The Relative Vitamin G Content of Alfalfa Meal

The Relative Vitamin G Content of Alfalfa Meal

The Relative Vitamin G Content of Alfalfa Meal H. S. WILGUS, JR., L. C. NORRIS AND G. F. HEUSER Department of Poultry Husbandry, Cornell University, I...

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The Relative Vitamin G Content of Alfalfa Meal H. S. WILGUS, JR., L. C. NORRIS AND G. F. HEUSER Department of Poultry Husbandry, Cornell University, Ithaca, New York (Received for publication April 28, 1936)

REEN feed has been considered to be of special value in poultry rations for many years. Recent investigations have shown that part of this value is due to vitamin A activity, or carotene, and numerous studies on the effect of various factors in the drying on the vitamin A potency, particularly of alfalfa, have been reported. Salmon (1927) found that velvet bean leaves are rich in the growth-promoting part of the vitamin B complex. Bethke, Record, and Kennard (1931) found that alfalfa leaf meal prevented the occurrence of nutritional paralysis in chicks and also stimulated growth. Hunt and co-workers (1933) showed that alfalfa meal is a rich source of vitamin G and that the amount of this factor in the meal is influenced by the stage of maturity of the plants and by weather conditions during curing. Norris et al (1934) indicated that the improvement in hatchability when alfalfa meal was added to rations low in vitamin G was due to the vitamin G thus added. It appeared probable, therefore, that alfalfa meal should be a good source of vitamin G. Accordingly, assays of the growthpromoting vitamin G content of alfalfa meals have been conducted in order to determine the variation in potency of market samples, the effect of method of drying, and the influence of the stage of maturity. Since it seemed probable that factors which would tend to improve the market grade and the analysis of the meals might also tend to maintain the vitamin G potency, correlations were made between the vitamin G po-

tency and the grade, protein, ether-extract, ash, and fiber analyses. The grade was determined by the Bureau of Agricultural Economics of the U.S.D.A., and is based largely upon proportion of leafy material and green color. RESULTS

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G

The method used in assaying these samples has been described elsewhere in detail (Wilgus, Norris, and Heuser, 1935). It consists essentially of determining the gains induced in White Leghorn chicks from the second to the sixth week of age when fed 5 percent of alfalfa meal in a ration otherwise deficient in growth-promoting vitamin G, over the gains of a negative control group fed the basal ration alone. These gains are then compared to those produced by feeding graded levels of a standard dried pork liver, and the potency is expressed in terms of this dried pork liver which is rated as 100. The relative vitamin G contents of the commercial samples studied are given in Table 1. Most of these meals were obtained on the Buffalo market in the fall of 1933 and 1934. In some instances, more than one meal was available from a given source. These were composited to obtain an average sample. The results on the artificially dehydrated products are reported separately from those on the sun-cured ones. The suncured meals had an average potency of 11 with a range from 9 to 17. Since dried skimmilk was found to possess an average relative potency of 19 (Wilgus et al, 1935), this class of alfalfa meals is about 60 per-

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The first pair of samples from farm B showed no differences between the suncured and the dehydrated meals. These were cut from the same plot at the early blossom

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stage of maturity in the third cutting in September, 1933. Both values were very low. The sun-cured sample was exposed for one day at an average temperature of 83 °F. The dehydrated sample was allowed to wilt in the field iy2 hours and then dried in three minutes at an air temperature of 1160°F. at the hot air intake and of 210°F. at the hot air exit. These low values cannot be explained unless the length of time in the dryer at this high temperature was detrimental. The sun-cured sample was badly bleached and the dehydrated one had a scorched odor. The second pair of samples, similarly produced on this farm in 1934, gave values in close agreement with those obtained with the commercial samples. Unfortunately, no detailed data were supplied concerning the history of these samples. The same dryer was used as in the preceding year. In general, the dehydrated samples of alfalfa studied tended to run higher in grade, protein, and ether extract and lower in fiber than the sun-cured ones. This might indicate the use of more immature alfalfa. In order to get some data on the effect of stage of maturity and number of the cutting upon the resulting meal, a few commercial samples of known history were obtained during the summer of 1935 from two farms producing dehydrated alfalfa meal in the same make of dryer. The data regarding their history, analysis and vitamin G potency are given in Table 3. Only rough comparisons indicating the effect of the cutting and the maturity of the stand are possible since the alfalfa cuttings were from different fields. The second cutting samples (from the western Pennsylvania farm) were superior in vitamin G potency to those from the first cutting. This was to be expected since the plants in the first cutting were much coarser and ranker and had the greater proportion of stem to leaf. Within each cutting, the more imma-

