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The Effects of Dietary Fat and Energy Levels on the Performance of Caged Laying Birds*
20
G. K. MORRIS AND H. L. FULLER ACKNOWLEDGMENT
We wish to thank Mr. Hamilton Laudani of the Stored Products Insect Section, Market Quality Research Division, AMS, U.S.D.A. for his suggestions in the design and conduct of these experiments.
The Effects of Dietary Fat and Energy Levels on the Performance of Caged Laying Birds* B. E. MARCH AND JACOB BIELY Poultry Nutrition Laboratory, The University of British Columbia, Vancouver, 8, B.C., Canada (Received for publication May 28, 1962)
T
HE FOLLOWING experiment was conducted to study the effects of introducing fat into the ration of mature laying birds previously fed starting, growing and laying diets not supplemented with fat. Data on body weight, mortality, egg production rate, egg size, albumen quality, egg shell thickness and feed consumption are presented. EXPERIMENTAL
The birds used were 300 White Leghorn pullets which were already in lay (11 months old) when they were fed the rations supplemented with different levels of * Publication # 144.
fat. Five and 10 percent of tallowt were fed to the birds in the rations shown in Table 1. The control ration and rations 2 and 3 were formulated to supply 1270 Cal. metabolizable energy per lb. (based on average energy values given by Potter et al., 1961). Ration 4 contained 10 percent tallow, but no attempt was made to have the ration isocaloric with the other rations, and its calculated metabolizable energy was 1470 Cal. per lb. In this way it was hoped to separate any effects of fat itself from the effects of energy contributed to the ration by supplementary fat. All rat The product used was a commercial mixture of fats from different sources, estimated metabolizable energy content 3420 Cal. per lb.
Downloaded from http://ps.oxfordjournals.org/ at toledo hospital on May 3, 2015
REFERENCES Bierer, B. W., and C. L. Vickers, 1959. The effect on egg size and production of fungicidetreated and fumigated grains fed to hens. J. Am. Vet. Med. Assn. 184: 452-453. Bondi, A., E. Olomucki and M. Calderon, 1955. Problems connected with ethylene dibromide fumigation of cereals. II. Feeding experiments with laying hens. J. Sci. Food Agric. 6: 600-602. Caylor, J. F., and C. K. Laurent, 1959. The effect of a grain fumigant on egg size of White Leghorn hens. Poultry Sci. 39: 216-219.
Fuller, H. L., and G. K. Morris, 1962. A study of the effects of ethylene dibromide fumigant components on egg production. Poultry Sci. 4 1 : 645-654. Kramer, C. Y., 1956. Extension of multiple range test to group means with unequal numbers of replications. Biometrics, 12: 307-310. Morgan, C. L., 1958. Effect of feeding oats treated with dowfume EB-5 to laying hens on egg size. Personal communication. Olomucki, E., and A. Bondi. 1955. Problems connected with ethylene dibromide fumigation of cereals. I. Sorption of ethylene dibromide by grain. J. Sci. Food Agric. 6: 592-600. Snedecor, G. W., 1956. Statistical Methods, 5th Ed. The Iowa State College Press. Ames, Iowa, 534 pp. Stenger, V. A., S. A. Shrader and A. W. Beshgetoor, 1939. Analytical method for methyl bromide. Ind. Eng. Chem., Anal. Ed. 11: 121.
