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The Relationship Between Classical and Corrected Metabolizable Energy Values
1007
RESEARCH NOTES
4 Nutritional Biochemical Corp., Cleveland. Tentative analysis by gas chromatography shows it to contain approximately 71-75% oleic acid. Other fatty acids possibly present are myristic, myristoleic, palmitic, palmitoleic, stearic, linoleic and linolenic.
4, 5 and 6) better production was noted and group 6 (200 mg. S. joetida oil-2000 mg. oleic acid daily) reached 50% production by the sixteenth week (age 31 weeks). Thus, oleic acid supplementation partially alleviated the delay in sexual maturity and egg production caused by S. joetida oil. Whether a higher level of oleic acid would allow better egg production must still be determined. Also unanswered is the possible mode of action of oleic acid on the pituitary-ovary complex, since onset of egg production was delayed 3 or 4 weeks. There is also the possibility that one of the contaminants in the oleic acid used may act as the alleviating agent. REFERENCES Evans, R. J., J. A. Davidson and S. L. Bandemer, 1961. Fatty acid and lipide distribution in egg yolks from hens fed cottonseed oil or Sterculia joetida seeds. J. Nutrition, 73: 282-290. Panos, T. C , G. F. Klein and J. C. Finerty, 1959. Effects of fat deficiency on pituitary-gonad relationships. J. Nutrition, 68: 509-540. Schneider, D. L., M. G. Vavich, A. A. Kurnick and A. R. Kemmerer, 1961. Effect of Sterculia joetida oil on mortality of the chick embryo. Poultry Sci. 40: 1644-1648. Schneider, D. L., A. A. Kurnick, M. G. Vavich and A. R. Kemmerer, 1962. Delay of sexual maturity in chickens by Sterculia joetida oil. Unpublished data.
THE RELATIONSHIP BETWEEN CLASSICAL AND CORRECTED METABOLIZABLE ENERGY VALUES I . R . SlBBALD AND S. J . SLINGER Departments of Nutrition and Poultry Science, Ontario Agricultural College, Guelph, Ontario, Canada (Received for publication February 7, 1962)
Armsby and Fries (1918) in a study of the net energy values of alfalfa hay and starch, when fed to a steer, corrected the observed energy of urine to a state of nitrogen equilibrium by adding 7.45 Cal. for each gm. of nitrogen retained by the
animal or by subtracting the same amount for each gm. of body nitrogen lost. The correction was considered to represent the energy of excretory materials temporarily retained in the body. It is an established fact that body protein when catabolized
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
ally supplemented daily by gelatin capsule as follows: group 1, empty capsule; group 2, 200 mg. of oleic acid;4 group 3, 200 mg. of S. joetida oil; group 4, 200 mg. of S. joetida oil plus 200 mg. of oleic acid; group 5, 200 mg. of S. joetida oil plus 1200 mg. of oleic acid; and group 6, 200 mg. of S. joetida oil plus 2000 mg. of oleic acid. Figure 1 shows the percent egg production of the groups during 18 weeks of supplementation. Both control groups, 1 and 2, started to lay by the seventh week of supplementation (age 22 weeks) and were in full production by the twelfth week (age 27 weeks), considered normal for this strain of pullets. None of the S. joetida oil treated groups started to lay until the tenth week of supplementation (age 25 weeks). When S. joetida oil was fed alone (group 3), only 2 of the 9 birds layed and then only an occasional egg throughout 18 weeks of supplementation. As the level of oleic acid was increased (groups
1008
RESEARCH NOTES
EXPERIMENTAL
The data employed were obtained during the course of 12 experiments conducted during 1959, 1960 and 1961. The M.E. values were for mixed diets and not for individual diet components since the latter are generally computed from corrected dietary M.E. data. A total of 742 pairs of values were examined. The classical M.E. values ranged from 1.76 to 4.00 Cal. per gm. while the protein levels in the diets ranged from 8.4 to 53.2 percent. Statistical analysis of the data followed the methods described by Snedecor (1956).
