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Energy Needs of Dwarf (dw) Broiler Breeder Hens
A G E AT HOUSING AND PERFORMANCE
when the eggs were sampled at 54 weeks of age, and to those caged at 16 or 21 weeks of age when sampled at 72 weeks. ACKNOWLEDGMENTS
REFERENCES Anonymous, 1974. Eighty-two percent of layers are in cages. Poultry Tribune: 26, 30. Duncan, D. B., 1955. Multiple range and multiple F tests. Biometrics, 11: 1-42.
Hartman, R. C , 1970. All-in-one cage house. Poultry Digest, 29 (344): 491-494. Magruder, N. D., and J. W. Nelson, 1968. Comparison of three growing programs on pullet performance. Poultry Sci. 47: 1691. Muir, F. V., P. C. Harris and R. W. Gerry, 1974. The influence of rearing environment and age at housing on laying house performance of Red x Rock sex-linked females. Poultry Sci. 53: 1853-1860. Powell, T. S., C. R. Douglas and R. H. Harms, 1972. A comparison of wire vs. litter floor for starting and growing pullets. Poultry Sci. 51: 1951-1955. Shupe, W. D., and J. H. Quisenberry, 1961. Effect of certain rearing and laying house environments on performance of incross egg production type pullets. Poultry Sci. 40: 1165-1171. Snedecor, G. W., and W. G. Cochran, 1969. Statistical Methods. The Iowa State University Press, Ames, Iowa. Wildey, H. E., C. J. Flegal and T. H. Coleman, 1968. Cage vs. floor rearing of replacement pullets. Poultry Sci. 47: 1732.
Energy Needs of Dwarf (dw) Broiler Breeder Hens PARK W . WALDROUP AND KENNY R. HAZEN
Department of Animal Sciences, University of Arkansas, Fayetteville 72701 (Received for publication March 4, 1975)
ABSTRACT Studies were conducted to determine the daily energy needs of the dwarf broiler breeder hen. In the first study, hens were control-fed diets ranging from 325 to 400 M.E. kcal./hen/day with ample amounts of other essential nutrients. Hens did not totally consume all of their daily allotment so in a second study the calorie allowance ranged from 260 to 320 M.E. kcal./hen/day. From the results of these studies it is estimated that the daily energy requirement of the dwarf broiler breeder hen is greater than 249 but no more than 269 M.E. kcal./day. POULTRY SCIENCE 54: 1931-1935, 1975
ATING the dwarf hen of the dw sexlinked type (Hutt, 1959) with the normal homozygous male has been proposed as a means of reducing feed and housing costs (Jaap, 1968). The reduced size of the dwarf hen was postulated by van Tienhoven et al. (1966) to be related to reduction in thyroid
M
Published with the approval of the Director of the Arkansas Agricultural Experiment Station.
hormone and growth hormone activity. Rajaratnam et al. (1969) also considered reduced thyroid activity to be a contributing factor of the sex-linked recessive dwarfism in the fowl. Rajaratnam et al. (1971) reported a significantly lower body temperature for the dwarf hen which suggested reduced metabolic processes. Increased fat deposition in the dwarf females noted by Guillaume (1969) and Rajaratnam et al. (1971) supports the hypothesis that basal metabolism is altered
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on November 8, 2014
The study reported herein was supported by the University of Maine Life Sciences and Agriculture Experiment Station. Appreciation is expressed to the Proctor and Gamble Company for the hydrolyzed animal and vegetable fat (HEF), and to Dawes' Laboratories, Inc., for the vitamin supplements used in this study.
