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Some Factors Influencing Shank and Skin Color in the Growing Chicken
Some Factors Influencing Shank and Skin Color in the Growing Chicken (Received for publication January 18, 1941)
CCORDING to Benjamin and Pierce - (1937) the skin color in market chickens may range from white through cream to golden yellow and even to a dark brownish yellow. They stated that the white, cream, or golden yellow colors are satisfactory, although the lighter colors are preferred by discriminating consumers. They also stated that the market preference is for smooth yellow shanks. It is common knowledge among producers that there is a marked preference for yellow shanks and skin in broilers on the New York live poultry market.
A
Lee (1911) reported that packers did not care about skin color except when they were supplying a special market that wanted deep yellow skin. These packers believed that deep yellow color could be obtained by adding molasses or, sometimes, artificial butter color to the fattening diet. Later, Lee (1914) found that the bleach produced by fattening with buttermilk varies with the quantity of milk solids in the diet. Fermor and Parkhurst (1933) reported that as good results were obtained with mixtures of ground Sussex oats and skimmilk when 6.66 percent of the total solids in the mixture was derived from the skimmilk as when 13.33 percent was derived from that source. Maw, Holcomb, Bemont, and Maw (1936) found that the color of the fat of the carcass is influenced by certain pigments in the cereal fed, and bears a close relationship to the quantity of fat deposited during the feeding period. Tomhave (1938) stated that there was no im-
provement in pigmentation as a result of feeding a commercial fattening mash in place of the regular broiler diet during the last 14 days. Penquite, Heller, and Thompson (1940) observed that the pigmentation of the shanks was deeper when a water extract of rice bran was added to the basal diet they used than when the basal diet was fed alone. The research reported in this paper was undertaken because the Department of Agriculture had received many requests for information about means of controlling the color of the shanks and skin of the yellowskin breeds. Most of these inquiries were for information on how to increase the pigmentation of the shanks and skin. Some of the inquirers suggested that cod liver oil might have a detrimental effect on pigmentation. EXPERIMENTAL
A series of six experiments was conducted. In each experiment 16 lots of 40 chicks each were used. The chicks were brooded under electrically heated brooders in a 16-pen, steam-heated brooder house. Soft wood shavings were used for litter. Three basal feed mixtures were used. The ingredients and the proportions in which they were used are tabulated in Table 1. Basal feed mixture A contained SO percent of yellow corn and 8 percent of dehydrated alfalfa leaf meal from which two ingredients it derived practically all of its pigment. It was one with which the writers had had considerable previous experi-
[437]
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JOHN C. HAMMOND AND HAROLD M. HARSHAW
Animal Nutrition Division, Bureau of Animal Industry, Beltsville Research Center, Beltsville, Maryland
438
JOHN C. HAMMOND AND HAROLD M. HARSHAW
Shank and skin color observations in the first two experiments were made each week beginning with the fourth week. Inasmuch as the color of the shank and skin did not change after the sixth week, in subsequent experiments color observations were made at this age. The values reported for the first two experiments are for the age of eight weeks and for the other experiments for the age of six weeks. When the shank color of Rhode Island Red chicks was observed, areas of the shank free from brown pigment were selected for scoring. Numerical values were assigned to the shades of shank and skin color as follows: No yellow pigment Very slightly yellow Slightly yellow Medium yellow Deep yellow Very deep yellow Very slightly orange Slightly orange Medium orange
0 1 2 3 4 5 6 7 8
In the first experiment a study was made of the effect of the pigment content of the diet, quantity of corn oil, source of vitamin D supplements, and the breed of chicken on the pigmentation of skin and shank. Four different sources of vitamin D, direct sunlight, fortified cod liver oil, ordinary cod liver oil, and activated animal provitamin D, each with and without 3 percent of
corn oil, were used to supplement the two basal feed mixtures A and B. Each diet was fed to a lot of 40 chicks which consisted of 10 chicks each of the Light Sussex, Single Comb White Leghorn, White Wyandotte, and Rhode Island Red breeds. TABLE 1.—Percentage of ingredients in the basal feed mixtures Ingredients
Ground white corn Ground yellow corn Ground whole oats Wheat flour middlings.. Wheat bran Ground whole w h e a t . . . Meat scrap Corn gluten meal Soybean meal Dried skimmilk Alfalfa leaf meal Alfalfa leaf meal substitute* Ground limestone Steamed bone meal Dried brewers' y e a s t . . . Salt mixturef Common salt
Basal feed mixture A parts
B parts 30.00
30.00 10.00 10.00 10.00
10.00 10.00 10.00
10.00
10.00
10.00 10.00 8.00
10.00 10.00
1.00 .50 99.50
C parts 40.00
21.00 10.00 10.00 10.00 3.00
8.00 1.00 .50
3.00 2.00 .50 .50
99.50 100.00
* The alfalfa leaf meal substitute contained 62.8 percent of dried whey, 28.4 percent of soybean meal, 5.4 percent of ground limestone, and 3.4 percent of feeding molasses. f The salt mixture contained 100 parts of common salt and 1.7 parts of anhydrous manganous sulfate.