EFFECTS OF FAT AND ENERGY ON PERFORMANCE
TABLE 1.—Composition of laying rations Ingredient
Ground wheat Wheat middling Ground yellow corn Ground oat hulls Soybean oil meal (44% protein) Herring meal (70% protein) Tallow*
Ration Ration 1 2 65
%
— 15 —
42 10 15 5
%
Ration 3 23 15 15 10
%
TABLE 2.—Body weight and mortality Ration 4
% — 15 —
Average Body Weight (lbs.) Diet
50.8
7
10
14
11.2
2
2 5
2 10
2 10
—
21
1 2 3 4
Mortality At beginning At completion of experiment of Experiment 4.7 4.8 4.7 4.8
4.9 4.9 4.9 4.8
Mortality with
%
involvement
33 32 23 25
5.3 2.7 2.7 4.0
out the experiment. Relative egg shell thickness from the different groups of birds was measured indirectly by ashing the shells plus shell membranes at 850-875°C. and expressing the weight of ash as percentage of the total egg weight. The ash * Stabilized with not more than 0.02 percent butylated determinations were made by mass ashing hydroxyanisole, 0.01 percent propylgallate and 0.004 percent citric acid. the shells and membranes from one day's production of eggs from the birds on each tions were formulated to contain 15 to 16 ration during May, June, July, August and percent protein. September. The birds were housed in community RESULTS cages each containing IS birds. Each ration The average weights of the birds are was assigned at random to five replicate given in Table 2. Supplementation of the cages in the cage house. The birds were rations with fat did not result in obesity. weighed at the beginning and the completion of the experiment. Birds which died The average weight of the birds fed the raduring the experiment were examined post tion of higher energy content was unchanged at the end of the 34-week period. mortem. Twenty-eight percent of the birds died in Record was kept of the number of eggs laid and of the total weight of eggs laid the course of the experiment. From the by the birds on each ration from February data given in Table 2, it will be seen that 6th to October 1st, 1961. The rate of pro- mortality was not increased when the birds duction and the total weight of eggs laid received supplementary fat. Furthermore, were determined for two week periods on a post mortem examination did not reveal hen-day basis. Interior quality, expressed any evidence that the percentage of fat in as Haugh values, was determined on the the diet influenced the causes of mortality. eggs produced on two successive days at The data on egg production are given intervals of two and three weeks through- in Table 3. The rate of production was not 2 2 4 2.5 0.375 0.0125 0.375
2 2 4 2.5 0.375 0.0125 0.375
2 2 4 2.5 0.375 0.0125 0.375
TABLE 3.—Egg production {rate, size and quality) and feed efficiency from February 6 to October 1, 1961
Diet
% production (hen-day basis)
Average weight gm.
lb. feed consumed/henday
lb. feed consumed/doz. eggs produced
lb. feed consumed/lb. eggs produced
Average Haugh values
1 2 3 4
55.2 61.8 55.5 56.7
61.4 61.5 60.5 61.2
0.273 0.298 0.245 0.264
5.93 5.79 5.30 5.59
3.65 3.56 3.31 3.45
73.0 73.6 74.6 73.6
Downloaded from http://ps.oxfordjournals.org/ at toledo hospital on May 3, 2015
Distillers' dried solubles 2 Dehydrated cereal grass 2 Li.nestone 4 Bone meal 2 S Iodized salt 0.375 Manganese sulphate 0 0125 Feeding oil 0 375 (2250 U.S.P.U. vitamin A 3001.C.U. vitamin D per gram)
22
B. E. MARCH AND J. BIELY
TABLE 4.—Percentage of total egg weight present as mineral in the shell and shell membranes
Downloaded from http://ps.oxfordjournals.org/ at toledo hospital on May 3, 2015
tality and post mortem findings during the 11 months that the birds were fed the exPercent Ash perimental rations, however, show no effect Ration No. May June August September on mortality attributable to the level of fat. July 1 4.7 4.8 4.5 4.5 4.5 The fact that the birds did not gain 5.0 4.7 4.6 4.5 2 4.5 4.5 4.8 4.5 4.5 3 appreciably in weight during the experi4.5 4.8 4.6 4.5 4.6 4 ment suggests that the strain of White Leghorns used ate only sufficient feed to satisfy affected by the fat or the energy level of their nutritive requirements. This is in conthe ration. The somewhat higher rate of trast to the obesity observed when rations production of the birds fed ration 2 was not of high energy content are fed to heavy statistically different from the production breeds of laying birds. Despite the fact that of the birds fed the other rations. The eggs the birds fed the ration containing 1470 Cal. laid by the birds fed ration 3 were signifimetabolizable energy per