A Study of Certain Factors that Influence Pigmentation in Broilers*

1373

COATING BROILER PARTS

ity of acetostearin products to water vapor. J. Agr. Food Chem. 2 : 558-563. Lovegren, N. V., and R. 0 . Feuge, 1955. Permeability of acetostearin products to carbon dioxide, oxygen, and nitrogen. J. Agr. Food Chem. 4: 634-638. Pool, M. F., E. P. Mecchi, H. Lineweaver and A. A. Klose, 1954. The effect of scalding temperature on processing and initial appearance of turkeys. Poultry Sci. 33:274-279. Ziegler, F., and W. J. Stadelman, 1955. The effect of different scald water temperatures on the shelflife of fresh, non-frozen fryers. Poultry Sci. 34: 237-238.

A Study of Certain Factors that Influence Pigmentation in Broilers* ELBERT J. DAY AND WOODIE P. WILLIAMS, J R . Mississippi Agricultural Experiment Station, State College, Mississippi (Received for publication April 8, 1958)

1

T HAS been amply demonstrated that the degree of pigmentation in broilers is controlled primarily by the level of pigmenting substances (xanthophyll) in the ration (Palmer, 1915; Heimen and Tigue, 1943; and Fritz et al., 1957). Certain feed ingredients have been shown to have a suppressing effect on pigmentation —cod liver oil and manganese (Hammond and Harshaw, 1941; Goldhaber et al., 1950) and meat scraps, fish meal and soybean oil meal (Culton and Bird, 1941). The use of antioxidants in the feed to increase the effectiveness of the pigments has produced conflicting results. Wilgus (1954), Potter et al. (1956), and Fritz et al. (1957) have reported an improvement in pigmentation with the use of diphenyl-pphenylenediamine (DPPD), and Potter et al. (1956) reported only a slight improvement in pigmentation with the use of dietertiary-butylpara-cresol (BHT). Whereas, Harms et al. (1958) reported

* Published with the approval of the Director of the Mississippi Agricultural Experiment Station as Journal Article No. 726.

that the addition of DPPD to broiler rations significantly depressed pigment deposition. House (1957) reported 9.5 to 10.0 mgs. of xanthophyll per pound of ration were necessary for adequate pigmentation of broilers. A dietary level of 12.5 mgs. per pound was considered to produce good pigmentation by Fritz et al. (1957). Evidence indicating a positive correlation between carcass fat and pigment deposition has been reported by Hill and Dansky (1951) and Maw (1939). The work reported herein was conducted in view of the lack of information and conflicting data concerning pigmentation. EXPERIMENTAL

General. New Hampshire chicks were wingbanded and randomly assigned to treatments in each trial; water and feed were supplied ad libitum. The chicks (25 per lot) were raised in batteries, except during Trial 2 (100 per lot) where floor pens were employed. Group feed con-

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poultry. Amer. Egg Poultry Review, 11(11): 8, 10. Gwin, J. M., 1951. A report of progress on the subscalding method of dressing poultry. Amer. Egg Poultry Review 12(10): 14, 73. Gwin, J. M., 1952. Sub-scalding saves pinning labor. U.S. Egg Poul. Mag. 58(1): 15. Klose, A. A., and M. F. Pool, 1954. The effect of scalding temperature on the quality of stored frozen turkeys. Poultry Sci. 33: 280-289. Lineweaver, EL, and A. A. Klose, 1952. Subscalding vs. semi-scalding. Turkey World, 27(11): 18, 66. Lovegren, N. V., and R. O. Feuge, 1954. Permeabil-

