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Factors Affecting the Metabolizable Energy Content of Poultry Feeds
Factors Affecting the Metabolizable Energy Content of Poultry Feeds 9. SODIUM CHLORIDE I. R. SIBBALD AND S. J. SLINGER Departments of Nutrition and Poultry Science, Ontario Agricultural College, Guelph, Ontario, Canada (Received for publication July 20, 1961)
T
HE available energy content of a poultry feed ingredient is not constant but may be influenced by the nature and quantities of the materials with which it is fed. Evidence of this fact was presented by Matterson et al. (1958) who reported that the metabolizable energy (M.E.) content of a sample of corn varied according to whether it was fed alone or in combination with other materials. This finding was reminiscent of that of Mitchell (1942) who reported on the "non-additive" effects of feeds in ruminant nutrition. Wilder et al. (1959) and Kalmbach and Potter (1959) provided evidence that the M.E. values of fats were not constant while Sibbald et al. (1959) demonstrated that dietary protein quality may influence energy availability. Since 1959 a number of reports demonstrating the "non-additivity" of M.E. values have appeared; a few contradictory findings have also been published. Sibbald et al. (1959, 1960a) reported that the M.E. content of corn was significantly (P<0.05) greater when fed in conjunction with a corn gluten basal than when either meat meal or soybean oil meal basals were employed; wheat did not show the same variation. This report suggested that protein quality might influence M.E. values. Baldini (1960) observed that the M.E. content of a methionine deficient diet was greater than that of the same diet in which the deficiency had been corrected. Work by Carew and Hill (1961)
failed to reveal an effect of methionine on M.E. values. Sibbald et al. (1962a) examined the effects of multiple deficiencies, including methionine, riboflavin, niacin and vitamin Bi2, on M.E. values and reported that the effect of methionine was not constant but could be positive, negative or neutral depending upon the other dietary components. Dietary protein level was implicated as a possible influence on M.E. values by Olsen el al. (1961) although it was suggested that sodium chloride rather than protein level might have been the agent which caused the observed variability in the M.E. data. Sibbald et al. (1960b, 1961a) observed that the M.E. values of fats were influenced by the protein levels of the rations with which they were combined; however, the M.E. values of cereal grains do not appear to be affected by the amount of protein in the ration (Sibbald etal., 1961b, 1962b). Metabolizable energy values of fats have revealed many peculiarities. Sibbald el al. (1960b, 1961a) found that not only were M.E. values of tallow and undegummed soybean oil influenced by the level of dietary inclusion and dietary protein content but that mixtures of the two fats had M.E. values greater than the arithmetric mean. Further evidence of synergistic relationships between fatty materials has been presented by Sibbald et al. (1961c, 1962c). Young and Renner (1960) reported that certain unsaturated
573
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I . R . SlBBALD AND S. J . SLINGER
fatty acids and mono- and tri-glycerides may influence fat absorption by the chick while Renner and Hill (1960) observed that the utilization of tallow varied according to the age of the birds to which it was fed; corn oil and lard did not exhibit this latter variation. The nutrient density of a mixed feed may influence the utilization of the energy of the individual components thereof. Anderson and Hill (1955) and Anderson et al. (1958) showed cellulose to have an M.E. value approximately equal to zero; however, Potter et al. (1958, 1960) reported a negative value for alpha cellulose. Sibbald et al. (1959, 1960a) reported positive M.E. values for alpha cellulose and postulated that such values might be attributable to the diluting effect of the cellulose. Further work on the effects of ration dilution (Sibbald et al., 1960c, 1961d) demonstrated that kaolin, an inorganic clay, contained as much M.E. as alpha cellulose thereby suggesting that dilution may increase energy availability although the magnitudes of the increases observed were quite small.
