The Comparative Utilization of Carotene and Pre-Formed Vitamin A in Broiler Type Chicks

The Comparative Utilization of Carotene and Pre-Formed Vitamin A in Broiler Type Chicks C. M.

ELY

Nopco Chemical Company, Harrison, New Jersey (Received for publication April 7, 1959)

LEDHILL and Smith (1955) found substantially higher liver stores of vitamin A in ten week old birds fed the natural or synthetic esters than among those receiving equivalent levels of carotene. Similar evidence has been reported by Harvey et al. (1955), Ascarelli and Bondi (1957), and Laughland and Phillips (1955). Working with laying hens, Russell et al. (1942) noted appreciably higher liver storage of carotene sources when the ration contained normal levels of fat as compared to the response on low fat diets. These investigators also concluded that vitamin A esters were more efficiently absorbed than carotene.

Earlier studies by Johnson et al. (1948) and by Rubin and Bird (1941) had resulted in an opposite view point. Both of these authors reported a higher level of vitamin A activity in the livers of birds fed carotene than that shown by chicks receiving fish liver oil. The purpose of the present series of trials was to investigate the comparative utilization of various carotene and preformed vitamin A sources in crossbred broiler-type chicks. It was specifically desired to obtain data which would have maximum applicability to present day field conditions.

for the purpose of studying vitamin A response had been demonstrated over a period of several years prior to its use in the presently reported experiments. For example, it had been established that commercially hatched chicks with normal reserves of vitamin A at one day old (approximately 50-85 units per total liver) could not survive on the non-supplemented Reid basal diet past the age of 4 weeks. For this reason, the studies reported here do not include a "negative control" lot. Chicks. All tests in this series were conducted on one-day old White Vantress cockerels purchased from a commercial hatchery. These chicks had a normal initial reserve of liver vitamin A, and were not depleted prior to assignment to the various dietary regimes. Each test lot consisted of sixteen chicks, which were subdivided into duplicate groups of eight birds each. TABLE 1.—Vitamin A deficient basal diet (Reid et al., 195S) Ingredient Ground milo Soybean oil meal, 44% protein Steamed bone meal Ground limestone Salt (NaCl) Vitamin premix*

EXPERIMENTAL PROCEDURE

Vitamin A Deficient Basal Diet. The vitamin A deficient basal diet used for these studies was that of Reid et al. (1955). The ingredient composition for this retion is presented in Table 1. The excellent adaptability of this diet

Percent of diet 60.0 34.0 2.0 1.5 0.5 2.0 100.0

* Adds per cwt. of diet: 200 mg. riboflavin; 500 mg. dl-calcium pantothenate; 1,200 mg. niacin; 2,000 mg. choline chloride (100% basis); 0.5 mg. vitamin B12; 40,000 I.C.U. vitamin D3; 200 mg. procaine penicillin; 10 gm. manganese sulfate plus soybean oil meal carrier.

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CAROTENE VS. VITAMIN A

regulation of the feed in the troughs to last a maximum of 4 to 5 days, (2) prior admixture of all experimental additives with appropriate quantities of the antioxidants butylated hydroxy anisole and butylated hydroxy toluene, and (3) retention of the test diets in cold storage (40°F.). Analyses of feed samples which had been purposely exposed for 7-12 days in the chick room showed little or no detectable loss of potency. In no instance did the discrepancy exceed the normal error of the analytical method. EXPERIMENTAL RESULTS

Series "A". Test Series "A" consisted of a four week liver storage trial in which carotene from two different samples of alfalfa meal was compared to vitamin A derived from fish liver oil, vitamin A palmitate in oil (absorbed on soya flour) and a wax-coated vitamin A dry carrier. All rations in this series were fortified to a level of 4,800 I.U. of vitamin A activity per pound of diet. The experimental data are summarized in Table 2. Referring to Table 2, it will be noted that the two samples of alfalfa meal (Lots 1 and 2) were virtually alike in terms of their biological effectiveness as vitamin A sources. Liver vitamin A activity in chicks fed these carotene sources (Samples #1 and #2) amounted to 2.2% and 2.4% of the amount ingested, respectively. Fish liver oil and vitamin A palmitate in oil (absorbed on soya flour) were also essentially equal in biological value. The percentage of ingested vitamin A found in the liver was 6.5% for fish liver oil, and 6.0% for vitamin A palmitate in oil. The storage level was approximately three times higher than that obtained with the alfalfa meal samples. Chicks fed the wax-coated dry carrier showed a liver reserve equal to 26.4% of the total vitamin A ingested. The storage