1374

E. J. DAY AND W. P. WILLIAMS, JR.

The method employed in determining pigmentation was a modification of the method of Heiman and Tigue (1943) as modified by Wilgus (1954). At the end of each trial, the shanks of each bird were wrapped in freezer-type paper and kept in cold storage (16°F.) until used for carotenoid determination. Twenty birds from each treatment were used in determining the average pigmentation score. In Trials 1 and 2 the pigmentation from each treatment of 20 birds was determined individually; whereas, in subsequent trials discs of skin from five birds were pooled, but a total of 20 birds from each treatment was used. In Trials 1 and 2 and in Trials 3, 4, 5, and 6, four and ten discs of skin from

the toe web area (each disc 7 mm. in diameter) were placed in Erlenmeyer flasks containing 5 and 10 ml. of acetone, respectively. The discs were kept in the acetone solution for 48 hours in the dark, with frequent shaking. The solutions were filtered, using No. 1 Whatman filter paper, and the volume was adjusted to 5 ml. in Trials 1 and 2 and to 10 ml. in Trials 3, 4, 5, and 6 prior to determining the density of each solution with the aid of a Coleman Junior spectrophotometer at a wave length of 436 millimicrons. Pigmentation was expressed as the micrograms of pigment per 100 square centimeters of toe web area after comparing the density values to a standard curve established for pure beta-carotene (Association of Official Agricultural Chemists, 1955). Rations. The composition of the basal rations used in Trials 1, 2, 5, and 6, and the composition of the master control rations used in Trials 1, 3, 4, and 5 are shown in Table 1. Other experimental rations were formulated, as indicated in the summary tables for each trial, by substituting the test materials as follows: Alfalfa meal and xanthophyll concentrates were substituted at the expense of wheat middlings, corn gluten meal was substituted for soybean oil meal, yellow corn was substituted for white corn and fat was substituted for corn, keeping the Calorie-protein ratios about equal to the basal and the master control rations, except in Trial 2 when fat was substituted for corn and no adjustment in the Calorieprotein ratios were made. All other additives to the basal or master control ration were made at the expense of corn. The productive energy values of Titus (1955) were used to calculate the energy content of the diets, except vegetable oil and beef tallow were considered to contain 2,900 Calories of productive energy per pound.

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sumption records and individual body weight data were obtained at 4 weeks of age and again at either 8 or 9 weeks of age in all trials. Approximately equal numbers of male and female birds were selected for determining the pigmentation score for each group and body weight data represent sex-corrected averages. Statistical examination of the pigmentation data was made by the analysis of variance (Federer, 1955) for all trials, and of the body weight data in Trial 6. The method of Duncan (1955) was used to test for significance among treatments. The xanthophyll content of dehydrated alfalfa meal, corn gluten meal and yellow corn were determined prior to the use of these feedstuffs in Trials 2 and 6, employing essentially the method of Bickoff et al. (1954). Dehydrated alfalfa meal (17% protein), corn gluten meal and yellow corn were found to contain approximately 91.0 mgs., 59.5 mgs., and 4.08 mgs. of xanthophyll per pound, respectively. These values were also used to calculate the xanthophyll content of the other experimental rations used in this study to facilitate the evaluation of various dietary changes and additives.

1375

PIGMENTATION IN BROILERS TABLE 1.—Composition of the basal and master (M.C.) control rations 2

1 and i1

4 , 5 , and 6

Ingredient White corn Yellow corn Soybean oil meal (44% prot.) Soybean oil meal (50% prot.) Fish meal (60% prot.) Corn gluten meal Alfalfa meal (17% prot.) Whey, dried (50% lactose) Wheat middlings Premix 1

M.C.

Basal

Basal

M.C.

