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The Botanical and Chemical Composition and Nutritive Value of Wheat Feed Screenings
The Botanical and Chemical Composition and Nutritive Value of Wheat Feed Screenings P. STAPLETON,1 D. B. BRAGG,2 AND J. BIELY2 University of British Columbia Vancouver, British Columbia., V6T 1W5 Canada (Received for publication August 1, 1978)
1980 Poultry Science 59:333-340 INTRODUCTION Wheat feed screenings o b t a i n e d in t h e process of cleaning w h e a t grains consist largely of b r o k e n and shrunken wheat kernels. T h e remainder is composed of wild b u c k w h e a t , wild oats, rapeseed, cow cockle, lady's t h u m b , ball m u s t a r d , and small seeds and dust (Biely a n d P o m e r a n z , 1 9 7 5 ) . T h e Canada Feeds Act ( 1 9 6 0 ) defines t h e c o m p o s i t i o n of four grades of screenings (Biely a n d P o m e r a n z , 1 9 7 5 ) . Wheat feed screenings, because of their high wheat c o n t e n t , are considered as a p o t e n t i a l s u b s t i t u t e for t h e grain p o r t i o n of p o u l t r y rations. T h e following s t u d y was designed t o determine t h e variation in botanical, chemical, and a m i n o acid c o n t e n t of w h e a t screenings a n d t o evaluate t h e p e r f o r m a n c e of broiler chicks fed rations containing w h e a t screenings. MATERIALS AND METHODS T h e chemical analyses were carried o u t b y t h e p r o c e d u r e s reported b y Biely and P o m e r a n z ( 1 9 7 5 ) and t h e a m i n o acid analyses according to t h e m e t h o d described b y P o m e r a n z and
1 2
School of Home Economics. Department of Poultry Sciences.
R o b i n s ( 1 9 7 3 ) . T h e chemical, a m i n o acid, and botanical compositions of five different commercial samples of w h e a t screenings are s h o w n in Tables 1 , 2 , and 3. T h e w h e a t screenings used in these e x p e r i m e n t s were supplied as N o . 1 w h e a t feed screenings. However, t h e y varied from t h e specifications as s h o w n b y t h e d a t a o n their actual c o m p o s i t i o n . Experiment 1. Wheat screenings were substituted for w h e a t o n a weight-for-weight basis. T h e c o m p o s i t i o n of t h e diets, t h e chemical analysis of t h e w h e a t screening rations, t h e w h e a t control, and a commercial broiler crumbles r a t i o n are given in Tables 4 , 5, and 6. Test diets were fed t o commercial broiler H u b b a r d chicks. Each test diet was fed t o five pens of male chicks, 11 birds per pen. T h e chicks were housed in b a t t e r y b r o o d e r s in an air-conditioned r o o m for a period of four weeks. Body weight of chicks and feed c o n s u m p t i o n were d e t e r m i n e d weekly. Experiment 2. T h e p r o c e d u r e for t h e second e x p e r i m e n t was t h e same as for t h e first. T h e c o m p o s i t i o n of five diets containing screenings and t h e w h e a t c o n t r o l is given in Table 7. Wheat was again replaced b y screenings. Tallow was a d d e d t o t h e rations t o equalize t h e i r fat content. Experiment 3. A c o m p o s i t e of t h e five samples of screenings used in E x p e r i m e n t s 1
333
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ABSTRACT The botanical, chemical, and amino acid content of wheat feed screenings was determined. The botanical composition showed that wheat screenings contained broken or shrunken particles of wheat, wild buckwheat, wild oats, rapeseed, and a variety of weed seeds. The average protein content of the screenings (13.9%) was higher than that of wheat (12.2%). The amino acid content of five samples of wheat screenings were remarkably uniform. The ash content (2.2%) of wheat screenings was nearly double that of wheat (1.2%). The fiber of wheat screenings varied from 2.56 to 4.18%, but, generally, as the fiber level increased, so did the fat content. In the first experiment, wheat screenings replaced wheat in broiler rations on a weight for weight basis. Experiment 2 was similar to Experiment 1 except that all rations were adjusted to contain the same amount of fat. Experiment 3 compared wheat to wheat screeenings in two types of rations, experimental and two commercially designed rations, in which the grain portion of the ration was substituted with wheat screenings. The results of the three experiments indicate that wheat feed screenings may substitute for wheat in balanced broiler rations without affecting chick growth or feed utilization.
STAPLETON ET AL.
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TABLE 1. Chemical analyses of wheat feed screenings
Sample 1 2 3 4 5 Wheat
Dry matter
Crude protein
Ether extract
87.9 86.9 87.9 87.0 87.4 86.2
14.6 a 13.5 14.0 13.9 12.2 12.2
6.60 3.17 6.63 3.66 6.40 1.62
(%)
Crude fiber
Ash
Ca
3.80 2.63 4.18 2.67 3.75 2.56
2.3 2.0 2.6 2.0 2.2 1.4
.12 .08 .15 .08 .11 .04
.39 .34 .39 .37 .36 .31
Mn
Zn
Cu
5 5 6 5 5 6
(ppm) 37 5 32 5 34 6 5 33 32 5 6 38
Fe
379 438 414 307 421 75
Mg
(%) .18 .16 .17 .16 .17 .12
All values expressed on an "as fed" basis.
broiler chicks, 6 5 chicks per g r o u p , totaling 1 5 6 0 chicks. T h e chemical c o m p o s i t i o n of t h e diets fed in E x p e r i m e n t 3 is s h o w n in Table 9. Weight gains and feed efficiencies were subjected t o analysis of variance (Snedecor, 1 9 5 6 ) and t r e a t m e n t comparisons were m a d e with t h e n e w multiple range test of D u n c a n ( 1 9 5 5 ) .
