- Email: [email protected]
In Vitro Uptake of Zinc by Rapeseed Meal and Soybean Meal*
IN VITRO U P T A K E O F ZINC B Y R A P E S E E D M E A L A N D S O Y B E A N M E A L * P . C. C. S E T H , D . R. CLANDININ AND R. T . HARDIN
Department of Animal Science, The University of Alberta, Edmonton, Alberta, Canada (Received for publication September 23, 1974)
ABSTRACT The binding of Zn65 by rapeseed meal and soybean meal was studied. Rapeseed meal was found to bind almost twice as much zinc as soybean meal. The zinc binding capacity of rapeseed meal appeared to be related to its content of bound tannins and possibly to some, as yet, undetermined factor(s) in the meal. POULTRY SCIENCE 54: 626-629, 1975
C
LANDININ and Heard (1968) reported that rapeseed meal contains about 3% of tannins. Since Jurd and Geissman (1956) have shown that tannins form complexes with metal ions it seemed reasonable to postulate that perhaps rapeseed meal binds zinc. As a consequence, in vitro studies were undertaken to determine the zinc binding capacity of rapeseed meal, rapeseed meal fractions and of rapeseed meal from which the more soluble tannins had been removed. MATERIALS AND METHODS
Three samples of commercial prepress-solvent processed rapeseed meal, one prepared from B. campestris, another from B. napus and a third from the variety Bronowski were used in this study. A large quantity of each meal was reground to pass through a 200 mesh screen and separated by air-classification into two fractions, one of low hull content and the other of high hull content. Three samples of commercial solvent-processed soybean meal were also included in the study for comparative purposes. In order to ensure that the meals were all low in fat content, small quantities of each meal were extracted with cold hexane, dried and reground to pass through a 40 mesh screen.
* Supported, in part, by grants from the National Research Council of Canada and the Alberta Agricultural Research Trust.
626
Soluble tannins (polyphenols) were extracted with methanol from the three samples of rapeseed meal by the procedure used by Yapar and Clandinin (1972). The ability of the extracted meals to bind zinc was measured as outlined above. An attempt was also made to determine the ability of the extracted tannins to bind zinc. For this purpose the tannins extracted from 0.2 g. of each of the three samples of commercial rapeseed meal were reacted with
Downloaded from http://ps.oxfordjournals.org/ at University of Texas at Austin on June 7, 2015
Zinc retention determinations were done in triplicate. 0.2 g. samples of the three soybean meals, the three rapeseed meals and their low-hull and high-hull fractions were each placed in a series of test tubes to which deionized water was added along with 50, 100, 200, 300, 400, 500 or 600 micro liters of Zn 65 solution to a total volume of 8 ml. The Zn 65 solution contained 37.5 mg. of zinc as zinc sulphate and 5 uC. of zinc as Zn 6 5 Cl 2 (of specific activity 500 MC per g.) per 100 ml. The tubes were stoppered, shaken vigorously for 10 minutes, centrifuged and decanted. The residues were subsequently washed twice with 4 ml. quantities of deionized water. The radioactivities of the washed residues were determined by use of a Nuclear Chicago well-type scintillation detector and ultrasealer. Percentage uptake of Zn 65 by the samples was calculated with reference to the radioactivity of sets of test tubes containing 50, 100, 200, 300, 400, 500 or 600 micro liters of the Zn 65 solution in 8 ml. of deionized water.
INTRODUCTION
3
0.70
Brassica napus 82.7a
Bronowski 82.0"
Comparison of the regular rapeseed meals against the soybean meals Regular rapeseed meal Soybean meal Averages 83.6b 50.3a SEM 0^38 'Within a meal type, values with the same superscripts are not significantly different, P s 0.05. 2 Average percentage uptake values represent the averages of uptake determinations done on each addition. 'Within a comparison, values with different superscripts are significantly different, P s 0.05.