It is apparent that many factors may influence the utilization of feed energy; however, from a practical standpoint M.E. values seem to be useful guides except for evaluating fatty materials. The present report concerns two experiments designed to study the effects of sodium chloride, present in either the feed or the drinking water, on energy availability. METHODS
The first experiment was of a randomized block design and involved 8 diet treatments each of which was fed, for 4 weeks, to 4 replicated pens of 20 chicks. Day-old, male, strain-cross White Leghorn chicks were randomly distributed between the 32 electrically heated, wire floored pens. The appropriate diets and tap-water were offered ad libitum. The treatments consisted of a chick starter diet (Table 1) supplemented with 0.0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0 or 16.0% of sodium chloride; the salt was added at the expense of an equal weight of basal diet. Excreta samples were collected from each pen on the 24th, 26th and 28th days Many other factors may influence M.E. of the experiment. The 3 samples from values. Brambila et al. (1960) demonstrat- each pen were pooled, freeze-dried, ground ed that the M.E. content of raw soybean and, together with samples of the diets, oil meal might be improved by the addi- assayed for gross energy using a Parr tion of trypsin. Sibbald et al. (1961e) ob- Oxygen Bomb Calorimeter, nitrogen by served that dietary calcium, phosphorus, the method of Kjeldahl (A.O.A.C, 1955) antibiotic and pantothenic acid levels and chromium sesquioxide by the method exert small and variable influences upon of Czarnocki et al. (1961). The calculation energy availability; however, Slinger et al. of M.E. values followed the procedures (1962), working with turkeys, were unable described by Sibbald et al. (1961a). to detect significant influences of calcium, On completion of the 4 week experiment chlortetracycline or reserpine. Mcintosh the chicks which had received feed conel al. (1962) observed that the form in taining 0.0, 4.0, 8.0 or 16.0% of sodium which a grain is fed, the availability of chloride were discarded. The remaining grit and the balance of the ration may in- birds were fed the chick starter diet fluence the M.E. values of cereal grains. (Table 1) supplemented with 0.5% of salt Begin (1961) has reported close agreement for 7 days. The chicks were then divided between calculated and determined M.E. into weight groups and the heavy and values. light birds were discarded. The remaining
575
SALT AND METABOLIZABLE ENERGY TABLE 1.—Composition of the chick starter diet1 Ingredient Ground wheat Ground corn Soybean oil meal (50% protein) Dehydrated alfalfa meal Meat meal (50% protein) Dried whey Distillers dried solubles Ground limestone Dicalcium phosphate Stabilized animal fat Vitamin A (10,000 I.U./gm.) Vitamin D 3 (1,650 I.C.U./gm.) DL methionine (feed grade) Riboflavin (24 gm./lb.) d-calcium pantothenate (2 gm./oz.) Niacin Procaine penicillin G (10 gm./lb.) Vitamin Bi2 (9 mg./lb.) Choline chloride (25%) 3-nitro, 4-hydroxy-phenylarsonic acid (10%) Manganese sulphate (75% MnS0 4 ) Calcium iodate Zinc oxide (80% Zn)
lb. 29.0 29.15 29.0 2.0 2.5 1.5 1.5 1.0 1.5 2.5 gm. 22.7 22.7 22.7 1.33 3.0 0.8 0.2 30.3 22.7 22.7 6.0 3.0 0.2
1 Diet also contained 0.3% chromium sesquioxide.
chicks were randomly distributed between 16 wire floored pens until each pen contained 10 birds. All chicks were fed the chick starter diet, with no added salt, ad libitum for two weeks, during which period 4 replicated pens of birds were offered water containing 0.0, 0.2, 0.4 or 0.8% of sodium chloride. Excreta and feed samples collected during the second week of this second experiment were used to determine M.E. values for the starter ration. The weight gain and feed consumption data collected during the course of these experiments form part of an earlier report (Sibbald^a/., 1962d). RESULTS AND DISCUSSION
The mean results obtained from the first experiment are presented in Table 2. As the amount of salt included in the diet increased the gross energy content decreased
thereby demonstrating that sodium chloride, in itself, is not a source of energy for the chick. The classical M.E. values for the entire diets were relatively uniform with the single exception of the low value for the diet containing 16% of salt. When the classical M.E. values were expressed as Cal. per gm. of basal it was found that increasing the dietary salt level tended to increase the availability of the energy of the non-salt portion. Similar findings were demonstrated by the corrected M.E. data. Analyses of variance revealed that both the classical and the corrected M.E. values for the basal portions of the rations increased in a significantly (P<0.01) linear manner as the level of dietary sodium chloride increased. The corrected M.E. data do not show as great a response to changing salt levels as do the classical values. The reason for this is that at high salt levels apparently more nitrogen was retained by the chicks; consequently, the correction for retained nitrogen increased as the dietary salt content increased. The metabolizable nitrogen (M.N.) data suggest that it was only when the diets contained 4, 8 or 16% of added salt that nitrogen retention increased appreciably. The excreta of the birds fed these diets was extremely wet and it is believed that as a consequence of this more nitrogen was lost through oxidaTABLE 2.—The mean results of experiment I Added NaCI
Gross energy of feed
%
Cal. 4.10 4.09 4.06 4.07 4.02 3.94 3.76 3.42
0.0
0.25 0.50 1.00 2.00 4.00 8.00 16.00 1 2
Classical M.E./gm.i'2 Diet
Basal
Cal. 3.00 3.04 2.98 3.05 3.06 3.08 3.01 2.80
Cal. 3.00 3.05 2.99 3.08 3.12 3.21 3.27 3.34
Correct M.E./g;m.i'»
M.N./ -
gm.a
•
. feed
Diet
Basal
mg.
Cal. 2.85 2.89 2.85 2.90 2.90 2.88 2.80 2.61
Cal. 2.86 2.90 2.86 2.93 2.96 3.00 3.04 3.10
16.9 17.4 15.0 17.2 18.2 23.8 23.9 22.6
Classical not corrected for nitrogen retained in the body. Diet refers to ration as fed whereas basal is corrected to a salt-free basis. 1 M.N. refers to metabolizable nitrogen.