Except for a few atypical individuals, the Light Sussex chicks in the eight lots fed basal feed mixture A, which contained a large quantity of yellow pigment, had shanks and skins that were white, whereas the White Leghorns, White Wyandottes, and Rhode Island Reds in each of these lots had shank color scores of 4 or over and skin color scores of 3 or over. All chicks that were fed basal feed mixture B, which contained neither yellow corn nor alfalfa leaf meal, had white skin and shanks. The feeding of corn oil or different sources of vitamin D did not affect the shank or skin color of any lot.
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ence. Basal feed mixture B contained almost no yellow pigment. It was similar to basal feed mixture A except that white corn was used in place of yellow corn, and a substitute was used in place of alfalfa leaf meal. This substitute contained 62.8 percent of dried whey, 28.4 percent of soybean meal, 5.4 percent of ground limestone, and 3.4 percent of feeding molasses. Basal feed mixture C contained somewhat less pigment than basal feed mixture A because it had a lower content of alfalfa leaf meal. Moreover, it contained no soybean meal, wheat byproducts, or ground oats and was much less bulky.
FACTORS INFLUENCING SHANK AND SKIN COLOR IN THE GROWING CHICKEN
LU
the number of units of vitamin D required. There seemed to be a slight but consistent lowering of color scores when ISO parts per million of manganese was added to the diet, which already contained SO parts per million of added manganese. The third experiment was planned for the purpose of ascertaining how cod liver
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FORTIFIED COD-LIVER-OIL IN THE DIET (PERCENT)
FIG. 1. Shank and skin color score plotted against fortified cod liver oil content of the diets used in the second experiment.
skin color were observed when the chicks were only four weeks old. In Figure 1 the average color scores of the several lots are plotted against the level of fortified cod liver oil in the diet. The scores for shank and skin color were found to be lower with each increase in quantity of fortified cod liver oil in the diet. Shank and skin color were not affected by activated animal provitamin D or irradiated ergosterol even though the levels fed supplied several times
oil suppresses pigmentation. It was theorized that the pigment might be destroyed by oxidation induced by the unsaturated compounds in the cod liver oil. Mineral oil, corn oil, cottonseed oil, and raw linseed oil, covering the range from non-drying to rapidly drying oils, potassium permanganate, an oxidizing agent, and stannous chloride, a reducing agent, were fed to test this theory. Liver meal and desiccated ox bile were fed to find out if contaminants
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In the second experiment the effects of feeding different levels of fortified cod liver oil, activated animal provitamin D, irradiated ergosterol, and two levels of manganese were studied. The basal feed mixture C was used in this experiment. Forty Rhode Island Red chicks were used in each of 16 lots. Striking differences in shank color and
439
440
JOHN C. HAMMOND AND HAROLD M.
such large quantities of pigment. Consequently, a fourth experiment was planned in which one-fourth, one-half, three-fourths, and all the alfalfa leaf meal of basal feed mixture A was replaced by the alfalfa leaf meal substitute mentioned above. The writers still thought that vitamin D carriers
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LEAF MEAL IN THE DIET (PERCENT)
FIG. 2. Shank and skin color score plotted against alfalfa leaf meal content of the diets used in the fifth experiment.
sardine oil, and ordinary cod liver oil was also studied. Basal feed mixture A was used. Because of its high pigment content, and other properties that will be discussed later, the pigmentation of all lots of chicks in this experiment was excellent. It seemed reasonable that differences in pigmentation did not appear when the basal feed mixture A was fed because it contained
differed in their effect on pigmentation, hence activated animal provitamin D, two levels of ordinary cod liver oil, and two levels of ordinary sardine oil were fed at each of the three levels of alfalfa leaf meal used. Activated animal provitamin D was used as the source of vitamin D in the diet in which all of the alfalfa leaf meal was replaced. Forty Rhode Island Red chicks
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from such sources might be present in cod liver oil and hence responsible for its effect on pigmentation. Blackstrap molasses was used for the purpose of finding out whether or not it would increase pigmentation. The effect on pigmentation of two different levels each of ordinary sardine oil, fortified
HARSHAW
FACTORS INFLUENCING SHANK AND SKIN COLOR IN THE GROWING CHICKEN
Bile, liver meal, and iodine, being possible liver oil contaminants, were also tested. Forty Rhode Island Red chicks were fed each of the 16 diets used. The results of this experiment are tabulated in Table 2. When a level of 3 percent of fortified cod liver oil was used the chicks fed basal feed mixture A had much better pigmentation than those fed basal feed mixture C. The
TABLE 2.—Pertinent ingredients of the diet and the average shank and skin color at six weeks of age of the Rhode Island Red chicks used in thefifthexperiment Shank and skin color of R.I. Red chicks at 6 weeks of age Average color score*
Ingredients of the diet Basal feed mixture
Lot No Designation
601 602 603
A A A
604 605 606 607
C C C C
608
C
609 610 611 61? 613 614 615 616
C C C C C C C C :
Modifications
Fortified Quan- cod tity liver oil Percent 99.9 97.0
Percent 0.1 3.0
97.0 99.9 97.0 87.0
3.0 0.1 3.0 3.0
Special ingredients Kind
Quantity
Shank
Skin
4.03 1.85
2.87 0.18
0.92 3.68 1.04 0.81
0.00 1.95 0.04 0.03
0.89
0.00
0.67 0.72 2.50 3.19 1.07 4.30 3.95 0.77 0.40
0.00 0.00 0.65 1.08 0.10 2.63 2.43 0.00 0.00
Per cent
Yellow corn replaced
Ground limestone replaced steamed bone m e a l . . . . 97.0 Soybean meal replaced corn gluten meal 97.0 87.0 97.0 97.0 92.0 50 p.p.m. iodine a d d e d . . . 99.9 99.8 92.0 95.0
Ground oats
10.0
3.0 3.0 3.0 3.0 0.1 0.1 3.0 3.0
Wheat bran 10.0 Ordinary cod liver oil no. 2 3.0 Ordinary sardine oil no. 3 . 3.0 5.0 Alfalfa leaf meal Desiccated ox bile "Argentine liver" meal...
