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The Effect on Xanthophyll Content and Color of Broiler Skin When Scald Additive Concentration Was Measured by pH1,2
1288
R. C. BAKER AND J. M. DARFLER
juiciness and tenderness of bologna. Food Technol. 8: 339-344. Townsend, W. E., S. A. Ackerman, L. P. Witnauer, W. E. Palm and C. E. Swift, 1971. Effects of types and levels of fats and rates and temperatures of comminution on the processing and characteristics of frankfurters. J. Food Sci. 36: 261-265. Young, L. L., and G. B. Lyon, 1973. The use of heat treated meat in chicken frankfurters. Poultry Sci. 52: 1868-1875.
The Effect on Xanthophyll Content and Color of Broiler Skin When Scald Additive Concentration Was Measured bypH 1 ' 2 J. L . HEATH AND C. J. WABECK
Department of Poultry Science, University of Maryland, College Park, Maryland 20742 (Received for publication December 10, 1974)
ABSTRACT Three experiments were used to determine that scald water pH could be altered by changing the concentration of a commercial scald additive without affecting color of the skin. The pH of the scald water which indicated the optimum level of additive for feather removal also retained the most yellow color in the skin. The pH of the scald water must be monitored constantly to maintain an optimum concentration of additive. The temperature of the scald water did not alter the lack of influence scald water pH had on skin color. POULTRY SCIENCE 54: 1288-1292, 1975
INTRODUCTION
S
EVERAL companies market a product to the poultry processing industry which, when added to the scald water, will increase the efficiency of the feather removal operation. One characteristic a large number of these scald additives have in common is they increase the pH of the scald water. The methods used to maintain concentrations of these additives require the addition of a specified amount per bird scalded. This is done by metering or periodic addition. These methods allow a wide range of scald water
pH to develop in a given period. The use of pH to measure and maintain a given concentration of additive has been suggested. The effect of scald water pH on the carcass has not been determined. Previous work, Heath and Thomas (1973, 1974), indicated scalding and picking conditions will alter the xanthophyll content and yellow color of the skin. This research was designed to determine if skin color was affected by scald water pH when increased by changing the concentration of a commercial additive. MATERIALS AND METHODS
1. Scientific Article No. A1989 Contribution No. 4928 of the Maryland Agricultural Experiment Station (Department of Poultry Science). 2. The use of trade names in this publication does not imply endorsement of the product by the University of Maryland.
Eight-week old male broiler chickens were used in the experiments. The broilers were reared and processed according to the method of Heath and Thomas (1974). A portion of skin was removed from the left side of the
Downloaded from http://ps.oxfordjournals.org/ at Uniwersytet Warszawski Biblioteka Uniwersytecka on April 11, 2015
Vadehra and R. C. Baker, 1973. Physical and functional properties of mechanically deboned poultry meat as used in the manufacture of frankfurters. Poultry Sci. 52: 1363-1369. Simon, S., J. C. Field, W. E. Kramlich and F. W. Tauber, 1965. Factors affecting frankfurter texture and a method of measurement. Food Technol. 19: 410-413. Swift, C. E., E. Weir and O. G. Hankins, 1954. Effect of variations in moisture and fat content on the
XANTHOPHYLL CONTENT AND COLOR OF BROILER SKIN
Skin moisture was determined by drying to constant weight at 100° C. Feather removal was evaluated using a range of 1-5. The carcasses with approximately 1/2 of their feathers remaining were given a rating of 1, those picked clean (no pinfeathers) were given a 5. One experienced evaluator was used to rate all carcasses. The data was analyzed using the analysis of variance technique and the Student-Newman-Keuls test presented in Steel and Torrie (1960). Experiment 1. Study 1. Two-hundred and eighty broilers were assigned to 7 treatment groups and were processed in replicates of 5 birds. The treatment groups were: (1) H 2 0 as it came from the local supply (pH 6.9), (2) H 2 0 + a commercial scald additive to give a pH of 7.9, 8.9 and 9.9, and (3) H 2 0 + NaOH to give a pH of 7.9, 8.9 and 9.9. The carcasses were scalded at 52° C. for60 seconds. The commercial additive used in this and subsequent experiments was Scal-