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cent as potent in this factor as dried skimmilk. The dehydrated samples had an average value of 16 with a range from 12 to 20. Thus they were about 40 percent more potent than the sun-cured meals and contained about 85 percent as much growth-promoting vitamin G as dried skimmilk. No particular significance could be attached to the particular state from which these samples originated. It is possible that some of the difference between the sun-cured and the artificially dehydrated meals was due to the use of more immature plants in the latter case rather than entirely to the method of drying. However, similar differences were found in samples prepared by sun-curing and by artificial dehydration from alfalfa cut from the same field at the same time. The results of this study are shown in Table 2. The three samples from farm A were cut at the half-blossom stage of the third cutting early in September, 1933. They were harvested from the same field at about noon. Sample 1S was allowed to cure naturally for Syi days. During this time, the weather was clear and dry, and the temperature ranged from 60° at night to 80° during the day. This sample had about the same vitamin G potency as the commercial samples of this type reported in Table 1. The dehydrated sample, 16, was dried immediately after cutting at an average temperature of about 185°F. for 25 minutes in a continuous type of hot air machine, whereas sample 17 was dried in the machine overnight at a temperature of about 90°F. Both of these samples were of average potency for this method of preparation. Although the temperature used in the one sample was higher, there was no greater destruction of vitamin G, due probably to the shorter time required for drying.

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NOTE:—

8 9 10 11 12 13 14

Col. N.M. Col. Col. Col. Neb. Calif.

1 2 3 4 5 6 7

1 1 4 1 1 4 4

2 1 1 5 S 1 1

Leaves

%

Green

%

16

20 18 18 15 15 13 12

fine special A.M. fine A.L.M. fine A.M. fine A.L.M. fine special A.M. fine special A.M. fine A.M.

#1-2 Ex. fine special A.M.

#1 ex. #1 ex. #2 ex. #1 ex. #1 ex. #2 ex. #2 ex. 59

62 65 47 70 68 48 51 68.9

72.5 85.0 45.0 85.0 65.0 80.0 50.0

35.4

64

#1-2 Extra fine A.M.

11 Dehydrated Meals

62.5 32.5 30.0 45.0 37.5 25.0 15.0

60 61 77 60 60 51 80

#2 ex. fine special A.M. #1 ex. fine A.M. Ex. green fine A.M. #1 ex. fine A.M. #1 ex. fine A.M. #2 ex. fine A.M. Ex. green ex. fine A.S.M.

Suncured Meals

Unofficial U. S. Grade

17 12 10 11 11 11 9

Samples Relative Composited Vitamin G No. Content

A.M. =Alfalfa Meal A.L.M. = Alfalfa Leaf Meal A.S.M. = Alfalfa Stem Meal

Average

Okla. Pa. Pa. Calif. Ohio Pa. Pa.

Average

State

Sample No.

19.4

20.2 22.6 17.3 21.2 20.1 17.4 16.9

15.9

18.7 17.8 13.6 14.6 14.3 15.7 16.5

%

Protein

TABLE 1.—The relative vitamin G content of commercial samples of alfalfa meal

om http://ps.oxfordjournals.org/ at Georgetown University on May 24, 2015 2.7

3.2 2.9 1.9 2.7 3.6 2.7 2.0

2.0

2.1 2.7 1.8 2.0 1.8 1.8 2.1

%

Ether Extract

8.3

9.1 9.3 8.2 7.6 8.5 7.2 8.2

8.8

8.4 9.2 10.2 10.3 8.2 8.6 6.8

%

Ash

24.1

20.7 23.4 27.9 19.6 22.4 25.5 29.2

24.9

20.1 18.8 28.1 27.0 29.6 27.1 23.3

%

Fiber

c/3

Z



-1^ 00

24.9 21.5

24.3

27.4 23.4

22.9 24.4

O

*-H OO

O N

©CN

16.9 20.3 30.0 62.5

19.3 22.2

CN CN

40.0 60.0

18.1

CN

62.5

20.2 19.1

HK)