0.1 5.0 2.0
Based on scale of 0 to 8 representing range from no yellow pigment to medium orange.
supplements had no appreciable effect on pigmentation although 2 percent of sardine oil seemed to suppress it slightly. The fifth experiment was an attempt to find out why the pigmentation of chicks fed basal feed mixture A and cod liver oil was so much better than that of chicks fed basal feed mixture C and cod liver oil. Fortified cod liver oil, ordinary cod liver oil, and ordinary sardine oil were again compared.
substitution of 5 percent of alfalfa leaf meal for an equal quantity of basal feed mixture C did not offset this effect, nor did the substitution of 10 percent of bran. When fed with basal feed mixture C, fortified cod liver oil suppressed pigmentation more than ordinary cod liver oil at the same level and, in turn, ordinary cod liver oil suppressed pigmentation more than sardine oil at the same level. The results of this experiment
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were fed each diet. The results of this experiment are plotted in Figure 2. Shank and skin color decreased as each 2 percent of the alfalfa leaf meal substitute was used in place of an equal quantity of alfalfa leaf meal. In other words, the color of shanks and skin was found to be closely associated with the quantity of alfalfa leaf meal in the diet as shown in Figure 2. The other
441
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JOHN C. HAMMOND AND HAROLD M. HARSHAW
4 volumes of N/5 sodium hydroxide solution. Both the oil and the washings were fed to see whether the treatment destroyed or removed the factor. A fourth portion was washed with 4 volumes of N/5 hydrochloric acid to remove any basic amines that might be present. The results of the sixth experiment are tabulated in Table 3. As in the fifth experi-
TABLE 3.—Pertinent ingredients of the diet and the average shank and skin color at stx weeks of age of the Rhode Island Red chicks used in the sixth experiment Shank and skin color of Rhode Island Red chicks at 6 weeks of age Average color scoref
Ingredients of the diet Lot no.
617 618 619 620* 621 622 623 624 625 626 627 628 629 630 631 632
Fish oils
Basal mixture C
Batch
Percent 99.9 97.0 97.0 97.0 97.0 97.0 97.0 97.0 97.0 97.0 97.0 97.0 97.0 97.0 97.0 97.0
Number 5 5 5a 5 6 7 8 7 5 5 5 5 5 5 9 10
Quantity Kind of treatment
Ordinary cod liver oil
Exposed to air and sunlight Washed with N / 5 NaOH solution. Washed with N / 5 HC1 solution. . . N / 5 NaOH washings N / 5 HC1 washings Fortified cod liver oil
Percent 0.1 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
Shank
Skin
3.43 0.94 0.94 0.50 1.64 1.17 0.96 1.29 1.06 2.76 0.94 0.81 3.18 3.53 1.21 2.63
0.54 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.24 0.00 0.03 0.60 0.55 0.00 0.06
* Chicks allowed access to direct sunlight. t Based on scale of 0 to 8 representing range from no yellow pigment to medium orange.