dex. 3 The product has been accepted by U.S.D.A. for use in poultry processing. The pH was monitored and adjusted after each replication. Skin moisture, xanthophyll content and color were determined on breast skin samples from each carcass. Study 2. One-hundred and forty broilers were processed under the same conditions as Study 1. The pH was not maintained but was recorded after each replicate of 5 carcasses were scalded. Experiment 2. Ninety broilers were divided into 3 groups of 30 birds each and processed in replicates of 5 birds. The scalding and picking conditions were the same as the first experiment. The treatment groups were: (1) H 2 0 as it came from the local supply (pH 6.5), (2) pH adjusted with the commercial additive to 8.5, (3) pH adjusted with the commercial additive to 10.5. The carcasses were evaluated for feather removal, skin color and xanthophyll content. Experiment 3. One-hundred and eighty broilers were divided into 9 treatment groups and were processed in replicates of 5 birds. The carcasses were scalded for 60 seconds and picked for 60 seconds. The treatment consisted of: scalding at 50, 52 and 54° C , and at each temperature the pH was adjusted to 6.5 ( H 2 0 no additive), 8.0 and 9.5. The last two pH's were adjusted using the commercial additive. A difference of treatment pH of 1.5 units was used instead of the 2.0 unit difference in experiment 2 in an attempt to have all treatments closer to the optimum level of pH 8.5 determined in the previous experiment. The pH was monitored after each replication and adjusted when necessary. Skin moisture, xanthophyll content, color and feather removal scores were obtained from each carcass. 3. Oxford Chemicals, P.O. Box 80202, Atlanta, Georgia 30341.
Downloaded from http://ps.oxfordjournals.org/ at Uniwersytet Warszawski Biblioteka Uniwersytecka on April 11, 2015
carcass and included the area between the sternal and pectoral feather tracts. The area removed started at the anterior end of the sternal tract and continued to the posterior end of the pectoral tract. Terminology used in this description can be found in Lucas and Stettenheim (1972). The samples were placed in plastic bags and stored in the dark at -10° C. until analysis could be accomplished. Skin color evaluation and xanthophyll extraction and determination was accomplished according to the method of Heath and Thomas (1973). Color was expressed in the 3 dimensions of b, L, and a. The b dimension measured yellowness when positive (+). The L dimension measured lightness and varied from black (0) to perfect white (100). The a dimension measured redness when positive (+), gray when (0) and greenness when negative ( - ) . A white tile was used as a uniform background for each sample.
1289
1290
• J. L. HEATH AND C. J. WABECK
RESULTS AND DISCUSSION
TABLE 1.-
Experiment 2. The purpose of this experiment was to determine if scald water pH was accurate enough to find the optimum concentration of the additive and study the effect of additive concentration on skin color and feather removal. The carcasses scalded in water adjusted with the commercial additive to pH 8.5 and 10.5 had more xanthophyll, yellow color (+b values) and were more green (—a values) than those scalded in water with no additive (Table 3). The carcasses scalded at pH 8.5 were
-The effect of using scald water pH as a measure of scald additive concentration on broiler skin color Breast skin Moisture
H 2 0 (no additive) H 2 0 + NaOH
H 2 0 + additive
pH 6.9 7.9 8.9 9.9 7.9 8.9 9.9
% 58.4 59.0 60.5 60.3 59.8 59.4 60.8
Xanthophyll mcg./gm. 10.9a 12.6a 10.8a 11.7a 11.2a 10.7a 14.6b
Color a -0.3 -0.9 -0.1 -0.9 -0.0 +2.0 + 1.1
L 74.3 75.0 74.5 76.0 74.1 74.0 73.0
b +23.6a +24.5a +24.7a +24.0a +25.2a +24.9a +26.5b
Values in columns followed by different letters are significanitly (P < 0.01) different.