50.0 50.0

% %

Ether Extract Protein Leaves

t

M O

lO O

3$

*. • ^ lO

CN

#3 fine A.M. #1finespecial A.M.

*0

OOOO

0\\0

«

<

MM

MM

»OVOt^

Sun-cured Dehydrated

#3 fine A.M. #1finespecial A.M.

CN">

Sun-cured Dehydrated

#2 ex.finespecial A.M.

.8

#2 fine A.M. #1 ex. fine A.M.

O

Sun-cured Dehydrated Special dehydrated

The gross correlations between the vitamin G content and percentage of leafy material, greenness, and analysis are given in Table 4. The estimation of the percentage of leafy material was significantly correlated statistically with vitamin G content. There was a slight positive relationship between

Is

Unofficial U. S. Grade

Since Fraps and Treichler (1933) and Guilbert (1935) have reported that the vitamin A, or carotene, content of alfalfa meal decreases rapidly during storage, the loss in v'^imin G potency occurring during storage was noted on three samples. The samples were held in ordinary cotton sacks from February, 1934, to February, 1935, in a service building. Because sun-cured samples 4 and 5 were found to possess the same potency (11) in 1934, they were composited and tested in 1935. This composite sample showed a value of 13. Dehydrated samples 12 and 21 had respective values of 15 and 16 in 1934 and of 14 and 13 in 1935. All of these differences are within the range of experimental error and showed that no marked destruction of vitamin G had occurred during storage under average conditions for this period.

&

O-H CNCN

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ture plants had a higher vitamin G, protein, and ether-extract content and a lower proportion of fiber. The high vitamin G potency of sample 26, second cutting, advanced stage of maturity, from the western New York farm, cannot be explained. The protein, ether-extract and fiber analyses indicate an inferior product. Samples 27 and 28 are low in value due probably to relatively advance maturity. The fourth cutting, sample 29, from very immature alfalfa was high in vitamin G, protein, and ether-extract and low in fiber. In general, these results show that there is a greater concentration of nutrients in the more immature plants and in cuttings after the first one, or in plants in which the fiber content (proportion of stem) is reasonably low.

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Relative Vitamin G Content

No.

Source

V O L . XV,

Method of Preparation

1936.

Sample No.

NOVEMBER,

20 11 12 21

Adv. blossom Full blossom Half blossom Early bud

2 2 3 4

26 27 28 29

A.M. = Alfalfa Meal A.L.M. = Alfalfa Leaf Meal

13 10 19 17

Early bud Early blossom Early blossom Half blossom

1 1 2 2

22 23 24 25

NOTE:—

Relative Vitamin G Content

Maturity of Stand

Cutting No.

Sample No.

fine fine fine fine

%

%

48 36 53 46

A.M. A.M. A.M. A.L.M.

56 49 71 68

Western New York Samples

#2 ex. fine A.M. #3 fine A.M. #2 ex. fine special A.M. #2 ex. fine special A.M.

#2 ex. #2 ex. #1 ex. #1 ex.