1931
1932
P. E. WALDROUP AND K. R. HAZEN
Because of the possibility that dwarf hens may become commercially feasible for use as broiler breeder stock, studies were initiated at this station to determine daily energy requirements of such hens, since energy intake levels are considered to be a prime factor in controlling weight gains of breeder hens. EXPERIMENTAL PROCEDURE Indian River dwarf breeder hens were hatched on June 1, 1971 and grown to 24 weeks of age on standard farm diets similar to those used in commercial production with no attempt to limit feed intake. Five experimental diets were formulated to be fed at a controlled rate of 125 grams per hen per day. Assuming that the feed was totally consumed the hens would have a daily protein intake of 22.5 grams per day with the daily
allowance of energy to range from 325 to 400 M.E. kcal./bird per day at 25 kcal. increments. Normal sized broiler breeder hens in commercial production are commonly fed 425 to 450 M.E. kcal./day in peak production so this range should have been sufficient to allow an estimate of the energy of the dwarf based on an reduction in body weight of 20 percent (Jaap, 1971) to 30 percent (Richard and Cochez, 1971). A fifth treatment was created by "phase feeding" the four energy levels. In this series the hens were given 325 M.E. kcal./day at 24 weeks of age and allowed 25 kcal./day more energy each two weeks until the 400 kcal./day level was reached. This level was then maintained for the remainder of the test period. The composition of the diets is given in Table 1. Variations in the energy content were achieved by an exchange of fat and washed builder's sand while keeping other ingredients constant. Dietary energy levels ranged from 2600 to 3200 M.E. kcal./kg. with a protein level of 18 percent. Each treatment was assigned to four litterfloored pens of 25 pullets each. Three normal-sized cockerels were placed in each pen. Trough-type feeders with sufficient space for all birds to eat at once were used. Space heaters were used to maintain a minimum temperature of 10° C. at bird level. During the test period measurements were made on rate of egg production, feed consumption, egg size, and body weight change. Measurements were made each 28 days for a 3 month test period. During the course of the first trial it became apparent that the daily energy allowance of the hens was apparently in excess of their needs since the hens did not completely consume their daily allotment of feed. Therefore at the end of three 28-day periods the first study was terminated and a second trial initiated. For the second study the same diets were used as in the first trial but the quantity of
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on November 8, 2014
by the dwgene. Bayley et al. (1971) observed that the dwarf bird had a more precisely regulated metabolic rate than that of the normal bird and had a lower maintenance requirement per unit of weight. These results would suggest that the energy needs for maintenance of the dwarf bird may be lower than expected on the basis of its body weight. Little work has been reported on specific nutrient requirements of the dwarf breeder hen during the laying period. Guillaume (1971) reported that the dwarf breeder hen needed approximately 285 M.E. kcal./day and 17 grams of protein which provided 0.77 grams of lysine and 0.64 grams of sulphur amino acids. Summers (1971) observed little or no effect on egg production or egg size of the dwarf egg-type hen when the energy level of the diet was increased from 2.87 to 3.31 M.E. kcal./gram of feed. Protein levels of 16 to 23 percent gave comparable results. Quisenberry et al. (1969), also using dwarf egg-type hens, observed that nutrient levels higher than needed for normal hens may be essential for maximum performance of dwarf hens.
1933
DWARF BREEDER ENERGY NEEDS TABLE 1.—Composition of diets Constant ingredients
% of diet 3.00 3.00 54.80 22.20 1.42 6.11 0.40 0.50 0.10
Alfalfa meal (17% protein) Fish meal (65% protein) Yellow corn Soybean meal (49% protein) Dicalcium phosphate Limestone Salt Vitamin mix 1 Trace mineral mix 2
Animal fat Sand Calculated Analysis: M.E. kcal./kg. Protein % Meth + Cys % Lysine %
J 0.70 7.77
2 3.30 5.17
3 5.90 2.57
4 8.47 0.00
2600 18.00 0.58 1.03
2800 18.00 0.58 1.03
3000 18.00 0.58 1.03
3200 18.00 0.58 1.03
1. Supplies per kg. of diet: 6600 I.U. vit. A; 2200 I.U. vit. D 3 ; 22 I.U. vit. E; 1.1 mg. vit. K; 6.6 mg. riboflavin; 17.6 mg. pantothinic acid; 44 mg. niacin; 1870 mg. choline; 11 meg. vit. B 12 ; 1.1 mg. folic acid and 125 mg. ethoxyquin. 2. Supplies per kg. of diet: 100 mg. Fe; 100 mg. Mn; 100 mg. Zn; 10 mg. Cu.