TABLE 2.-—Change
H20 H 2 0 + NaOH
H 2 0 + additive
in scald water pH
0
5
6.9 7.9 8.9 9.9 7.9 8.9 9.9
7.1 7.8 8.2 9.8 7.6 8.2 9.6
Number of carcasses scalded 10 15 7.1 7.5 7.5 9.6 7.4 7.7 9.2
6.7 7.2 7.3 9.1 7.3 7.5 8.8
20 6.7 7.2 7.2 9.1 7.3 7.3 8.4
Downloaded from http://ps.oxfordjournals.org/ at Uniwersytet Warszawski Biblioteka Uniwersytecka on April 11, 2015
Experiment 1. The purpose of this experiment was to determine the effect on broiler skin color of pH produced by varying the concentration of either a commercial scald additive or NaOH. Study 1. Adjusting the pH to 7.9, 8.9 and 9.9 using NaOH produced no changes in xanthophyll content, color or percent moisture of the skin (Table 1). When the commercial additive was used, the only differences produced were at pH 9.9 where both xanthophyll content and yellowness (+b values) were retained to a greater degree. Study 2. In Table 2, the pH of the scald water was not maintained. When either NaOH or a commercial additive were used, a decrease in pH occurred as the number of carcasses scalded increased. When water with no additive was used, the pH increased after 5 and 10 carcasses were scalded and
decreased after 15 and 20. The decrease in pH was attributed to material brought into the scald water by the carcasses such as blood, feces, dirt, drop contents, etc. The additive was in solution and neither additive nor water were added. Therefore, the amount of solution removed on the carcasses should not affect the concentration of the solution.
1291
XANTHOPHYLL CONTENT AND COLOR OF BROILER SKIN
more yellow and had more feathers removed than those scalded at pH 10.5. There were no differences in skin xanthophyll of carcasses scalded in water adjusted with the additive. This data indicated that an additive concentration which was most effective could be determined using pH as the indicator.
TABLE 3.—The effect on xanthophyll content, color and feather removal of scald additive concentration measured by pH of the scald water
H 2 0 only Adjusted Adjusted
Initial pH
Xanthophyll mcg./gm.
L
a
b
Feather removal score
6.5 8.5 10.5
11.2a 12.6b 12.8b
70.4 71.7 70.9
-0.3x -l.ly -1.2y
+26.3x +28.5y +27.5z
3.6 4.4 3.3
Color
A range of 1-5 was used. 1—All feathers on carcass; 5—All feathers and pinfeathers removed. Values in columns followed by different letters are significantly different, (a b = P s 0.01, xyz = P < 0.05). TABLE 4.—The effect of scald water temperature on broiler skin when scald additive concentration was measured by pH Temp. °C. 50 52 54
Moisture PH 6.5 6.5 6.5
50 52 54 50 52 54
Color
Feather removal score
%
Xanthophyll mcg./gm.
L
a
62.8 61.7 60.1
13.3c 11.4bc 6.0a
77.9ab 78.2ab 80.0b
-1.7 -2.3 -2.1
+24.8a +24.8a +24.8a
3.6 4.0 4.6
8.0 8.0 8.0
57.9 60.5 63.9
11.3bc 9.7b 7.1a
77.4ab 78.8ab 80.3b
-2.0 -2.1 -2.3
+25.8ab +26. lab +24.8a
3.6 4.2 4.4
9.5 9.5 9.5
62.7 60.9 61.8
13.4c ll.Obc 10.2bc
78.7ab 78.6ab 76.8a
-1.8 -1.5 -0.9
+27.6b +27.5b +26.2ab
2.9 3.7 4.4
b
Values in columns followed by different letters were significantly (P s 0.01) different.