RESULTS
Regression analysis supported the initial observation of a close relationship between corrected (Y) and classical (X) M.E. data. The correlation coefficient obtained was 0.996 at 740 degrees of freedom which suggests that 99.2% of the variation in the corrected data was associated with changes in the classical values. The regression equation resulting from the analysis had the form: Y = -0.018 + 0.9588 X Fiducial limits (T = 0.01) calculated for the regression line were very small, consequently graphical presentation became impractical. At the mean classical M.E. value (3.02 Cal. per gm.) the limits were ± 0.0032 Cal., at the lower end of the regression line (1.80 Cal. per gm.) ±0.0108 Cal. and at the upper end (4.00 Cal. per gm.) ±0.0092 Calories. When one realizes that 99% of the experimental data fell within the limits described it becomes apparent that one can predict the corrected M.E. value of a feed, with a high degree of accuracy, from a knowledge of its classical M.E. value. DISCUSSION Although application of the regression equation could substantially reduce the amount of laboratory work involved in deriving corrected M.E. data the major point of interest is that the amount and source of the dietary protein had little if any effect upon the magnitude of the nitrogen correction. Baldini (1961) examining the effect of methionine deficiency on energy utilization by the chick observed that the correction of M.E. data to nitrogen equilibrium did not change the relative M.E. values of the several diet treatments. This would support the finding that the source of the dietary protein had little effect upon
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
is not completely oxidized but instead yields excretory products containing an appreciable quantity of chemical energy. Working with chicks, Hill and Anderson (1958) applied a nitrogen correction of 8.22 Cal. per gm. of nitrogen retained. It was assumed that tissue protein when catabolized would yield uric acid as the sole excretory product although as the authors pointed out this assumption is not strictly correct. Titus et al. (1959) proposed that a nitrogen correction factor of 8.73 Cal. be employed as this more truly represents the energy content of the nitrogen-containing excretory products of the chicken. Today most workers conducting metabolizable energy (M.E.) studies with poultry apply one or other of these nitrogen corrections. During recent years experiments conducted at this institution have yielded a large number of M.E. values. It was observed that the differences between classical and corrected M.E. values were quite small and relatively uniform. This report contains the findings of a study designed to determine whether a relationship exists between the two types of M.E. data; a discussion of the merits of the nitrogen correction is also included.
RESEARCH NOTES
the nitrogen correction. When the regression equation was applied to 22 classical M.E. values presented by Baldini (1961) it was observed that the calculated corrected M.E. data were somewhat lower (mean 0.06, range 0.04 to 0.08 Cal. per gm.) than those obtained by measuring nitrogen retention; however, the variation was quite low and differences obtained might have been due to the use of a correction factor other than 8.73 Cal. per gm. of nitrogen. The practical value of applying the nitrogen correction to M.E. data has been questioned (Swift and French, 1954; Baldini, 1961). In growing birds it would seem unfair to exact a penalty for nitrogen storage especially when the amount of tissue protein which is catabolized is small relative to the amount stored. Similarly, with laying hens the amount of body protein which is degraded is small relative to that deposited in eggs. If protein quality
1009
exerted a major effect upon the size of the nitrogen correction then adjustment to nitrogen equilibrium would be justified but the findings reported herein suggest that protein quality is a relatively unimportant factor.
EFFECT OF IPRONIAZID TREATMENT ON THE METABOLISM OF LABELLED EPINEPHRINE IN THE LEGHORN CHICKEN1-2 JOSEPH
L.
SCOTT
Department of Zoology, University of Connecticut, Storrs (Received for publication February 12, 1962)
The results of recent investigations concerning the metabolism of epinephrine by mammals has encouraged the initiation of similar studies upon the chicken and other lower forms of vertebrates. The role of two enzymes,o-methyl-transferase and monoamine oxidase, has been clarified in 'Sincere thanks are extended to Dr. Oscar Resnick, Worcester Foundation for Experimental Biology, Shrewsbury, Mass., for his continuous counsel and guidance. 2 The research was supported by the National Institutes of Health Grant #H-3829.
the cat (Kirschner, 1960) and in the mouse and rat (Alexrod, 1960). The evidence from radioactivity recovery experiments performed upon 6-7 week old Leghorn chickens is reported as an initial indication that a monoamine oxidase is involved in the inactivation of epinephrine in this animal. Nine Leghorn chickens were divided into three groups and treated by intraperitoneal injections as follows: 1) Experiment 1, each of three birds received 0.7 mg. DLepinephrine-D-bitartrate-C14'3 in water,
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
REFERENCES Armsby, H. P., and J. A. Fries, 1918. Net energy values of alfalfa hay and of starch. J. Agr. Res. IS: 269-289. Baldini, J. T., 1961. The effect of dietary deficiency on the energy metabolism of the chick. Poultry Sci. 40: 1177-1183. Hill, F. W., and D. L. Anderson, 1958. Comparison of metabolizable energy and productive energy determinations with growing chicks. J. Nutrition, 64: 587-603. Snedecor, G. W., 1956. Statistical Methods, Fifth Edition, Iowa State College Press, Ames, Iowa. Swift, R. W., and C. E. French, 1954. Energy Metabolism and Nutrition, p. 96. The Scarecrow Press, Washington, D.C. Titus, H. W., A. L. Mehring, Jr., D. Johnson, Jr., L. L. Nesbitt and T. Tomas, 1959. An evaluation of M.C.F. (Micro-Cel-Fat), a new type of fat product. Poultry Sci. 38: 1114-1119.