Leaves

Green

40.0 32.5 45.0 85.0

50.0 25.0 77.5 72.5

Western Pennsylvania Samples

Unofficial U. S. Grade

16.4 15.0 16.5 19.8

18.1 15.0 22.1 21.0

%

Protein

1.8 1.8 2.1 2.7

3.5 1.8 2.5 2.1

%

Ether Extract

TABLE 3.—The relative vitamin G content of commercial samples of dehydrated alfalfa meal of known history

om http://ps.oxfordjournals.org/ at Georgetown University on May 24, 2015 6.0 6.5 7.1 7.8

7.9 7.6 7.6 6.4

%

Ash

31.5 31.1 26.3 19.8

23.3 33.3 19.7 23.9

%

Fiber

w

O

H

n

W Ki

c!

o

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TABLE 4.—The correlations between vitamin G potency and the character and composition of alfalfa meals Correlation between relative vitamin G content and; Leaves, percent Green, percent Protein, percent Ether extract, percent Ash, percent Fiber, percent

+0.676 + +0.230 ± +0.449 + +0.329 + +0.107 + - 0.345 ±

0.101 0.176 0.148 0.166 0.184 0.164

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percent of the possible variables and those in the smaller one, for only 28 percent. This demonstrates that only part of the factors having some relation with vitamin G potency were included in this study. DISCUSSION

This investigation has substantiated the findings of Hunt et al (1933) and of Norris and co-workers (1934) that alfalfa meal is a good source of vitamin G. The superiority in vitamin G content of the artificially dehydrated samples over the sun-cured ones is not surprising, since many investigators have shown that the artificially dehydrated meals are generally superior in carotene content. The difference may be much greater in the case of carotene, probably because carotene is more easily oxidized or destroyed under adverse conditions than is vitamin G. While artificial dehydration generally appears to be superior to natural sun-curing, it is possible that sun-cured meals of high vitamin G value may be produced under highly favorable climatic conditions. These results are also essentially in agreement with those of Hunt et al (1933) in showing that the vitamin G potency and the protein content of the alfalfa meal tend to decrease and the amount of fiber to increase with increasing maturity. The insignificant correlation between green color and vitamin G potency does not agree with the results of the Ohio workers. Of all the factors studied, the percentage of leafy material was most closely correlated with the TABLE 5.—The relative vitamin G content of different grades of alfalfa products Relative Vitamin G Content Grade

Alfalfa stem meal = Alfalfa meal = Special alfalfa meal = Alfalfa leaf meal =

Maximum

Minimum

Average

20 20 21

8 8 15

9 12 15 18

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vitamin G content and percentage of protein and of ether-extract, and a slight negative one with the percentage of fiber. No appreciable correlation was found with the percentage of ash or of greenness. In general, the better samples classified as special meals or as leaf meals according to tentative government standards, as shown in Table 5. These were nearly all artificially dehydrated. The correlation between any single factor and vitamin G content was not sufficiently great to be a reliable criterion of the vitamin G potency of alfalfa products. However, the multiple correlation between the relative vitamin G content and the percentage of leaves, protein, ether-extract, and fiber was found to be 0.684. This shows that when these factors, having the better gross correlations, are considered collectively, they may be of some value in estimating the vitamin G content of the product. Since it is not always possible to obtain an estimation of the percentage of leaves, a multiple correlation was run between vitamin G potency and the percentage of protein, etherextract, and fiber. This value was found to be 0.533. Therefore, a high protein and ether extract and a low fiber analysis will also be of some aid in estimating the vitamin G potency of alfalfa products. This lower correlation when percentage of leaves was omitted substantiates the gross correlations in showing that the percentage of leafy material is the most valuable single factor in this estimation. The factors used in the higher multiple correlation accounted for 47

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From the points of view of the poultryman and feed dealer, the grade, based primarily on proportion of leafy material, and analysis are not wholly reliable as criteria of the vitamin G potency of the alfalfa products. Nevertheless, the chances of obtaining a highly potent and nutritious alfalfa meal will be increased by specifying that it

SCIENCE

should have a high percentage of leafy material (meeting the requirements of the tentative U. S. grade of alfalfa leaf meal or special alfalfa meal), that it should have a high protein and ether-extract, and a low fiber analysis. SUMMARY