56.3

—

54.1

61.0

— —

—

— —

— —

7.5 50.0

27.3

56.3 22.3

5.0

5.0 5.0 3.0 3.0 2.0 3.4

— —

3.0 5.0 3.4

100 925 21.1 44

—

100 916 21.1 43 8.0

25.4 4.0

— —

3.0 10.05 3.45 100 924 22 42

—

26.2 4.0 •

—

—

2.0 3.35 3.45 100 955 21.7 44

—

—

22.6 4.0 5.0 3.0 2.0 2.45 3.45 100 929 22 42 7.8

1

The premix furnished 1.5% bone meal (Ca 24%, P 13%) and 1.0% ground limestone to all rations. It also provided the following vitamins and minerals per pound of ration: vitamin A, 4, 540 I.U.; vitamin D3, 408 I.C.U.; vitamin E, 8.0 I.U.; vitamin B12, 9.0 meg.; thiamin, 0.45 mg.; d-biotin, 0.045 mg.; choline chloride, 237.0 mg.; folic acid, 0.454 mg.; riboflavin, 2.0 mg.; pantothenic acid, 4.0 mg.; niacin, 9.0 mg.; vitamin K, 6.8 mg.; and manganese, 31.8 mg. In Trial 2 the premix also furnished 0.05% of a trace mineral supplement containing 6.0% manganese, 0.12% iodine, 2.0% iron, 0.2% copper, 0.006% zinc, 0.02% cobalt, and 27% calcium.

The xanthophyll concentrates used were of two types: (1) the liquid type was an extract from alfalfa with an oil carrier and contained 1.25 grams of xanthophyll per pound; (2) the dry form was an extract from alfalfa with navy bean meal carrier and contained 0.25 grams of xanthophyll per pound. RESULTS AND DISCUSSION

The Influence of BHT on Pigmentation. Supplementation of broiler rations with BHT (0.0125%) as shown in Table 2 did not consistently enhance the utilization of xanthophyll. A significant increase in pigmentation was obtained only in lot 9; whereas, in lots 3 and 7 a highly significant reduction in pigmentation was observed, and in lots 5, 11, and 13 there was no significant effect of BHT on pigmentation. In view of the inconsistent results obtained in Trial 1, a higher level of BHT (0.025%) was tested during a second

trial, in the presence and absence of beef tallow (5% level) as indicated in Table 3. In most instances the utilization of xanthophyll was poorer when BHT was included in the ration but this difference was not significant according to the statistical data (Table 4). In a subsequent test a significant reduction in pigmentation was noted when a trace mineral supplement was added (0.1%) to the ration, but in the presence of added BHT, the trace mineral supplement did not significantly depress pigmentation (Table 6, lots 5 and 4). Pigmentation was also reduced when the supplementary vitamin E (81.U./lb.) was removed from the ration but this was not significant (lot 5). Added BHT improved pigmentation only slightly in the absence of supplementary vitamin E (lot 6). Also, increasing the dietary level of vitamin B12 did not increase pigmentation (lot 7). The fact that a high level of supple-

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Total (%) Prod. Cal./lb. Crude protein (%) C/P ratio Xanthophyll (mg./lb.)

Basal

TABLE 2.—The results offeeding dehydrated alfalfa meal (A.M.), corn gluten meal {C.G.M.), a dry xanthophyll concentrate (D.X.C), and a liquid xanthophyll concentrate (L.X.C), with and without BHT, on pigmentation of broilers (eight week data, Trial 1)

Avg. wt. (lbs.)

Ration and treatment 1

Lot

Basal M.C. M.C. plus BHT Basal plus 3 % A.M. Lot 4 plus BHT Basal plus 3 % A.M.; 5% C.G.M. Lot 6 plus BHT Basal plus 5 % C.G.M. Lot 8 plus BHT Basal plus 0.05% L.X.C. Lot 10 plus B H T Basal plus 0.25% L.X.C. Lot 12 plus BHT Basal plus 0.25% D.X.C.

