lower temperature (89 vs. 70 kcal). Estimates of energetic efficiencies at 21 C varied from 60.9% for the 12% protein diet to 72.4% for the 18% protein diets. At 32 C, similar diets showed lower energetic efficiencies for ME conversion to net energy (50.6% for the 12% protein diet and 70.6% at 20% protein) due to lower feed intakes. Egg weights were significantly higher at the lower environmental temperature, and at each temperature they were increased with the feeding of the higher protein diets. The average feed efficiency (g egg/g feed) was significantly better at the higher environmental temperature (.46 vs. .53). Calculations of heat increment (HI) plus activity values from a parabolic regression developed in relation to protein intakes showed higher (HI plus activity) values with either low or high protein intakes. Thus, the feeding of dietary protein levels which result in intakes commensurate with needs should result in maximum energetic efficiencies and dietary net energy. (Key words: energy utilization, protein, temperature stress, laying hens, metabolizable energy)
ENERGY UTILIZATION
The above studies led to our evaluation of the effects of dietary protein level on the utilization of ME by laying hens at constant temperatures of 21 and 32 C.
MATERIALS AND METHODS
Single Comb White Leghorn pullets of 1.75 to 1.90 kg body weight were housed in individual laying cages in two houses and were maintained at constant temperatures of 21 ± 1 and 32 ± 1 C. The birds were acclimated at these temperatures for a 2-week pre-experimental period and were fed the experimental diets for the subsequent 3 weeks. The experimental diets employed in this study are shown in Table 1. Dietary protein levels of 12, 14, 16, 18, and 20% were employed in isocaloric diets formulated by linear programming techniques. Each of the experimental diets was fed ad lib. and at two restricted levels in order to provide data for regression analyses. Within each dietary treatment at 21 C, birds were fed ad lib. 90 and 70 g of feed/bird/day. Restriction levels of 60 and 40 g of feed/bird/day were fed in addition to the ad lib. level at 32 C. A total of 5 birds were fed each of the levels for each diet at each temperature. The chromium oxide marker technique of Edwards and Gillis (1959) was employed for die determination of apparent ME values calculated from gross energy data on feed and fecal samples collected during the last week of the 21-day study. The birds were fed individually each day and feed consumption records main-
tained. Tap water was supplied ad lib. throughout the experiment, and data on egg weight and egg production were recorded daily. Energy output calculations were based on 1.6 kcal/g whole egg (Brody, 1945; Romanoff and Romanoff, 1949; Tasaki and Sasa, 1970; Grimbergen, 1970; Hoffman and Schiemann, 1973) and 5 kcal/g change in body weight (Davis et al., 1972, 1973; Reid et al, 1978). Energy balance, determined as the algebraic sum of energy output in eggs and body weight gain or loss, was employed as the dependent variable in regression analyses in order to arrive at an evaluation of the treatment effects. The regression technique employed in these studies was that of Farrell (1974), in which ME consumption/BW-75 as the independent variable was regressed on energy balance/BW- 7 5 ; the resulting equation predicts the maintenance energy requirement as the intercept on the x-axis and the fasting heat production (FHP) as the intercept on the y-axis. The slope of the regression line estimates the efficiency of ME conversion to NE. Similar regression calculations employing feed consumption as the independent variable provide an estimate of the NE content of the diet as the slope of the regression line.
RESULTS AND DISCUSSION
The feeding of isocaloric diets varying in total protein level from 12 to 20% resulted in maintenance ME estimates of 127 to 144 kcal/BW-7 5 at 21 C in comparison with values of 113 to 135 at 3 2 C (Table 2). The average maintenance ME at 21 C was 134 kcal/BW-75 and 121 at 32 C. Although not significantly different within housing temperature, the birds fed the lower protein diets had higher maintenance ME requirements at each temperature (Table 2). These findings show that the birds fed the protein deficient diets at each temperature had higher heat increments and activities than birds fed more adequate protein levels. The FHP values obtained in the present study were quite constant within each housing temperature and were not affected by dietary protein level (Table 2). The average FHP was 27% higher at 21 C than at 32 C in this study. Morrison and Leeson (1978) measured the FHP of "efficient" and "inefficient" hens. These differences were investigated further by measurements of activity, and the inefficient hens were found to spend more time eating, although the results were quite variable.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on February 28, 2015
Evaluations of energy utilization by laying hens have been reported by a number of workers employing either energy balance trials or calorimetric techniques (Waring and Brown, 1965; van Es et al, 1970, Burlacu and Baltac, 1971; Grimbergen, 1970; Davis et al, 1972, 1973). The studies employing energy balance techniques have estimated energetic efficiencies of ME conversion to net energy (NE) as 60 to 74%, depending on the diet employed. Davidson et al. (1968), in a comparison between die techniques found less heat production in calorimetry studies than with the balance technique, but differences between the two methods were in the order of 3 to 12%. Employing the balance technique with young cockerels, the mean rate of heat loss was 223 kcal/kg physiological body weight (BW 7 5 ) when 19.3% protein was fed and 239 kcal/BW 75 at 16.9% dietary protein.