Downloaded from http://ps.oxfordjournals.org/ at Uniwersytet Warszawski Biblioteka Uniwersytecka on April 11, 2015
Experiment 3. This experiment was conducted to determine if scald additive concentration measured as pH would affect the skin at different temperatures. Only at 54° C. and pH 9.5 did pH have an influence on xanthophyll content. Under these conditions, the xanthophyll content was not reduced by the increased scald temperature when compared to pH 6.5, 54° C. and pH 8.0, 54° C. (Table 4). The carcasses which had less xanthophyll were also whiter (L
values); this was expected. The differences found in xanthophyll content were not reflected by differences in yellowness (+b values). No difference in yellowness was found attributable to temperature. An effect due to pH or additive concentration was noticed when carcasses scalded at 50 and 52° C. and pH 9.5 were found to be more yellow than those scalded at the same temperature and pH 6.5. The carcasses scalded at the higher temperatures for each pH had more feathers removed. No differences in skin moisture were found. The only effect on skin color due to pH found in these experiments could be attributed to the concentration at which the additive was most effective. The pH must be monitored constantly to maintain a specific concentration. The optimum pH range can be
1292
J. L. HEATH AND C. J. WABECK
determined using p H as a m e a s u r e of additive concentration.
REFERENCES
Vitamin E or Vitamin A Protects Chickens Against E. coli Infectionl ROBERT P . TENGERDY
Department
of
Microbiology
CHERYL F . NOCKELS
Department
of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523 (Received for publication December 10, 1974)
ABSTRACT The supplementation of either vitamin E (300 mg./kg. diet) or vitamin A (60,000 I.U./kg. diet) to a standard chick ration increased the protection of six week old immunized chickens against E coli infection, decreasing mortality from about 40% to 5%. The combination of the two vitamins, however, did not give as much protection as either vitamin alone. Vitamin E or A did not protect chicks from weight loss and severe morbidity due to infection, but slightly increased the rate of recovery. POULTRY SCIENCE 54: 1292-1296, 1975
I
N an earlier publication we have reported the protective effect of dietary supplementation of vitamin E against E. coli infection in young three week old chicks (Heinzerling et al., 1974). Although the protection was closely associated with an increased hemagglutination antibody titer, there was no proof that this antibody had a direct role in protection. The increased antibody production may only be an indication of a general increase in the immune responses of the chicken. A more direct proof for the role of increased immunity in protection is the resistance of immunized birds to reinfection, / 1. This research was supported by a grant from Hoffmann LaRoche, Inc.
such as the case of protection in vaccinated birds. Therefore, in the present study we first infected (immunized) three week old chicks with E. coli, then at six weeks of age reinfected the survivors with a massive dose of E. coli that would kill about 40% of immunized chicks, but 100% of normal chicks. We correlated antibody titers with survival in various dietary groups. The dietary variables included vitamin E and A, alone or in combination. It was reported recently that vitamin A acts as an adjuvant and a steroid antagonist in the immune response (Cohen and Cohen, 1973). We wanted to find out if vitamin A may also have a protective effect similar to vitamin E if supplemented to diets in pharmacological doses, alone or in combination with vitamin E.
Downloaded from http://ps.oxfordjournals.org/ at Uniwersytet Warszawski Biblioteka Uniwersytecka on April 11, 2015
Heath, J. L., and 0. P. Thomas, 1973. The xanthophyll content and color of broiler skin after scalding. Poultry Sci. 52:967-971. Heath, J. L., and O. P. Thomas, 1974. The effect
of feather removal during processing on the xanthophyll content of broiler skin. Poultry Sci. 53: 291295. Lucas, A. M., and P. R. Stettenheim, 1972. Avian Anatomy Integument, Part II, Agriculture Handbook 362, U.S. Government Printing Office, Washington, D.C. Steel, R. F. D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Company, Inc., New York.
R. C. BAKER AND J. M. DARFLER
juiciness and tenderness of bologna. Food Technol. 8: 339-344. Townsend, W. E., S. A. Ackerman, L. P. Witnauer, W. E. Palm and C. E. Swift, 1971. Effects of types and levels of fats and rates and temperatures of comminution on the processing and characteristics of frankfurters. J. Food Sci. 36: 261-265. Young, L. L., and G. B. Lyon, 1973. The use of heat treated meat in chicken frankfurters. Poultry Sci. 52: 1868-1875.