The average growth-promoting vitamin G content of commercial samples of suncured alfalfa meals was found to be nearly 60 percent that of dried skimmilk. The average growth-promoting vitamin G content of commercial samples of artificially dehydrated alfalfa meals was found to be about 85 percent that of dried skimmilk. Considerable variation occurred in both types of meals but especially in the dehydrated samples. Artificial dehydration was generally superior to sun-curing in samples produced from the same fields. The gross correlations between the vitamin G potency of the alfalfa products and the percentages of leafy material, protein, ether-extract, or fiber were not sufficiently great to make any one of these factors a reliable criterion of vitamin G potency. The percentage of leafy material showed the highest correlation. The multiple correlation also was not great enough to be infallible as a guide. However, an alfalfa product, having a high percentage of leafy material and having a high protein and ether-extract content and a low fiber analysis, should tend to have a high vitamin G content. ACKNOWLEDGMENT

Acknowledgment is hereby made of the cooperation of the following: The Grange League Federation, Exchange, Inc., of Ithaca, New York, which made this investigation possible by establishing a temporary investigatorship in the Department of Poultry Husbandry at Cornell University; L. H. Moulton of the White Swan Farms at Fair-

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vitamin G content, indicating a concentration of vitamin G in the leaves. Woodman and Evans (1935) have shown that the nutritive value of the leaves, as evidenced by the amount and digestibility of protein and the amount of fiber, minerals, and ether extract, is superior to that of the stems and that the proportion of leafy material is greatest in the more immature plants and in later cuttings. From the standpoint of the manufacturer of alfalfa products, it therefore appears that the alfalfa should be cut at a relatively immature stage in order to obtain a meal of the highest nutritive value. However, stage of maturity is not the sole consideration, since other factors affecting the proportion of stem to leaf, insect injury, and amount of foreign grasses and weeds undoubtedly have an influence. Furthermore, the unfavorable effect of cutting at an immature stage on the life span and condition of the stand cannot generally be ignored. In an excellent investigation of the nutritive value of alfalfa, Woodman and Evans (1935) demonstrated that, although cutting alfalfa in the prebud stage of maturity gave a slightly higher yield of leaf meal the first year than cuttings at later stages, there was a marked decline in yield the second year and a concurrent increase in the proportion of foreign grasses and weeds in the plot cut in the prebud stage the first year. They suggested, therefore, that it would be more economical to manufacture a leaf meal by screening from alfalfa cut in the blossom stage rather than to produce a comparable meal from alfalfa in the prebud stage without screening.

POULTRY

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1936.

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view, Pennsylvania, Dr. J. E. Hunter of the Department of Agricultural Chemistry at Pennsylvania State College, and J. F. Moulton of the Genesee Valley Alfalfa Corporation, Avon, New York, who supplied the alfalfa meals of known history; and W. H. Hosterman of the Bureau of Agricultural Economics, U.S.D.A., through whose courtesy all of the meals were graded. REFERENCES

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tene content of alfalfa hay and meal. J. Nutr., 10:45-62. Hunt, C. H., P. R. Record, W. Wilder and R. M. Bethke, 1933. Factors influencing the vitamin B and vitamin G content of hays. Ohio Agr. Exp. Sta. Bi-monthly Bull. 18, No. 163 :104-106. Norris, L. C , G. F. Heuser, A. T. Ringrose, H. S. Wilgus, Jr. and V. Heiman, 1934. The vitamin G requirement of poultry. 5th Cong. Mondiale di Pollicultura Atti, 2:512-520. Salmon, W. D., 1927. On the existence of two active factors in the vitamin B complex. Jour. Biol. Chem., 73:483-497. Wilgus, H. S., Jr., L. C. Norris, and G. F. Heuser, 1935. The relative protein efficiency and the relative vitamin G content of common protein supplements used in poultry rations. Jour. Agr. Research 51:383-399. Woodman, H. E. and R. E. Evans, 1935. Nutritive value of lucerne. IV. The leaf-stem ratio. Jour. Agr. Sci., 25:578-597.

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Bethke, R. M., P. R. Record and D. C. Kennard, 1931. A type of nutritional leg paralysis affecting chicks. Poultry Sci., 10:3SS-368. Fraps, G. S., and R. Treichler, 1933. Effect of storage on vitamin A in dried foods. Indus. Engin. Chem., 25:465-466. Guilbert, H. R., 1935. Factors affecting the caro-

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