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I . R . SlBBALD AND S. J . SLINGER
TABLE 3.—The mean results of experiment 2 NaCl in water
%
0.0 0.2 0.4 0.8
Classical M.E./gm. feed
M.N./gm. feed
Correct M.E./gm. feed
Cal. 2.89 2.96 3.03 3.09
mg. 11.6 13.6 16.0 24.5
Cal. 2.79 2.84 2.89 2.88
tion. Nitrogen lost to the atmosphere is considered to be nitrogen retained in studies of this type for carcass analyses are rarely performed; consequently, it is believed that the M.N. data for the high salt diets are too large and that therefore the classical M.E. values represent a more correct evaluation of the effect of dietary salt on energy availability than do corrected values. The mean results obtained from the second experiment are presented in Table 3. As the level of salt in the drinking water increased, the classical M.E. values for the ration, containing no added salt, increased in a linear manner (P<0.01). The corrected M.E. values also tended to increase (P<0.05) but not to the same degree. Again it may be noted that the M.N. values tended to increase with salt levels and thereby reduce the corrected M.E. data disproportionately. The results of the two experiments support one another and demonstrate that sodium chloride may have a considerable influence upon energy availability. Olsen et al. (1961) put forward the hypothesis that increasing dietary salt levels may decrease energy availability. The results presented herein contradict this hypothesis and suggest that the type of protein rather than the salt content may explain the results of this group. As was mentioned earlier, evidence for an effect of protein quality has been obtained. From a purely practical standpoint it is doubtful if the levels of salt generally in-
corporated into poultry rations would have any major effect upon energy availability; however, the results indicate that in the derivation of M.E. data the difference in salt content between control and test diets might cause misleading values to be obtained. There is apparently much to be learned before M.E. data can be accepted without reservations. SUMMARY
Two randomized block design experiments were conducted to study the effects of sodium chloride, added either to the feed or to the drinking water, on metabolizable energy (M.E.) values. When high levels of salt were fed the excreta was extremely wet and it is believed that there was a considerable nitrogen loss which introduced a bias into the corrected M.E. data. The classical M.E. values demonstrated that as the level of sodium chloride in the feed or drinking water increased, the availability of the energy of the nonsalt portions of the ration also increased. At low levels of salt in the feed small variations had no practical effect on metabolizable energy values; however, it is suggested that the difference in salt content between control and test diets in the determination of M.E. data may have an important effect. REFERENCES Anderson, D. L., and F. W. Hill, 1955. Determination of metabolizable energy values for chicks of pure carbohydrates, cellulose, fat and casein. Poultry Sci. 34: 1176. Anderson, D. L., F. W. Hill and R. Renner, 1958. Studies of the metabolizable and productive energy of glucose for the growing chick. J. Nutrition, 65: 561-574. Association of Official Agricultural Chemists, 1955. Methods of Analysis, 8th Edition, Washington, D. C. Baldini, J. T., 1960. The effect of dietary deficiency on the energy metabolism of the chick. Poultry Sci. 39: 1232.
SALT AND METABOLIZABLE ENERGY Begin, J. J., 1961. A comparison of calculated and determined metabolizable energy values. Poultry Sci. 40: 674-676. Brambila, S., M. C. Nesheim and F. W. Hill, 1960. Studies of the effect of trypsin on the utilization of a raw soybean oil meal by the chick. Poultry Sci. 39:1237. Carew, L. B., Jr., and F. W. Hill, 1961. Effect of methionine deficiency on the utilization of energy by the chick. J. Nutrition, 74: 185-190. Czarnocki, J., I. R. Sibbald and E. V. Evans, 1961. The determination of chromic oxide in samples of feed and excreta by acid digestion and spectrophotometry. Can. J. Animal Sci. 41:167-179. Kalmbach, M. P., and L. M. Potter, 1959. Studies in evaluating energy content of feeds for the chick. 3. The comparative values of corn oil and tallow. Poultry Sci. 38:1217. Matterson, L. D., L. M. Potter, A. W. Arnold and E. P. Singsen, 1958. Studies in evaluating energy content of feeds for the chick. 2. Methods of evaluating feed ingredients for their metabolizable energy in the chick. Poultry Sci. 37: 1225. Mcintosh, J. I., S. J. Slinger, I. R. Sibbald and G. C. Ashton, 1962. Factors affecting the metabolizable energy content of poultry feeds. 7. The effects of grinding, pelleting and grit feeding on the availability of the energy of wheat, corn, oats and barley. Poultry Sci. 41: 445—156. Mitchell, H. H., 1942. The evaluation of feeds on the basis of digestible and metabolizable nutrients. J. An. Sci. 1: 159-173. Olsen, G., W. C. Lockhart, D. W. Bolin and R. L. Bryant, 1961. Metabolizable energy values of soybean oil meal and meat meal as affected by protein level and type. Poultry Sci. 40: 260-262. Potter, L. M., L. D. Matterson, A. W. Arnold, W. J. Pudelkiewicz and E. P. Singsen, 1958. Studies in evaluating energy content of feed for the chick. 1. The evaluation of alpha cellulose for its metabolizable and productive energy. Poultry Sci. 37: 1234. Potter, L. M., L. D. Matterson, A. W. Arnold, W. J. Pudelkiewicz and E. P. Singsen, 1960. Studies in evaluating energy content of feeds for the chick. 1. The evaluation of the metabolizable energy and productive energy of alpha cellulose. Poultry Sci. 39: 1166-1178. Renner, R., and F. W. Hill, 1960. The utilization of corn oil, lard and tallow by chickens of various ages. Poultry Sci. 39: 849-854. Sibbald, I. R., J. D. Summers and S. J. Slinger, 1959. Factors affecting the metabolizable energy content of poultry feeds. Poultry Sci. 38: 1247. Sibbald, I. R., J. D. Summers and S. J. Slinger,