stability. Six nationally known brands of fish oils were fed. Portions of one of these (designated as no. 5) were treated in several ways in an attempt to remove or destroy the pigmentation-suppressing factor. One portion was exposed to air and direct sunlight for three days to find out if excessive irradiation of the vitamin D or partial oxidation of the oil might change the effects of the oil. Another portion was heated to 230°C. in a vacuum for three hours to see if the factor could be destroyed by heat. A third portion was washed with
ment, when oils were fed at a 3 percent level, pigmentation was suppressed more by fortified oils than by ordinary cod liver oil and more by ordinary cod liver oil than by sardine oil. The four nationally known brands of fortified cod liver oil were approximately equal in their effect on pigmentation. Of the treatments given to fortified cod liver oil no. 5, only heating in a vacuum at 230°C. destroyed any of its inhibiting effect on pigmentation. The free fat acid content (as percent oleic acid) and peroxide values of each of
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confirmed our opinion that there is a pigmentation-suppressing factor in some feeds. It also raised the possibility that there might be counteracting factors in other feeds. The sixth experiment was conducted in an attempt to find out the extent of distribution of the pigmentation-suppressing factor in fish oils and something about its
FACTORS INFLUENCING SHANK AND SKIN COLOR IN THE GROWING CHICKEN
DISCUSSION
A comparison of the results of the first three experiments indicates that the pigmentation-suppressing factor of cod liver oil was less effective when basal feed mixture A was fed than when basal feed mixture C was fed. Inasmuch as basal feed mixture A contained 5 percent more alfalfa leaf meal than basal feed mixture C it was thought that the additional pigment from the alfalfa leaf meal might have offset the effect of the cod liver oil. The fourth experiment was planned to clarify this point, but it failed to do so. Although in this experiment pigmentation decreased with each decrease of alfalfa leaf meal, cod liver oil did not suppress pigmentation when alfalfa leaf meal was included in the diet at low levels as it did when fed with basal feed mixture C. This difference between the two basal feed mixtures was brought out more fully in the fifth experiment. Basal feed mixture A with 3 percent of fortified cod liver oil permitted nearly twice as much pigmentation in the shanks and skin as basal feed mixture C with 5 percent of alfalfa leaf meal and 3 percent of fortified cod liver oil. When 3 percent of fortified cod liver oil was mixed with 97 percent of basal feed mixture A in which 10 percent of yellow corn was substituted for the ground oats, pigmentation was very much lower; yet when an equal quantity of ground oats was added to basal feed mix-
ture C pigmentation was equally low. This tends to indicate that more factors are involved in pigmentation than the quantity of pigment in the diet and the quantity of pigmentation-suppressing factor in the diet. The fortified cod liver oils were used at levels 24 times as high as needed to supply the chicks with adequate vitamin D under practical conditions simply because it had been found in the previous experiments that this level of fortified cod liver oil was sure to suppress pigmentation. In this series of experiments confirmation was obtained of the opinion of certain poultrymen and feed manufacturers that sardine oil permits better pigmentation than cod liver oil. At a 3 percent level of intake, fortified cod liver oil suppressed pigmentation more than twice as much as ordinary cod liver oil and more than three times as much as ordinary sardine oil. This finding was supported by similar results obtained in the sixth experiment in which oils from different sources were used. It is not yet known why heating at 230°C. in a vacuum removed a large percentage of the pigmentation-suppressing factor from the fortified cod liver oil. Unfortunately, the distillate, which amounted to less than 0.01 percent of the oil treated, was not saved for feeding so it is not possible to say definitely that the factor in question is partially heat labile. Work now in progress may solve some of the interesting problems indicated by the results of these experiments. SUMMARY AND CONCLUSIONS
A total of 3,840 growing chicks were used in six experiments in which the effects of breed and diet on shank and skin color were observed. Light Sussex chicks were found to have almost no yellow pigment in either shanks or skin, regardless of the diet fed. White Wyandottes, White Leghorn, and Rhode Island Red chicks were found
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the fish oils used were determined. No relationship could be found between the free fat acid content or the peroxide value and the effect the several oils had on pigmentation. In the second, fifth, and sixth experiments several of the chicks in the lots fed basal feed mixture C and 3 percent or more of fortified or ordinary cod liver oil showed symptoms of encephalomalacia during and after the fourth week of the experiment.
443
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JOHN C. HAMMOND AND HAROLD M. HARSHAW
xanthophyll pigment in the diet, and by the quantity of a pigmentation-suppressing factor in the diet. REFERENCES
Benjamin, E. W., and H. C. Pierce, 1937. Marketing poultry products. John Wiley & Sons, Inc. pp. 80. Fermor, C. E., and R. T. Parkhurst, 1933. Table poultry production with a section on battery brooding. Min. Agr. and Fisheries Bull. 64:1921. Lee, A. R., 1911. Fattening poultry. U.S.D.A., B. A. I., Bull. 140:1-60. , 1914. Commercial fattening of poultry. U.S.D.A. Bull. 21 :l-55. Maw, W. A., R. Holcomb, L. H. Bemont, and A. J. G. Maw, 1936. The cereals in the fattening ration and their effect upon the edible quality of the finished carcass. Proc. Sixth World's Poultry Cong. Leipzig, Germany, Band 1, 6:298-302. Penquite, Robert, V. G. Heller, and R. B. Thompson, 1940. Investigations of the cause and prevention of perosis. Okla. Sta. Bull. 243. Tomhave, A. E., 1938. Broiler feeding experiment. Univ. of Del. Agr. Expt. Sta. Bull. 210:1-20.
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to have approximately the same shank and skin color on any given diet. In these yellow-skin breeds the color of the shanks and skin was found to depend upon the interaction of two factors, the quantity of yellow pigment and the quantity of a pigmentation-suppressing factor in the diet. Four different brands of fortified cod liver oil were found to be potent sources of the pigmentation-suppressing factor, ordinary cod liver oil was about one-half as potent, and ordinary sardine oil about one-third as potent as the fortified cod liver oils. The practical significance of these findings is still in doubt because each oil was fed at a level that was several times that needed for protection against vitamin D deficiency. Fortified cod liver oil was freed of a large portion of the pigmentation-suppressing factor by heating at 230°C. in a vacuum for three hours. It is concluded that in the growing chicken the shank and skin color is influenced by breed, by the quantity of
CCORDING to Benjamin and Pierce - (1937) the skin color in market chickens may range from white through cream to golden yellow and even to a dark brownish yellow. They stated that the white, cream, or golden yellow colors are satisfactory, although the lighter colors are preferred by discriminating consumers. They also stated that the market preference is for smooth yellow shanks. It is common knowledge among producers that there is a marked preference for yellow shanks and skin in broilers on the New York live poultry market.
