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The True Metabolizable Energy Values of the Seeds of Brassica campestris, B. hirta and B. napus1
The True Metabolizable Energy Values of the Seeds of Brassica campestris, B. hirta and B. napus1 I. R. SIBBALD and K. PRICE Animal Research Institute and Statistical Research Service, Agriculture Canada, Central Experimental Farm, Ottawa, Ontario, K1A 0C6 (Received for publication January 3, 1977) ABSTRACT Whole seeds of 9 varieties of Brassica campestris, 4 varieties of B. hirta and 10 varieties of B. napus were ground in a pin mill and then assayed for true metabolizable energy (T.M.E.) content. The ground samples were also assayed for dry matter, gross energy, protein (N X 6.25), ether extract, crude fibre and ash. The mean T.M.E. values for B. napus, B. hirta and B. campestris were 5.08, 4.82 and 4.52 kcal./g. of dry matter, respectively. Only 49% of the variation in T.M.E. values, on a dry matter basis, was accounted for by multiple regression on the other variables measured. Poultry Science 56:1329-1331, 1977
INTRODUCTION Although full-fat rapeseed has been studied as a dietary component, there is little published information concerning the available energy content of this and similar material. This report describes the true metabolizable energy (T.M.E.) values of 23 samples of Brassica seeds. MATERIALS AND METHODS Twenty-three samples of seeds including 9 varieties of B. campestris, 4 varieties of B. hirta and 10 varieties of B. napus were ground in a pin mill. The free flowing, finely ground materials were assayed for T.M.E. by the method of Sibbald (1976), using adult Single Comb White Leghorn roosters; five determinations were made on each sample. The ground seeds were also assayed for protein (N X 6.25), ether extract, crude fibre and ash by the methods of the A.O.A.C. (1975). There was insufficient material for additional assays. The original seed samples were characterized as to erucic acid and glucosinolate content. (A. J. Klassen, private communication). RESULTS AND DISCUSSION The experimental data are given in Table 1, the T.M.E. values as the means of five determi-
1
Contribution no. 678, Animal Research Institute.
nations on each sample. These T.M.E. values ranged from 3.91 to 5.71, with a mean of 4.82 kcal./g. of dry matter; the average standard error of the value for each sample was 0.10. For B. napus, B. hirta and B. campestirs the mean T.M.E. values were 5.08, 4.82 and 4.52 kcal./g. of dry matter, respectively. Analysis of variance showed a significant difference (P<0.01) between the means of B. campestris and B. napus, but there was a substantial amount of variation among strains within species: some B. campestris samples contained more T.M.E. than did some B. napus samples. The mean T.M.E. of B. hirta was not significantly (P>0.05) different from either of the other means. Linear regression analysis was used to measure the relationships between the variables listed in Table 1. None of the correlations with T.M.E. were significant (P>0.05). There were significant (P<0.01) negative correlations between protein and gross energy and between protein and ether extract. A positive correlation (P<0.01) was observed between gross energy and ether extract. Multiple linear regression was used to assess the feasibility of predicting the T.M.E. values of Brassica seeds from the physical and chemical variables measured. Gross energy, protein, ether extract, crude fibre and ash together explained only 48.7% of the variation in T.M.E. It is apparent that there are other variables which play a major role in determining T.M.E. values;
1329
Midas Oro Target Turret Argentine Bronowski Tower SZN 73-1371 SZN 73-1306 SZN 73-1448
B. napus
H H H H H L L L L L
H H H H
H H H H H H L L L
Glucosinolates c
17.6 25.6 28.0 29.0 28.7 30.7 24.6 25.0 26.2 26.3 •O.055
0.381
37.5 31.7 36.9 38.0
22.6 28.9 26.2 23.4 29.1 24.6 24.6 25.1 24.6
%
Protein
7.05 6.88 6.73 6.82 6.65 6.77 6.90 6.82 6.83 6.93
6.10 6.17 6.12 5.76
6.68 6.62 6.79 6.73 6.61 7.03 6.37 6.78 6.66
Gross energy kcal./g.
0.34
44.5 42.9 41.7 45.2 40.9 38.6 44.6 43.1 48.1 42.5
24.9 26.4 24.6 20.7
42.1 37.5 36.4 39.7 36.5 44.2 33.9 40.2 36.9
%
Ether extrac
Each value is the mean of five determinations; average standard error = 0.10 kcal./g.
The meal from the seed is considered to be low (L) or high (H) in glucosinolate content.
The oil from the seed is considered to be low (L), medium (M), high (H) or very high (VH) in erucic acid content.
Data expressed on a dry matter basis.
Correlation with T.M.E. r =
H H VH L
Yellow-2 Gisilba Sabre 926
B. hirta
L L H H H M L L L L
L L M M M VH L L L
Torch Span Echo Arlo Polish R-500 CZY3-1813 CZY3-1821 CZY4-941
Erucic acidb
B. campestris
Species
Variety or strain
TABLE 1. — The true metaboUzable energy values and the chemical compositions of several varieties of B
RESEARCH NOTES one such variable may be tannin, which Yapar and Clandinin (1972) showed to have a major effect on the metabolizable energy of rapeseed meal. ACKNOWLEDGEMENTS The authors wish to thank Drs. R. K. Downey and A. J. Klassen of Agriculture Canada, Saskatoon for providing the seeds and for characterizing them. The protein, ether extract, crude fibre and ash analyses were conducted by the Chemical and Biological
1331
Research Institute, Ottawa. Thanks are also extended to Mrs. S. Tobin for excellent technical assistance.