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1960a. Factors affecting the metabolizable energy content of poultry feeds. Poultry Sci. 39: 544-556. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1960b. A synergistic relationship between tallow and undegummed soybean oil. Poultry Sci. 39: 1295. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1960c. The metabolizable energy content of a chick starter diet diluted with cellulose and with kaolin. Poultry Sci. 39: 1294-1295. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1961a. Factors affecting the metabolizable energy content of poultry feeds. 2. Variability in the M.E. values attributed to samples of tallow and undegummed soybean oil. Poultry Sci. 40: 303-308. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1961b. The effect of level of protein and of test material on metabolizable energy values. Poultry Sci. 40: 1455. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1961c. Nutritional evaluation of a number of fatty materials and mixtures thereof. Poultry Sci. 401455. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1961d. Factors affecting the metabolizable energy content of poultry feeds. 3. The influence of kaolin and Alphacel when used as ration diluents. Poultry Sci. 40: 454-458. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1961e. Factors affecting the metabolizable energy content of poultry feeds. 4. The influences of calcium, phosphorus, antibiotics and pantothenic acid. Poultry Sci. 40: 945-951. Sibbald, I. R., S. J. Slinger and W. F. Pepper, 1962a. Interrelationships between riboflavin, niacin, vitamin B12 and methionine measured in terms of chick weight gains and dietary metabolizable energy values. Poultry Sci. 41:380-386. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1962b. Factors affecting the metabolizable energy content of poultry feeds. 5. The level of protein and of test material in the diet. 6. A note on the relationship between digestible and metabolizable energy values. Poultry Sci. 41: 107-116. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1962c. The utilization of a number of fats, fatty materials and mixtures thereof evaluated in terms of metabolizable energy, chick weight gains and gain: feed ratios. Poultry Sci. 41:46-61. Sibbald, I. R., W. F. Pepper and S. J. Slinger, 1962d. Sodium chloride in the feed and drinking water of chicks. Poultry Sci. 41: 541-545. Slinger, S. J., W. F. Pepper, I. Motzok and I. R. Sibbald, 1962. Studies on the calcium requirements of turkeys. 3. Influence of chlortetracy-
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cline and reserpine during the starting and growing periods. Poultry Sci. 41: 460-467. Wilder, 0 . H. M., M. P. Cullen and O. G. Rasmussen, 1959. Metabolizable energy values of different types and grades of fats used in practical
chick diets. Poultry Sci. 38: 1259-1260. Young, R. J., and R. Renner, 1960. Factors affecting the utilization of fats and fatty acids by the chicken. Proc. Cornell Nutrition Conference, pp. 75-80.
Further Studies on the Relationship of Egg Production Rate as Affected by Feed to Haugh Units of Eggs 1 R. H. HARMS, W. B. LESTER AND P. W. WALDROTJP Department of Poultry Science, Florida Agricultural Experiment Stations, Gainesville (Received for publication July 25, 1961)
H
ARMS and Douglas (1960) suggested that a valid comparison could not be made on Haugh unit values of eggs from hens producing at different rates in nutritional experiments. They found a negative correlation between rate of past egg production as influenced by dietary treatment and Haugh units of eggs. In order to gather more information on this relationship, Haugh units of eggs were determined from pullets fed diets which varied sufficiently in protein and energy so as to greatly affect rate of egg production. PROCEDURE
Commerical egg production type pullets were used in these experiments. They were grown in confinement and "full fed" during the entire growing period. The starter diet fed during the first eight weeks contained 22 percent protein and 940 Calories of productive energy per pound of diet. The grower diet, fed from 8 to 20 weeks, contained 16 percent protein in experiment 1 and 9 percent protein in experiment 2 with each having 940 Calories of productive energy per pound of diet. The pullets were housed in individual 1 Florida Agricultural Experiment Stations, Journal Series No. 1295.
TABLE 1.—Composition of basal diets Experiment 1 Ingredients
Basal No. 1
Yellow corn Pulverized oats Oat hulls Soybean oil meal (50% protein) Stabilized animal fat Alfalfa meal (17% protein) Ground limestone Defluorinated phosphate (34% C a + 1 8 % P) Iodized salt Micro ingredients 1
—
39.4 13.0 23.2 13.5 3.0 4.6 2.4 0.4 0.5
2
Experiment 2 Basal No. 3
(Lbs./cwt.) 56.0 63.6
—
— —
7.4 22.3 3.4 3.0 4.6
21.6 4.4 3.0 4.2
2.4 0.4 0.5
2.3 0.4 0.5
1 Supplies per pound of diet: 2,000 I.U. vitamin A, 700 I.C.U. vitamin D3, 6 meg. vitamin B12, 2 mg. riboflavin, 4 mg. calcium pantothenate, 6 mg. niacin, 227 mg. choline chloride, 2.5 I.U. vitamin E, and 80 mg. MnSOa.