feed offered to the hens was reduced to 100 grams per hen per day, thus providing for 260, 280, 300 and 320 M.E. kcal./hen/day with 18 grams of protein per day. Hens from the first study were used in the second trial after a 14 day feeding period on a standard farm breeder hen diet. One replicate pen from each treatment in the first trial was reassigned to each energy level for the second trial, resulting in five pens for each energy level. The phase feeding system was not used in the second trial. Cockerels were removed from the pens to more accurately evaluate the energy needs of the dwarf hens. The second trial was also conducted for three 28 day periods with identical measurements made as in the first trial. The data from both studies were subjected to the analysis of variance as outlined by Steel and Torrie (1960) with significant differences between treatment means determined by the multiple range test of Duncan (1955).
RESULTS AND DISCUSSION The most significant observation in the first trial was the inability of the dwarf hens to consume all of the calories offered to them (Table 2). The voluntary intake of energy on all diets was less than the lowest level offered. Voluntary consumption ranged from 296 to 316 M.E. kcal./day. The lowest level of protein intake in the first trial was 17.8 grams per day (Table 2). This level of protein intake was apparently not detrimental to rate of egg production or egg size (Table 2). Body weight gains paralleled the caloric intake, modified to some extent by the protein intake (Table 2). An example of reduced weight gains affected by protein intake levels can be seen in hens offered the 400 M.E. kcal./day who consumed only 17.8 grams of protein. Studies by Waldroup et al. (1966) have shown a significant reduction in body weights of broiler breeder hens related to
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on November 8, 2014
% of diet
Variable ingredients
1934
P. E. WALDROUP AND K. R. HAZEN
TABLE 2.—Response of dwarf broiler breeder hens to different energy intake levels (Experiment M.E. kcal./hen/day offered 350 375
325 M. E. kcal./hen/day Grams protein/hen/day % Hen-day egg production Average egg weight (g.) Initial body weight (g.) Final body weight (g.) Weight gain (g.)
2% 20.5 57.1 49.8 1912 2014 102
306 19.7 56.3 49.7 1868 2076 208
316 19.0 50.6 49.7 1776 2060 284
400
Phase
316 17.8 54.2 49.5 1888 2046 158
306 18.4 55.9 50.1 1835 2061 226
M.E. kcal./hen/day Grams protein/hen/day % Hen-day production' Average egg weight (g.) Initial body weight (g.) Final body weight (g.) Weight gain (g.)
249 17.2 51.1b 56.8 2081 2125 44
M.E. kcal./hen /day offered 300 280 269 17.3 57.9a 56.0 2023 2114 91
277 16.6 58.8a 56.5 2088 2184 96
2)
320 284 16.0 58.5a 56.0 2065 2190 125
'Where indicated, means having the same superscript do not differ significantly (P < 0.05).
reduced protein intake levels without impairment of egg production. While lower energy levels were offered in the second trial, the only hens that consumed virtually all of their feed were those offered the lowest level of 260 M.E. kcal. /day (Table 3). The trough design may not have allowed complete consumption of the feed in this case. Rate of egg production was depressed at this level of intake but this was the only criterion to be adversely affected. Egg weights and body weight gains were not significantly affected by any energy treatment although weight gains tended to increase at the higher energy intake levels. It can be concluded that the daily energy needs of the dwarf breeder hens used in these studies was greater than 249 but no more than 269 M.E. kcal./day in the absence of cockerels. This is in agreement with the value of 285 M.E. kcal. suggested by Guillaume (1971). Additional energy would need to be supplied for maintenance of the cockerel. This energy level represents only about 65 percent of that normally consumed by normal
sized broiler breeder hens in commercial production. This reduction in daily energy needs for maintenance could be a contributing factor towards acceptance of the dwarf hen in commercial practice. ACKNOWLEDGEMENTS The authors express their appreciation to Indian River Poultry Farms, Nacagdoches, Texas, for donation of the pullets used in this study. REFERENCES Bayley, H. S., M. S. McDonald and P. Hunton, 1971. Comparison of the metabolic rates of normal and dwarf meat-type chickens. Poultry Sci. 50: 1551. Duncan, D. B., 1955. Multiple range and multiple F test. Biometrics, 11: 1-42. Guillaume, J., 1971. Some nutritional and physiological traits of the dw chick. World's Poultry Sci. J. 27: 284. Hutt, F. B., 1959. Sex-linked dwarfism in the fowl. J. Heredity, 50: 209-221. Jaap, R. G., 1968. Sex-linked dwarfism and broiler production. Poultry Sci. 47: 1684. Jaap, R. G., 1971. Effect of sex-linked genes on body