lb. did not gain cantly lighter in weight than those laid by in weight, the metabolizable energy intake the other groups. Feed consumption, calcuper lb. of eggs produced was higher than lated on the basis of either pounds of feed with the rations containing 1270 Cal. per dozen eggs or pounds of feed per pound metabolizable energy per lb. An interesting of eggs produced was reduced when fat comparison may be made of the results obwas added to the ration, either isocaloritained with those reported by Davidson cally or with an increase in the energy et al. (1961) with regard to the effect of level of the ration. The average Haugh sub-optimal protein level and amino acid values of the eggs were similar for all imbalance upon the utilization of metabogroups. In Table 4 are shown the percentlizable energy by the chick for growth. ages of ash in the shell plus shell memThese authors conclude that, in attempting branes of the eggs laid by the pullets on to compensate for a low protein/metabothe different diets. The dietary treatments lizable energy ratio, the growing chick did not affect shell thickness. consumes more than the normal amount of energy and may dispose of the extra energy DISCUSSION In a previous experiment (Biely and as heat. Recognizing the fact that their March, 1962) 10 percent of supplementary data are in variance with the more common fat was fed to birds from day-old to three observation that excess dietary energy is years of age. Mortality from liver dis- reflected in the deposition of fat in the orders in this earlier experiment was ap- body, they suggest that there may be proximately doubled when either 5 or 10 genetic differences in the manner in which percent of the fat was fed, but no other un- birds are able to dispose of excess dietary energy. It would appear that, in the prestoward effects on mortality were noted. In contrast to the previous experiment ent experiment, with the particular strain in which birds were accustomed to high- of White Leghorns employed, and with the fat diets from the time they were hatched, particular balance of protein level, amino in the present experiment supplementary acid pattern and metabolizable energy level fat was introduced into the diet of mature in ration 4, the excess metabolizable energy birds which had been fed a ration without intake was not utilized for productive puradded fat. It was considered that the die- poses. tary fat might, in the latter case, impose a Romanoff and Romanoff (1949) congreater dietary stress. The records of mor- cluded after reviewing the literature that—
EFFECTS OF FAT AND ENERGY ON PERFORMANCE
From the results in the present experiment it cannot be deduced that the supplementary fat per se affected egg size, nor was egg size related to the metabolizable
energy level of the rations in this case Rather, feed intake appeared to be the causative factor. Whether the reduced feed intake of the birds fed the 1270 Cal. ration containing 10 percent added fat was due to poor palatability of this ration, or to satiety induced by the ration, is not known. Hill and Dansky (1954) encountered a somewhat similar situation when they fed growing chicks diets supplying a wide range of energy levels produced by introducing oat hulls into the diet. They found that the birds on the different diets did not consume equal amounts of energy. The bulk of the ration was not, however, the sole factor limiting feed consumption, since the birds did not eat to physical capacity. From Table 3 it will be seen that the hen-day capacity of the birds was at least 0.298 lb. of feed. The 0.245 lb. of feed consumed per hen-day by the birds on ration 3, although not limiting the rate of production, nevertheless was not sufficient for maximum egg size. SUMMARY
The effects of adding fat, with and without a concomitant increase in energy level, to the ration fed to 11-months old laying birds are reported. Body weight, mortality, rate of egg production, albumen quality and shell thickness were not significantly affected by the level of fat in the ration. Egg size was reduced when 10 percent of fat was added to the ration without increasing the energy level. It is concluded that the reduction in egg size was related to the decrease in feed intake of the birds fed this ration. ACKNOWLEDGMENTS
The study was carried out with the financial assistance of the British Columbia Department of Agriculture, Victoria, B.C., and the British Columbia Feed Manufacturers' Association, Vancouver, B.C.