RESULTS Experiment 1. T h e m e a n b o d y weights and feed efficiency ratios of broiler chicks fed either wheat or w h e a t screening ratios are presented in Table 1 0 . Chicks fed commercial broiler crumbles attained a significantly
TABLE 2. Percent amino acid in wheat feed
screenings^'0
Sample
1
2
3
4
5
Wheat
Lysine Threonine Valine Leucine Isoleucine Methionine Cystine Phenylalanine Tyrosine Histidine Arginine Aspartate Glutamate Glycine Alanine Serine Proline
.42 .37 .47 .82 .40 .28 .15 .54 .32 .29 .64 .72 3.40 .46 .44 .49 2.23
.38 .34 .45 .78 .38 .24 .15 .54 .29 .28 .61 .64 3.69 .45 .39 .38 2.14
.44 .37 .47 .83 .41 .27 .14 .55 .30 .29 .68 .71 3.43 .48 .43 .50 2.06
.37 .33 .44 .79 .37 .27 .15 .55 .32 .28 .57 .65 3.81 .43 .39 .47 2.20
.44 .37 .48 .82 .40 .28 .15 .54 .33 .30 .68 .72 3.34 .48 .44 .48 2.04
.33 .28 .38 .65 .30 .21 .14 .42 .27 .23 .52 .54 2.92 .39 .34 .40 1.41
All values expressed on an "as fed" basis. Proteins were hydrolyzed in HC1 and amino acids determined with an amino acid analyser (Beckman 121) Pomeranz and Robins (1973).
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and 2 was m a d e and i n c o r p o r a t e d i n t o broiler r a t i o n s . T h e c o m p o s i t i o n of t h e six rations is shown in Table 8. Screenings replaced w h e a t o n a weight-for-weight basis in diet 2. Screenings also replaced t h e total grain o n a weight-forweight basis in t h e commercially modified rations which were prepared at t h e commercial feed mill. T h e t w o experimental diets, t h e t w o commercial diets, and t h e commercially m o d i fied diets, in which screenings replaced all of t h e grains, were fed t o broiler chicks of t h e same strain used in t h e t w o previous experim e n t s . T h e chicks in this e x p e r i m e n t were housed o n t h e floor for a period of six w e e k s . Each r a t i o n was fed t o four groups of u n s e x e d
335
WHEAT SCREENINGS IN BROILER DIETS TABLE 3. Botanical composition of wheat feed screenings
Sample
Cracked wheat
Wild buckwheat
Cracked barley
Rapeseed
Weed seeds
1 2 3 4 5
67 75 60 76 59
10 4 9 4 12
3 5 4 2 5
8 5 11 5 11
3 1 5 2 3
Chaff
Flax seed
Mineral
Fines a
10
Material that passes through a 1.79 mm mesh, chiefly wheat and small weed seeds.
weights of chicks fed screenings ranged from 7 3 8 g t o 795 g. No statistically significant differences existed a m o n g t h e g r o u p s fed either wheat or screenings. T h e feed efficiency ratios given in T a b l e 11 show t h a t t w o rations containing screenings (screenings # 1 and # 3 ) gave ratios (1.90) which were significantly higher t h a n t h a t given b y t h e commercial ration. As was t h e case with b o d y weights, no significant differences existed in t h e feed efficiency ratio of chicks fed t h e w h e a t or w h e a t screenings diets. Experiment 3. T h e w h e a t screenings used in this e x p e r i m e n t were a c o m p o s i t e of t h e five samples used in E x p e r i m e n t s 1 and 2 . T h e m e a n b o d y weights of chicks a n d t h e feed efficiency ratios are given in Table 1 2 . T h e r e was no significant difference in b o d y weights or feed efficiency ratio of chicks fed either t h e w h e a t control or wheat screenings. T h e chicks fed t h e commercial broiler rations (diets 3 and 5) were significantly heavier
TABLE 4. Composition of experimental diets (Experiment 1) Ingredients (%)
Wheat control
Wheat Wheat screenings Soybean meal (48.5% protein) Meat meal (50% protein) Alfalfa meal (20% protein) Tallow Limestone Vitamin — mineral premixb
62.0 23.0 7.0 1.0 5.0 1.0 1.0
Screenings 1
62.0 23.0 7.0 1.0 5.0 1.0 1.0
Composition of diet in which five wheat screenings samples replaced wheat. Supplied per kilogram of diet: vitamin A, 11,000 IU; vitamin D, 880 ICU; vitamin E, 10 IU; menadione, 2.2 mg; vitamin B 12 , 13.2 meg; riboflavin, 6.6 mg; Ca pantothenate, 24.2 mg; niacin, 36.2 mg; biotin, .04 mg; choline CI, 500 mg; NaCl 3.52 g; Mn, 86 mg; Zn, 49 mg; Cu, 7.7 mg.
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higher b o d y weight t h a n t h e chicks fed either t h e w h e a t ration or rations containing wheat screenings, replacing wheat o n a weightfor-weight basis. T h e r e was little difference in final b o d y weights of t h e chicks fed w h e a t ( 6 9 2 g) c o m p a r e d w i t h t h e weights of t h o s e fed screenings (range 7 0 4 t o 725 g). No significant difference was observed in feed efficiency ratio b e t w e e n t h e seven groups. Experiment 2. Diets containing either w h e a t or w h e a t screenings were fed t o broiler chicks for four weeks. T h e weight of t h e chicks and feed efficiency ratios are given in Table 1 1 . T h e weight of t h e chicks ( 8 4 8 g) fed t h e commercial broiler crumbles (diet 7) was n o t significantly higher t h a n t h e b o d y weight of chicks fed w h e a t (783 g) or screenings in diet 3 ( 7 9 5 g). However, t h e b o d y weight of t h e chicks fed t h e commercial ration was significantly heavier t h a n t h e weights of chicks fed screenings in diets 2, 4 , 5, and 6. Final b o d y
336
STAPLETON ET AL. TABLE 5. Chemical analyses of experimental diets (Experiment 1)
Dietary treatments
Crude protein
Ether extract
Crude fiber
Wheat Screenings #1 Screenings #2 Screenings #3 Screenings #4 Screenings #5 Commercial broiler a
21.3 22.7 22.3 22.4 22.3 22.0 21.2
6.5 9.6 7.8 10.1 7.9 9.4 9.0
3.1 3.9 3.2 4.3 3.3 3.8 4.1
Zn Ash
5.7 6.3 5.9 6.2 5.8 5.9 5.3
Ca
P
Mg
1.19 1.28 1.23 1.25 1.16 1.22 1.04
.69 .76 .71 .73 .73 .74 .78
.18 .21 .20 .21 .19 .21 .20
Cu
Fe
Mn
Dry matter
s "> )
96 93 93 92 89 86 97
22 14 14 16 20 14 15
sPF"V
242 304 307 312 316 268 227
132 134 130 127 140 120 96
Commercial broiler diet was fed in crumble form.