SEM
Comparison'' of the regular rapeseed meals Brassica campestris 86.2b
Comparison* of the averages for the regular rapeseed meals against the averages for their low-hull and hig Regular rapeseed meal LH fraction HH fraction Averages 83.6a 88.8b 84.2a SEM 0.42
Comparison1 of rapeseed meals and their fractions and soybean meals within type or variety Brassica campestris Brassica napus Bronowski R LH HH R LH HH R LH 2 a b a a b a a Averages 86.2 91.0 86.8 82.7 85.4 83.9 82.0 90. l b SEM 0.70 0.49 0.51
TABLE 1.—Percentage uptake of Zn65 by rapeseed meals, their low-hull and high-hull frac
ed from http://ps.oxfordjournals.org/ at University of Texas at Austin on June 7, 2015
628
RESEARCH NOTES
RESULTS AND DISCUSSION It was found (Table 1) that, on the average, the low-hull fractions of rapeseed meal bound more zinc than the rapeseed meals or the high-hull fractions. This could be related to
the significantly higher average tannin content of the low-hull fractions (Table 2) as compared to the meals or the high-hull fractions. Although the high-hull fractions contained, on the average, slightly less tannins than the regular commercial meals from which they were produced they bound a similar amount of zinc. The greater amounts of zinc bound by the high-hull fractions than was expected on the basis of their tannin contents could have been due to the fact that these fractions had been originally ground to pass through a 200 mesh screen whereas the regular commercial meal had been ground to pass through a 40 mesh screen. The finer grind could have increased the surface area for the zinc to act upon. The results reported in Table 1 also indicate that the rapeseed meals bound significantly more zinc than the
TABLE 2.—Percentage of tannins in rapeseed meals Type or variety of rapeseed meal from which meals were produced Meal Regular Low-hull High-hull Regular after extraction with methanol SEM
B. campestris 3.7C' 4.3 d 2.8 b 1.8" 0.1
B. napus
Bronowski
Average
2.7° 4.0 d 3.7 b
3.6C 3.9C 2.4 b
3.3 C 4.0 d 2.6 b
1.8" 0.04
1.7" 0.08
1.8" 0.04
'Within a column values with the same superscript are not significantly different, P s 0.05. TABLE 3.—Percentage uptakes of Zn65 by rapeseed meals and rapeseed meals extracted with methanol to remove soluble tannins Comparison* of regular versus extracted meal within type or variety Type or variety of rapeseed meal from which the meals were produced B. campestris B. napus Bronowski Regular Extracted Regular Regular Extracted Extracted 86.2b 82.7" 71.6" Averages2 81.3" 81.9b 79.5" 2.24 SEM 1.57 1.14 Comparison* of regular meals against extracted meals Regular rapeseed meal Extracted rapeseed meal Averages 83.6" 77.4" 0.89 SEM '•2JAs in Table 1.
Downloaded from http://ps.oxfordjournals.org/ at University of Texas at Austin on June 7, 2015
the quantitities of zinc referred to above. The tannins were then precipitated with lead acetate, recovered by centrifugation and washed twice with deionized water. The radioactivities of the precipitates were measured as referred to above. The data were analyzed by multi-way analyses of variance. Comparisons of means were made using Duncan's multiple range test (Steel and Torrie, 1960) and since levels of inclusion of Zn 65 showed no consistant level effect the variations among samples were used as measures of error.
629
RESEARCH NOTES
The results of this study indicated that rapeseed meal has greater zinc binding capacity than soybean and that the zinc binding capacity of rapeseed meal appears to be related to its content of bound tannins or to some, as yet, unidentified factor(s) in the meal rather than to its content of methanol extractable tannins.
REFERENCES Clandinin, D. R., and J. Heard, 1968. Tannins in prepress-solvent and solvent-processed rapeseed meal. Poultry Sci. 47: 688-689. Jurd,L.,andT. A. Geissman, 1956. Absorption spectra of metal complexes of flavanoid compounds. J. Org. Chem. 27: 1395-1401. Steel, R. G. D., and J. H. Torrie, 1960. Statistical Principles in Experimental Design. McGraw-Hill Book Company, Inc., New York. Yapar, Z., and D. R. Clandinin, 1972. Effect of tannins in rapeseed meal on its nutritional value for chicks. Poultry Sci. 51: 222-228.