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on November 8, 2014
TABLE 3.—Response of dwarf broiler breeder hens to different energy intake levels (Experiment 260
1)
1935
DWARF BREEDER ENERGY NEEDS
hens in a meat-type strain of domestic fowl. World's Poultry Sci. J. 27: 292. Steel, R. G. D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw Hill Co., New York, N.Y. Summers, J. D., 1971. Nutrition of the dwarf layer. World's Poultry Sci. J. 27: 287. vanTienhoven, A., J. H.Williamson, M.C. Tomlinson and K. L. Maclnnes, 1966. Possible role of the thyroid and pituitary glands in sex-linked dwarfism in the fowl. Endocrinology, 78: 950-957. Waldroup, P. W., B. L. Damron and R. H. Harms, 1966. Effect of low protein and high fiber grower diets on the performance of broiler pullets. Poultry Sci. 45: 393-402.
The Influence of Intestinal (Ceca) Flora on Serum and Egg Yolk Cholesterol Levels in Laying Hens F . TORTUERO, A . BRENES AND J . RlOPEREZ
Institute) de Alimentation y Productividad Animal, C.S.I.C.- Ciudad Universitaria, Madrid -3, Spain (Received for publication March 4, 1975)
ABSTRACT Normal and cecectomized laying hens were used to study the influence of intestinal (ceca) flora and the implantation of Lactobacillus acidophylus on the levels of serum and egg yolk cholesterol. The ceca had been surgically removed when the experimental birds were 16 months of age. Serum cholesterol levels of cecectomized laying hens were higher than that of normal birds; the Lactobacillus acidophylus implantation resulted in a significant decrease in serum cholesterol levels in both normal and cecectomized birds. The normal intestinal (ceca) flora and Lactobacillus acidophylus implantation did not influence fat digestibility. Egg yolk cholesterol levels were higher for cecectomized birds. A constant relationship between serum and egg yolk cholesterol was not observed. POULTRY SCIENCE 54: 1935-1938, 1975
INTRODUCTION
I
the
degree
of
hypercholesterolemia
and
T has been nearly 50 years since physicians
coronary atherosclerosis. However, this cor-
first linked serum cholesterol with heart
relation is not always observed in laying hens
disease. The facts are that cholesterol is only one of the factors that contribute to atheromatosis. It is true that atherogenesis, plasma lipids
(Kurnick, 1958). On the other hand, individual chickens exhibit different plasma and egg yolk cholesterol levels, particularly when fed a diet
and cholesterol levels may be affected by
containing cholesterol (March et al., 1964).
dietary constituents. Some workers, such as
Similar differences may also be observed in
Christensen (1964) and Banerjee et al. (1965),
the rates of cholesterol synthesis, absorption
showed an increase in cholesterol of the aorta
and elimination from the body.
of cockerels fed cholesterol and Pick et al.
The role of intestinal microorganisms in
(1967) found a positive relationship between
the cholesterol destruction or degradation in
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on November 8, 2014
size and reproduction. World's Poultry Sci. J. 27: 281. Quisenberry, J. H., A. G. Delfino and J. W. Bradley, 1969. Effects of density and dietary protein level on performance of midgets versus normal layers. Poultry Sci. 48: 1861. Rajaratnam, G., T. Selvarajah and J. D. Summers, 1969. The effect of thyroprotein on growth rate of dwarf pullets. Poultry Sci. 48: 1768-1770. Rajaratnam, G., J. D. Summers, A. S. Wood and E. T. Moran, Jr., 1971. Some physiological and nutritional aspects of the dwarf chicken. Can. J. An. Sci. 51: 209-216. Ricard, F. M., and L. P. Cochez, 1971. Effects of the sex-linked dwarf gene, dw, on performance of
when the eggs were sampled at 54 weeks of age, and to those caged at 16 or 21 weeks of age when sampled at 72 weeks. ACKNOWLEDGMENTS
REFERENCES Anonymous, 1974. Eighty-two percent of layers are in cages. Poultry Tribune: 26, 30. Duncan, D. B., 1955. Multiple range and multiple F tests. Biometrics, 11: 1-42.