DISCUSSION The nutritive value of wheat screenings was determined using five different samples of wheat screenings. The percentage of botanical components of the samples (Table 3) differed widely from that reported by Biely and Pom-
eranz (1975). The samples used in the present study contained more rapeseed (8%) and cracked barley (3.8%) compared to the values reported in the literature (2.1% and . 1 % , respectively). The wild buckwheat content of 29.9% reported by Biely and Pomeranz, (1975) was far higher than the 7.8% reported here. Table 13 shows the botanical composition of 21 commercial samples of No.l wheat screenings, obtained during 1975—76. The results shown in this table emphasize the variability in composition of screenings. The percentage of the major ingredients reported in Table 13 differ from those of Table 3 and from the values of Biely and Pomeranz (1975). The chemical analysis of the screenings (Table 1) shows that wheat screenings have an average protein content of about 14% compared to a 12.2% protein level in wheat. The amino acid composition of wheat screenings (Table 2) shows them to be at least the equal of wheat itself. Tkachuk and Mellish (1977) reported the
TABLE 6. Calculated analysis: amino acid composition of experimental diets (Experiment I)
*
Lysine Arginine Valine Leucine Isoleucine Threonine Methionine and cystine Phenylalanine and tyrosine Tryptophan
Wheat screenings
Wheat
1
2
3
4
5
1.2 1.4 1.0 1.5 .9 .8 .7 1.6 .3
1.3 1.5 1.1 1.6 1.0 .8 .7 1.7 .3
1.3 1.4 1.0 1.6 .9 .8 .7 1.7 .3
1.3 1.5 1.1 1.6 1.0 .8 .7 1.7 .3
1.2 1.4 1.0 1.6 .9 .8 .7 1.7 .3
1.3 1.5 1.1 1.6 1.0 .8 .7 1.7 .3
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(1390 g and 1435 g, respectively) than the chicks fed two experimental rations (diets 1 and 2) which averaged 1270 g and 1295 g, respectively. The replacement of the grain in the commercial rations by wheat screenings did not significantly change the final body weights of the birds but it did significantly increase the feed efficiency ratio from 1.95 (diet 3) to 2.07 (diet 4). Commercially formulated rations with or without screenings (except diet 4) produced significantly better feed efficiency rations that did the experimental diets 1 and 2. Mortality was low in all experiments and was not related to dietary regimens.
337
WHEAT SCREENINGS IN BROILER DIETS TABLE 7. Composition of diets fed in Experiment 2" Ingredients Wheat screenings Wheat Soybean meal (48.5% protein) Tallow Cellulose
2
1
4
3
5
6
63.8
57.8
63.5
58.5
61.9
55.1 26.3 8.3 1.3
21.3 5.0 .4
24.2 7.3 1.2
22.0 5.0 .0
23.8 7.0 1.2
23.0 5.2 .4
3058 9.3 23.2 1.3 1.5 1.1 1.6 1.0 .8 .7 1.7 .3 1.0 .5
2858 9.3 22.2 1.2 1.4 1.0 1.6 .9 .8 .7 1.6 .3 1.0 .5
2972 9.3 22.6 1.3 1.4 1.1 1.6 1.0 .8 .7 1.7 .3 1.0 .5
2820 9.3 22.4 1.3 1.4 1.0 1.6 .9 .8 .7 1.6 .3 1.0 .5
2955 9.3 22.6 1.3 1.4 1.0 1.6 .9 .8 .7 1.7 .3 1.0 .5
2866 9.3 22.6 1.3 1.5 1.1 1.6 1.0 .8 .7 1.7 .3 1.0 .5
Calculated analyses
All diets contained 7% meat meal, 1% alfalfa meal, .5% limestone, and 1% vitamin and mineral premix (same as Experiment 1)
amino acid content of weed seeds usually present in screenings and found that many weeds have an excellent amino acid balance and also a higher content of essential amino acids than do commonly grown cereals. The contamination of wheat screenings with weed seeds may, in fact, improve the protein quality of the screenings. An interesting relationship was noted between the ether-extract and fiber contents
TABLE 8. Diets used in Experiment 3 Wheat control (61% wheat)a Wheat screenings replaced wheat in wheat control3Commercial # 1 (Company A) Wheat screenings replaced the grain in commercial #1 5. Commercial # 2 (Company B) 6. Wheat screenings replaced the grain in commercial #2
1. 2. 3. 4.
Rations contained 24% soyabean meal, 7% meat meal, 5.5% tallow, 1% alfalfa meal, .5% limestone, and 1% vitamin and mineral premix (same as Experiment 1).
(Table 1). Screenings high in fiber are also high in ether-extract and screenings with lower fiber content have lower ether-extract contents and the correlation coefficient for these factors is .94. Wheat screenings have an average ash content of 2.2% compared to wheat values of 1.4% (Table 1). The calcium and iron concentrations of the screenings were significantly higher than those in wheat, while the magnesium content was also higher than in wheat. Harrold and Malewaja (1977) analyzed 15 species of weed seeds for ash and mineral content and found that weed seeds had a high mineral content. The high mineral content of wheat screenings, as compared to wheat, may in part be due to the weed seeds which are normally present in wheat screenings. The replacement of wheat with wheat screenings in broiler rations resulted in statistically insignificant gains in body weights of the chicks (Table 10). Body weight of the chicks was not directly related to either the fat content of individual samples of wheat screenings or of the individual diet. Feed efficiency ratios were similar for all diets.
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Energy (kcal/kg) Fat (%) Protein (%) Lysine (%) Arginine Valine Leucine Isoleucine Threonine Methionine and cystine Phenylalanine and tyrosine Tryptophan Calcium Available phosphorus
STAPLETON ET AL.