REFERENCES Association of Official Analytical Chemists, 1975. Official Methods of Analysis, 12th ed. Washington, D.C. Sibbald, I. R., 1976. A bioassay for true metabolizable energy in feedingstuffs. Poultry Sci. 55:303-308. Yapar, Z., and D. R. Clandinin, 1972. Effect of tannins in rapeseed meal on its nutritional value for chicks. Poultry Sci. 51:222-228.
INTRODUCTION Although full-fat rapeseed has been studied as a dietary component, there is little published information concerning the available energy content of this and similar material. This report describes the true metabolizable energy (T.M.E.) values of 23 samples of Brassica seeds. MATERIALS AND METHODS Twenty-three samples of seeds including 9 varieties of B. campestris, 4 varieties of B. hirta and 10 varieties of B. napus were ground in a pin mill. The free flowing, finely ground materials were assayed for T.M.E. by the method of Sibbald (1976), using adult Single Comb White Leghorn roosters; five determinations were made on each sample. The ground seeds were also assayed for protein (N X 6.25), ether extract, crude fibre and ash by the methods of the A.O.A.C. (1975). There was insufficient material for additional assays. The original seed samples were characterized as to erucic acid and glucosinolate content. (A. J. Klassen, private communication). RESULTS AND DISCUSSION The experimental data are given in Table 1, the T.M.E. values as the means of five determi-
1
Contribution no. 678, Animal Research Institute.
nations on each sample. These T.M.E. values ranged from 3.91 to 5.71, with a mean of 4.82 kcal./g. of dry matter; the average standard error of the value for each sample was 0.10. For B. napus, B. hirta and B. campestirs the mean T.M.E. values were 5.08, 4.82 and 4.52 kcal./g. of dry matter, respectively. Analysis of variance showed a significant difference (P<0.01) between the means of B. campestris and B. napus, but there was a substantial amount of variation among strains within species: some B. campestris samples contained more T.M.E. than did some B. napus samples. The mean T.M.E. of B. hirta was not significantly (P>0.05) different from either of the other means. Linear regression analysis was used to measure the relationships between the variables listed in Table 1. None of the correlations with T.M.E. were significant (P>0.05). There were significant (P<0.01) negative correlations between protein and gross energy and between protein and ether extract. A positive correlation (P<0.01) was observed between gross energy and ether extract. Multiple linear regression was used to assess the feasibility of predicting the T.M.E. values of Brassica seeds from the physical and chemical variables measured. Gross energy, protein, ether extract, crude fibre and ash together explained only 48.7% of the variation in T.M.E. It is apparent that there are other variables which play a major role in determining T.M.E. values;
1329
Midas Oro Target Turret Argentine Bronowski Tower SZN 73-1371 SZN 73-1306 SZN 73-1448
B. napus
H H H H H L L L L L
H H H H
H H H H H H L L L
Glucosinolates c
17.6 25.6 28.0 29.0 28.7 30.7 24.6 25.0 26.2 26.3 •O.055
0.381
37.5 31.7 36.9 38.0
22.6 28.9 26.2 23.4 29.1 24.6 24.6 25.1 24.6
%
Protein
7.05 6.88 6.73 6.82 6.65 6.77 6.90 6.82 6.83 6.93
6.10 6.17 6.12 5.76
6.68 6.62 6.79 6.73 6.61 7.03 6.37 6.78 6.66
Gross energy kcal./g.
0.34
44.5 42.9 41.7 45.2 40.9 38.6 44.6 43.1 48.1 42.5
24.9 26.4 24.6 20.7
42.1 37.5 36.4 39.7 36.5 44.2 33.9 40.2 36.9
%
Ether extrac
Each value is the mean of five determinations; average standard error = 0.10 kcal./g.
The meal from the seed is considered to be low (L) or high (H) in glucosinolate content.
The oil from the seed is considered to be low (L), medium (M), high (H) or very high (VH) in erucic acid content.
Data expressed on a dry matter basis.
Correlation with T.M.E. r =
H H VH L
Yellow-2 Gisilba Sabre 926
B. hirta
L L H H H M L L L L
L L M M M VH L L L
Torch Span Echo Arlo Polish R-500 CZY3-1813 CZY3-1821 CZY4-941
Erucic acidb
B. campestris
Species
Variety or strain
TABLE 1. — The true metaboUzable energy values and the chemical compositions of several varieties of B
RESEARCH NOTES one such variable may be tannin, which Yapar and Clandinin (1972) showed to have a major effect on the metabolizable energy of rapeseed meal. ACKNOWLEDGEMENTS The authors wish to thank Drs. R. K. Downey and A. J. Klassen of Agriculture Canada, Saskatoon for providing the seeds and for characterizing them. The protein, ether extract, crude fibre and ash analyses were conducted by the Chemical and Biological
1331
Research Institute, Ottawa. Thanks are also extended to Mrs. S. Tobin for excellent technical assistance.
REFERENCES Association of Official Analytical Chemists, 1975. Official Methods of Analysis, 12th ed. Washington, D.C. Sibbald, I. R., 1976. A bioassay for true metabolizable energy in feedingstuffs. Poultry Sci. 55:303-308. Yapar, Z., and D. R. Clandinin, 1972. Effect of tannins in rapeseed meal on its nutritional value for chicks. Poultry Sci. 51:222-228.