Hartman, R. C , 1970. All-in-one cage house. Poultry Digest, 29 (344): 491-494. Magruder, N. D., and J. W. Nelson, 1968. Comparison of three growing programs on pullet performance. Poultry Sci. 47: 1691. Muir, F. V., P. C. Harris and R. W. Gerry, 1974. The influence of rearing environment and age at housing on laying house performance of Red x Rock sex-linked females. Poultry Sci. 53: 1853-1860. Powell, T. S., C. R. Douglas and R. H. Harms, 1972. A comparison of wire vs. litter floor for starting and growing pullets. Poultry Sci. 51: 1951-1955. Shupe, W. D., and J. H. Quisenberry, 1961. Effect of certain rearing and laying house environments on performance of incross egg production type pullets. Poultry Sci. 40: 1165-1171. Snedecor, G. W., and W. G. Cochran, 1969. Statistical Methods. The Iowa State University Press, Ames, Iowa. Wildey, H. E., C. J. Flegal and T. H. Coleman, 1968. Cage vs. floor rearing of replacement pullets. Poultry Sci. 47: 1732.
Energy Needs of Dwarf (dw) Broiler Breeder Hens PARK W . WALDROUP AND KENNY R. HAZEN
Department of Animal Sciences, University of Arkansas, Fayetteville 72701 (Received for publication March 4, 1975)
ABSTRACT Studies were conducted to determine the daily energy needs of the dwarf broiler breeder hen. In the first study, hens were control-fed diets ranging from 325 to 400 M.E. kcal./hen/day with ample amounts of other essential nutrients. Hens did not totally consume all of their daily allotment so in a second study the calorie allowance ranged from 260 to 320 M.E. kcal./hen/day. From the results of these studies it is estimated that the daily energy requirement of the dwarf broiler breeder hen is greater than 249 but no more than 269 M.E. kcal./day. POULTRY SCIENCE 54: 1931-1935, 1975
ATING the dwarf hen of the dw sexlinked type (Hutt, 1959) with the normal homozygous male has been proposed as a means of reducing feed and housing costs (Jaap, 1968). The reduced size of the dwarf hen was postulated by van Tienhoven et al. (1966) to be related to reduction in thyroid
M
Published with the approval of the Director of the Arkansas Agricultural Experiment Station.
hormone and growth hormone activity. Rajaratnam et al. (1969) also considered reduced thyroid activity to be a contributing factor of the sex-linked recessive dwarfism in the fowl. Rajaratnam et al. (1971) reported a significantly lower body temperature for the dwarf hen which suggested reduced metabolic processes. Increased fat deposition in the dwarf females noted by Guillaume (1969) and Rajaratnam et al. (1971) supports the hypothesis that basal metabolism is altered
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on November 8, 2014
The study reported herein was supported by the University of Maine Life Sciences and Agriculture Experiment Station. Appreciation is expressed to the Proctor and Gamble Company for the hydrolyzed animal and vegetable fat (HEF), and to Dawes' Laboratories, Inc., for the vitamin supplements used in this study.