2.67 2.66 2.58 2.62 2.57 2.82 2.48 2.59 2.54 2.77 2.65 2.81 2.65 2.67

%

^2

2.35 2.40 2.53 2.46 2.54 2.31 2.55 2.27 2.60 2.25 2.50 2.35 2.35 2.74

Average Average Xan. pigmenCons. tation 3 (nig.) score

Rffic. score4

—

97.5 70.7 74.5 90.1 90.8 86.8 89.0 94.0 93.1 95.4 96.7 92.8 92.1 96.8

214.5 178.1 51.3 47.8 78.0 59.8 24.1 32.5 14.6 5.8 33.8 40.3 6.5

50.9 52.0 17.6 17.9 37.3 36.1 17.5 19.7 3.9 4.1 19.0 18.3 4.4

4.19 3.43** 2.91 2.67 2.09 1.66** 1.37 1.65* 3.76 1.14 1.77 2.24 1.49

* Significant at the 5% probability level. ** Significant at the 1% probability level. 1 BHT was added at the 0.0125% level. 2 Average percent transmission as recorded from the spectrophotometer. 3 Micrograms of xanthophyll per 100 cm2, of toe web area. 4 Pigmentation value divided by the milligrams of xanthophyll consumed. TABLE 3.—The effects of added animal fat, with and without BHT, on the utilization of xanthophyll from xanthophyll concentrates and alfalfa meal when fed to broilers to eight weeks of a^ e (Trial 2)1

Lot

Xan. level (mg./lb.)

Avg. wt. (lbs.)

Feed %T gain

Pigmentation

Xan. intake

Effic.

(nig.)

1

0.76% L.X.C.

9.5

2.23

2.62

87.12

95.22

55.57

1.71

2

0.76% L.X.C., 5 % fat

9.5

2.43

2.51

83.29

124.46

57.85

2.15

0.76% L.X.C., 0.025% B H T

9.5

2.39

2.58

84.76

115.36

58.81

1.96

0.76% L.X.C. 0.025% BHT, 5% fat

9.5

2.21

2.69

85.41

108.54

56.62

1.92

5

3.8% D.X.C.

9.5

2.24

2.66

86.76

100.42

56.61

1.77

6

3.8% D . X . C , 5 % fat

9.5

2.26

2.55

84.76

115.36

54.72

2.11

3.8% D . X . C , 0.025% B H T

9.5

2.45

2.62

87.00

97.82

61.08

1.60

3.8% D . X . C , 0.025% BHT, 5 % fat

9.5

2.38

2.54

85.91

105.29

57.38

1.83

9

10% A.M.

9.1

2.25

2.69

78.88

160.14

55.30

2.89

10

10% A.M., 5% fat

9.1

2.24

2.71

80.53

147.86

55.48

2.67

10% A.M., 0.025% B H T

9.1

2.19

2.91

81.06

144.61

58.72

2.46

10% A.M., 0.025 BHT, 5 % fat

9.1

2.13

2.73

79.12

160.21

53.02

3.02

3 4

7 8

11 12 1

Supplement to basal

See the footnotes under Table 2 for the explanation of the symbols used.

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1 2 3 4 5 6 7 8 9 10 11 12 13 14

Feed

1377

PIGMENTATION IN BROILERS TABLE 4.—The degrees of freedom and mean squares of the pigmentation data {Trial 2) Source

d.f.

Xanthophyll (A) Antioxidant (B) Fat (C) AXB AXC BXC AXBXC Error

2 1 1 2 2 1 2 192

M.S. 760.41** 5.18 60.94* 2.84 11.43 2.28 69.31** 13.88

mentary vitamin E (8 I.U./lb.) was used in this study may be the reason why BHT did not consistently enhance xanthophyll utilization in these two trials as has been noted by other workers (Wilgus, 1954; Potter, 1956; Fritz et al., 1957). However, one group of workers reported a significant reduction in pigmentation when the

TABLE 5.—The effects of changing the Calorie-protein ratio of the ration during the finishing period on pigmentation {Trial 3)

Lot

1 2 3 4

Modification of M.C.

1

C: P, 50 (7-9 wks.) (added white corn) C: P, 50 (7-9 wks.) (added yellow corn) C:P, 50 (7-9 wks.) (added fat)

gain

Results (9 weeks) Avg. plg % " / oT 1 ment score

Avg. Xan. cons. (mg.)

Effic. score

2.77 2.85 2.77 2.63

70.1 69.5 68.8 69.7

51.6 53.2 54.5 52.1

3.32 3.42 3.43 3.45

Avg. wt. (lbs.)