The Effect on Xanthophyll Content and Color of Broiler Skin When Scald Additive Concentration Was Measured bypH 1 ' 2 J. L . HEATH AND C. J. WABECK
Department of Poultry Science, University of Maryland, College Park, Maryland 20742 (Received for publication December 10, 1974)
ABSTRACT Three experiments were used to determine that scald water pH could be altered by changing the concentration of a commercial scald additive without affecting color of the skin. The pH of the scald water which indicated the optimum level of additive for feather removal also retained the most yellow color in the skin. The pH of the scald water must be monitored constantly to maintain an optimum concentration of additive. The temperature of the scald water did not alter the lack of influence scald water pH had on skin color. POULTRY SCIENCE 54: 1288-1292, 1975
INTRODUCTION
S
EVERAL companies market a product to the poultry processing industry which, when added to the scald water, will increase the efficiency of the feather removal operation. One characteristic a large number of these scald additives have in common is they increase the pH of the scald water. The methods used to maintain concentrations of these additives require the addition of a specified amount per bird scalded. This is done by metering or periodic addition. These methods allow a wide range of scald water
pH to develop in a given period. The use of pH to measure and maintain a given concentration of additive has been suggested. The effect of scald water pH on the carcass has not been determined. Previous work, Heath and Thomas (1973, 1974), indicated scalding and picking conditions will alter the xanthophyll content and yellow color of the skin. This research was designed to determine if skin color was affected by scald water pH when increased by changing the concentration of a commercial additive. MATERIALS AND METHODS
1. Scientific Article No. A1989 Contribution No. 4928 of the Maryland Agricultural Experiment Station (Department of Poultry Science). 2. The use of trade names in this publication does not imply endorsement of the product by the University of Maryland.
Eight-week old male broiler chickens were used in the experiments. The broilers were reared and processed according to the method of Heath and Thomas (1974). A portion of skin was removed from the left side of the
Downloaded from http://ps.oxfordjournals.org/ at Uniwersytet Warszawski Biblioteka Uniwersytecka on April 11, 2015
Vadehra and R. C. Baker, 1973. Physical and functional properties of mechanically deboned poultry meat as used in the manufacture of frankfurters. Poultry Sci. 52: 1363-1369. Simon, S., J. C. Field, W. E. Kramlich and F. W. Tauber, 1965. Factors affecting frankfurter texture and a method of measurement. Food Technol. 19: 410-413. Swift, C. E., E. Weir and O. G. Hankins, 1954. Effect of variations in moisture and fat content on the
XANTHOPHYLL CONTENT AND COLOR OF BROILER SKIN
Skin moisture was determined by drying to constant weight at 100° C. Feather removal was evaluated using a range of 1-5. The carcasses with approximately 1/2 of their feathers remaining were given a rating of 1, those picked clean (no pinfeathers) were given a 5. One experienced evaluator was used to rate all carcasses. The data was analyzed using the analysis of variance technique and the Student-Newman-Keuls test presented in Steel and Torrie (1960). Experiment 1. Study 1. Two-hundred and eighty broilers were assigned to 7 treatment groups and were processed in replicates of 5 birds. The treatment groups were: (1) H 2 0 as it came from the local supply (pH 6.9), (2) H 2 0 + a commercial scald additive to give a pH of 7.9, 8.9 and 9.9, and (3) H 2 0 + NaOH to give a pH of 7.9, 8.9 and 9.9. The carcasses were scalded at 52° C. for60 seconds. The commercial additive used in this and subsequent experiments was Scal-