INFLUENCE OF A FAT-MOBILIZING SUBSTANCE FROM GEESE URINE ON GEESE AND CHICKENS I . N l R 1 AND ZAFRIRA NlTSAN 2
Department of Animal Science, Faculty of Agriculture, Hebrew University of Jerusalem, and2 Division of Poultry Science, Agricultural Research Organization, The Volcani Center, Rehovot, Israel (Received for publication October 1, 1974)
ABSTRACT A fat-mobilizing substance (FMS) was extracted from the urine of fasting, ad-libitum-fed or over-fed colostomized geese. Injection of these materials into geese and cockerels caused increases in plasma-free fatty acids (FFA). A marked anorexigenic effect was obtained in cockerels only, by the FMS obtained from ad-libitum-fed geese. The daily amount of FMS excreted in the urine was proportional to the amount of feed consumed. POULTRY SCIENCE 54: 629-632, 1975
MATERIALS AND METHODS
P
REPARATION of FMS. Two adult geese from a local breed already described (Nir and Perek, 1971) were prepared with colostomies by the method of Ariyoshi and Morimoto (1956). They were kept in metabolic cages and the urine was collected
in containers kept on crushed ice. FMS was extracted from pooled samples as described by Nir et al. (1969). The diet used was a 16% protein commercial mash. When force fed, a mash composed of corn and 10% soybean meal was used (Nir et al., 1973). Force feeding was performed with a funnel
Downloaded from http://ps.oxfordjournals.org/ at University of Texas at Austin on June 7, 2015
soybean meals (83.6% vs. 50.3%) and that different samples of rapeseed meal or of soybean meal may differ significantly in their zinc binding capacity. Zinc uptakes of the rapeseed meals which had been subjected to tannin extraction, presented in Table 3, indicate that removal of the soluble polyphenols significantly decreased the zinc binding properties of the meals. It would appear, however, that the tannins (Table 2) that remained in the meals after methanol extraction or some, as yet, undetermined factors in the meals were more important in the retention of zinc than the tannins which were extracted by the procedure followed. No zinc was found in the tannins precipitated by lead acetate. Any zinc that complexed with these polyphenols compounds was probably replaced by lead ions during the precipitation process and washed out of the precipitates.
Department of Animal Science, The University of Alberta, Edmonton, Alberta, Canada (Received for publication September 23, 1974)
ABSTRACT The binding of Zn65 by rapeseed meal and soybean meal was studied. Rapeseed meal was found to bind almost twice as much zinc as soybean meal. The zinc binding capacity of rapeseed meal appeared to be related to its content of bound tannins and possibly to some, as yet, undetermined factor(s) in the meal. POULTRY SCIENCE 54: 626-629, 1975
C
LANDININ and Heard (1968) reported that rapeseed meal contains about 3% of tannins. Since Jurd and Geissman (1956) have shown that tannins form complexes with metal ions it seemed reasonable to postulate that perhaps rapeseed meal binds zinc. As a consequence, in vitro studies were undertaken to determine the zinc binding capacity of rapeseed meal, rapeseed meal fractions and of rapeseed meal from which the more soluble tannins had been removed. MATERIALS AND METHODS
Three samples of commercial prepress-solvent processed rapeseed meal, one prepared from B. campestris, another from B. napus and a third from the variety Bronowski were used in this study. A large quantity of each meal was reground to pass through a 200 mesh screen and separated by air-classification into two fractions, one of low hull content and the other of high hull content. Three samples of commercial solvent-processed soybean meal were also included in the study for comparative purposes. In order to ensure that the meals were all low in fat content, small quantities of each meal were extracted with cold hexane, dried and reground to pass through a 40 mesh screen.
* Supported, in part, by grants from the National Research Council of Canada and the Alberta Agricultural Research Trust.