cages at 20 weeks of age, at which time they were randomly assigned to the various groups and placed on the experimental layer diets. Six replicate groups, each containing five pullets, were fed on each of the experimental diets. The composition of the basal diets is shown in Table 1. Basal diets 1 and 2 were used in experiment 1. These diets were formulated to contain equivalent levels of energy and protein. The major difference between these diets was that oats was the only cereal grain used in basal 1, and yellow corn in basal 2. Basal 1 and 2 were modified to form six other experimental diets with various levels of energy as shown in Table 2. These adjustments were
T
HE available energy content of a poultry feed ingredient is not constant but may be influenced by the nature and quantities of the materials with which it is fed. Evidence of this fact was presented by Matterson et al. (1958) who reported that the metabolizable energy (M.E.) content of a sample of corn varied according to whether it was fed alone or in combination with other materials. This finding was reminiscent of that of Mitchell (1942) who reported on the "non-additive" effects of feeds in ruminant nutrition. Wilder et al. (1959) and Kalmbach and Potter (1959) provided evidence that the M.E. values of fats were not constant while Sibbald et al. (1959) demonstrated that dietary protein quality may influence energy availability. Since 1959 a number of reports demonstrating the "non-additivity" of M.E. values have appeared; a few contradictory findings have also been published. Sibbald et al. (1959, 1960a) reported that the M.E. content of corn was significantly (P<0.05) greater when fed in conjunction with a corn gluten basal than when either meat meal or soybean oil meal basals were employed; wheat did not show the same variation. This report suggested that protein quality might influence M.E. values. Baldini (1960) observed that the M.E. content of a methionine deficient diet was greater than that of the same diet in which the deficiency had been corrected. Work by Carew and Hill (1961)
failed to reveal an effect of methionine on M.E. values. Sibbald et al. (1962a) examined the effects of multiple deficiencies, including methionine, riboflavin, niacin and vitamin Bi2, on M.E. values and reported that the effect of methionine was not constant but could be positive, negative or neutral depending upon the other dietary components. Dietary protein level was implicated as a possible influence on M.E. values by Olsen el al. (1961) although it was suggested that sodium chloride rather than protein level might have been the agent which caused the observed variability in the M.E. data. Sibbald et al. (1960b, 1961a) observed that the M.E. values of fats were influenced by the protein levels of the rations with which they were combined; however, the M.E. values of cereal grains do not appear to be affected by the amount of protein in the ration (Sibbald etal., 1961b, 1962b). Metabolizable energy values of fats have revealed many peculiarities. Sibbald el al. (1960b, 1961a) found that not only were M.E. values of tallow and undegummed soybean oil influenced by the level of dietary inclusion and dietary protein content but that mixtures of the two fats had M.E. values greater than the arithmetric mean. Further evidence of synergistic relationships between fatty materials has been presented by Sibbald et al. (1961c, 1962c). Young and Renner (1960) reported that certain unsaturated
573
574
I . R . SlBBALD AND S. J . SLINGER
fatty acids and mono- and tri-glycerides may influence fat absorption by the chick while Renner and Hill (1960) observed that the utilization of tallow varied according to the age of the birds to which it was fed; corn oil and lard did not exhibit this latter variation. The nutrient density of a mixed feed may influence the utilization of the energy of the individual components thereof. Anderson and Hill (1955) and Anderson et al. (1958) showed cellulose to have an M.E. value approximately equal to zero; however, Potter et al. (1958, 1960) reported a negative value for alpha cellulose. Sibbald et al. (1959, 1960a) reported positive M.E. values for alpha cellulose and postulated that such values might be attributable to the diluting effect of the cellulose. Further work on the effects of ration dilution (Sibbald et al., 1960c, 1961d) demonstrated that kaolin, an inorganic clay, contained as much M.E. as alpha cellulose thereby suggesting that dilution may increase energy availability although the magnitudes of the increases observed were quite small.
It is apparent that many factors may influence the utilization of feed energy; however, from a practical standpoint M.E. values seem to be useful guides except for evaluating fatty materials. The present report concerns two experiments designed to study the effects of sodium chloride, present in either the feed or the drinking water, on energy availability. METHODS