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The selection of a popular broiler crossbred for these studies was influenced in part by a desire to obtain data with maximum practical significance. The experimental information presented in the succeeding paragraphs is felt to be analogous to what might be expected under field conditions with similar meat-type chickens. Care and Feeding. All experiments reported here were of 24 to 31 days duration During this period, the chicks were housed in electrically heated starting batteries and supplied with feed and water ad libitum. A special effort was made to minimize the effect of cage position upon the biological response. The individual rations were prepared at frequent intervals from a freshly mixed large batch of non-supplemented basal diet. After assaying for vitamin A potency (or activity) by the methods described below, the experimental samples were added to a weighed quantity of this feed in amounts necessary to achieve the desired supplemental level. The natural carotene sources were analyzed for vitamin A activity by procedures which had been found by past experience to give the most reliable results. In the case of the alfalfa meal samples, the A.O.A.C. chromatographic method (1955) was used, while for the corn meal, a special cold saponification technique developed by Callison et al. (1953) was employed. The potency of the pre-formed vitamin A sources was determined by the method described in the fifteenth edition of the United States Pharmacopoeia (1950). A purified beta-carotene product used in Series " C " was assayed for vitamin A activity by a specific technique recommended by the manufacturer, Hoffmann La-Roche, Inc. (1955). Rigid precautions were taken to insure the stability of the vitamin A source in the experimental rations. These included (1)

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TABLE 2.—Results of Series "A" liver storage experiments (28 days) (16 chicks per lot) All diets fortified to a level of 4,800 international units of vitamin A per lb. Liver storage data

Growth data Experimental vit. A source

1

Alfalfa Meal #1» (17% dehy.; 67,000 int. units vitamin A activity per lb.)

2

3 4

5

1 2 8

1

Total vit. Vit. A 2 ac- %ofingestA ingested tivity, I.U./ edvit. A (int. units) Total liver found in liver

4 wk. gain (gms.)

Feed/ Gain

351.4

2.118

7,876

175

2.2

Alfalfa Meal #2 (17% dehy.; 103,000 int. units vitamin A activity per lb.)

348.6

2.134

7,872

190

2.4

Fish Liver Oil (96,650 int. units vitamin A per gram)

354.8

1.969

7,392

480

6.5

Vitamin A Palmitate in Oil absorbed on Soya Flour Carrier (100,000 int. units vitamin A per gram)

342.4

2.074

7,517

450

6.0

Wax Coated Vitamin A dry carrier (31,800 int. units vitamin A per gram)

352.0

2.099

7,819

2,065

26.4

3

BHA and BHT were added to all experimental samples as antioxidants. Includes initial activity of 58 Int. units of vitamin A per total liver. Substituted in the Reid diet on a pound for pound basis to replace ground milo.

level in this case was about twelve times higher than that of the carotene sources (alfalfa meal), and four times higher than that obtained with fish liver oil or vitamin A palmitate in oil. Series "B". As noted previously, there is published evidence (Russell et al., 1942) which indicates that better utilization of carotene is achieved in the presence of added fat. Test Series " B " was conducted for the purpose of checking this theory, using alfalfa meal (Sample #1) alone and in the presence of 4% stabilized tallow. The same pre-formed vitamin A products fed in Series "A" were also included in this trial, which was of 24 days duration rather than 28. As in Series "A", all diets were fortified to a level of 4,800 Int. units of vitamin A per poind. The data are presented in Table 3. The results obtained in Lot 2 of this series (as compared to Lot #1) indicate a small improvement in carotene utilization

in the presence of 4% added fat. It should be noted, however, that the magnitude of difference is within the range of experimental error for tests of this type. Chick response to fish liver oil and vitamin A palmitate in oil (Lots 3 and 4) followed the pattern shown in Series "A''. Liver storage was again almost exactly alike on the two materials, although both were somewhat better utilized on a "percent of ingested" basis than was true in the earlier trial. The wax-coated dry carrier elicited by far the highest liver storage of any product tested in Series " B " (Lot 5). The assay value of 1,810 I.U. of vitamin A per total liver represented 30.7% of the amount ingested. Series "C". In the third series of experiments, two new pro-vitamin A sources were introduced into the experimental design. These were (1) corn meal, which was fed in combination with alfalfa meal to

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Lot No.