Feed

2.41 2.42 2.47 2.56

174.5 181.8 186.9 179.5

1 All groups received the master control ration the first seven weeks. The birds in lots 2, 3, and 4 were changed to a finishing ration (C:P, 50) during the last two weeks by varying the percentage of soybean oil meal and adding white corn, yellow corn or fat.

TABLE 6.—The effects of vitamin B12, vitamin E, BHT, C'.P ratio and trace minerals on pigmentation {9 wk. data, Trial 4)

Lot

Modification of M.C.

Finishing ration 7-9 wks.; C:P, 50 Plus trace mineral suppl. 0 . 1 % ' Lot 3 plus 0.025% B H T Minus suppl. Vit. E (8 I.U./lb.) Lot 5 plus BHT 0.025% Plus vitamin Bu, 45 mcg./lb.

Avg. wt. (lbs.)

Feed

2.84 2.76 2.73 2.71 2.80 2.79 2.72

2.91 2.90 2.85 2.89 2.83 2.92 2.90

%T gain 63.0 60.5 70.2 67.0 69.0 69.5 64.3

Average Avg. xan. Pigmentacone. tion score (mg.) 231.1 295.4 174.7 198.9 182.3 179.2 221.2

* Significant at .05% confidence level. 1 Delamix; see footnote under Table 1 for the composition of this supplement.

62.8 65.3 62.5 62.9 63.4 61.9 63.3

Effic. score 3.68 4.56* 2.80* 3.16 2.87 2.90 3.41

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* Significant at the 5% probability level. ** Significant at the 1% probability level.

antioxidant DPPD was added to the ration (Harms et al., 1958). The efficiency scores for the groups fed a ration with a Calorie-protein ratio of 50 were essentially the same regardless of the source of energy used to widen the Calorie -protein ratio, but they were considerably better than the group fed the ration with a Calorie-protein ratio of 42 during the finishing period (lot 1, Table 5). None of the differences in pigmentation of the groups of birds was significantly different, not even the group fed the ration with added fat, which significantly increased pigmentation in the previous trial. A significant increase in pigmentation was obtained during Trial 4 (Table 6) by substituting yellow corn for soybean oil meal and changing the Calorie-protein ratio from 42 to 50 during the last two

1378

E. J. DAY AND W. P. WILLIAMS, J R .

TABLE 7.—Influence of time of feeding on xanthophyll utilization (Trial 5) T r e a t m e n t a n d time Lot 1 2 3 4 5 1

Basal

0-4 0-6 0-7 0-8

1

weeks weeks weeks weeks

Master control 1 0-9 4-9 6-9 7-9 8-9

weeks weeks weeks weeks weeks

Average pigmentation score

Avg. xan. cons, (mg.)

Effic. score

231.1 187.2 158.1 142.5 74.6

62.8 51.2 36.4 25.3 12.7

3.68 3.65 4.34 5.63 5.86

See Table 1 (Trial 1) for the composition of these rations.

gluten meal and yellow corn, used in Trial 1 was not actually determined, it is not possible to compare the efficiency of utilization of the xanthophyll in this test. However, it was noted after using the xanthophyll values as later determined for comparable samples of feedstuffs to calculate the xanthophyll content of these rations, the master control ration containing yellow corn produced birds with a higher pigmentation score than was expected in relation to the other groups (lots 2 and 3). These results suggested that either the method of analysis for xanthophyll in yellow corn was yielding low results or that the efficiency of utilization of the xanthophyll in yellow corn was much better than the xanthophyll from other sources. A trial was conducted in which dehydrated alfalfa meal, corn gluten meal and yellow corn were each used singly in broiler rations as the only source of pigment to furnish the same level of xanthophyll (2.5 mg./lb.). Results from the biological tests indicated the xanthophyll in the alfalfa meal and corn gluten meal was only about 36% as effective as the xanthophyll in yellow corn for pigmentation. The pigmentation scores of the groups fed the ration containing yellow corn, alfalfa meal and corn gluten meal were 144.4, 54.4, and 49.6 at nine weeks of age, respectively. Prior to the termination of the above trial, a test designed to determine the interchangeability of feedstuffs as sources of xanthophyll and the level of xanthophyll needed for pigmentation was initiated. A summary of the results and the experimental design of this trial are shown in Table 8. Again, the xanthophyll from the yellow corn was more efficiently utilized than that from the other sources or the determined level by analysis was incorrect. However, the difference in utili-