dex. 3 The product has been accepted by U.S.D.A. for use in poultry processing. The pH was monitored and adjusted after each replication. Skin moisture, xanthophyll content and color were determined on breast skin samples from each carcass. Study 2. One-hundred and forty broilers were processed under the same conditions as Study 1. The pH was not maintained but was recorded after each replicate of 5 carcasses were scalded. Experiment 2. Ninety broilers were divided into 3 groups of 30 birds each and processed in replicates of 5 birds. The scalding and picking conditions were the same as the first experiment. The treatment groups were: (1) H 2 0 as it came from the local supply (pH 6.5), (2) pH adjusted with the commercial additive to 8.5, (3) pH adjusted with the commercial additive to 10.5. The carcasses were evaluated for feather removal, skin color and xanthophyll content. Experiment 3. One-hundred and eighty broilers were divided into 9 treatment groups and were processed in replicates of 5 birds. The carcasses were scalded for 60 seconds and picked for 60 seconds. The treatment consisted of: scalding at 50, 52 and 54° C , and at each temperature the pH was adjusted to 6.5 ( H 2 0 no additive), 8.0 and 9.5. The last two pH's were adjusted using the commercial additive. A difference of treatment pH of 1.5 units was used instead of the 2.0 unit difference in experiment 2 in an attempt to have all treatments closer to the optimum level of pH 8.5 determined in the previous experiment. The pH was monitored after each replication and adjusted when necessary. Skin moisture, xanthophyll content, color and feather removal scores were obtained from each carcass. 3. Oxford Chemicals, P.O. Box 80202, Atlanta, Georgia 30341.
Downloaded from http://ps.oxfordjournals.org/ at Uniwersytet Warszawski Biblioteka Uniwersytecka on April 11, 2015
carcass and included the area between the sternal and pectoral feather tracts. The area removed started at the anterior end of the sternal tract and continued to the posterior end of the pectoral tract. Terminology used in this description can be found in Lucas and Stettenheim (1972). The samples were placed in plastic bags and stored in the dark at -10° C. until analysis could be accomplished. Skin color evaluation and xanthophyll extraction and determination was accomplished according to the method of Heath and Thomas (1973). Color was expressed in the 3 dimensions of b, L, and a. The b dimension measured yellowness when positive (+). The L dimension measured lightness and varied from black (0) to perfect white (100). The a dimension measured redness when positive (+), gray when (0) and greenness when negative ( - ) . A white tile was used as a uniform background for each sample.
1289
1290
• J. L. HEATH AND C. J. WABECK
RESULTS AND DISCUSSION
TABLE 1.-
Experiment 2. The purpose of this experiment was to determine if scald water pH was accurate enough to find the optimum concentration of the additive and study the effect of additive concentration on skin color and feather removal. The carcasses scalded in water adjusted with the commercial additive to pH 8.5 and 10.5 had more xanthophyll, yellow color (+b values) and were more green (—a values) than those scalded in water with no additive (Table 3). The carcasses scalded at pH 8.5 were
-The effect of using scald water pH as a measure of scald additive concentration on broiler skin color Breast skin Moisture
H 2 0 (no additive) H 2 0 + NaOH
H 2 0 + additive
pH 6.9 7.9 8.9 9.9 7.9 8.9 9.9
% 58.4 59.0 60.5 60.3 59.8 59.4 60.8
Xanthophyll mcg./gm. 10.9a 12.6a 10.8a 11.7a 11.2a 10.7a 14.6b
Color a -0.3 -0.9 -0.1 -0.9 -0.0 +2.0 + 1.1
L 74.3 75.0 74.5 76.0 74.1 74.0 73.0
b +23.6a +24.5a +24.7a +24.0a +25.2a +24.9a +26.5b
Values in columns followed by different letters are significanitly (P < 0.01) different.