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VALENCIA ET AL. TABLE 1. Experimental diets (% composition) Protein (%)
Ingredients
12
14
16
Milo Soybean meal Meat scraps Dehydrated alfalfa meal Animal fat Calcium carbonate Dicalcium phosphate Salt Trace mineral mix 1 Vitamin mix 2 DL-Methionine
75.25 6.25 3.00 5.00 1.25 7.00 .75 .40 .10 1.00
67.50 12.50 3.00 5.00 2.75 7.00
61.00 18.25 3.00 5.00 3.50 7.00
54.50 24.00 3.00 5.00 4.25 7.00
48.00 29.75 3.00 5.00 5.00 7.00
.75 .40 .10
.75 .40 .10
.75 .40 .10
.75 .40 .10
1.00
1.00
.06
.08
.02
1.00 .025
3
Nutrient levels % Protein (N X 6.25) %Ca % P (total) % Lysine % M+ C ME (kcal/g), determined 1
12.13 3.26 .58 .52 .42 2.91
14.19 3.27
16.14 3.28
18.09 3.29
20.04 3.30
.60 .67 .49
.62 .82 .55
.64 .96 .63
1.10
2.95
2.96
2.98
2.98
.66 .70
Supplied the following (ppm): 20 Fe, 60 Zn, 60 Mn, 4 Cu, and 1 Mo.
^Supplied the following per kilogram of diet: 3,690 IU vitamin A, 615 ICU vitamin D , , 1.76 mg riboflavin, 11 mg niacin, 4.4 mg calcium pantothenate, 5.3 Mg vitamin B 1 2 , 2.2 IU d-alpha-tocopheryl acetate, .9 mgmenadione sodium bisulfite, 175 choline chloride, and 50 mg ethoxyquin. 3
Percent protein determined by the Kjeldahl method; other nutrients were calculated.
Dietary NE values, measured as the slope of die regression employing ME consumed/BW-75/ day as the independent variable and energy balance/BW-75/day as the dependent variable, ranged from 1.72 kcal/g feed for the 12% protein diet at 21 C to 2.09 when a protein level of 18% was fed at this temperature. At the higher environmental temperature (32 C), the 12% protein diet had a NE value of 1.51 kcal/g, while a value comparable to the maximum values obtained at 21 C was attained only when 20% protein was fed. This interaction of NE, protein level, and temperature can be explained on the basis of protein consumption at the different temperatures. Although a significant difference in NE was obtained between the 12% protein diets at the two temperatures, the intake of protein was only 10.3 g at 32 C, while at 21 C the protein intake was 13.3 g. Increases in dietary NE with increasing dietary protein were to be expected in view of the decreased maintenance requirements noted above. Forbes et al. (1935) also reported decreased heat loss (heat increment) with the feeding of higher dietary protein levels to rats. As shown in Table 2, energetic efficiencies
of ME conversion to NE were significantly improved by increasing the dietary protein level from 12 to 18% at 21 C and from 12 to 20% at 32 C. These improved energetic efficiencies were related to protein intake and were not affected by temperature. Calculations of heat increment plus activity, as dietary ME X (1 - energetic efficiency), suggest a minimum at or near the protein intake requirement for the hens in this study. A parabolic curve, which showed a significantly lower variance than the linear regression, was fitted to these data in the form HI + activity (kcal/g diet) = A (g protein/day) 2 + B (g protein/day) + C with a correlation coefficient of .939 where A = .004, B = .179, and C = 2.80. The summary of the performance data for the ad lib. fed groups is shown in Table 3. Due to the small number of birds employed and the short duration of the experiment, no significant differences were obtained among the dietary protein levels with regard to egg production at either 21 or 32 C. However, a significant decrease in average egg production was observed for those birds housed at the higher environmental temperature. Feed efficiency measured as grams of egg per grams of feed consumed
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1.00
20
ENERGY UTILIZATION
2511
TABLE 2. Effect of dietary protein and ambient temperature on energy utilization % Dietary protein Criteria
12
14
16
18
20
Mean ± SD
Maintenance ME, kcal/BW-75 21 C 32 C
144Y i35xy
139Y 125 x y
130y 118 x
i27y 114 x
130y 113 x
134 a ± 7 121b ± 9
88y 69x
89y 71x
89y 71*
87y 69x
9iy 72 x
89a± 1 70b+ 1
Fasting heat production, kcal/BW-75 21 C 32 C
1.72b 1.51 a
Energetic efficiency, % 21 C 32 C
60.9 C 50.6 a
Heat increment + activity, kcal/g feed 21 C 32C
2.03 d 1.90c
1.85c 1.68b 64.2 d 56.8b
68.5 e 64.8 d
1.06b 1.27c
1.14c 1.44 d
2.09 d 2.09 d
2.09 d 1.94c 72.4 f 65.ld
.93ab 1.04 b
70.ief 70.6 e f .89 a .88 a
.82a 1.04b
sbodpfxv 1 > 1 1 . . -/Means not having common letter superscripts within each criteria are significantly different (P<.05).