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weeks of the growing period (lot 2). These data suggest that widening the Calorieprotein ratio of the ration results in better utilization of the xanthophyll since pigmentation was significantly increased with only a very slight increase in xanthophyll intake. Other workers have noted that the use of high-energy grains which are conducive to more fat deposition in the carcass of birds also enhances pigmentation (Hill and Dansky, 1951; Maw, 1939). It is well known that widening the Calorie-protein ratio of the ration results in increased fat deposition in chickens. Influence of Time of Feeding on Xanthophyll Utilization. The results of a feeding trial in which groups of broilers were fed rations containing no pigments for varying lengths of time during the growing period, and switched to a ration containing xanthophyll are summarized in Table 7. I t is evident from these data that the greatest benefit from xanthophyll can be obtained by feeding it during the latter weeks of the growing period. These results indicate that xanthophyll utilization is greater during the latter period of growth; however, xanthophyll utilization may be the same for all ages since it is known that the pigments are slowly excreted and oxidized from the skin of birds (Heiman andTighe, 1943). Influence of Source of Xanthophyll on Pigmentation. Since the xanthophyll in the feedstuffs, dehydrated alfalfa meal, corn

PIGMENTATION IN BROILERS

1379

TABLE 8.—Inlerchangeability offeedstuffs as xanthophyll sources for pigmentation of broilers (P wk. data, Trial 6)

Lot

11

12

13 14

15 16

1

Xan. level (mg./lb.)

Avg. wt. (lbs.)

Feed • gain

%T

Avg. pigment score

Avg. xan. cone. (mg.) 2

Effic. score

61.0 Y.C. 2.75 A.M.

5.00

2.63

2.62

77.8

138.8

33.7

4.11

61.0 4.2

Y.C. C.G.M.

5.00

2.61

2.66

77.5

140.6

34.3

4.10

30.5 Y.C. 4.2 C.G.M. 1.38 A.M.

5.00

2.57

2.91

75.7

153.6

37.4

4.11

4.2 C.G.M. 2.76 A.M.

5.00

2.65

2.52

82.0

110.6

33.5

3.30

61.0 Y.C. 4.2 C.G.M. 1.38 A.M.

6.25

2.61

2.77

68.

203.8

44.9

4.54

30.5 Y.C. 4.2 C.G.M. 2.76 A.M.

6.25

2.42

2.80

71.2

182.5

42.2

4.33

30.5 8.4

Y.C. C.G.M.

6.25

2.59

2.55

72.7

173.7

41.2

4.22

61.0 Y.C. 4.2 C.G.M. 2.76 A.M.

7.50

2.45

2.81

67.8

210.1

51.4

4.10

61.0 8.4

Y.C. C.G.M.

7.50

2.69

2.60

65.8

227.2

52.0

4.39

30.5 8.4 1.38 61.0 8.4 1.38

Y.C. C.G.M. A.M. Y.C. C.G.M. A.M.

7.50

2.64

2.70

67.7

210.1

53.4

3.93

8.75

2.69

2.74

64.2

239.7

64.2

3.73

8.75

2.64

2.61

64.8

236.1

60.2

3.93

8.75

2.64

2.89

65.0

234.0

66.5

3.52

11.25

2.59

2.81

59.5

230.8

81.7

3.44

11.25

2.46

2.98

60.5

271.7

82.3

3.30

12.5

2.50

2.97

56.0

312.0

92.6

3.37

30.5 Y.C. 8.4 C.G.M. 2.76 A.M. 30.5 12.6 61.0 12.6 1.38

Y.C. C.G.M. Y.C. C.G.M. A.M.