626
Soluble tannins (polyphenols) were extracted with methanol from the three samples of rapeseed meal by the procedure used by Yapar and Clandinin (1972). The ability of the extracted meals to bind zinc was measured as outlined above. An attempt was also made to determine the ability of the extracted tannins to bind zinc. For this purpose the tannins extracted from 0.2 g. of each of the three samples of commercial rapeseed meal were reacted with
Downloaded from http://ps.oxfordjournals.org/ at University of Texas at Austin on June 7, 2015
Zinc retention determinations were done in triplicate. 0.2 g. samples of the three soybean meals, the three rapeseed meals and their low-hull and high-hull fractions were each placed in a series of test tubes to which deionized water was added along with 50, 100, 200, 300, 400, 500 or 600 micro liters of Zn 65 solution to a total volume of 8 ml. The Zn 65 solution contained 37.5 mg. of zinc as zinc sulphate and 5 uC. of zinc as Zn 6 5 Cl 2 (of specific activity 500 MC per g.) per 100 ml. The tubes were stoppered, shaken vigorously for 10 minutes, centrifuged and decanted. The residues were subsequently washed twice with 4 ml. quantities of deionized water. The radioactivities of the washed residues were determined by use of a Nuclear Chicago well-type scintillation detector and ultrasealer. Percentage uptake of Zn 65 by the samples was calculated with reference to the radioactivity of sets of test tubes containing 50, 100, 200, 300, 400, 500 or 600 micro liters of the Zn 65 solution in 8 ml. of deionized water.
INTRODUCTION
3
0.70
Brassica napus 82.7a
Bronowski 82.0"
Comparison of the regular rapeseed meals against the soybean meals Regular rapeseed meal Soybean meal Averages 83.6b 50.3a SEM 0^38 'Within a meal type, values with the same superscripts are not significantly different, P s 0.05. 2 Average percentage uptake values represent the averages of uptake determinations done on each addition. 'Within a comparison, values with different superscripts are significantly different, P s 0.05.
SEM
Comparison'' of the regular rapeseed meals Brassica campestris 86.2b
Comparison* of the averages for the regular rapeseed meals against the averages for their low-hull and hig Regular rapeseed meal LH fraction HH fraction Averages 83.6a 88.8b 84.2a SEM 0.42
Comparison1 of rapeseed meals and their fractions and soybean meals within type or variety Brassica campestris Brassica napus Bronowski R LH HH R LH HH R LH 2 a b a a b a a Averages 86.2 91.0 86.8 82.7 85.4 83.9 82.0 90. l b SEM 0.70 0.49 0.51
TABLE 1.—Percentage uptake of Zn65 by rapeseed meals, their low-hull and high-hull frac
ed from http://ps.oxfordjournals.org/ at University of Texas at Austin on June 7, 2015
628
RESEARCH NOTES
RESULTS AND DISCUSSION It was found (Table 1) that, on the average, the low-hull fractions of rapeseed meal bound more zinc than the rapeseed meals or the high-hull fractions. This could be related to
the significantly higher average tannin content of the low-hull fractions (Table 2) as compared to the meals or the high-hull fractions. Although the high-hull fractions contained, on the average, slightly less tannins than the regular commercial meals from which they were produced they bound a similar amount of zinc. The greater amounts of zinc bound by the high-hull fractions than was expected on the basis of their tannin contents could have been due to the fact that these fractions had been originally ground to pass through a 200 mesh screen whereas the regular commercial meal had been ground to pass through a 40 mesh screen. The finer grind could have increased the surface area for the zinc to act upon. The results reported in Table 1 also indicate that the rapeseed meals bound significantly more zinc than the
TABLE 2.—Percentage of tannins in rapeseed meals Type or variety of rapeseed meal from which meals were produced Meal Regular Low-hull High-hull Regular after extraction with methanol SEM
B. campestris 3.7C' 4.3 d 2.8 b 1.8" 0.1
B. napus
Bronowski
Average
2.7° 4.0 d 3.7 b
3.6C 3.9C 2.4 b
3.3 C 4.0 d 2.6 b
1.8" 0.04
1.7" 0.08
1.8" 0.04
'Within a column values with the same superscript are not significantly different, P s 0.05. TABLE 3.—Percentage uptakes of Zn65 by rapeseed meals and rapeseed meals extracted with methanol to remove soluble tannins Comparison* of regular versus extracted meal within type or variety Type or variety of rapeseed meal from which the meals were produced B. campestris B. napus Bronowski Regular Extracted Regular Regular Extracted Extracted 86.2b 82.7" 71.6" Averages2 81.3" 81.9b 79.5" 2.24 SEM 1.57 1.14 Comparison* of regular meals against extracted meals Regular rapeseed meal Extracted rapeseed meal Averages 83.6" 77.4" 0.89 SEM '•2JAs in Table 1.