The first experiment was of a randomized block design and involved 8 diet treatments each of which was fed, for 4 weeks, to 4 replicated pens of 20 chicks. Day-old, male, strain-cross White Leghorn chicks were randomly distributed between the 32 electrically heated, wire floored pens. The appropriate diets and tap-water were offered ad libitum. The treatments consisted of a chick starter diet (Table 1) supplemented with 0.0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0 or 16.0% of sodium chloride; the salt was added at the expense of an equal weight of basal diet. Excreta samples were collected from each pen on the 24th, 26th and 28th days Many other factors may influence M.E. of the experiment. The 3 samples from values. Brambila et al. (1960) demonstrat- each pen were pooled, freeze-dried, ground ed that the M.E. content of raw soybean and, together with samples of the diets, oil meal might be improved by the addi- assayed for gross energy using a Parr tion of trypsin. Sibbald et al. (1961e) ob- Oxygen Bomb Calorimeter, nitrogen by served that dietary calcium, phosphorus, the method of Kjeldahl (A.O.A.C, 1955) antibiotic and pantothenic acid levels and chromium sesquioxide by the method exert small and variable influences upon of Czarnocki et al. (1961). The calculation energy availability; however, Slinger et al. of M.E. values followed the procedures (1962), working with turkeys, were unable described by Sibbald et al. (1961a). to detect significant influences of calcium, On completion of the 4 week experiment chlortetracycline or reserpine. Mcintosh the chicks which had received feed conel al. (1962) observed that the form in taining 0.0, 4.0, 8.0 or 16.0% of sodium which a grain is fed, the availability of chloride were discarded. The remaining grit and the balance of the ration may in- birds were fed the chick starter diet fluence the M.E. values of cereal grains. (Table 1) supplemented with 0.5% of salt Begin (1961) has reported close agreement for 7 days. The chicks were then divided between calculated and determined M.E. into weight groups and the heavy and values. light birds were discarded. The remaining
575
SALT AND METABOLIZABLE ENERGY TABLE 1.—Composition of the chick starter diet1 Ingredient Ground wheat Ground corn Soybean oil meal (50% protein) Dehydrated alfalfa meal Meat meal (50% protein) Dried whey Distillers dried solubles Ground limestone Dicalcium phosphate Stabilized animal fat Vitamin A (10,000 I.U./gm.) Vitamin D 3 (1,650 I.C.U./gm.) DL methionine (feed grade) Riboflavin (24 gm./lb.) d-calcium pantothenate (2 gm./oz.) Niacin Procaine penicillin G (10 gm./lb.) Vitamin Bi2 (9 mg./lb.) Choline chloride (25%) 3-nitro, 4-hydroxy-phenylarsonic acid (10%) Manganese sulphate (75% MnS0 4 ) Calcium iodate Zinc oxide (80% Zn)
lb. 29.0 29.15 29.0 2.0 2.5 1.5 1.5 1.0 1.5 2.5 gm. 22.7 22.7 22.7 1.33 3.0 0.8 0.2 30.3 22.7 22.7 6.0 3.0 0.2
1 Diet also contained 0.3% chromium sesquioxide.
chicks were randomly distributed between 16 wire floored pens until each pen contained 10 birds. All chicks were fed the chick starter diet, with no added salt, ad libitum for two weeks, during which period 4 replicated pens of birds were offered water containing 0.0, 0.2, 0.4 or 0.8% of sodium chloride. Excreta and feed samples collected during the second week of this second experiment were used to determine M.E. values for the starter ration. The weight gain and feed consumption data collected during the course of these experiments form part of an earlier report (Sibbald^a/., 1962d). RESULTS AND DISCUSSION
The mean results obtained from the first experiment are presented in Table 2. As the amount of salt included in the diet increased the gross energy content decreased
thereby demonstrating that sodium chloride, in itself, is not a source of energy for the chick. The classical M.E. values for the entire diets were relatively uniform with the single exception of the low value for the diet containing 16% of salt. When the classical M.E. values were expressed as Cal. per gm. of basal it was found that increasing the dietary salt level tended to increase the availability of the energy of the non-salt portion. Similar findings were demonstrated by the corrected M.E. data. Analyses of variance revealed that both the classical and the corrected M.E. values for the basal portions of the rations increased in a significantly (P<0.01) linear manner as the level of dietary sodium chloride increased. The corrected M.E. data do not show as great a response to changing salt levels as do the classical values. The reason for this is that at high salt levels apparently more nitrogen was retained by the chicks; consequently, the correction for retained nitrogen increased as the dietary salt content increased. The metabolizable nitrogen (M.N.) data suggest that it was only when the diets contained 4, 8 or 16% of added salt that nitrogen retention increased appreciably. The excreta of the birds fed these diets was extremely wet and it is believed that as a consequence of this more nitrogen was lost through oxidaTABLE 2.—The mean results of experiment I Added NaCI
Gross energy of feed
%
Cal. 4.10 4.09 4.06 4.07 4.02 3.94 3.76 3.42
0.0
0.25 0.50 1.00 2.00 4.00 8.00 16.00 1 2
Classical M.E./gm.i'2 Diet
Basal
Cal. 3.00 3.04 2.98 3.05 3.06 3.08 3.01 2.80
Cal. 3.00 3.05 2.99 3.08 3.12 3.21 3.27 3.34
Correct M.E./g;m.i'»
M.N./ -
gm.a
•
. feed
Diet
Basal
mg.
Cal. 2.85 2.89 2.85 2.90 2.90 2.88 2.80 2.61
Cal. 2.86 2.90 2.86 2.93 2.96 3.00 3.04 3.10
16.9 17.4 15.0 17.2 18.2 23.8 23.9 22.6
Classical not corrected for nitrogen retained in the body. Diet refers to ration as fed whereas basal is corrected to a salt-free basis. 1 M.N. refers to metabolizable nitrogen.