338
TABLE 9. Chemical analyses of rations in Experiment 3
Protein
Crude fiber
Ash
Ca
P
Cu
Fe
Mn
6.93 7.06
2.39 3.42
5.52 6.03
1.14 1.07
.74 .73
13 16
111 203
114 116
85 85
.15 .17
5.95
3.14
5.70
.97
.94
12
188
90
92
.20
6.76
4.09
6.00
1.02
.91
22
164
95
104
.21
4.73
2.57
5.36
1.08
.76
12
488
107
94
.17
7.25
3.44
5.86
1.06
.81
19
392
112
102
.19
Zn
Mg
(%)
Expressed on an "as fed" basis.
TABLE 10. Average body weight and feed efficiency of broilers (four weeks of age) fed wheat feed screenings (Experiment 1)
Diet
Body weight (g)
Feed efficiency ratio (feed consumed/gain)
1 2 3 4 5 6 7
692 ± 29a>x 718±15 a 708 ±19 a 723 ± 17a 725 *16 a 704± 18 a
1.77 1.81 1.76 1.80 1.70 1.81
794 ± 2 2 b
1.77 ± .05 a
Wheat Wheat screenings 1 Wheat screenings 2 Wheat screenings 3 Wheat screenings 4 Wheat screenings 5 Commercial broiler crumbles
+ .02 a ± .04 a ± .02 a ± .02 a ± .02 a ± .05 a
Mean ± standard deviation. ab ' Means within columns with different superscripts are significantly different (P<.05).
TABLE 11. Average body weight and feed efficiency of broiler chicks at four weeks of age (Experiment 2)
Diet
Body weight (g)
Feed efficiency ratio (feed consumed/gain)
1 2 3 4 5 6 7
783* 21ab.! 738 * 46 a 795 * 16 ab 745 * 25a 763 * 19a 766* 31a
1.81 ± .02 a b 1.90+ ,05 b 1.81 ± . 0 3 a b 1.90 ± .06 b 1.86 + . 0 3 a b 1.84 ± . 0 3 a b
848* 15b
1.77 ± .02 a
Wheat Wheat screenings 1 Wheat screenings 2 Wheat screenings 3 Wheat screenings 4 Wheat screenings 5 Commercial broiler crumbles
Mean ± standard deviation. a 'b Means within columns with different superscripts are statistically significantly different from one another (P<.05).
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1 Wheat 21.7 a 2 Screenings 24.1 3 Commercial # 1 (Company A) 23.6 4 Screenings replaced grain in # 3 25.4 5 Commercial # 2 (Company B) 22.3 6 Screenings replaced grain in # 5 23.9
Fat
339
WHEAT SCREENINGS IN BROILER DIETS TABLE 12. Average body weight and feed efficiency of six-week old broilers fed control, wheat feed screenings, and commercial diets (Experiment 3)
Diet
Body weight (g)
Feed efficiency ratio (feed consumed/gain)
1 2 3 4
1270 ± 29*°.! 1295 ±47 a b 1390+ 18 cd
2.12 ± .03 c 2.07 + .06 c 1.95 ± .01°
1352 + 35 bc 1435 ± 26 cd
2.07 ± .06 c 1.89 ± . 0 1 a b
1468 ± 26 d
1.81 ± .08 a
Wheat control Wheat screenings Commercial 1 (Company A) Screenings replaced grain in # 3 5 Commercial 2 6 Screenings replaced grain in # 5 Mean ± standard deviation. a
When diets containing either wheat or wheat screenings were made to contain the same fat levels, no significant difference was observed in final body weights at four weeks or in the feed efficiency ratios. The variability in botanical composition of the wheat screenings may be the cause of some of the variation in body weights of the chicks. These variations are quite small, however, and generally show that the replacement of wheat in broiler rations with wheat screenings resulted in small increases in weight gain. The high nutritional value of screenings is further emphasized by the results obtained when a composite of the five samples of screenings was fed in broiler rations. When screenings replaced wheat, a slight improvement in weight gain was achieved (Table 12). When wheat screenings replaced the grain in two commercially available broiler rations, a slightly lower body weight was observed in one
group while a small gain in body weight was obtained in the second group. Feed efficiency ratios were not significantly affected by the incorporation of wheat screenings into broiler rations. The results show that rations containing wheat feed screenings as a wheat substitute perform effectively in broiler production. ACKNOWLEDGMENTS
The authors wish to thank Y. Pomeranz, US Grain Marketing Research Center, Manhattan, KS, for assistance with the amino acid analysis. The cooperation of A. J. Leslie of RitchieSmith Ltd., Abbotsford, B.C., in formulation of the commercial rations is greatly appreciated. REFERENCES Biely, J., and Y. Pomeranz, 1975. The amino acid composition of wild buckwheat and No. 1 wheat feed screenings. Poultry Sci. 54:761-766.
TABLE 13. Botanical composition of 21 samples of # 1 wheat feed screenings obtained from feed grain elevators
Cracked wheat Minimum Maximum Mean Standard deviation
Wild buckwheat
68.0a 85.0 77.0
12.0 28.5 17.3
+ 4.12
± 4.26
Ball mustard
Wild oats
Lady's thumb
Cockles
Rape seed
Small seeds and dust
.5 1.0 .58
.4 2.0 .94
.5 2.0 1.29
.5 1.0 .78
.5 2.0 1.13
.5 3.5 1.6
± .20
± .39
± .48
+ .24
+ .56
± .86
Percent of total seeds. Mean within columns of two values only.
Chaff .3 1.0 .65b
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' ' ' Means with different superscripts are statistically significantly different from one another (P<.05).
340
STAPLETON ET AL.
Canada Feeds Act, 1960. C/4 and Feeds Regulations, 1967. Queen's Printer and Controller of Stationery, Ottawa, Canada. Duncan, D. B., 1955. Multiple range and multiple F tests. Biometrics 1 1 : 1—42. Harrold, R. L., and J. D. Malewaja, 1977. Proximate, mineral and amino acid composition of 15 weed seeds. J. Anim. Sci. 44: 389-394.
Pomeranz, Y., and G. S. Robins, 1973. Amino acid composition of buckwheat. Agr. Food Chem. 20:272-274. Snedecor, G. W., 1956. Statistical methods. 5th Ed. Iowa State University Press, Ames, IA. Tkachuk, R., and V. J. Mellish, 1977. Amino acid and proximate analyses of weed seeds. Can. J. Plant Sci. 57:243-249.