TABLE 3. Dietary protein and temperature effects on performance of ad lib fed bens % Dietary protein Criteria
12
% Production 21 C 32C
16
20
18
Mean ± SD
90.5 X 80.0 X
92.6 X 87.lx
86.3 X 85.0 X
94.7 X 83.0 X
93.7 X 89.0 X
91.6 a ± 84.8 b +
.44 .51
.45 .54
.46 .55
.48 .57
.48 .48
.46 a ± .53 b +
Feed efficiency, g egg/g feed 21 C 32C Feed consumption, g/bird/day 21 C 32 C
14
111 86
120 89
116 84
119 81
119 110
117 90
3.3 3.5 .02 .04
±
3.7 11.6
+
Egg weight, g 21C 32C
53.8 X 54.9 X
58.5 x y 54.9 X
60.9y 54.6 X
60.4y 60.8y 55.3 x y 59.9y
59.1 a ± 55.9b ±
3.2 2.2
Egg output, g egg/day 21 C 32C
48.7y 43.9 X
54.2y 47.8 x y
53.4y 46.4 x y
57.2y 57.oy 45.9 x y 53.3y
54.1 a ± 47.5b ±
3.5 3.6
Body weight change, g/day 21 C 32C
-4.5y -7.8Z
-2.6xy -6.5Z
27w -4.3y
40w -2.2X
ME consumed above maintenance, kcal/day 21 C 32 C
85.3 X 115.4y 52.2™ 73.7 X
a
.C>,w,x,y,z^ eans (P<.05).
nQt
nav;ng
126.8 Z 101.4y
1.1™ 3.1w
152.8 Z 141.9 Z 95.3y 147.6 Z
common letter superscript within each criteria are significantly different
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Net energy, kcal/g feed 21 C 32 C
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VALENCIA ET AL.
At the lower housing temperature birds fed the 12 and 14% protein diets lost body weight during the experiment, while birds fed 16% dietary protein and above gained from 1.1 to 4.0 g/bird/day (Table 3). At the higher environmental temperature, only those birds fed the 20% protein diet showed a positive change in body weight while birds fed the lower protein diets lost weight during the experiment. Consumption of ME, calculated as kilocalories per day, above maintenance ranged from 85 to 153 kcal at 21 C. The energy available above maintenance was higher in diets containing 16% protein and above. Differences in energy consumption above maintenance for the 16, 18, and 20% protein diets at 21 C were not significant (Table 3). Birds housed at 32 C showed energy consumptions above maintenance ranging from 52.2 kcal/day with the feeding of the 12% protein diet to 147.6 with the feeding of the 20% protein diet. Only the 20% dietary protein level supported energy intakes comparable to the maximum levels obtained at the lower environmental temperature. Earlier work (Reid and Weber, 1973) has indicated that energy consumption became first limiting at high temperatures and that increased protein intakes only partially overcame the adverse temperature effects.