RESEARCH NOTES
4 Nutritional Biochemical Corp., Cleveland. Tentative analysis by gas chromatography shows it to contain approximately 71-75% oleic acid. Other fatty acids possibly present are myristic, myristoleic, palmitic, palmitoleic, stearic, linoleic and linolenic.
4, 5 and 6) better production was noted and group 6 (200 mg. S. joetida oil-2000 mg. oleic acid daily) reached 50% production by the sixteenth week (age 31 weeks). Thus, oleic acid supplementation partially alleviated the delay in sexual maturity and egg production caused by S. joetida oil. Whether a higher level of oleic acid would allow better egg production must still be determined. Also unanswered is the possible mode of action of oleic acid on the pituitary-ovary complex, since onset of egg production was delayed 3 or 4 weeks. There is also the possibility that one of the contaminants in the oleic acid used may act as the alleviating agent. REFERENCES Evans, R. J., J. A. Davidson and S. L. Bandemer, 1961. Fatty acid and lipide distribution in egg yolks from hens fed cottonseed oil or Sterculia joetida seeds. J. Nutrition, 73: 282-290. Panos, T. C , G. F. Klein and J. C. Finerty, 1959. Effects of fat deficiency on pituitary-gonad relationships. J. Nutrition, 68: 509-540. Schneider, D. L., M. G. Vavich, A. A. Kurnick and A. R. Kemmerer, 1961. Effect of Sterculia joetida oil on mortality of the chick embryo. Poultry Sci. 40: 1644-1648. Schneider, D. L., A. A. Kurnick, M. G. Vavich and A. R. Kemmerer, 1962. Delay of sexual maturity in chickens by Sterculia joetida oil. Unpublished data.
THE RELATIONSHIP BETWEEN CLASSICAL AND CORRECTED METABOLIZABLE ENERGY VALUES I . R . SlBBALD AND S. J . SLINGER Departments of Nutrition and Poultry Science, Ontario Agricultural College, Guelph, Ontario, Canada (Received for publication February 7, 1962)
Armsby and Fries (1918) in a study of the net energy values of alfalfa hay and starch, when fed to a steer, corrected the observed energy of urine to a state of nitrogen equilibrium by adding 7.45 Cal. for each gm. of nitrogen retained by the
animal or by subtracting the same amount for each gm. of body nitrogen lost. The correction was considered to represent the energy of excretory materials temporarily retained in the body. It is an established fact that body protein when catabolized
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
ally supplemented daily by gelatin capsule as follows: group 1, empty capsule; group 2, 200 mg. of oleic acid;4 group 3, 200 mg. of S. joetida oil; group 4, 200 mg. of S. joetida oil plus 200 mg. of oleic acid; group 5, 200 mg. of S. joetida oil plus 1200 mg. of oleic acid; and group 6, 200 mg. of S. joetida oil plus 2000 mg. of oleic acid. Figure 1 shows the percent egg production of the groups during 18 weeks of supplementation. Both control groups, 1 and 2, started to lay by the seventh week of supplementation (age 22 weeks) and were in full production by the twelfth week (age 27 weeks), considered normal for this strain of pullets. None of the S. joetida oil treated groups started to lay until the tenth week of supplementation (age 25 weeks). When S. joetida oil was fed alone (group 3), only 2 of the 9 birds layed and then only an occasional egg throughout 18 weeks of supplementation. As the level of oleic acid was increased (groups
1008
RESEARCH NOTES
EXPERIMENTAL
The data employed were obtained during the course of 12 experiments conducted during 1959, 1960 and 1961. The M.E. values were for mixed diets and not for individual diet components since the latter are generally computed from corrected dietary M.E. data. A total of 742 pairs of values were examined. The classical M.E. values ranged from 1.76 to 4.00 Cal. per gm. while the protein levels in the diets ranged from 8.4 to 53.2 percent. Statistical analysis of the data followed the methods described by Snedecor (1956).