30.5 12.6 2.76 61.0 12.6 2.76

Y.C. C.G.M. A.M. Y.C. C.G.M. A.M.

All rations were kept approximately equal with respect to energy level and Calorie-protein ratio (C:P 42 and 50 during starting and finishing period, respectively). 2 Results of xanthophyll determinations were: yellow corn, 4.08 mg.; corn gluten meal, 59.5 and alfalfa meal 91.0 mg. per pound. The above results indicate that the xanthophyll of the yellow corn was about 25% more efficiently utilized than that of alfalfa meal and corn gluten meal.

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10

Modification of basal treatment 1

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E. J. DAY AND W. P. WILLIAMS, J R .

Xanthophyll Requirements for Adequate Pigmentation. Pigmentation was considered to be adequate when the pigmentation score was 175 or greater in these tests (fairly deep yellow color). It is evident that a dietary level of xanthophyll necessary for producing a given degree of pigmentation cannot be stated with any degree of accuracy without taking into consideration the xanthophyll source, composition of the ration and disease problem. From the results presented in Table 8, it is evident that a dietary xanthophyll level of 6.25 mg. per pound was adequate when a combination of feedstuffs was used to provide the xanthophyll. However, a dietary xanthophyll level of 5.0 mg. per pound was inadequate. When all of the

xanthophyll in the ration was furnished by alfalfa meal or xanthophyll concentrates, a dietary level of slightly over 9.0 mg. per pound was inadequate (Table 3). House (1957) and Fritz et al. (1957) reported values for adequate pigmentation to be approximately 9.5 to 10.0 and 12.5 mg. per pound, respectively. Alfalfa meal was used as the source of xanthophyll in these studies, which probably accounts for the primary difference between the dietary xanthophyll levels found to be necessary for adequate pigmentation by these workers and as reported herein (6.25 mg./lb.). SUMMARY AND CONCLUSIONS

Six trials were conducted to study the effect of dietary modifications upon pigment deposition, body weight and feed efficiency of broilers. The addition of BHT to the ration at the 0.0125% and 0.025% levels reduced pigmentation somewhat in most instances but this difference was not significant except in two groups of birds in the first trial. Stabilized beef tallow (5% level) significantly increased the utilization of xanthophyll when it replaced an equal amount of white corn in broiler rations. Increasing the Calorie-protein ratio of the ration during the last two weeks of the finishing period from 42 to 50 by replacing soybean oil meal with yellow corn significantly increased pigmentation in one trial; however, in another trial the use of yellow corn, white corn or stabilized beef tallow to change the Calorie-protein ratio from 42 to 50 did not result in a significant increase in pigment deposition during the last two week period. The xanthophyll in yellow corn was found to be more efficiently utilized for pigmentation than the xanthophyll supplied by corn gluten meal and alfalfa meal

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zation was not as great as it was in the previous trial. The xanthophyll from yellow corn was only about 25% more effective than the xanthophyll from other sources. The xanthophyll in alfalfa meal and corn gluten meal appeared to be utilized to about the same extent in this trial. Other workers have noted that yellow corn improves pigmentation more than would be expected based on the reported values for its xanthophyll content (Wilgus, 1954; Fritz el al, 1957). A comparison of the relative effectiveness of the xanthophyll furnished by alfalfa meal and xanthophyll concentrates can be seen in Table 3. Based on the determined level of xanthophyll in alfalfa meal and the manufacturers' guarantees of the xanthophyll content of the concentrates, the xanthophyll furnished by alfalfa meal was utilized to a greater extent than that furnished by the concentrates (almost 50% greater). However, the xanthophyll concentrates (liquid and dry carriers) appeared to be about equally effective in promoting pigment deposition when used to provide comparable levels of xanthophyll.