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I . R . SlBBALD AND S. J . SLINGER
TABLE 3.—The mean results of experiment 2 NaCl in water
%
0.0 0.2 0.4 0.8
Classical M.E./gm. feed
M.N./gm. feed
Correct M.E./gm. feed
Cal. 2.89 2.96 3.03 3.09
mg. 11.6 13.6 16.0 24.5
Cal. 2.79 2.84 2.89 2.88
tion. Nitrogen lost to the atmosphere is considered to be nitrogen retained in studies of this type for carcass analyses are rarely performed; consequently, it is believed that the M.N. data for the high salt diets are too large and that therefore the classical M.E. values represent a more correct evaluation of the effect of dietary salt on energy availability than do corrected values. The mean results obtained from the second experiment are presented in Table 3. As the level of salt in the drinking water increased, the classical M.E. values for the ration, containing no added salt, increased in a linear manner (P<0.01). The corrected M.E. values also tended to increase (P<0.05) but not to the same degree. Again it may be noted that the M.N. values tended to increase with salt levels and thereby reduce the corrected M.E. data disproportionately. The results of the two experiments support one another and demonstrate that sodium chloride may have a considerable influence upon energy availability. Olsen et al. (1961) put forward the hypothesis that increasing dietary salt levels may decrease energy availability. The results presented herein contradict this hypothesis and suggest that the type of protein rather than the salt content may explain the results of this group. As was mentioned earlier, evidence for an effect of protein quality has been obtained. From a purely practical standpoint it is doubtful if the levels of salt generally in-
corporated into poultry rations would have any major effect upon energy availability; however, the results indicate that in the derivation of M.E. data the difference in salt content between control and test diets might cause misleading values to be obtained. There is apparently much to be learned before M.E. data can be accepted without reservations. SUMMARY
Two randomized block design experiments were conducted to study the effects of sodium chloride, added either to the feed or to the drinking water, on metabolizable energy (M.E.) values. When high levels of salt were fed the excreta was extremely wet and it is believed that there was a considerable nitrogen loss which introduced a bias into the corrected M.E. data. The classical M.E. values demonstrated that as the level of sodium chloride in the feed or drinking water increased, the availability of the energy of the nonsalt portions of the ration also increased. At low levels of salt in the feed small variations had no practical effect on metabolizable energy values; however, it is suggested that the difference in salt content between control and test diets in the determination of M.E. data may have an important effect. REFERENCES Anderson, D. L., and F. W. Hill, 1955. Determination of metabolizable energy values for chicks of pure carbohydrates, cellulose, fat and casein. Poultry Sci. 34: 1176. Anderson, D. L., F. W. Hill and R. Renner, 1958. Studies of the metabolizable and productive energy of glucose for the growing chick. J. Nutrition, 65: 561-574. Association of Official Agricultural Chemists, 1955. Methods of Analysis, 8th Edition, Washington, D. C. Baldini, J. T., 1960. The effect of dietary deficiency on the energy metabolism of the chick. Poultry Sci. 39: 1232.
SALT AND METABOLIZABLE ENERGY Begin, J. J., 1961. A comparison of calculated and determined metabolizable energy values. Poultry Sci. 40: 674-676. Brambila, S., M. C. Nesheim and F. W. Hill, 1960. Studies of the effect of trypsin on the utilization of a raw soybean oil meal by the chick. Poultry Sci. 39:1237. Carew, L. B., Jr., and F. W. Hill, 1961. Effect of methionine deficiency on the utilization of energy by the chick. J. Nutrition, 74: 185-190. Czarnocki, J., I. R. Sibbald and E. V. Evans, 1961. The determination of chromic oxide in samples of feed and excreta by acid digestion and spectrophotometry. Can. J. Animal Sci. 41:167-179. Kalmbach, M. P., and L. M. Potter, 1959. Studies in evaluating energy content of feeds for the chick. 3. The comparative values of corn oil and tallow. Poultry Sci. 38:1217. Matterson, L. D., L. M. Potter, A. W. Arnold and E. P. Singsen, 1958. Studies in evaluating energy content of feeds for the chick. 2. Methods of evaluating feed ingredients for their metabolizable energy in the chick. Poultry Sci. 37: 1225. Mcintosh, J. I., S. J. Slinger, I. R. Sibbald and G. C. Ashton, 1962. Factors affecting the metabolizable energy content of poultry feeds. 7. The effects of grinding, pelleting and grit feeding on the availability of the energy of wheat, corn, oats and barley. Poultry Sci. 41: 445—156. Mitchell, H. H., 1942. The evaluation of feeds on the basis of digestible and metabolizable nutrients. J. An. Sci. 1: 159-173. Olsen, G., W. C. Lockhart, D. W. Bolin and R. L. Bryant, 1961. Metabolizable energy values of soybean oil meal and meat meal as affected by protein level and type. Poultry Sci. 40: 260-262. Potter, L. M., L. D. Matterson, A. W. Arnold, W. J. Pudelkiewicz and E. P. Singsen, 1958. Studies in evaluating energy content of feed for the chick. 1. The evaluation of alpha cellulose for its metabolizable and productive energy. Poultry Sci. 37: 1234. Potter, L. M., L. D. Matterson, A. W. Arnold, W. J. Pudelkiewicz and E. P. Singsen, 1960. Studies in evaluating energy content of feeds for the chick. 1. The evaluation of the metabolizable energy and productive energy of alpha cellulose. Poultry Sci. 39: 1166-1178. Renner, R., and F. W. Hill, 1960. The utilization of corn oil, lard and tallow by chickens of various ages. Poultry Sci. 39: 849-854. Sibbald, I. R., J. D. Summers and S. J. Slinger, 1959. Factors affecting the metabolizable energy content of poultry feeds. Poultry Sci. 38: 1247. Sibbald, I. R., J. D. Summers and S. J. Slinger,