Downloaded from http://ps.oxfordjournals.org/ at toledo hospital on May 3, 2015
"Changes in quantity or quality of the ration tend to affect egg production before modifying egg weight." More recent evidence, however, indicates that egg size is affected by protein and energy intake. Berg and Bearse (1957) found that a high protein-high energy diet increased egg size and that a low protein-low energy diet decreased it. Hochreich et al. (1958) and Treat et al. (1960) reported that the addition of fat to laying rations increased egg weight. Orr et al. (1958) on the other hand, stated that the addition of fat to a laying ration did not affect egg weight. Combs et al. (1961) reported that egg size could be reduced by restricting energy intake, while maintaining the level of other nutrients. In view of these findings it is difficult to understand why, in the present study, the only response obtained with regard to egg size from the addition of fat to the laying ration should have been a decrease in egg size when 10 percent of fat was fed in a ration isocaloric with the control ration. Gaghir et al. (1960) fed 12 percent of fat in diets isocaloric and isonitrogenous with a control diet without supplementary fat, without significantly affecting egg weight. Harms and Waldroup (1960) conducted an experiment in which laying birds were fed diets similar in energy content but composed of different ingredients. A ration which contained 4.8 percent of supplementary fat and a mixture of ground oats and yellow corn as the cereal resulted in smaller eggs than did a ration containing yellow corn only, and no supplementary fat. Harms and Waldroup conclude that their data substantiate the findings of Jensen et al. (1957) in indicating the presence of a factor in yellow corn necessary for maximum egg weight.
23
24
B. E. MARCH AND J. BIELY
The tallow (Sta-Y-Fat) used in the study was kindly supplied by Gordon Young (B.C.) Ltd. REFERENCES
Sci. 3 7 : 212-214.
Potter, L. M., L. D. Matterson, M. W. Stutz and E. P. Singsen, 1961. The metabolisable energy of feed ingredients for chickens. Progress Report 39 (revised), Experiment Station, College of Agriculture, University of Connecticut. Romanoff, A. L., and A. J. Romanoff, 1949. The Avian Egg. John Wiley and Sons Inc., New York. Treat, C. M., B. L. Reid, R. E. Davies and J. R. Couch, 1960. The effect of animal fat and mixtures of animal fatty acids on performance of cage layers. Poultry Sci: 39: 1550-1555.
Effect of Phosphate Treatment on Carcass-Weight Changes and Organoleptic Quality of Cut-Up Chicken 1 K. N. MAY, 2 R. L. HELMER 3 AND R. L. SAFFLE3 University of Georgia, and Market Quality Research Division, AMS, Athens, Georgia
USDA,
(Received for publication May 28, 1962)
EIGHT loss from eviscerated chicken carcasses due to dehydration is a common problem in the commercial processing industry. The changes in carcass weight during processing and holding of whole carcasses have been investigated by many workers including Bigbee and Dawson (1961), Fromm and Monroe (1958), Kotula et al. (1960a, b), Thomson et al. (1961), and Tarver et al. (1956). Cut-up birds, held in a fresh state, lose more mois-
ture than whole carcasses. Jordan and Saunders (1958) reported a 1.9 percent loss and a 0.6 percent loss when broilers "Journal Paper No. 231, College Experiment Station, College of Agriculture Experiment Stations, University of Georgia, Athens, Georgia. 2 Poultry Department, University of Georgia and Field Crops and Animal Products Branch, Market Quality Research Division, AMS, U.S. Department of Agriculture. 3 Food Technology Department, University of Georgia.