PIGMENTATION IN BROILERS

ACKNOWLEDGEMENT

The authors are thankful to the Bowman Feed Products, Inc^ Holland, Michigan for donating the commercial xanthophyll concentrates and to the Koppers Company, Inc., Pittsburgh, Pennsylvania for the BHT used in this study. REFERENCES Association of Official Agricultural Chemists, 1955. Official Methods of Analysis. Washington 4, D. C. Bickoff, E. M., L. I. Livingston, G. F. Bailey and C. R. Thompson, 1954. Xanthophyll determination in dehydrated alfalfa meal. J. Assoc. Off.

Agri. Chem. 37: 894-902. Culton, T. G., and H. R. Bird, 1941. The effect of certain protein supplements in inhibiting pigment deposition in growing chickens. Poultry Sci. 20: 432-436. Duncan, D . B., 1955. Multiple range and multiple F tests. Biometrics, 11:1-42. Federer, W. T., 1955. Experimental Design. The Macmillan Company, New York. Fritz, J. C , F. D. Wharton, Jr. and L. J. Classen, 1957. Influence of feed on broiler pigmentation. Feedstuffs, 29: 18. Goldhaber, P., L. Zacharias and V. E. Kinsey, 1950. Vitamin E deficiencies in chicks. Plasma xanthophyll level and vitamin E deficiency symptoms. J. Nutr. 42: 453^62. Hammond, J. C , and H. M. Harshaw, 1941. Some factors influencing shank and skin color in the growing chicken. Poultry Sci. 20: 437-444. Harms, R. H., J. H. Quisenberry and J. R. Couch, 1958. The effects on broiler pigmentation of incorporating milo, dehydrated alfalfa meal, and diphenyl-p-phenylenediamine (DPPD) in the diet. Poultry Sci. 37: 143-147. Heiman, V., and L. W. Tighe, 1943. Observations on the shank pigmentation of chicks. Poultry Sci. 22: 102-107. Hill, F . W., and L. M. Dansky, 1951. The influence of diet on body composition of growing chicks. Proc. Cornell Nutr. Conf. pp. 27-32. House, W. B., 1957. Carcass and shank pigmentation. Feedstuffs, 29: 29-31. Maw, W. A., 1939. Cereals in the poultry ration. Seventh World's Poultry Congress Proc. pp. 177-178. Palmer, L. S., 1915. Xanthophyll, the principal natural yellow pigment of the egg yolk, body fat and blood serum of the hen. The physiological relationship of the pigments to the xanthophylls of plants. J. Biol. Chem. 23: 261-279. Potter, L. M., R. H. Bunnell, L. D. Matterson and E. P. Singsen, 1956. The effect of antioxidants and a vitamin B12 concentrate on the utilization of carotenoid pigments by the chick. Poultry Sci. 35: 452-456. Titus, H., 1955. The Scientific Feeding of Chickens. Interstate Printers and Publishers, Danville, Illinois. Wilgus, H. S., 1954. Effect of DPPD on utilization of different sources of carotenoid pigment. Experiment B854 Xan. Peter Hand Foundation, Chicago, Illinois.

AUGUST 4-7. POULTRY SCIENCE ASSOCIATION ANNUAL MEETING, IOWA STATE COK ,EGE, AMES, IOWA.

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or the method of analysis yielded low values for the xanthophyll content of yellow corn. The xanthophyll in alfalfa meal and corn gluten meal was found to be utilized to about the same extent for pigmentation in broilers. Commercial xanthophyll concentrates were found not to be as effective as they should have been when compared to alfalfa meal as a source of xanthophyll, based on their respective levels of xanthophyll. Adequate pigmentation was obtained with as little as 6.25 mg. of xanthophyll per pound of ration when yellow corn was used to contribute a portion of the xanthophyll; however, when alfalfa meal, corn gluten meal or a combination these two feedstuffs are used as the source of xanthophyll, the dietary level needed for adequate pigmentation may be somewhat higher. Xanthophyll was found to be more effective in increasing pigmentation when given during the latter weeks of the growing period. Whether or not this was due to more efficient utilization or due to less loss by excretion and oxidation of the pigments from the skin was not determined.

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