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1980 Poultry Science 59:333-340 INTRODUCTION Wheat feed screenings o b t a i n e d in t h e process of cleaning w h e a t grains consist largely of b r o k e n and shrunken wheat kernels. T h e remainder is composed of wild b u c k w h e a t , wild oats, rapeseed, cow cockle, lady's t h u m b , ball m u s t a r d , and small seeds and dust (Biely a n d P o m e r a n z , 1 9 7 5 ) . T h e Canada Feeds Act ( 1 9 6 0 ) defines t h e c o m p o s i t i o n of four grades of screenings (Biely a n d P o m e r a n z , 1 9 7 5 ) . Wheat feed screenings, because of their high wheat c o n t e n t , are considered as a p o t e n t i a l s u b s t i t u t e for t h e grain p o r t i o n of p o u l t r y rations. T h e following s t u d y was designed t o determine t h e variation in botanical, chemical, and a m i n o acid c o n t e n t of w h e a t screenings a n d t o evaluate t h e p e r f o r m a n c e of broiler chicks fed rations containing w h e a t screenings. MATERIALS AND METHODS T h e chemical analyses were carried o u t b y t h e p r o c e d u r e s reported b y Biely and P o m e r a n z ( 1 9 7 5 ) and t h e a m i n o acid analyses according to t h e m e t h o d described b y P o m e r a n z and
1 2
School of Home Economics. Department of Poultry Sciences.
R o b i n s ( 1 9 7 3 ) . T h e chemical, a m i n o acid, and botanical compositions of five different commercial samples of w h e a t screenings are s h o w n in Tables 1 , 2 , and 3. T h e w h e a t screenings used in these e x p e r i m e n t s were supplied as N o . 1 w h e a t feed screenings. However, t h e y varied from t h e specifications as s h o w n b y t h e d a t a o n their actual c o m p o s i t i o n . Experiment 1. Wheat screenings were substituted for w h e a t o n a weight-for-weight basis. T h e c o m p o s i t i o n of t h e diets, t h e chemical analysis of t h e w h e a t screening rations, t h e w h e a t control, and a commercial broiler crumbles r a t i o n are given in Tables 4 , 5, and 6. Test diets were fed t o commercial broiler H u b b a r d chicks. Each test diet was fed t o five pens of male chicks, 11 birds per pen. T h e chicks were housed in b a t t e r y b r o o d e r s in an air-conditioned r o o m for a period of four weeks. Body weight of chicks and feed c o n s u m p t i o n were d e t e r m i n e d weekly. Experiment 2. T h e p r o c e d u r e for t h e second e x p e r i m e n t was t h e same as for t h e first. T h e c o m p o s i t i o n of five diets containing screenings and t h e w h e a t c o n t r o l is given in Table 7. Wheat was again replaced b y screenings. Tallow was a d d e d t o t h e rations t o equalize t h e i r fat content. Experiment 3. A c o m p o s i t e of t h e five samples of screenings used in E x p e r i m e n t s 1
333
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ABSTRACT The botanical, chemical, and amino acid content of wheat feed screenings was determined. The botanical composition showed that wheat screenings contained broken or shrunken particles of wheat, wild buckwheat, wild oats, rapeseed, and a variety of weed seeds. The average protein content of the screenings (13.9%) was higher than that of wheat (12.2%). The amino acid content of five samples of wheat screenings were remarkably uniform. The ash content (2.2%) of wheat screenings was nearly double that of wheat (1.2%). The fiber of wheat screenings varied from 2.56 to 4.18%, but, generally, as the fiber level increased, so did the fat content. In the first experiment, wheat screenings replaced wheat in broiler rations on a weight for weight basis. Experiment 2 was similar to Experiment 1 except that all rations were adjusted to contain the same amount of fat. Experiment 3 compared wheat to wheat screeenings in two types of rations, experimental and two commercially designed rations, in which the grain portion of the ration was substituted with wheat screenings. The results of the three experiments indicate that wheat feed screenings may substitute for wheat in balanced broiler rations without affecting chick growth or feed utilization.
STAPLETON ET AL.
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TABLE 1. Chemical analyses of wheat feed screenings
Sample 1 2 3 4 5 Wheat
Dry matter
Crude protein
Ether extract
87.9 86.9 87.9 87.0 87.4 86.2
14.6 a 13.5 14.0 13.9 12.2 12.2
6.60 3.17 6.63 3.66 6.40 1.62
(%)
Crude fiber
Ash
Ca
3.80 2.63 4.18 2.67 3.75 2.56
2.3 2.0 2.6 2.0 2.2 1.4
.12 .08 .15 .08 .11 .04
.39 .34 .39 .37 .36 .31
Mn
Zn
Cu
5 5 6 5 5 6
(ppm) 37 5 32 5 34 6 5 33 32 5 6 38
Fe
379 438 414 307 421 75
Mg
(%) .18 .16 .17 .16 .17 .12
All values expressed on an "as fed" basis.
broiler chicks, 6 5 chicks per g r o u p , totaling 1 5 6 0 chicks. T h e chemical c o m p o s i t i o n of t h e diets fed in E x p e r i m e n t 3 is s h o w n in Table 9. Weight gains and feed efficiencies were subjected t o analysis of variance (Snedecor, 1 9 5 6 ) and t r e a t m e n t comparisons were m a d e with t h e n e w multiple range test of D u n c a n ( 1 9 5 5 ) .