Downloaded from http://ps.oxfordjournals.org/ at toledo hospital on May 3, 2015
Berg, R., and G. E. Bearse, 1957. The effect of protein and energy content of the diet on the performance of laying hens. Poultry Sci. 36: 1105. Combs, G. F., B. Gattis and C. S. Shaffner, 1961. Studies with laying birds. 2. Energy restriction. Poultry Sci. 40: 220-224. Daghir, N. J., W. W. Marion and S. L. Balloun, 1960. Influence of dietary fat and choline on serum and egg yolk cholesterol in the laying chicken. Poultry Sci. 39: 1459-1466. Davidson, J., I. McDonald, J. Mathieson and R. B. Williams, 1961. Utilisation of dietary energy by poultry. II. Effects of indigestible organic matter and protein on the utilisation of metabolisable energy for growth. J. Sci. Food Agric. 12: 425-439. Harms, R. H., and P. W. Waldroup, 1961. The effect of composition of diet upon weight of eggs. Poultry Sci. 40: 564-567. Hill, F. W., and L. M. Dansky, 1954. Studies on the energy requirements of chickens. 1. The effect of dietary energy level on growth and
feed consumption. Poultry Sci. 33: 112-119. Hochreich, H. J., C. R. Douglas, I. H. Kidd and R. H. Harms, 1958. The effect of dietary protein and energy levels upon production of Single Comb White Leghorn hens. Poultry Sci. 37: 949-953. Jensen, L. S., J. B. Aldred, R. E. Fry and J. McGinnis, 1957. Studies on an unidentified factor necessary for maximum egg weight. Poultry Sci. 36: 1130. March, B. E., and J. Biely, 1962. The effect of dietary fat level on the rate of mortality in caged layers. Poultry Sci. 4 1 : 9—12. Orr, H. L., E. S. Snyder and S. J. Slinger, 1958. The effect of animal fat, arsonic acid and range vs. confinement rearing on egg quality. Poultry
G. K. MORRIS AND H. L. FULLER ACKNOWLEDGMENT
We wish to thank Mr. Hamilton Laudani of the Stored Products Insect Section, Market Quality Research Division, AMS, U.S.D.A. for his suggestions in the design and conduct of these experiments.
The Effects of Dietary Fat and Energy Levels on the Performance of Caged Laying Birds* B. E. MARCH AND JACOB BIELY Poultry Nutrition Laboratory, The University of British Columbia, Vancouver, 8, B.C., Canada (Received for publication May 28, 1962)
T
HE FOLLOWING experiment was conducted to study the effects of introducing fat into the ration of mature laying birds previously fed starting, growing and laying diets not supplemented with fat. Data on body weight, mortality, egg production rate, egg size, albumen quality, egg shell thickness and feed consumption are presented. EXPERIMENTAL
The birds used were 300 White Leghorn pullets which were already in lay (11 months old) when they were fed the rations supplemented with different levels of * Publication # 144.
fat. Five and 10 percent of tallowt were fed to the birds in the rations shown in Table 1. The control ration and rations 2 and 3 were formulated to supply 1270 Cal. metabolizable energy per lb. (based on average energy values given by Potter et al., 1961). Ration 4 contained 10 percent tallow, but no attempt was made to have the ration isocaloric with the other rations, and its calculated metabolizable energy was 1470 Cal. per lb. In this way it was hoped to separate any effects of fat itself from the effects of energy contributed to the ration by supplementary fat. All rat The product used was a commercial mixture of fats from different sources, estimated metabolizable energy content 3420 Cal. per lb.
Downloaded from http://ps.oxfordjournals.org/ at toledo hospital on May 3, 2015
REFERENCES Bierer, B. W., and C. L. Vickers, 1959. The effect on egg size and production of fungicidetreated and fumigated grains fed to hens. J. Am. Vet. Med. Assn. 184: 452-453. Bondi, A., E. Olomucki and M. Calderon, 1955. Problems connected with ethylene dibromide fumigation of cereals. II. Feeding experiments with laying hens. J. Sci. Food Agric. 6: 600-602. Caylor, J. F., and C. K. Laurent, 1959. The effect of a grain fumigant on egg size of White Leghorn hens. Poultry Sci. 39: 216-219.
Fuller, H. L., and G. K. Morris, 1962. A study of the effects of ethylene dibromide fumigant components on egg production. Poultry Sci. 4 1 : 645-654. Kramer, C. Y., 1956. Extension of multiple range test to group means with unequal numbers of replications. Biometrics, 12: 307-310. Morgan, C. L., 1958. Effect of feeding oats treated with dowfume EB-5 to laying hens on egg size. Personal communication. Olomucki, E., and A. Bondi. 1955. Problems connected with ethylene dibromide fumigation of cereals. I. Sorption of ethylene dibromide by grain. J. Sci. Food Agric. 6: 592-600. Snedecor, G. W., 1956. Statistical Methods, 5th Ed. The Iowa State College Press. Ames, Iowa, 534 pp. Stenger, V. A., S. A. Shrader and A. W. Beshgetoor, 1939. Analytical method for methyl bromide. Ind. Eng. Chem., Anal. Ed. 11: 121.