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1960a. Factors affecting the metabolizable energy content of poultry feeds. Poultry Sci. 39: 544-556. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1960b. A synergistic relationship between tallow and undegummed soybean oil. Poultry Sci. 39: 1295. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1960c. The metabolizable energy content of a chick starter diet diluted with cellulose and with kaolin. Poultry Sci. 39: 1294-1295. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1961a. Factors affecting the metabolizable energy content of poultry feeds. 2. Variability in the M.E. values attributed to samples of tallow and undegummed soybean oil. Poultry Sci. 40: 303-308. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1961b. The effect of level of protein and of test material on metabolizable energy values. Poultry Sci. 40: 1455. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1961c. Nutritional evaluation of a number of fatty materials and mixtures thereof. Poultry Sci. 401455. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1961d. Factors affecting the metabolizable energy content of poultry feeds. 3. The influence of kaolin and Alphacel when used as ration diluents. Poultry Sci. 40: 454-458. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1961e. Factors affecting the metabolizable energy content of poultry feeds. 4. The influences of calcium, phosphorus, antibiotics and pantothenic acid. Poultry Sci. 40: 945-951. Sibbald, I. R., S. J. Slinger and W. F. Pepper, 1962a. Interrelationships between riboflavin, niacin, vitamin B12 and methionine measured in terms of chick weight gains and dietary metabolizable energy values. Poultry Sci. 41:380-386. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1962b. Factors affecting the metabolizable energy content of poultry feeds. 5. The level of protein and of test material in the diet. 6. A note on the relationship between digestible and metabolizable energy values. Poultry Sci. 41: 107-116. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1962c. The utilization of a number of fats, fatty materials and mixtures thereof evaluated in terms of metabolizable energy, chick weight gains and gain: feed ratios. Poultry Sci. 41:46-61. Sibbald, I. R., W. F. Pepper and S. J. Slinger, 1962d. Sodium chloride in the feed and drinking water of chicks. Poultry Sci. 41: 541-545. Slinger, S. J., W. F. Pepper, I. Motzok and I. R. Sibbald, 1962. Studies on the calcium requirements of turkeys. 3. Influence of chlortetracy-
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cline and reserpine during the starting and growing periods. Poultry Sci. 41: 460-467. Wilder, 0 . H. M., M. P. Cullen and O. G. Rasmussen, 1959. Metabolizable energy values of different types and grades of fats used in practical
chick diets. Poultry Sci. 38: 1259-1260. Young, R. J., and R. Renner, 1960. Factors affecting the utilization of fats and fatty acids by the chicken. Proc. Cornell Nutrition Conference, pp. 75-80.
Further Studies on the Relationship of Egg Production Rate as Affected by Feed to Haugh Units of Eggs 1 R. H. HARMS, W. B. LESTER AND P. W. WALDROTJP Department of Poultry Science, Florida Agricultural Experiment Stations, Gainesville (Received for publication July 25, 1961)
H
ARMS and Douglas (1960) suggested that a valid comparison could not be made on Haugh unit values of eggs from hens producing at different rates in nutritional experiments. They found a negative correlation between rate of past egg production as influenced by dietary treatment and Haugh units of eggs. In order to gather more information on this relationship, Haugh units of eggs were determined from pullets fed diets which varied sufficiently in protein and energy so as to greatly affect rate of egg production. PROCEDURE
Commerical egg production type pullets were used in these experiments. They were grown in confinement and "full fed" during the entire growing period. The starter diet fed during the first eight weeks contained 22 percent protein and 940 Calories of productive energy per pound of diet. The grower diet, fed from 8 to 20 weeks, contained 16 percent protein in experiment 1 and 9 percent protein in experiment 2 with each having 940 Calories of productive energy per pound of diet. The pullets were housed in individual 1 Florida Agricultural Experiment Stations, Journal Series No. 1295.
TABLE 1.—Composition of basal diets Experiment 1 Ingredients
Basal No. 1
Yellow corn Pulverized oats Oat hulls Soybean oil meal (50% protein) Stabilized animal fat Alfalfa meal (17% protein) Ground limestone Defluorinated phosphate (34% C a + 1 8 % P) Iodized salt Micro ingredients 1
—
39.4 13.0 23.2 13.5 3.0 4.6 2.4 0.4 0.5
2
Experiment 2 Basal No. 3
(Lbs./cwt.) 56.0 63.6
—
— —
7.4 22.3 3.4 3.0 4.6
21.6 4.4 3.0 4.2
2.4 0.4 0.5
2.3 0.4 0.5
1 Supplies per pound of diet: 2,000 I.U. vitamin A, 700 I.C.U. vitamin D3, 6 meg. vitamin B12, 2 mg. riboflavin, 4 mg. calcium pantothenate, 6 mg. niacin, 227 mg. choline chloride, 2.5 I.U. vitamin E, and 80 mg. MnSOa.
cages at 20 weeks of age, at which time they were randomly assigned to the various groups and placed on the experimental layer diets. Six replicate groups, each containing five pullets, were fed on each of the experimental diets. The composition of the basal diets is shown in Table 1. Basal diets 1 and 2 were used in experiment 1. These diets were formulated to contain equivalent levels of energy and protein. The major difference between these diets was that oats was the only cereal grain used in basal 1, and yellow corn in basal 2. Basal 1 and 2 were modified to form six other experimental diets with various levels of energy as shown in Table 2. These adjustments were