Downloaded from http://ps.oxfordjournals.org/ at University of Texas at Austin on June 7, 2015
the quantitities of zinc referred to above. The tannins were then precipitated with lead acetate, recovered by centrifugation and washed twice with deionized water. The radioactivities of the precipitates were measured as referred to above. The data were analyzed by multi-way analyses of variance. Comparisons of means were made using Duncan's multiple range test (Steel and Torrie, 1960) and since levels of inclusion of Zn 65 showed no consistant level effect the variations among samples were used as measures of error.
629
RESEARCH NOTES
The results of this study indicated that rapeseed meal has greater zinc binding capacity than soybean and that the zinc binding capacity of rapeseed meal appears to be related to its content of bound tannins or to some, as yet, unidentified factor(s) in the meal rather than to its content of methanol extractable tannins.
REFERENCES Clandinin, D. R., and J. Heard, 1968. Tannins in prepress-solvent and solvent-processed rapeseed meal. Poultry Sci. 47: 688-689. Jurd,L.,andT. A. Geissman, 1956. Absorption spectra of metal complexes of flavanoid compounds. J. Org. Chem. 27: 1395-1401. Steel, R. G. D., and J. H. Torrie, 1960. Statistical Principles in Experimental Design. McGraw-Hill Book Company, Inc., New York. Yapar, Z., and D. R. Clandinin, 1972. Effect of tannins in rapeseed meal on its nutritional value for chicks. Poultry Sci. 51: 222-228.
INFLUENCE OF A FAT-MOBILIZING SUBSTANCE FROM GEESE URINE ON GEESE AND CHICKENS I . N l R 1 AND ZAFRIRA NlTSAN 2
Department of Animal Science, Faculty of Agriculture, Hebrew University of Jerusalem, and2 Division of Poultry Science, Agricultural Research Organization, The Volcani Center, Rehovot, Israel (Received for publication October 1, 1974)
ABSTRACT A fat-mobilizing substance (FMS) was extracted from the urine of fasting, ad-libitum-fed or over-fed colostomized geese. Injection of these materials into geese and cockerels caused increases in plasma-free fatty acids (FFA). A marked anorexigenic effect was obtained in cockerels only, by the FMS obtained from ad-libitum-fed geese. The daily amount of FMS excreted in the urine was proportional to the amount of feed consumed. POULTRY SCIENCE 54: 629-632, 1975
MATERIALS AND METHODS
P
REPARATION of FMS. Two adult geese from a local breed already described (Nir and Perek, 1971) were prepared with colostomies by the method of Ariyoshi and Morimoto (1956). They were kept in metabolic cages and the urine was collected
in containers kept on crushed ice. FMS was extracted from pooled samples as described by Nir et al. (1969). The diet used was a 16% protein commercial mash. When force fed, a mash composed of corn and 10% soybean meal was used (Nir et al., 1973). Force feeding was performed with a funnel
Downloaded from http://ps.oxfordjournals.org/ at University of Texas at Austin on June 7, 2015
soybean meals (83.6% vs. 50.3%) and that different samples of rapeseed meal or of soybean meal may differ significantly in their zinc binding capacity. Zinc uptakes of the rapeseed meals which had been subjected to tannin extraction, presented in Table 3, indicate that removal of the soluble polyphenols significantly decreased the zinc binding properties of the meals. It would appear, however, that the tannins (Table 2) that remained in the meals after methanol extraction or some, as yet, undetermined factors in the meals were more important in the retention of zinc than the tannins which were extracted by the procedure followed. No zinc was found in the tannins precipitated by lead acetate. Any zinc that complexed with these polyphenols compounds was probably replaced by lead ions during the precipitation process and washed out of the precipitates.