EFFECTS OF FAT AND ENERGY ON PERFORMANCE
TABLE 1.—Composition of laying rations Ingredient
Ground wheat Wheat middling Ground yellow corn Ground oat hulls Soybean oil meal (44% protein) Herring meal (70% protein) Tallow*
Ration Ration 1 2 65
%
— 15 —
42 10 15 5
%
Ration 3 23 15 15 10
%
TABLE 2.—Body weight and mortality Ration 4
% — 15 —
Average Body Weight (lbs.) Diet
50.8
7
10
14
11.2
2
2 5
2 10
2 10
—
21
1 2 3 4
Mortality At beginning At completion of experiment of Experiment 4.7 4.8 4.7 4.8
4.9 4.9 4.9 4.8
Mortality with
%
involvement
33 32 23 25
5.3 2.7 2.7 4.0
out the experiment. Relative egg shell thickness from the different groups of birds was measured indirectly by ashing the shells plus shell membranes at 850-875°C. and expressing the weight of ash as percentage of the total egg weight. The ash * Stabilized with not more than 0.02 percent butylated determinations were made by mass ashing hydroxyanisole, 0.01 percent propylgallate and 0.004 percent citric acid. the shells and membranes from one day's production of eggs from the birds on each tions were formulated to contain 15 to 16 ration during May, June, July, August and percent protein. September. The birds were housed in community RESULTS cages each containing IS birds. Each ration The average weights of the birds are was assigned at random to five replicate given in Table 2. Supplementation of the cages in the cage house. The birds were rations with fat did not result in obesity. weighed at the beginning and the completion of the experiment. Birds which died The average weight of the birds fed the raduring the experiment were examined post tion of higher energy content was unchanged at the end of the 34-week period. mortem. Twenty-eight percent of the birds died in Record was kept of the number of eggs laid and of the total weight of eggs laid the course of the experiment. From the by the birds on each ration from February data given in Table 2, it will be seen that 6th to October 1st, 1961. The rate of pro- mortality was not increased when the birds duction and the total weight of eggs laid received supplementary fat. Furthermore, were determined for two week periods on a post mortem examination did not reveal hen-day basis. Interior quality, expressed any evidence that the percentage of fat in as Haugh values, was determined on the the diet influenced the causes of mortality. eggs produced on two successive days at The data on egg production are given intervals of two and three weeks through- in Table 3. The rate of production was not 2 2 4 2.5 0.375 0.0125 0.375
2 2 4 2.5 0.375 0.0125 0.375
2 2 4 2.5 0.375 0.0125 0.375
TABLE 3.—Egg production {rate, size and quality) and feed efficiency from February 6 to October 1, 1961
Diet
% production (hen-day basis)
Average weight gm.