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CAROTENE VS. VITAMIN A TABLE 3.—Results of Series "B" liver storage experiments (24 days) (16 chicks per lot) All diets fortified to a level of 4,800 international units of vitamin A per pound Liver storage data

Growth data Experimental vit. A source

1

Alfalfa Meal #1 3 (17% dehy.; 67,000 int. units vitamin A activity per lb.)

2 3 4

5

1 2 3

1

Total vit. Vit. A ac- % of ingested A ingested tivity 2 1.U./ vit. A (int. units) Total liver found in liver

24 day gain (gms.)

Feed/ Gain

268.7

2.069

5,882

125

2.1

Alfalfa Meal #1 plus 4 % Stabilized Tallow

273.2

2.040

5,897

190

3.2

Fish Liver Oil (96,650 int. units vit. A per gram)

261.5

1.932

5,347

460

8.6

Vitamin A Palmitate in Oil absorbed on Soya Flour Carrier (100,000 int. units vitamin A per gram)

265.9

1.991

5,602

475

8.5

Wax Coated Vitamin A dry carrier (31,800 int. units vitamin A per gram)

268.8

1.944

5,899

1,810

30.7

3

BHA and BHT were added to all experimental samples as antioxidants. Includes initial activity of 76 Int. units of vitamin A per total liver. Substituted in the Reid diet on a pound for pound basis to replace ground milo.

supply a portion of the supplemental provitamin A, and (2) a beta-carotene concentrate, which was added to the diet in two different forms. The sample of alfalfa meal (#1) and the wax-coated vitamin A dry carrier used previously in Series "A" and " B " were employed as controls in the present trial. In this trial, as in Series "A" and " B " , all diets were fed at a level of 4,800 I.U. of vitamin A activity per pound. The design of the Series " C " experiments, and a summary of the results obtained are presented in Table 4. As shown in Table 4, there were no significant differences in liver storage between chicks fed alfalfa meal or a corn meal-alfalfa meal combination as the primary vitamin A source. The storage level expressed as "percent of ingested" vitamin A was in the same range as that obtained in Series "A" and " B . " The beta-carotene concentrate was

even more poorly utilized than the feedstuff sources of pro-vitamin A. Chicks fed this material absorbed on a soya flour carrier actually lost some of their reserve liver activity of vitamin A at the end of the 4 week test period as compared to the amount present at hatching time. When the sample of beta-carotene concentrate was prepared in the form of a wax-coated dry carrier, there was a slight but nonsignificant improvement in liver storage. The wax-coated dry carrier made with pre-formed vitamin A was far more efficiently utilized than any of the carotene sources. This finding was in full agreement with data from the two prevous trials. Series "D". In order to attain a supplemental level of 4,800 International units of vitamin A activity per pound of diet, it had been necessary in Series "A" through " C " to feed abnormally high levels of alfalfa meal (approximately 5 to 8 percent of the total diet). In the final series of

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Lot No.

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C. M.

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TABLE 4.—Results of Series "C" liver storage experiments (28 days) (16 chicks per lot) All diets fortified to 4,800 international units of vitamin A per pound Liver storage data

Growth data Lot No.

1

Experimental vit. A source

Total vit. Vit. A % of ingestA ingested stored2 I.U./ ed vit. A (int. units) Total liver found in liver

Feed/ Gain

393.3

2.196

9,140

285

3.1

Alfalfa Meal #1 plus Corn Meal (1,280 int. units vitamin A activity per lb.)

366.5

2.006

7,780

275

3.5

Beta Carotene Concentrate (393,000 int. units vitamin A activity per gm.) absorbed on Soya Flour Carrier

391.2

1.961

,117

28

0.35

Beta Carotene Concentrate (393,000 int. units vitamin A activity per gm.) prepared as a Wax Coated Dry Carrier

384.1

2.058

,336

92

1.1

Wax Coated Vitamin A (ester) Dry Carrier (31,800 int. units vitamin A per gm.)