RESULTS Experiment 1. T h e m e a n b o d y weights and feed efficiency ratios of broiler chicks fed either wheat or w h e a t screening ratios are presented in Table 1 0 . Chicks fed commercial broiler crumbles attained a significantly
TABLE 2. Percent amino acid in wheat feed
screenings^'0
Sample
1
2
3
4
5
Wheat
Lysine Threonine Valine Leucine Isoleucine Methionine Cystine Phenylalanine Tyrosine Histidine Arginine Aspartate Glutamate Glycine Alanine Serine Proline
.42 .37 .47 .82 .40 .28 .15 .54 .32 .29 .64 .72 3.40 .46 .44 .49 2.23
.38 .34 .45 .78 .38 .24 .15 .54 .29 .28 .61 .64 3.69 .45 .39 .38 2.14
.44 .37 .47 .83 .41 .27 .14 .55 .30 .29 .68 .71 3.43 .48 .43 .50 2.06
.37 .33 .44 .79 .37 .27 .15 .55 .32 .28 .57 .65 3.81 .43 .39 .47 2.20
.44 .37 .48 .82 .40 .28 .15 .54 .33 .30 .68 .72 3.34 .48 .44 .48 2.04
.33 .28 .38 .65 .30 .21 .14 .42 .27 .23 .52 .54 2.92 .39 .34 .40 1.41
All values expressed on an "as fed" basis. Proteins were hydrolyzed in HC1 and amino acids determined with an amino acid analyser (Beckman 121) Pomeranz and Robins (1973).
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and 2 was m a d e and i n c o r p o r a t e d i n t o broiler r a t i o n s . T h e c o m p o s i t i o n of t h e six rations is shown in Table 8. Screenings replaced w h e a t o n a weight-for-weight basis in diet 2. Screenings also replaced t h e total grain o n a weight-forweight basis in t h e commercially modified rations which were prepared at t h e commercial feed mill. T h e t w o experimental diets, t h e t w o commercial diets, and t h e commercially m o d i fied diets, in which screenings replaced all of t h e grains, were fed t o broiler chicks of t h e same strain used in t h e t w o previous experim e n t s . T h e chicks in this e x p e r i m e n t were housed o n t h e floor for a period of six w e e k s . Each r a t i o n was fed t o four groups of u n s e x e d
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WHEAT SCREENINGS IN BROILER DIETS TABLE 3. Botanical composition of wheat feed screenings
Sample
Cracked wheat
Wild buckwheat
Cracked barley
Rapeseed
Weed seeds
1 2 3 4 5
67 75 60 76 59
10 4 9 4 12
3 5 4 2 5
8 5 11 5 11
3 1 5 2 3
Chaff
Flax seed
Mineral
Fines a
10
Material that passes through a 1.79 mm mesh, chiefly wheat and small weed seeds.
weights of chicks fed screenings ranged from 7 3 8 g t o 795 g. No statistically significant differences existed a m o n g t h e g r o u p s fed either wheat or screenings. T h e feed efficiency ratios given in T a b l e 11 show t h a t t w o rations containing screenings (screenings # 1 and # 3 ) gave ratios (1.90) which were significantly higher t h a n t h a t given b y t h e commercial ration. As was t h e case with b o d y weights, no significant differences existed in t h e feed efficiency ratio of chicks fed t h e w h e a t or w h e a t screenings diets. Experiment 3. T h e w h e a t screenings used in this e x p e r i m e n t were a c o m p o s i t e of t h e five samples used in E x p e r i m e n t s 1 and 2 . T h e m e a n b o d y weights of chicks a n d t h e feed efficiency ratios are given in Table 1 2 . T h e r e was no significant difference in b o d y weights or feed efficiency ratio of chicks fed either t h e w h e a t control or wheat screenings. T h e chicks fed t h e commercial broiler rations (diets 3 and 5) were significantly heavier
TABLE 4. Composition of experimental diets (Experiment 1) Ingredients (%)
Wheat control
Wheat Wheat screenings Soybean meal (48.5% protein) Meat meal (50% protein) Alfalfa meal (20% protein) Tallow Limestone Vitamin — mineral premixb
62.0 23.0 7.0 1.0 5.0 1.0 1.0
Screenings 1
62.0 23.0 7.0 1.0 5.0 1.0 1.0
Composition of diet in which five wheat screenings samples replaced wheat. Supplied per kilogram of diet: vitamin A, 11,000 IU; vitamin D, 880 ICU; vitamin E, 10 IU; menadione, 2.2 mg; vitamin B 12 , 13.2 meg; riboflavin, 6.6 mg; Ca pantothenate, 24.2 mg; niacin, 36.2 mg; biotin, .04 mg; choline CI, 500 mg; NaCl 3.52 g; Mn, 86 mg; Zn, 49 mg; Cu, 7.7 mg.
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higher b o d y weight t h a n t h e chicks fed either t h e w h e a t ration or rations containing wheat screenings, replacing wheat o n a weightfor-weight basis. T h e r e was little difference in final b o d y weights of t h e chicks fed w h e a t ( 6 9 2 g) c o m p a r e d w i t h t h e weights of t h o s e fed screenings (range 7 0 4 t o 725 g). No significant difference was observed in feed efficiency ratio b e t w e e n t h e seven groups. Experiment 2. Diets containing either w h e a t or w h e a t screenings were fed t o broiler chicks for four weeks. T h e weight of t h e chicks and feed efficiency ratios are given in Table 1 1 . T h e weight of t h e chicks ( 8 4 8 g) fed t h e commercial broiler crumbles (diet 7) was n o t significantly higher t h a n t h e b o d y weight of chicks fed w h e a t (783 g) or screenings in diet 3 ( 7 9 5 g). However, t h e b o d y weight of t h e chicks fed t h e commercial ration was significantly heavier t h a n t h e weights of chicks fed screenings in diets 2, 4 , 5, and 6. Final b o d y
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STAPLETON ET AL. TABLE 5. Chemical analyses of experimental diets (Experiment 1)
Dietary treatments
Crude protein
Ether extract
Crude fiber
Wheat Screenings #1 Screenings #2 Screenings #3 Screenings #4 Screenings #5 Commercial broiler a
21.3 22.7 22.3 22.4 22.3 22.0 21.2
6.5 9.6 7.8 10.1 7.9 9.4 9.0
3.1 3.9 3.2 4.3 3.3 3.8 4.1
Zn Ash
5.7 6.3 5.9 6.2 5.8 5.9 5.3
Ca
P
Mg
1.19 1.28 1.23 1.25 1.16 1.22 1.04
.69 .76 .71 .73 .73 .74 .78
.18 .21 .20 .21 .19 .21 .20
Cu
Fe
Mn
Dry matter
s "> )
96 93 93 92 89 86 97
22 14 14 16 20 14 15
sPF"V
242 304 307 312 316 268 227
132 134 130 127 140 120 96
Commercial broiler diet was fed in crumble form.