lb. feed consumed/henday
lb. feed consumed/doz. eggs produced
lb. feed consumed/lb. eggs produced
Average Haugh values
1 2 3 4
55.2 61.8 55.5 56.7
61.4 61.5 60.5 61.2
0.273 0.298 0.245 0.264
5.93 5.79 5.30 5.59
3.65 3.56 3.31 3.45
73.0 73.6 74.6 73.6
Downloaded from http://ps.oxfordjournals.org/ at toledo hospital on May 3, 2015
Distillers' dried solubles 2 Dehydrated cereal grass 2 Li.nestone 4 Bone meal 2 S Iodized salt 0.375 Manganese sulphate 0 0125 Feeding oil 0 375 (2250 U.S.P.U. vitamin A 3001.C.U. vitamin D per gram)
22
B. E. MARCH AND J. BIELY
TABLE 4.—Percentage of total egg weight present as mineral in the shell and shell membranes
Downloaded from http://ps.oxfordjournals.org/ at toledo hospital on May 3, 2015
tality and post mortem findings during the 11 months that the birds were fed the exPercent Ash perimental rations, however, show no effect Ration No. May June August September on mortality attributable to the level of fat. July 1 4.7 4.8 4.5 4.5 4.5 The fact that the birds did not gain 5.0 4.7 4.6 4.5 2 4.5 4.5 4.8 4.5 4.5 3 appreciably in weight during the experi4.5 4.8 4.6 4.5 4.6 4 ment suggests that the strain of White Leghorns used ate only sufficient feed to satisfy affected by the fat or the energy level of their nutritive requirements. This is in conthe ration. The somewhat higher rate of trast to the obesity observed when rations production of the birds fed ration 2 was not of high energy content are fed to heavy statistically different from the production breeds of laying birds. Despite the fact that of the birds fed the other rations. The eggs the birds fed the ration containing 1470 Cal. laid by the birds fed ration 3 were signifimetabolizable energy per lb. did not gain cantly lighter in weight than those laid by in weight, the metabolizable energy intake the other groups. Feed consumption, calcuper lb. of eggs produced was higher than lated on the basis of either pounds of feed with the rations containing 1270 Cal. per dozen eggs or pounds of feed per pound metabolizable energy per lb. An interesting of eggs produced was reduced when fat comparison may be made of the results obwas added to the ration, either isocaloritained with those reported by Davidson cally or with an increase in the energy et al. (1961) with regard to the effect of level of the ration. The average Haugh sub-optimal protein level and amino acid values of the eggs were similar for all imbalance upon the utilization of metabogroups. In Table 4 are shown the percentlizable energy by the chick for growth. ages of ash in the shell plus shell memThese authors conclude that, in attempting branes of the eggs laid by the pullets on to compensate for a low protein/metabothe different diets. The dietary treatments lizable energy ratio, the growing chick did not affect shell thickness. consumes more than the normal amount of energy and may dispose of the extra energy DISCUSSION In a previous experiment (Biely and as heat. Recognizing the fact that their March, 1962) 10 percent of supplementary data are in variance with the more common fat was fed to birds from day-old to three observation that excess dietary energy is years of age. Mortality from liver dis- reflected in the deposition of fat in the orders in this earlier experiment was ap- body, they suggest that there may be proximately doubled when either 5 or 10 genetic differences in the manner in which percent of the fat was fed, but no other un- birds are able to dispose of excess dietary energy. It would appear that, in the prestoward effects on mortality were noted. In contrast to the previous experiment ent experiment, with the particular strain in which birds were accustomed to high- of White Leghorns employed, and with the fat diets from the time they were hatched, particular balance of protein level, amino in the present experiment supplementary acid pattern and metabolizable energy level fat was introduced into the diet of mature in ration 4, the excess metabolizable energy birds which had been fed a ration without intake was not utilized for productive puradded fat. It was considered that the die- poses. tary fat might, in the latter case, impose a Romanoff and Romanoff (1949) congreater dietary stress. The records of mor- cluded after reviewing the literature that—
EFFECTS OF FAT AND ENERGY ON PERFORMANCE
From the results in the present experiment it cannot be deduced that the supplementary fat per se affected egg size, nor was egg size related to the metabolizable
energy level of the rations in this case Rather, feed intake appeared to be the causative factor. Whether the reduced feed intake of the birds fed the 1270 Cal. ration containing 10 percent added fat was due to poor palatability of this ration, or to satiety induced by the ration, is not known. Hill and Dansky (1954) encountered a somewhat similar situation when they fed growing chicks diets supplying a wide range of energy levels produced by introducing oat hulls into the diet. They found that the birds on the different diets did not consume equal amounts of energy. The bulk of the ration was not, however, the sole factor limiting feed consumption, since the birds did not eat to physical capacity. From Table 3 it will be seen that the hen-day capacity of the birds was at least 0.298 lb. of feed. The 0.245 lb. of feed consumed per hen-day by the birds on ration 3, although not limiting the rate of production, nevertheless was not sufficient for maximum egg size. SUMMARY
The effects of adding fat, with and without a concomitant increase in energy level, to the ration fed to 11-months old laying birds are reported. Body weight, mortality, rate of egg production, albumen quality and shell thickness were not significantly affected by the level of fat in the ration. Egg size was reduced when 10 percent of fat was added to the ration without increasing the energy level. It is concluded that the reduction in egg size was related to the decrease in feed intake of the birds fed this ration. ACKNOWLEDGMENTS
The study was carried out with the financial assistance of the British Columbia Department of Agriculture, Victoria, B.C., and the British Columbia Feed Manufacturers' Association, Vancouver, B.C.