425.4

1.967

5,856

3,050

34.4

Alfalfa Meal fV> (17% deny.; 67,000 int. units vitamin A activity per lb.) 3

1 2 3

BHA and BHT were added to all experimental samples as antioxidants. Includes initial activity of 68 Int. units of vitamin A per total liver. Substituted in the Reid diet on a pound for pound basis to replace ground milo.

comparisons, it was decided to use a combination of corn meal and alfalfa meal which would be typical of that found in present day commercial broiler rations. This change in design had the effect of reducing the total level of vitamin A activity in the diet from 4,800 I.U. per pound to 2,315 I.U. per pound (Lot 1). Lot 2 in Series " D " was fed vitamin A from fish liver oil at a potency level of 2,315 I.U. per pound of feed (same as Lot 1). As a further comparison, Lot 3 was provided with a diet containing an identical level from a wax-coated dry carrier. The ration supplied to Lot 4 was typical of present day commercial broiler feeds insofar as sources of vitamin A activity are concerned. This diet contained both carotene (from alfalfa and corn meal) and preformed vitamin A (from a wax-coated dry carrier). The response of the birds to this

regime was compared with that of a similar group fed only the wax-coated dry carrier (Lot 5). The total level of vitamin A activity in the diet of Lots 4 and 5 was 4,800 I.U. per pound. The results obtained in Series " D " are presented in Table 5. The experimental data in Table 5 reveal a sharp drop in liver storage on all products studied when the feed potency was reduced from 4,800 I.U. of vitamin A activity per pound to 2,315 I.U. per pound. Birds receiving carotene sources at levels corresponding to those used in commercial practice (Lot 1) showed essentially the same liver reserves of vitamin A at the end of four weeks as had been present at one-day old. Fish liver oil elicited a small increase in liver reserve during this same period, however, this product was considerably less effective in

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28 day gain (gms.)

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CAROTENE VS. VITAMIN A T A B L E 5.—Results of Series "D" liver storage experiments

(31 days) (16 chicks per lot)

Growth data Level of vit. A activity 31 day gain Feed/ in diet Gain (I.U./lb.) (gms.)

Liver storage data -

Total vit. Vitamin A2 % of ingestA ingested stored I.U./ ed vit. A (int. units) Total found in liver liver

Experimental1 vit. A source

1

55% Corn Meal (1,280 Int. 3 units vitamin A activity per pound) plus 1\% Alfalfa Meal #1 (67,000 Int. units vitamin A activity/ pound)

2,315

507.2

1.838

9,864

66

0.67

2

Fish Liver Oil (96,650 Int. units vitamin A per gram)

2,315

513.0

1.893

10,277

135

1.3

3

Wax Coated Vitamin A Dry Carrier (31,800 Int. units vitamin A per gram)

2,315

510.2

1.855

10,013

470

4.7

4

55% Corn Meal, 2J% Alfalfa3 Meal (as in Lot 1) plus Wax Coated Dry Carrier (as in Lot 3)

4,800*

502.5

1.930

10,262

630

6.1

S

Wax Coated Dry Carrier (same sample as in Lots 3 and 4)

4,800

507.3

1.888

10,138

4,020

39.6

* Of the total potency, 2,315 units were derived from corn meal and alfalfa meal, and 2,485 units were derived from the wax coated dry 1carrier. BHA and BHT were added to all experimental samples as antioxidants. 2 Includes initial activity of 67 Int. units of vitamin A per total liver. 5 Substituted in the Reid diet on a pound for pound basis to replace ground milo.

this respect than the wax-coated dry carrier. Even though Lots 4 and 5 were fed diets of equal potency, there was a wide variation in total liver storage. Examination of the data reveals that approximately equal parts of carotene and preformed vitamin A were utilized much less efficiently than the latter material fed alone (to provide full potency). Furthermore, liver storage on the carotene sources (corn and alfalfa meals) was not enhanced in the presence of the wax-coated dry carrier. The effect of combining the two sources appeared to be merely additive, with no trend toward synergism. DISCUSSION

Gledhill and Smith (1955) reported that ten week old chicks fed a stabilized "dry A" at a sub-optimal level (1,000 I.U. per pound) weighed more and showed better feed conversion than birds supplied with feeds containing an equal potency of vitamin A from fish oil or alfalfa. This same phenomenon has been noted in published evidence from this laboratory (Nopco, 1958) in which a wax-coated dry

vitamin A was compared to fish liver oil at levels ranging from 200 to 1,200 I.U. of vitamin A per pound of diet. Since all diets used in the present series of experiments contained appreciably more than the requirement level of vitamin A, we neither anticipated nor obtained any differences among the additives studied in terms of their effect on growth and feed efficiency. The use of liver storage values as a criterion for evaluating vitamin A supplements has been shown by Harms et al. (1955) to have tangible practical significance. These workers demonstrated that the onset of deficiency symptoms and survival time among birds ingesting an essentially vitamin A free diet is directly related to the amount of vitamin A stored in the liver prior to the time the use of such a diet is initiated. Birds with high liver stores of vitamin A are more resistant to the onset of deficiency symptoms, and also survive longer (and vice versa). The pattern of results established in Series "A" remained constant throughout the remaining three trials. As evidenced by liver storage, carotene was very poorly

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Lot No.