A
Lee (1911) reported that packers did not care about skin color except when they were supplying a special market that wanted deep yellow skin. These packers believed that deep yellow color could be obtained by adding molasses or, sometimes, artificial butter color to the fattening diet. Later, Lee (1914) found that the bleach produced by fattening with buttermilk varies with the quantity of milk solids in the diet. Fermor and Parkhurst (1933) reported that as good results were obtained with mixtures of ground Sussex oats and skimmilk when 6.66 percent of the total solids in the mixture was derived from the skimmilk as when 13.33 percent was derived from that source. Maw, Holcomb, Bemont, and Maw (1936) found that the color of the fat of the carcass is influenced by certain pigments in the cereal fed, and bears a close relationship to the quantity of fat deposited during the feeding period. Tomhave (1938) stated that there was no im-
provement in pigmentation as a result of feeding a commercial fattening mash in place of the regular broiler diet during the last 14 days. Penquite, Heller, and Thompson (1940) observed that the pigmentation of the shanks was deeper when a water extract of rice bran was added to the basal diet they used than when the basal diet was fed alone. The research reported in this paper was undertaken because the Department of Agriculture had received many requests for information about means of controlling the color of the shanks and skin of the yellowskin breeds. Most of these inquiries were for information on how to increase the pigmentation of the shanks and skin. Some of the inquirers suggested that cod liver oil might have a detrimental effect on pigmentation. EXPERIMENTAL
A series of six experiments was conducted. In each experiment 16 lots of 40 chicks each were used. The chicks were brooded under electrically heated brooders in a 16-pen, steam-heated brooder house. Soft wood shavings were used for litter. Three basal feed mixtures were used. The ingredients and the proportions in which they were used are tabulated in Table 1. Basal feed mixture A contained SO percent of yellow corn and 8 percent of dehydrated alfalfa leaf meal from which two ingredients it derived practically all of its pigment. It was one with which the writers had had considerable previous experi-
[437]
Downloaded from http://ps.oxfordjournals.org/ at Frankfurt University Library, Section Stadt- und Universitaetsbibliothek on April 8, 2015
JOHN C. HAMMOND AND HAROLD M. HARSHAW
Animal Nutrition Division, Bureau of Animal Industry, Beltsville Research Center, Beltsville, Maryland
438
JOHN C. HAMMOND AND HAROLD M. HARSHAW
Shank and skin color observations in the first two experiments were made each week beginning with the fourth week. Inasmuch as the color of the shank and skin did not change after the sixth week, in subsequent experiments color observations were made at this age. The values reported for the first two experiments are for the age of eight weeks and for the other experiments for the age of six weeks. When the shank color of Rhode Island Red chicks was observed, areas of the shank free from brown pigment were selected for scoring. Numerical values were assigned to the shades of shank and skin color as follows: No yellow pigment Very slightly yellow Slightly yellow Medium yellow Deep yellow Very deep yellow Very slightly orange Slightly orange Medium orange
0 1 2 3 4 5 6 7 8
In the first experiment a study was made of the effect of the pigment content of the diet, quantity of corn oil, source of vitamin D supplements, and the breed of chicken on the pigmentation of skin and shank. Four different sources of vitamin D, direct sunlight, fortified cod liver oil, ordinary cod liver oil, and activated animal provitamin D, each with and without 3 percent of
corn oil, were used to supplement the two basal feed mixtures A and B. Each diet was fed to a lot of 40 chicks which consisted of 10 chicks each of the Light Sussex, Single Comb White Leghorn, White Wyandotte, and Rhode Island Red breeds. TABLE 1.—Percentage of ingredients in the basal feed mixtures Ingredients
Ground white corn Ground yellow corn Ground whole oats Wheat flour middlings.. Wheat bran Ground whole w h e a t . . . Meat scrap Corn gluten meal Soybean meal Dried skimmilk Alfalfa leaf meal Alfalfa leaf meal substitute* Ground limestone Steamed bone meal Dried brewers' y e a s t . . . Salt mixturef Common salt
Basal feed mixture A parts
B parts 30.00
30.00 10.00 10.00 10.00
10.00 10.00 10.00
10.00
10.00
10.00 10.00 8.00
10.00 10.00
1.00 .50 99.50
C parts 40.00
21.00 10.00 10.00 10.00 3.00
8.00 1.00 .50
3.00 2.00 .50 .50
99.50 100.00
* The alfalfa leaf meal substitute contained 62.8 percent of dried whey, 28.4 percent of soybean meal, 5.4 percent of ground limestone, and 3.4 percent of feeding molasses. f The salt mixture contained 100 parts of common salt and 1.7 parts of anhydrous manganous sulfate.