1931
1932
P. E. WALDROUP AND K. R. HAZEN
Because of the possibility that dwarf hens may become commercially feasible for use as broiler breeder stock, studies were initiated at this station to determine daily energy requirements of such hens, since energy intake levels are considered to be a prime factor in controlling weight gains of breeder hens. EXPERIMENTAL PROCEDURE Indian River dwarf breeder hens were hatched on June 1, 1971 and grown to 24 weeks of age on standard farm diets similar to those used in commercial production with no attempt to limit feed intake. Five experimental diets were formulated to be fed at a controlled rate of 125 grams per hen per day. Assuming that the feed was totally consumed the hens would have a daily protein intake of 22.5 grams per day with the daily
allowance of energy to range from 325 to 400 M.E. kcal./bird per day at 25 kcal. increments. Normal sized broiler breeder hens in commercial production are commonly fed 425 to 450 M.E. kcal./day in peak production so this range should have been sufficient to allow an estimate of the energy of the dwarf based on an reduction in body weight of 20 percent (Jaap, 1971) to 30 percent (Richard and Cochez, 1971). A fifth treatment was created by "phase feeding" the four energy levels. In this series the hens were given 325 M.E. kcal./day at 24 weeks of age and allowed 25 kcal./day more energy each two weeks until the 400 kcal./day level was reached. This level was then maintained for the remainder of the test period. The composition of the diets is given in Table 1. Variations in the energy content were achieved by an exchange of fat and washed builder's sand while keeping other ingredients constant. Dietary energy levels ranged from 2600 to 3200 M.E. kcal./kg. with a protein level of 18 percent. Each treatment was assigned to four litterfloored pens of 25 pullets each. Three normal-sized cockerels were placed in each pen. Trough-type feeders with sufficient space for all birds to eat at once were used. Space heaters were used to maintain a minimum temperature of 10° C. at bird level. During the test period measurements were made on rate of egg production, feed consumption, egg size, and body weight change. Measurements were made each 28 days for a 3 month test period. During the course of the first trial it became apparent that the daily energy allowance of the hens was apparently in excess of their needs since the hens did not completely consume their daily allotment of feed. Therefore at the end of three 28-day periods the first study was terminated and a second trial initiated. For the second study the same diets were used as in the first trial but the quantity of
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on November 8, 2014
by the dwgene. Bayley et al. (1971) observed that the dwarf bird had a more precisely regulated metabolic rate than that of the normal bird and had a lower maintenance requirement per unit of weight. These results would suggest that the energy needs for maintenance of the dwarf bird may be lower than expected on the basis of its body weight. Little work has been reported on specific nutrient requirements of the dwarf breeder hen during the laying period. Guillaume (1971) reported that the dwarf breeder hen needed approximately 285 M.E. kcal./day and 17 grams of protein which provided 0.77 grams of lysine and 0.64 grams of sulphur amino acids. Summers (1971) observed little or no effect on egg production or egg size of the dwarf egg-type hen when the energy level of the diet was increased from 2.87 to 3.31 M.E. kcal./gram of feed. Protein levels of 16 to 23 percent gave comparable results. Quisenberry et al. (1969), also using dwarf egg-type hens, observed that nutrient levels higher than needed for normal hens may be essential for maximum performance of dwarf hens.
1933
DWARF BREEDER ENERGY NEEDS TABLE 1.—Composition of diets Constant ingredients
% of diet 3.00 3.00 54.80 22.20 1.42 6.11 0.40 0.50 0.10
Alfalfa meal (17% protein) Fish meal (65% protein) Yellow corn Soybean meal (49% protein) Dicalcium phosphate Limestone Salt Vitamin mix 1 Trace mineral mix 2
Animal fat Sand Calculated Analysis: M.E. kcal./kg. Protein % Meth + Cys % Lysine %
J 0.70 7.77
2 3.30 5.17
3 5.90 2.57
4 8.47 0.00
2600 18.00 0.58 1.03
2800 18.00 0.58 1.03
3000 18.00 0.58 1.03
3200 18.00 0.58 1.03
1. Supplies per kg. of diet: 6600 I.U. vit. A; 2200 I.U. vit. D 3 ; 22 I.U. vit. E; 1.1 mg. vit. K; 6.6 mg. riboflavin; 17.6 mg. pantothinic acid; 44 mg. niacin; 1870 mg. choline; 11 meg. vit. B 12 ; 1.1 mg. folic acid and 125 mg. ethoxyquin. 2. Supplies per kg. of diet: 100 mg. Fe; 100 mg. Mn; 100 mg. Zn; 10 mg. Cu.
feed offered to the hens was reduced to 100 grams per hen per day, thus providing for 260, 280, 300 and 320 M.E. kcal./hen/day with 18 grams of protein per day. Hens from the first study were used in the second trial after a 14 day feeding period on a standard farm breeder hen diet. One replicate pen from each treatment in the first trial was reassigned to each energy level for the second trial, resulting in five pens for each energy level. The phase feeding system was not used in the second trial. Cockerels were removed from the pens to more accurately evaluate the energy needs of the dwarf hens. The second trial was also conducted for three 28 day periods with identical measurements made as in the first trial. The data from both studies were subjected to the analysis of variance as outlined by Steel and Torrie (1960) with significant differences between treatment means determined by the multiple range test of Duncan (1955).