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C. M.

An interesting sidelight resulting from these studies is the surprising relationship between the biological effectiveness of purified beta-carotene and that of carotene derived from alfalfa meal. Under normal circumstances, it would not seem logical to assume that a highly concentrated source of pro-vitamin A would elicit a lower liver storage than a much more "dilute" source such as alfalfa meal. It is evident that the high fiber content of the latter material did not interfere with the efficient breakdown, conversion and assimilation of the carotene derived therefrom. It should be stressed that the storage values reported in. the various tables represent the total vitamin A activity of the freshly removed livers. Separate analyses for beta-carotene per se were conducted on several samples taken from birds fed high levels of pro-vitamin A. It was found that only a minor portion of the vitamin A activity was attributable to non-converted carotene. In no instance

1000

2O0O

WOO

WOO

WOO

.

MOO

VITAMIN A FED I.U. FEE. POUND OF DIET

•

Wax coated vitamin A dry carrier Fish liver oil or vitamin A palmitate in oil Carotene from alfalfa meal or corn meal

FIG. 1. The effect of different sources of vitamin A on liver storage in 4 wk. old White Vantress cockerals.

did the analytical value for pro-vitamin A exceed 15 percent of the total activity. Since liver storage of vitamin A is a logarithmic function, the relative effectiveness of various sources must of necessity be determined from a response curve. Figure 1 depicts the approximate storage values for the materials used in these trials over a wide range of feed potencies. In determining the shape of the curves, previously published experimental data of the type reported here were used to a large extent, (Nopco, 1958). A series of readings taken from these response curves is shown in Table 6. Referring to Table 6, it will be noted that fish liver oil and vitamin A palmitate in oil averaged about 1.3 times as effective as carotene derived from alfalfa or corn meal in promoting liver storage of vitamin A. Furthermore, the wax-coated dry carrier was 2.6 times as effective as caro-

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utilized in these studies regardless of whether it was supplied in the form of alfalfa meal, corn meal or as a purified concentrate. A considerably higher plane of biological response was obtained from products containing pre-formed vitamin A such as fish liver oil, vitamin A palmitate in oil (absorbed on a soya flour carrier) and a wax-coated dry carrier. The latter material proved far superior to any other source of vitamin A fed when evaluated on the basis of liver storage at 24 to 31 days of age. The biological relationships observed between carotene and pre-formed vitamin A are in agreement with those of Gledhill and Smith (1955). The substantially higher liver storage values obtained with the vitamin A dry carrier as compared to fish liver oil would tend to confirm the recent findings of Ascarelli (1957).

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CAROTENE VS. VITAMIN A

TABLE 6.—The relative biological effectiveness of various vitamin A sources for four week old broilers

Vitamin A source

Desired liver storage level, I.U./Total liver

Approximate feed potency required, I.U. per lb.

Ratio of biological effectiveness compared to carotene Individual readings

Average

250 500 1,000

5,000 6,400 (est.) 7,600 (est.)

1.0 1.0 1.0

1.0

Fish Liver Oil; Vitamin A Palmitate in Oil

250 500 1,000

3,600 4,800 6,100

1.4 1.3 1.2

1.3

Wax Coated Vitamin A Dry Carrier

250 500 1,000

1,900 2,400 3,200

2.6 2.7 2.4

2.6

tene, and about twice as effective as fish liver oil or vitamin A palmitate in oil. From a practical standpoint, it is obvious from the data reviewed above that commonly used levels of corn and alfalfa meal will barely provide the basic vitamin A needs of broilers even when elaborate steps are taken to protect the stability of the carotene derived therefrom. Under field conditions, unavoidable losses in potency would greatly magnify the problem of providing a high enough level of provitamin A to insure good nutrition. Not only do these tests clearly define the need for substantial levels of supplemental preformed vitamin A in broiler feeds, but they also underscore the advantages of determining the biological response to any given material which may be chosen for fortification purposes. SUMMARY