Downloaded from http://ps.oxfordjournals.org/ at toledo hospital on May 3, 2015
"Changes in quantity or quality of the ration tend to affect egg production before modifying egg weight." More recent evidence, however, indicates that egg size is affected by protein and energy intake. Berg and Bearse (1957) found that a high protein-high energy diet increased egg size and that a low protein-low energy diet decreased it. Hochreich et al. (1958) and Treat et al. (1960) reported that the addition of fat to laying rations increased egg weight. Orr et al. (1958) on the other hand, stated that the addition of fat to a laying ration did not affect egg weight. Combs et al. (1961) reported that egg size could be reduced by restricting energy intake, while maintaining the level of other nutrients. In view of these findings it is difficult to understand why, in the present study, the only response obtained with regard to egg size from the addition of fat to the laying ration should have been a decrease in egg size when 10 percent of fat was fed in a ration isocaloric with the control ration. Gaghir et al. (1960) fed 12 percent of fat in diets isocaloric and isonitrogenous with a control diet without supplementary fat, without significantly affecting egg weight. Harms and Waldroup (1960) conducted an experiment in which laying birds were fed diets similar in energy content but composed of different ingredients. A ration which contained 4.8 percent of supplementary fat and a mixture of ground oats and yellow corn as the cereal resulted in smaller eggs than did a ration containing yellow corn only, and no supplementary fat. Harms and Waldroup conclude that their data substantiate the findings of Jensen et al. (1957) in indicating the presence of a factor in yellow corn necessary for maximum egg weight.
23
24
B. E. MARCH AND J. BIELY
The tallow (Sta-Y-Fat) used in the study was kindly supplied by Gordon Young (B.C.) Ltd. REFERENCES
Sci. 3 7 : 212-214.
Potter, L. M., L. D. Matterson, M. W. Stutz and E. P. Singsen, 1961. The metabolisable energy of feed ingredients for chickens. Progress Report 39 (revised), Experiment Station, College of Agriculture, University of Connecticut. Romanoff, A. L., and A. J. Romanoff, 1949. The Avian Egg. John Wiley and Sons Inc., New York. Treat, C. M., B. L. Reid, R. E. Davies and J. R. Couch, 1960. The effect of animal fat and mixtures of animal fatty acids on performance of cage layers. Poultry Sci: 39: 1550-1555.
Effect of Phosphate Treatment on Carcass-Weight Changes and Organoleptic Quality of Cut-Up Chicken 1 K. N. MAY, 2 R. L. HELMER 3 AND R. L. SAFFLE3 University of Georgia, and Market Quality Research Division, AMS, Athens, Georgia
USDA,
(Received for publication May 28, 1962)
EIGHT loss from eviscerated chicken carcasses due to dehydration is a common problem in the commercial processing industry. The changes in carcass weight during processing and holding of whole carcasses have been investigated by many workers including Bigbee and Dawson (1961), Fromm and Monroe (1958), Kotula et al. (1960a, b), Thomson et al. (1961), and Tarver et al. (1956). Cut-up birds, held in a fresh state, lose more mois-
ture than whole carcasses. Jordan and Saunders (1958) reported a 1.9 percent loss and a 0.6 percent loss when broilers "Journal Paper No. 231, College Experiment Station, College of Agriculture Experiment Stations, University of Georgia, Athens, Georgia. 2 Poultry Department, University of Georgia and Field Crops and Animal Products Branch, Market Quality Research Division, AMS, U.S. Department of Agriculture. 3 Food Technology Department, University of Georgia.
Downloaded from http://ps.oxfordjournals.org/ at toledo hospital on May 3, 2015
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