Except for a few atypical individuals, the Light Sussex chicks in the eight lots fed basal feed mixture A, which contained a large quantity of yellow pigment, had shanks and skins that were white, whereas the White Leghorns, White Wyandottes, and Rhode Island Reds in each of these lots had shank color scores of 4 or over and skin color scores of 3 or over. All chicks that were fed basal feed mixture B, which contained neither yellow corn nor alfalfa leaf meal, had white skin and shanks. The feeding of corn oil or different sources of vitamin D did not affect the shank or skin color of any lot.
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ence. Basal feed mixture B contained almost no yellow pigment. It was similar to basal feed mixture A except that white corn was used in place of yellow corn, and a substitute was used in place of alfalfa leaf meal. This substitute contained 62.8 percent of dried whey, 28.4 percent of soybean meal, 5.4 percent of ground limestone, and 3.4 percent of feeding molasses. Basal feed mixture C contained somewhat less pigment than basal feed mixture A because it had a lower content of alfalfa leaf meal. Moreover, it contained no soybean meal, wheat byproducts, or ground oats and was much less bulky.
FACTORS INFLUENCING SHANK AND SKIN COLOR IN THE GROWING CHICKEN
LU
the number of units of vitamin D required. There seemed to be a slight but consistent lowering of color scores when ISO parts per million of manganese was added to the diet, which already contained SO parts per million of added manganese. The third experiment was planned for the purpose of ascertaining how cod liver
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FORTIFIED COD-LIVER-OIL IN THE DIET (PERCENT)
FIG. 1. Shank and skin color score plotted against fortified cod liver oil content of the diets used in the second experiment.
skin color were observed when the chicks were only four weeks old. In Figure 1 the average color scores of the several lots are plotted against the level of fortified cod liver oil in the diet. The scores for shank and skin color were found to be lower with each increase in quantity of fortified cod liver oil in the diet. Shank and skin color were not affected by activated animal provitamin D or irradiated ergosterol even though the levels fed supplied several times
oil suppresses pigmentation. It was theorized that the pigment might be destroyed by oxidation induced by the unsaturated compounds in the cod liver oil. Mineral oil, corn oil, cottonseed oil, and raw linseed oil, covering the range from non-drying to rapidly drying oils, potassium permanganate, an oxidizing agent, and stannous chloride, a reducing agent, were fed to test this theory. Liver meal and desiccated ox bile were fed to find out if contaminants
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In the second experiment the effects of feeding different levels of fortified cod liver oil, activated animal provitamin D, irradiated ergosterol, and two levels of manganese were studied. The basal feed mixture C was used in this experiment. Forty Rhode Island Red chicks were used in each of 16 lots. Striking differences in shank color and
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JOHN C. HAMMOND AND HAROLD M.
such large quantities of pigment. Consequently, a fourth experiment was planned in which one-fourth, one-half, three-fourths, and all the alfalfa leaf meal of basal feed mixture A was replaced by the alfalfa leaf meal substitute mentioned above. The writers still thought that vitamin D carriers
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FIG. 2. Shank and skin color score plotted against alfalfa leaf meal content of the diets used in the fifth experiment.
sardine oil, and ordinary cod liver oil was also studied. Basal feed mixture A was used. Because of its high pigment content, and other properties that will be discussed later, the pigmentation of all lots of chicks in this experiment was excellent. It seemed reasonable that differences in pigmentation did not appear when the basal feed mixture A was fed because it contained
differed in their effect on pigmentation, hence activated animal provitamin D, two levels of ordinary cod liver oil, and two levels of ordinary sardine oil were fed at each of the three levels of alfalfa leaf meal used. Activated animal provitamin D was used as the source of vitamin D in the diet in which all of the alfalfa leaf meal was replaced. Forty Rhode Island Red chicks
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from such sources might be present in cod liver oil and hence responsible for its effect on pigmentation. Blackstrap molasses was used for the purpose of finding out whether or not it would increase pigmentation. The effect on pigmentation of two different levels each of ordinary sardine oil, fortified
HARSHAW
FACTORS INFLUENCING SHANK AND SKIN COLOR IN THE GROWING CHICKEN
Bile, liver meal, and iodine, being possible liver oil contaminants, were also tested. Forty Rhode Island Red chicks were fed each of the 16 diets used. The results of this experiment are tabulated in Table 2. When a level of 3 percent of fortified cod liver oil was used the chicks fed basal feed mixture A had much better pigmentation than those fed basal feed mixture C. The
TABLE 2.—Pertinent ingredients of the diet and the average shank and skin color at six weeks of age of the Rhode Island Red chicks used in thefifthexperiment Shank and skin color of R.I. Red chicks at 6 weeks of age Average color score*
Ingredients of the diet Basal feed mixture
Lot No Designation
601 602 603
A A A
604 605 606 607
C C C C
608
C
609 610 611 61? 613 614 615 616
C C C C C C C C :
Modifications
Fortified Quan- cod tity liver oil Percent 99.9 97.0
Percent 0.1 3.0
97.0 99.9 97.0 87.0
3.0 0.1 3.0 3.0
Special ingredients Kind
Quantity
Shank
Skin
4.03 1.85
2.87 0.18
0.92 3.68 1.04 0.81
0.00 1.95 0.04 0.03
0.89
0.00
0.67 0.72 2.50 3.19 1.07 4.30 3.95 0.77 0.40
0.00 0.00 0.65 1.08 0.10 2.63 2.43 0.00 0.00
Per cent
Yellow corn replaced
Ground limestone replaced steamed bone m e a l . . . . 97.0 Soybean meal replaced corn gluten meal 97.0 87.0 97.0 97.0 92.0 50 p.p.m. iodine a d d e d . . . 99.9 99.8 92.0 95.0
Ground oats
10.0
3.0 3.0 3.0 3.0 0.1 0.1 3.0 3.0
Wheat bran 10.0 Ordinary cod liver oil no. 2 3.0 Ordinary sardine oil no. 3 . 3.0 5.0 Alfalfa leaf meal Desiccated ox bile "Argentine liver" meal...