Four liver storage trials involving twenty lots of 16 White Van tress Cockerel chicks each were conducted to determine the relative biological effectiveness of various sources of pro-vitamin A and preformed vitamin A. The results of these investigations may be summarized as follows: 1. On the basis of comparative liver

storage values, carotene derived from alfalfa meal and/or corn meal was poorly utilized as a source of vitamin A in the diet of chicks up to 31 days of age. When fed at levels commonly used in present day broiler rations, a combination of alfalfa meal and corn meal barely maintained the initial reserve level of vitamin A activity which was present in the liver at hatching time. A purified beta-carotene concentrate supplied in two different physical forms was even less efficient in promoting liver storage of vitamin A than carotene derived from alfalfa meal and corn meal. Liver storage of vitamin A in birds fed fish liver oil and synthetic vitamin A palmitate in oil was substantially higher than on the various carotene sources. Neither of these products ranked favorably with the degree of utilization noted on a waxcoated dry carrier. Calculations based on a response curve showed fish liver oil or vitamin A palmitate in oil to be about 1.3 times as effective as carotene in promoting liver storage. The same calculation applied to the wax-

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Natural Carotene (Alfalfa Meal and Corn Meal)

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REFERENCES Ascarelli, I., 1957. The use of vitamin A protected by DPPD (diphenyl-p-phenylene-diamine) for the growth of chickens. Poultry Sci. 36: 349-351. Ascarelli, I., and A. Bondi, 1957. The effect of different plant sources on the utilization of carotene by chickens. J. Agric. Sci. 49: 113-119. Association of Official Agricultural Chemists, 1955 Methods of Analysis. Carotenes. Eighth Edition, pp. 816-817. CaUison, E. C , L. F. Halliman, W. F . Martin and E. Oreat-Keiles, 1953. Comparison of chemical analysis and bio-assay as measures of vitamin A value: yellow corn meal. J. Nutr. 50: 85-100. Gledhill, R. H., and S. B. Smith, 1955. The effective-

ness of different vitamin A sources for poultry Poultry Sci. 34: 942-948. Harms, R. H., B. L. Reid and J. R. Couch, 1955. Storage of vitamin A in chick livers as a criterion of stability, availability and dietary level. Poultry Sci. 34: 1125-1133. Harvey, J. D., D. B. Parrish, P. E. Sanford and J. S. Hughes, 1955. The utilization of carotene and vitamin A by chicks during the first week after hatching. Poultry Sci. 34: 1348-1357. Hoffmann La-Roche, Inc., 1954. Spectrophotometric assay of products containing beta-carotene (a technical brochure). Johnson, E . W., C. W. Garrick and S. M. Hauge, 1948. The vitamin A requirements of young chickens. Poultry Sci. 27: 308-314. Laughland, D. R., and W. E. J. Phillips, 1955. The utilization of vitamin A by normal and duoectomized chicks. Poultry Sci. 34: 1359-1361. Nopco Chemical Company, 1958. "Biological availability of NOPCAY TYPE V for the chick" (a technical brochure). Pharmacopeia of the United States, 1950. Vitamin A Assay. Fifteenth edition, pp. 941-942. Reid, B. L.,'H. K. Dougherty and J. R. Couch, 1955. The stability of vitamin A in mixed feeds and premixes. Poultry Sci. 34: 603-608. Rubin, M., and H. R. Bird, 1941. Some experiments on the physiology of vitamin A storage in the chick. Poultry Sci. 20: 291-297. Russell, W. C , M. W. Taylor, H. A. Walker and L. J. Polskin, 1942. The absorption and retention of carotene and vitamin A by hens on normal and low fat rations. J. Nutr. 24: 199-211.

Ability of Corn Fermentation Condensed Solubles to Replace Unidentified Growth Factor Sources for Chickens JOSEPH M. RUSSO AND VICTOR HEIMAN Animal Nutrition Department, Corn Products Company, Waverly, New York (Received for publication April 9, 1959)

A

PREVIOUS report by the authors (1959) showed improved chick growth where corn fermentation condensed solubles was added to a variety of "practical" chick rations. This effect was observed with both mash and crumbled

diets. Additions of corn fermentation condensed solubles were made in these tests at the expense of either com meal or a combination of corn meal and soybean oil meal. The work reported here deals with the

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coated dry carrier indicated an effectiveness ratio of approximately 2.6 to 1 over the materials containing pro-vitamin A. 5. The problem of maintaining a satisfactory reserve of vitamin A activity in the liver would be greatly magnified under field conditions due to unavoidable losses in feed potency. The results obtained in this series of experiments clearly demonstrate the need for supplemental pre-formed vitamin A which is both stable and easily utilized by the chick.

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