DISCUSSION The nutritive value of wheat screenings was determined using five different samples of wheat screenings. The percentage of botanical components of the samples (Table 3) differed widely from that reported by Biely and Pom-
eranz (1975). The samples used in the present study contained more rapeseed (8%) and cracked barley (3.8%) compared to the values reported in the literature (2.1% and . 1 % , respectively). The wild buckwheat content of 29.9% reported by Biely and Pomeranz, (1975) was far higher than the 7.8% reported here. Table 13 shows the botanical composition of 21 commercial samples of No.l wheat screenings, obtained during 1975—76. The results shown in this table emphasize the variability in composition of screenings. The percentage of the major ingredients reported in Table 13 differ from those of Table 3 and from the values of Biely and Pomeranz (1975). The chemical analysis of the screenings (Table 1) shows that wheat screenings have an average protein content of about 14% compared to a 12.2% protein level in wheat. The amino acid composition of wheat screenings (Table 2) shows them to be at least the equal of wheat itself. Tkachuk and Mellish (1977) reported the
TABLE 6. Calculated analysis: amino acid composition of experimental diets (Experiment I)
*
Lysine Arginine Valine Leucine Isoleucine Threonine Methionine and cystine Phenylalanine and tyrosine Tryptophan
Wheat screenings
Wheat
1
2
3
4
5
1.2 1.4 1.0 1.5 .9 .8 .7 1.6 .3
1.3 1.5 1.1 1.6 1.0 .8 .7 1.7 .3
1.3 1.4 1.0 1.6 .9 .8 .7 1.7 .3
1.3 1.5 1.1 1.6 1.0 .8 .7 1.7 .3
1.2 1.4 1.0 1.6 .9 .8 .7 1.7 .3
1.3 1.5 1.1 1.6 1.0 .8 .7 1.7 .3
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(1390 g and 1435 g, respectively) than the chicks fed two experimental rations (diets 1 and 2) which averaged 1270 g and 1295 g, respectively. The replacement of the grain in the commercial rations by wheat screenings did not significantly change the final body weights of the birds but it did significantly increase the feed efficiency ratio from 1.95 (diet 3) to 2.07 (diet 4). Commercially formulated rations with or without screenings (except diet 4) produced significantly better feed efficiency rations that did the experimental diets 1 and 2. Mortality was low in all experiments and was not related to dietary regimens.
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WHEAT SCREENINGS IN BROILER DIETS TABLE 7. Composition of diets fed in Experiment 2" Ingredients Wheat screenings Wheat Soybean meal (48.5% protein) Tallow Cellulose
2
1
4
3
5
6
63.8
57.8
63.5
58.5
61.9
55.1 26.3 8.3 1.3
21.3 5.0 .4
24.2 7.3 1.2
22.0 5.0 .0
23.8 7.0 1.2
23.0 5.2 .4
3058 9.3 23.2 1.3 1.5 1.1 1.6 1.0 .8 .7 1.7 .3 1.0 .5
2858 9.3 22.2 1.2 1.4 1.0 1.6 .9 .8 .7 1.6 .3 1.0 .5
2972 9.3 22.6 1.3 1.4 1.1 1.6 1.0 .8 .7 1.7 .3 1.0 .5
2820 9.3 22.4 1.3 1.4 1.0 1.6 .9 .8 .7 1.6 .3 1.0 .5
2955 9.3 22.6 1.3 1.4 1.0 1.6 .9 .8 .7 1.7 .3 1.0 .5
2866 9.3 22.6 1.3 1.5 1.1 1.6 1.0 .8 .7 1.7 .3 1.0 .5
Calculated analyses
All diets contained 7% meat meal, 1% alfalfa meal, .5% limestone, and 1% vitamin and mineral premix (same as Experiment 1)
amino acid content of weed seeds usually present in screenings and found that many weeds have an excellent amino acid balance and also a higher content of essential amino acids than do commonly grown cereals. The contamination of wheat screenings with weed seeds may, in fact, improve the protein quality of the screenings. An interesting relationship was noted between the ether-extract and fiber contents
TABLE 8. Diets used in Experiment 3 Wheat control (61% wheat)a Wheat screenings replaced wheat in wheat control3Commercial # 1 (Company A) Wheat screenings replaced the grain in commercial #1 5. Commercial # 2 (Company B) 6. Wheat screenings replaced the grain in commercial #2
1. 2. 3. 4.
Rations contained 24% soyabean meal, 7% meat meal, 5.5% tallow, 1% alfalfa meal, .5% limestone, and 1% vitamin and mineral premix (same as Experiment 1).
(Table 1). Screenings high in fiber are also high in ether-extract and screenings with lower fiber content have lower ether-extract contents and the correlation coefficient for these factors is .94. Wheat screenings have an average ash content of 2.2% compared to wheat values of 1.4% (Table 1). The calcium and iron concentrations of the screenings were significantly higher than those in wheat, while the magnesium content was also higher than in wheat. Harrold and Malewaja (1977) analyzed 15 species of weed seeds for ash and mineral content and found that weed seeds had a high mineral content. The high mineral content of wheat screenings, as compared to wheat, may in part be due to the weed seeds which are normally present in wheat screenings. The replacement of wheat with wheat screenings in broiler rations resulted in statistically insignificant gains in body weights of the chicks (Table 10). Body weight of the chicks was not directly related to either the fat content of individual samples of wheat screenings or of the individual diet. Feed efficiency ratios were similar for all diets.
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Energy (kcal/kg) Fat (%) Protein (%) Lysine (%) Arginine Valine Leucine Isoleucine Threonine Methionine and cystine Phenylalanine and tyrosine Tryptophan Calcium Available phosphorus
STAPLETON ET AL.