0.1 5.0 2.0
Based on scale of 0 to 8 representing range from no yellow pigment to medium orange.
supplements had no appreciable effect on pigmentation although 2 percent of sardine oil seemed to suppress it slightly. The fifth experiment was an attempt to find out why the pigmentation of chicks fed basal feed mixture A and cod liver oil was so much better than that of chicks fed basal feed mixture C and cod liver oil. Fortified cod liver oil, ordinary cod liver oil, and ordinary sardine oil were again compared.
substitution of 5 percent of alfalfa leaf meal for an equal quantity of basal feed mixture C did not offset this effect, nor did the substitution of 10 percent of bran. When fed with basal feed mixture C, fortified cod liver oil suppressed pigmentation more than ordinary cod liver oil at the same level and, in turn, ordinary cod liver oil suppressed pigmentation more than sardine oil at the same level. The results of this experiment
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were fed each diet. The results of this experiment are plotted in Figure 2. Shank and skin color decreased as each 2 percent of the alfalfa leaf meal substitute was used in place of an equal quantity of alfalfa leaf meal. In other words, the color of shanks and skin was found to be closely associated with the quantity of alfalfa leaf meal in the diet as shown in Figure 2. The other
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JOHN C. HAMMOND AND HAROLD M. HARSHAW
4 volumes of N/5 sodium hydroxide solution. Both the oil and the washings were fed to see whether the treatment destroyed or removed the factor. A fourth portion was washed with 4 volumes of N/5 hydrochloric acid to remove any basic amines that might be present. The results of the sixth experiment are tabulated in Table 3. As in the fifth experi-
TABLE 3.—Pertinent ingredients of the diet and the average shank and skin color at stx weeks of age of the Rhode Island Red chicks used in the sixth experiment Shank and skin color of Rhode Island Red chicks at 6 weeks of age Average color scoref
Ingredients of the diet Lot no.
617 618 619 620* 621 622 623 624 625 626 627 628 629 630 631 632
Fish oils
Basal mixture C
Batch
Percent 99.9 97.0 97.0 97.0 97.0 97.0 97.0 97.0 97.0 97.0 97.0 97.0 97.0 97.0 97.0 97.0
Number 5 5 5a 5 6 7 8 7 5 5 5 5 5 5 9 10
Quantity Kind of treatment
Ordinary cod liver oil
Exposed to air and sunlight Washed with N / 5 NaOH solution. Washed with N / 5 HC1 solution. . . N / 5 NaOH washings N / 5 HC1 washings Fortified cod liver oil
Percent 0.1 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
Shank
Skin
3.43 0.94 0.94 0.50 1.64 1.17 0.96 1.29 1.06 2.76 0.94 0.81 3.18 3.53 1.21 2.63
0.54 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.24 0.00 0.03 0.60 0.55 0.00 0.06
* Chicks allowed access to direct sunlight. t Based on scale of 0 to 8 representing range from no yellow pigment to medium orange.