RESULTS AND DISCUSSION The most significant observation in the first trial was the inability of the dwarf hens to consume all of the calories offered to them (Table 2). The voluntary intake of energy on all diets was less than the lowest level offered. Voluntary consumption ranged from 296 to 316 M.E. kcal./day. The lowest level of protein intake in the first trial was 17.8 grams per day (Table 2). This level of protein intake was apparently not detrimental to rate of egg production or egg size (Table 2). Body weight gains paralleled the caloric intake, modified to some extent by the protein intake (Table 2). An example of reduced weight gains affected by protein intake levels can be seen in hens offered the 400 M.E. kcal./day who consumed only 17.8 grams of protein. Studies by Waldroup et al. (1966) have shown a significant reduction in body weights of broiler breeder hens related to
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on November 8, 2014
% of diet
Variable ingredients
1934
P. E. WALDROUP AND K. R. HAZEN
TABLE 2.—Response of dwarf broiler breeder hens to different energy intake levels (Experiment M.E. kcal./hen/day offered 350 375
325 M. E. kcal./hen/day Grams protein/hen/day % Hen-day egg production Average egg weight (g.) Initial body weight (g.) Final body weight (g.) Weight gain (g.)
2% 20.5 57.1 49.8 1912 2014 102
306 19.7 56.3 49.7 1868 2076 208
316 19.0 50.6 49.7 1776 2060 284
400
Phase
316 17.8 54.2 49.5 1888 2046 158
306 18.4 55.9 50.1 1835 2061 226
M.E. kcal./hen/day Grams protein/hen/day % Hen-day production' Average egg weight (g.) Initial body weight (g.) Final body weight (g.) Weight gain (g.)
249 17.2 51.1b 56.8 2081 2125 44
M.E. kcal./hen /day offered 300 280 269 17.3 57.9a 56.0 2023 2114 91
277 16.6 58.8a 56.5 2088 2184 96
2)
320 284 16.0 58.5a 56.0 2065 2190 125
'Where indicated, means having the same superscript do not differ significantly (P < 0.05).
reduced protein intake levels without impairment of egg production. While lower energy levels were offered in the second trial, the only hens that consumed virtually all of their feed were those offered the lowest level of 260 M.E. kcal. /day (Table 3). The trough design may not have allowed complete consumption of the feed in this case. Rate of egg production was depressed at this level of intake but this was the only criterion to be adversely affected. Egg weights and body weight gains were not significantly affected by any energy treatment although weight gains tended to increase at the higher energy intake levels. It can be concluded that the daily energy needs of the dwarf breeder hens used in these studies was greater than 249 but no more than 269 M.E. kcal./day in the absence of cockerels. This is in agreement with the value of 285 M.E. kcal. suggested by Guillaume (1971). Additional energy would need to be supplied for maintenance of the cockerel. This energy level represents only about 65 percent of that normally consumed by normal
sized broiler breeder hens in commercial production. This reduction in daily energy needs for maintenance could be a contributing factor towards acceptance of the dwarf hen in commercial practice. ACKNOWLEDGEMENTS The authors express their appreciation to Indian River Poultry Farms, Nacagdoches, Texas, for donation of the pullets used in this study. REFERENCES Bayley, H. S., M. S. McDonald and P. Hunton, 1971. Comparison of the metabolic rates of normal and dwarf meat-type chickens. Poultry Sci. 50: 1551. Duncan, D. B., 1955. Multiple range and multiple F test. Biometrics, 11: 1-42. Guillaume, J., 1971. Some nutritional and physiological traits of the dw chick. World's Poultry Sci. J. 27: 284. Hutt, F. B., 1959. Sex-linked dwarfism in the fowl. J. Heredity, 50: 209-221. Jaap, R. G., 1968. Sex-linked dwarfism and broiler production. Poultry Sci. 47: 1684. Jaap, R. G., 1971. Effect of sex-linked genes on body