338
TABLE 9. Chemical analyses of rations in Experiment 3
Protein
Crude fiber
Ash
Ca
P
Cu
Fe
Mn
6.93 7.06
2.39 3.42
5.52 6.03
1.14 1.07
.74 .73
13 16
111 203
114 116
85 85
.15 .17
5.95
3.14
5.70
.97
.94
12
188
90
92
.20
6.76
4.09
6.00
1.02
.91
22
164
95
104
.21
4.73
2.57
5.36
1.08
.76
12
488
107
94
.17
7.25
3.44
5.86
1.06
.81
19
392
112
102
.19
Zn
Mg
(%)
Expressed on an "as fed" basis.
TABLE 10. Average body weight and feed efficiency of broilers (four weeks of age) fed wheat feed screenings (Experiment 1)
Diet
Body weight (g)
Feed efficiency ratio (feed consumed/gain)
1 2 3 4 5 6 7
692 ± 29a>x 718±15 a 708 ±19 a 723 ± 17a 725 *16 a 704± 18 a
1.77 1.81 1.76 1.80 1.70 1.81
794 ± 2 2 b
1.77 ± .05 a
Wheat Wheat screenings 1 Wheat screenings 2 Wheat screenings 3 Wheat screenings 4 Wheat screenings 5 Commercial broiler crumbles
+ .02 a ± .04 a ± .02 a ± .02 a ± .02 a ± .05 a
Mean ± standard deviation. ab ' Means within columns with different superscripts are significantly different (P<.05).
TABLE 11. Average body weight and feed efficiency of broiler chicks at four weeks of age (Experiment 2)
Diet
Body weight (g)
Feed efficiency ratio (feed consumed/gain)
1 2 3 4 5 6 7
783* 21ab.! 738 * 46 a 795 * 16 ab 745 * 25a 763 * 19a 766* 31a
1.81 ± .02 a b 1.90+ ,05 b 1.81 ± . 0 3 a b 1.90 ± .06 b 1.86 + . 0 3 a b 1.84 ± . 0 3 a b
848* 15b
1.77 ± .02 a
Wheat Wheat screenings 1 Wheat screenings 2 Wheat screenings 3 Wheat screenings 4 Wheat screenings 5 Commercial broiler crumbles
Mean ± standard deviation. a 'b Means within columns with different superscripts are statistically significantly different from one another (P<.05).
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1 Wheat 21.7 a 2 Screenings 24.1 3 Commercial # 1 (Company A) 23.6 4 Screenings replaced grain in # 3 25.4 5 Commercial # 2 (Company B) 22.3 6 Screenings replaced grain in # 5 23.9
Fat
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WHEAT SCREENINGS IN BROILER DIETS TABLE 12. Average body weight and feed efficiency of six-week old broilers fed control, wheat feed screenings, and commercial diets (Experiment 3)
Diet
Body weight (g)
Feed efficiency ratio (feed consumed/gain)
1 2 3 4
1270 ± 29*°.! 1295 ±47 a b 1390+ 18 cd
2.12 ± .03 c 2.07 + .06 c 1.95 ± .01°
1352 + 35 bc 1435 ± 26 cd
2.07 ± .06 c 1.89 ± . 0 1 a b
1468 ± 26 d
1.81 ± .08 a
Wheat control Wheat screenings Commercial 1 (Company A) Screenings replaced grain in # 3 5 Commercial 2 6 Screenings replaced grain in # 5 Mean ± standard deviation. a
When diets containing either wheat or wheat screenings were made to contain the same fat levels, no significant difference was observed in final body weights at four weeks or in the feed efficiency ratios. The variability in botanical composition of the wheat screenings may be the cause of some of the variation in body weights of the chicks. These variations are quite small, however, and generally show that the replacement of wheat in broiler rations with wheat screenings resulted in small increases in weight gain. The high nutritional value of screenings is further emphasized by the results obtained when a composite of the five samples of screenings was fed in broiler rations. When screenings replaced wheat, a slight improvement in weight gain was achieved (Table 12). When wheat screenings replaced the grain in two commercially available broiler rations, a slightly lower body weight was observed in one
group while a small gain in body weight was obtained in the second group. Feed efficiency ratios were not significantly affected by the incorporation of wheat screenings into broiler rations. The results show that rations containing wheat feed screenings as a wheat substitute perform effectively in broiler production. ACKNOWLEDGMENTS
The authors wish to thank Y. Pomeranz, US Grain Marketing Research Center, Manhattan, KS, for assistance with the amino acid analysis. The cooperation of A. J. Leslie of RitchieSmith Ltd., Abbotsford, B.C., in formulation of the commercial rations is greatly appreciated. REFERENCES Biely, J., and Y. Pomeranz, 1975. The amino acid composition of wild buckwheat and No. 1 wheat feed screenings. Poultry Sci. 54:761-766.
TABLE 13. Botanical composition of 21 samples of # 1 wheat feed screenings obtained from feed grain elevators
Cracked wheat Minimum Maximum Mean Standard deviation
Wild buckwheat
68.0a 85.0 77.0
12.0 28.5 17.3
+ 4.12
± 4.26
Ball mustard
Wild oats
Lady's thumb
Cockles
Rape seed
Small seeds and dust
.5 1.0 .58
.4 2.0 .94
.5 2.0 1.29
.5 1.0 .78
.5 2.0 1.13
.5 3.5 1.6
± .20
± .39
± .48
+ .24
+ .56
± .86
Percent of total seeds. Mean within columns of two values only.
Chaff .3 1.0 .65b
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' ' ' Means with different superscripts are statistically significantly different from one another (P<.05).
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STAPLETON ET AL.
Canada Feeds Act, 1960. C/4 and Feeds Regulations, 1967. Queen's Printer and Controller of Stationery, Ottawa, Canada. Duncan, D. B., 1955. Multiple range and multiple F tests. Biometrics 1 1 : 1—42. Harrold, R. L., and J. D. Malewaja, 1977. Proximate, mineral and amino acid composition of 15 weed seeds. J. Anim. Sci. 44: 389-394.
Pomeranz, Y., and G. S. Robins, 1973. Amino acid composition of buckwheat. Agr. Food Chem. 20:272-274. Snedecor, G. W., 1956. Statistical methods. 5th Ed. Iowa State University Press, Ames, IA. Tkachuk, R., and V. J. Mellish, 1977. Amino acid and proximate analyses of weed seeds. Can. J. Plant Sci. 57:243-249.
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