stability. Six nationally known brands of fish oils were fed. Portions of one of these (designated as no. 5) were treated in several ways in an attempt to remove or destroy the pigmentation-suppressing factor. One portion was exposed to air and direct sunlight for three days to find out if excessive irradiation of the vitamin D or partial oxidation of the oil might change the effects of the oil. Another portion was heated to 230°C. in a vacuum for three hours to see if the factor could be destroyed by heat. A third portion was washed with
ment, when oils were fed at a 3 percent level, pigmentation was suppressed more by fortified oils than by ordinary cod liver oil and more by ordinary cod liver oil than by sardine oil. The four nationally known brands of fortified cod liver oil were approximately equal in their effect on pigmentation. Of the treatments given to fortified cod liver oil no. 5, only heating in a vacuum at 230°C. destroyed any of its inhibiting effect on pigmentation. The free fat acid content (as percent oleic acid) and peroxide values of each of
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confirmed our opinion that there is a pigmentation-suppressing factor in some feeds. It also raised the possibility that there might be counteracting factors in other feeds. The sixth experiment was conducted in an attempt to find out the extent of distribution of the pigmentation-suppressing factor in fish oils and something about its
FACTORS INFLUENCING SHANK AND SKIN COLOR IN THE GROWING CHICKEN
DISCUSSION
A comparison of the results of the first three experiments indicates that the pigmentation-suppressing factor of cod liver oil was less effective when basal feed mixture A was fed than when basal feed mixture C was fed. Inasmuch as basal feed mixture A contained 5 percent more alfalfa leaf meal than basal feed mixture C it was thought that the additional pigment from the alfalfa leaf meal might have offset the effect of the cod liver oil. The fourth experiment was planned to clarify this point, but it failed to do so. Although in this experiment pigmentation decreased with each decrease of alfalfa leaf meal, cod liver oil did not suppress pigmentation when alfalfa leaf meal was included in the diet at low levels as it did when fed with basal feed mixture C. This difference between the two basal feed mixtures was brought out more fully in the fifth experiment. Basal feed mixture A with 3 percent of fortified cod liver oil permitted nearly twice as much pigmentation in the shanks and skin as basal feed mixture C with 5 percent of alfalfa leaf meal and 3 percent of fortified cod liver oil. When 3 percent of fortified cod liver oil was mixed with 97 percent of basal feed mixture A in which 10 percent of yellow corn was substituted for the ground oats, pigmentation was very much lower; yet when an equal quantity of ground oats was added to basal feed mix-
ture C pigmentation was equally low. This tends to indicate that more factors are involved in pigmentation than the quantity of pigment in the diet and the quantity of pigmentation-suppressing factor in the diet. The fortified cod liver oils were used at levels 24 times as high as needed to supply the chicks with adequate vitamin D under practical conditions simply because it had been found in the previous experiments that this level of fortified cod liver oil was sure to suppress pigmentation. In this series of experiments confirmation was obtained of the opinion of certain poultrymen and feed manufacturers that sardine oil permits better pigmentation than cod liver oil. At a 3 percent level of intake, fortified cod liver oil suppressed pigmentation more than twice as much as ordinary cod liver oil and more than three times as much as ordinary sardine oil. This finding was supported by similar results obtained in the sixth experiment in which oils from different sources were used. It is not yet known why heating at 230°C. in a vacuum removed a large percentage of the pigmentation-suppressing factor from the fortified cod liver oil. Unfortunately, the distillate, which amounted to less than 0.01 percent of the oil treated, was not saved for feeding so it is not possible to say definitely that the factor in question is partially heat labile. Work now in progress may solve some of the interesting problems indicated by the results of these experiments. SUMMARY AND CONCLUSIONS
A total of 3,840 growing chicks were used in six experiments in which the effects of breed and diet on shank and skin color were observed. Light Sussex chicks were found to have almost no yellow pigment in either shanks or skin, regardless of the diet fed. White Wyandottes, White Leghorn, and Rhode Island Red chicks were found
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the fish oils used were determined. No relationship could be found between the free fat acid content or the peroxide value and the effect the several oils had on pigmentation. In the second, fifth, and sixth experiments several of the chicks in the lots fed basal feed mixture C and 3 percent or more of fortified or ordinary cod liver oil showed symptoms of encephalomalacia during and after the fourth week of the experiment.
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xanthophyll pigment in the diet, and by the quantity of a pigmentation-suppressing factor in the diet. REFERENCES
Benjamin, E. W., and H. C. Pierce, 1937. Marketing poultry products. John Wiley & Sons, Inc. pp. 80. Fermor, C. E., and R. T. Parkhurst, 1933. Table poultry production with a section on battery brooding. Min. Agr. and Fisheries Bull. 64:1921. Lee, A. R., 1911. Fattening poultry. U.S.D.A., B. A. I., Bull. 140:1-60. , 1914. Commercial fattening of poultry. U.S.D.A. Bull. 21 :l-55. Maw, W. A., R. Holcomb, L. H. Bemont, and A. J. G. Maw, 1936. The cereals in the fattening ration and their effect upon the edible quality of the finished carcass. Proc. Sixth World's Poultry Cong. Leipzig, Germany, Band 1, 6:298-302. Penquite, Robert, V. G. Heller, and R. B. Thompson, 1940. Investigations of the cause and prevention of perosis. Okla. Sta. Bull. 243. Tomhave, A. E., 1938. Broiler feeding experiment. Univ. of Del. Agr. Expt. Sta. Bull. 210:1-20.
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to have approximately the same shank and skin color on any given diet. In these yellow-skin breeds the color of the shanks and skin was found to depend upon the interaction of two factors, the quantity of yellow pigment and the quantity of a pigmentation-suppressing factor in the diet. Four different brands of fortified cod liver oil were found to be potent sources of the pigmentation-suppressing factor, ordinary cod liver oil was about one-half as potent, and ordinary sardine oil about one-third as potent as the fortified cod liver oils. The practical significance of these findings is still in doubt because each oil was fed at a level that was several times that needed for protection against vitamin D deficiency. Fortified cod liver oil was freed of a large portion of the pigmentation-suppressing factor by heating at 230°C. in a vacuum for three hours. It is concluded that in the growing chicken the shank and skin color is influenced by breed, by the quantity of