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on November 8, 2014
TABLE 3.—Response of dwarf broiler breeder hens to different energy intake levels (Experiment 260
1)
1935
DWARF BREEDER ENERGY NEEDS
hens in a meat-type strain of domestic fowl. World's Poultry Sci. J. 27: 292. Steel, R. G. D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw Hill Co., New York, N.Y. Summers, J. D., 1971. Nutrition of the dwarf layer. World's Poultry Sci. J. 27: 287. vanTienhoven, A., J. H.Williamson, M.C. Tomlinson and K. L. Maclnnes, 1966. Possible role of the thyroid and pituitary glands in sex-linked dwarfism in the fowl. Endocrinology, 78: 950-957. Waldroup, P. W., B. L. Damron and R. H. Harms, 1966. Effect of low protein and high fiber grower diets on the performance of broiler pullets. Poultry Sci. 45: 393-402.
The Influence of Intestinal (Ceca) Flora on Serum and Egg Yolk Cholesterol Levels in Laying Hens F . TORTUERO, A . BRENES AND J . RlOPEREZ
Institute) de Alimentation y Productividad Animal, C.S.I.C.- Ciudad Universitaria, Madrid -3, Spain (Received for publication March 4, 1975)
ABSTRACT Normal and cecectomized laying hens were used to study the influence of intestinal (ceca) flora and the implantation of Lactobacillus acidophylus on the levels of serum and egg yolk cholesterol. The ceca had been surgically removed when the experimental birds were 16 months of age. Serum cholesterol levels of cecectomized laying hens were higher than that of normal birds; the Lactobacillus acidophylus implantation resulted in a significant decrease in serum cholesterol levels in both normal and cecectomized birds. The normal intestinal (ceca) flora and Lactobacillus acidophylus implantation did not influence fat digestibility. Egg yolk cholesterol levels were higher for cecectomized birds. A constant relationship between serum and egg yolk cholesterol was not observed. POULTRY SCIENCE 54: 1935-1938, 1975
INTRODUCTION
I
the
degree
of
hypercholesterolemia
and
T has been nearly 50 years since physicians
coronary atherosclerosis. However, this cor-
first linked serum cholesterol with heart
relation is not always observed in laying hens
disease. The facts are that cholesterol is only one of the factors that contribute to atheromatosis. It is true that atherogenesis, plasma lipids
(Kurnick, 1958). On the other hand, individual chickens exhibit different plasma and egg yolk cholesterol levels, particularly when fed a diet
and cholesterol levels may be affected by
containing cholesterol (March et al., 1964).
dietary constituents. Some workers, such as
Similar differences may also be observed in
Christensen (1964) and Banerjee et al. (1965),
the rates of cholesterol synthesis, absorption
showed an increase in cholesterol of the aorta
and elimination from the body.
of cockerels fed cholesterol and Pick et al.
The role of intestinal microorganisms in
(1967) found a positive relationship between
the cholesterol destruction or degradation in
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on November 8, 2014
size and reproduction. World's Poultry Sci. J. 27: 281. Quisenberry, J. H., A. G. Delfino and J. W. Bradley, 1969. Effects of density and dietary protein level on performance of midgets versus normal layers. Poultry Sci. 48: 1861. Rajaratnam, G., T. Selvarajah and J. D. Summers, 1969. The effect of thyroprotein on growth rate of dwarf pullets. Poultry Sci. 48: 1768-1770. Rajaratnam, G., J. D. Summers, A. S. Wood and E. T. Moran, Jr., 1971. Some physiological and nutritional aspects of the dwarf chicken. Can. J. An. Sci. 51: 209-216. Ricard, F. M., and L. P. Cochez, 1971. Effects of the sex-linked dwarf gene, dw, on performance of