RESULTS
Regression analysis supported the initial observation of a close relationship between corrected (Y) and classical (X) M.E. data. The correlation coefficient obtained was 0.996 at 740 degrees of freedom which suggests that 99.2% of the variation in the corrected data was associated with changes in the classical values. The regression equation resulting from the analysis had the form: Y = -0.018 + 0.9588 X Fiducial limits (T = 0.01) calculated for the regression line were very small, consequently graphical presentation became impractical. At the mean classical M.E. value (3.02 Cal. per gm.) the limits were ± 0.0032 Cal., at the lower end of the regression line (1.80 Cal. per gm.) ±0.0108 Cal. and at the upper end (4.00 Cal. per gm.) ±0.0092 Calories. When one realizes that 99% of the experimental data fell within the limits described it becomes apparent that one can predict the corrected M.E. value of a feed, with a high degree of accuracy, from a knowledge of its classical M.E. value. DISCUSSION Although application of the regression equation could substantially reduce the amount of laboratory work involved in deriving corrected M.E. data the major point of interest is that the amount and source of the dietary protein had little if any effect upon the magnitude of the nitrogen correction. Baldini (1961) examining the effect of methionine deficiency on energy utilization by the chick observed that the correction of M.E. data to nitrogen equilibrium did not change the relative M.E. values of the several diet treatments. This would support the finding that the source of the dietary protein had little effect upon
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
is not completely oxidized but instead yields excretory products containing an appreciable quantity of chemical energy. Working with chicks, Hill and Anderson (1958) applied a nitrogen correction of 8.22 Cal. per gm. of nitrogen retained. It was assumed that tissue protein when catabolized would yield uric acid as the sole excretory product although as the authors pointed out this assumption is not strictly correct. Titus et al. (1959) proposed that a nitrogen correction factor of 8.73 Cal. be employed as this more truly represents the energy content of the nitrogen-containing excretory products of the chicken. Today most workers conducting metabolizable energy (M.E.) studies with poultry apply one or other of these nitrogen corrections. During recent years experiments conducted at this institution have yielded a large number of M.E. values. It was observed that the differences between classical and corrected M.E. values were quite small and relatively uniform. This report contains the findings of a study designed to determine whether a relationship exists between the two types of M.E. data; a discussion of the merits of the nitrogen correction is also included.
RESEARCH NOTES
the nitrogen correction. When the regression equation was applied to 22 classical M.E. values presented by Baldini (1961) it was observed that the calculated corrected M.E. data were somewhat lower (mean 0.06, range 0.04 to 0.08 Cal. per gm.) than those obtained by measuring nitrogen retention; however, the variation was quite low and differences obtained might have been due to the use of a correction factor other than 8.73 Cal. per gm. of nitrogen. The practical value of applying the nitrogen correction to M.E. data has been questioned (Swift and French, 1954; Baldini, 1961). In growing birds it would seem unfair to exact a penalty for nitrogen storage especially when the amount of tissue protein which is catabolized is small relative to the amount stored. Similarly, with laying hens the amount of body protein which is degraded is small relative to that deposited in eggs. If protein quality
1009
exerted a major effect upon the size of the nitrogen correction then adjustment to nitrogen equilibrium would be justified but the findings reported herein suggest that protein quality is a relatively unimportant factor.
EFFECT OF IPRONIAZID TREATMENT ON THE METABOLISM OF LABELLED EPINEPHRINE IN THE LEGHORN CHICKEN1-2 JOSEPH
L.
SCOTT
Department of Zoology, University of Connecticut, Storrs (Received for publication February 12, 1962)
The results of recent investigations concerning the metabolism of epinephrine by mammals has encouraged the initiation of similar studies upon the chicken and other lower forms of vertebrates. The role of two enzymes,o-methyl-transferase and monoamine oxidase, has been clarified in 'Sincere thanks are extended to Dr. Oscar Resnick, Worcester Foundation for Experimental Biology, Shrewsbury, Mass., for his continuous counsel and guidance. 2 The research was supported by the National Institutes of Health Grant #H-3829.
the cat (Kirschner, 1960) and in the mouse and rat (Alexrod, 1960). The evidence from radioactivity recovery experiments performed upon 6-7 week old Leghorn chickens is reported as an initial indication that a monoamine oxidase is involved in the inactivation of epinephrine in this animal. Nine Leghorn chickens were divided into three groups and treated by intraperitoneal injections as follows: 1) Experiment 1, each of three birds received 0.7 mg. DLepinephrine-D-bitartrate-C14'3 in water,
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
REFERENCES Armsby, H. P., and J. A. Fries, 1918. Net energy values of alfalfa hay and of starch. J. Agr. Res. IS: 269-289. Baldini, J. T., 1961. The effect of dietary deficiency on the energy metabolism of the chick. Poultry Sci. 40: 1177-1183. Hill, F. W., and D. L. Anderson, 1958. Comparison of metabolizable energy and productive energy determinations with growing chicks. J. Nutrition, 64: 587-603. Snedecor, G. W., 1956. Statistical Methods, Fifth Edition, Iowa State College Press, Ames, Iowa. Swift, R. W., and C. E. French, 1954. Energy Metabolism and Nutrition, p. 96. The Scarecrow Press, Washington, D.C. Titus, H. W., A. L. Mehring, Jr., D. Johnson, Jr., L. L. Nesbitt and T. Tomas, 1959. An evaluation of M.C.F. (Micro-Cel-Fat), a new type of fat product. Poultry Sci. 38: 1114-1119.