Data collected in this study support these relationships. REFERENCES Brody, S., 1945. Bioenergetics and growth. Reinhold, New York, NY. Burlacu, G., 1969. The specific dynamic action of amino acids in hens. Page 149—157 in Energy metabolism of farm animals. K. L. Blaxter, J. Kielanowski, and G. Thorbek, ed. Oriel Press, Newcastle upon Tyne. Burlacu, G., and M. Baltac, 1971. Efficiency of the utilization of the energy of food in laying hens. J. Agr. Sci. Camb. 77:405-411. Davidson, J., W. R. Hepburn, J. Mathieson, and J. D. Pullar, 1968. Comparisons of heat loss from young cockerels by direct measurement and by indirect assessment involving body analysis. Brit. Poultry Sci. 9:93-109. Davis, R. H., O.E.M. Hassan, and A. H. Sykes, 1972. The adaptation of energy utilization in the laying hen to warm and cool ambient temperatures. J. Agr. Sci. Camb. 79:363-369. Davis, R. H., O.E.M. Hassan, and A. H. Sykes, 1973. Energy utilization in the laying hen in relation to ambient temperature. J. Agr. Sci. Camb. 80: 173-177. Edwards, H. M., and M. B. Gillis, 1959. A chromic oxide balance method for determining phosphate availability. Poultry Sci. 38:569-574. Farrell, D. J., 1974. General principles and assumptions of calorimetry. Page 1—24/M Energy requirements of poultry. T. R. Morris and B. M. Freeman, ed. Brit. Poultry Sci. Ltd., Edinburgh. Forbes, E. B., R. W. Swift, A. Black, and O. J. Kahlenberg, 1935. The utilization of energy producing nutriment and protein as affected by individual nutrient deficiencies. III. The effects of the plane of protein intake. J. Nutr. 10:461-479. Grimbergen, A.H.M., 1970. The energy requirement for maintenance and production of laying hens. Netherlands J. Agr. Sci. 18:195-206. Guillaume, J., and J. D. Summers, 1970. Influence of amino acid excess on energy utilization in the growing chick. Can. J. Anim. Sci. 50:355—362. Hoffman, L., and R. Schiemann, 1973. Die Verwertung der Futterenergie durch die Legende Henne. Arch. Tierernahr 23:105-132. Morrison, W. D., and S. Leeson, 1978. Relationship of feed efficiency to carcass composition and metabolic rate in laying birds. Poultry Sci. 57:735-739. Reid, B. L., 1976. Estimated daily protein requirements of laying hens. Poultry Sci. 55:1641—1645. Reid, B. L., M. E. Valencia, and P. M. Maiorino, 1978. Energy utilization by laying hens. I. Energetic efficiencies of maintenance and production. Poultry Sci. 57:461-465. Reid, B. L., and C. W. Weber, 1973. Dietary protein and sulfur amino acid levels for laying hens during heat stress. Poultry Sci. 52:1335-1343. Romanoff, A. L., and A. J. Romanoff, 1949. The avian egg. John Wiley and Sons, New York, NY. Tasaki, I., and Y. Sasa, 1970. Energy metabolism in laying hens. Page 197—200 in Energy metabolism
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showed a significant improvement for those birds housed at 32 C compared to the birds at the lower temperature (.53 vs. .46). Feed consumptions were lower at the higher temperature by an average of 23%. There was higher than anticpated feed intake for birds fed the 20% protein diet at 32 C. Average egg weight was increased with increasing dietary protein levels at each of die environmental temperatures employed in this study. Those birds fed the 12% protein diet showed an average egg weight of 53.8 g, which was increased to 60.9 g with the feeding of 16% dietary protein. No additional increase in egg weight was noted with the higher protein diets for the birds housed at 21 C. The birds housed at 32 C showed increases in egg weight only at the highest protein level (20%). Average egg weight was significantly lower for birds housed at the higher temperature. A combination of the data for egg production and egg weight, calculated as egg output in grams egg per day, also failed to show a significant effect of dietary protein level. Egg output for -birds housed at 21 C was significantly improved over that for similar birds at 32 C.
ENERGY UTILIZATION
of farm animals. A. Schiirch and C. Wenk, ed. Juris Druck Verlag, Zurich. van Es, A.J.H., L. Vik-Mo, H. Janssen, A. Bosch, W. Spreenwenberg, J. E. Vogt, and H. J. Nijkamp, 1 9 7 0 . Balance trials with laying hens. Page 201—204 in Energy metabolism of farm animals.
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A. Schiirch and C. Wenk, ed. Juris D r u c k Verlag, Zurich. Waring, J. J., and W. O. Brown, 1 9 6 5 . A respiration c h a m b e r for t h e s t u d y of energy utilization for m a i n t e n a n c e and p r o d u c t i o n in t h e laying hen. J. Agr. Sci. C a m b . 6 5 : 1 3 9 - 1 4 6 .
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