TABLE 2.-—Change
H20 H 2 0 + NaOH
H 2 0 + additive
in scald water pH
0
5
6.9 7.9 8.9 9.9 7.9 8.9 9.9
7.1 7.8 8.2 9.8 7.6 8.2 9.6
Number of carcasses scalded 10 15 7.1 7.5 7.5 9.6 7.4 7.7 9.2
6.7 7.2 7.3 9.1 7.3 7.5 8.8
20 6.7 7.2 7.2 9.1 7.3 7.3 8.4
Downloaded from http://ps.oxfordjournals.org/ at Uniwersytet Warszawski Biblioteka Uniwersytecka on April 11, 2015
Experiment 1. The purpose of this experiment was to determine the effect on broiler skin color of pH produced by varying the concentration of either a commercial scald additive or NaOH. Study 1. Adjusting the pH to 7.9, 8.9 and 9.9 using NaOH produced no changes in xanthophyll content, color or percent moisture of the skin (Table 1). When the commercial additive was used, the only differences produced were at pH 9.9 where both xanthophyll content and yellowness (+b values) were retained to a greater degree. Study 2. In Table 2, the pH of the scald water was not maintained. When either NaOH or a commercial additive were used, a decrease in pH occurred as the number of carcasses scalded increased. When water with no additive was used, the pH increased after 5 and 10 carcasses were scalded and
decreased after 15 and 20. The decrease in pH was attributed to material brought into the scald water by the carcasses such as blood, feces, dirt, drop contents, etc. The additive was in solution and neither additive nor water were added. Therefore, the amount of solution removed on the carcasses should not affect the concentration of the solution.
1291
XANTHOPHYLL CONTENT AND COLOR OF BROILER SKIN
more yellow and had more feathers removed than those scalded at pH 10.5. There were no differences in skin xanthophyll of carcasses scalded in water adjusted with the additive. This data indicated that an additive concentration which was most effective could be determined using pH as the indicator.
TABLE 3.—The effect on xanthophyll content, color and feather removal of scald additive concentration measured by pH of the scald water
H 2 0 only Adjusted Adjusted
Initial pH
Xanthophyll mcg./gm.
L
a
b
Feather removal score
6.5 8.5 10.5
11.2a 12.6b 12.8b
70.4 71.7 70.9
-0.3x -l.ly -1.2y
+26.3x +28.5y +27.5z
3.6 4.4 3.3
Color
A range of 1-5 was used. 1—All feathers on carcass; 5—All feathers and pinfeathers removed. Values in columns followed by different letters are significantly different, (a b = P s 0.01, xyz = P < 0.05). TABLE 4.—The effect of scald water temperature on broiler skin when scald additive concentration was measured by pH Temp. °C. 50 52 54
Moisture PH 6.5 6.5 6.5
50 52 54 50 52 54
Color
Feather removal score
%
Xanthophyll mcg./gm.
L
a
62.8 61.7 60.1
13.3c 11.4bc 6.0a
77.9ab 78.2ab 80.0b
-1.7 -2.3 -2.1
+24.8a +24.8a +24.8a
3.6 4.0 4.6
8.0 8.0 8.0
57.9 60.5 63.9
11.3bc 9.7b 7.1a
77.4ab 78.8ab 80.3b
-2.0 -2.1 -2.3
+25.8ab +26. lab +24.8a
3.6 4.2 4.4
9.5 9.5 9.5
62.7 60.9 61.8
13.4c ll.Obc 10.2bc
78.7ab 78.6ab 76.8a
-1.8 -1.5 -0.9
+27.6b +27.5b +26.2ab
2.9 3.7 4.4
b
Values in columns followed by different letters were significantly (P s 0.01) different.
Downloaded from http://ps.oxfordjournals.org/ at Uniwersytet Warszawski Biblioteka Uniwersytecka on April 11, 2015
Experiment 3. This experiment was conducted to determine if scald additive concentration measured as pH would affect the skin at different temperatures. Only at 54° C. and pH 9.5 did pH have an influence on xanthophyll content. Under these conditions, the xanthophyll content was not reduced by the increased scald temperature when compared to pH 6.5, 54° C. and pH 8.0, 54° C. (Table 4). The carcasses which had less xanthophyll were also whiter (L
values); this was expected. The differences found in xanthophyll content were not reflected by differences in yellowness (+b values). No difference in yellowness was found attributable to temperature. An effect due to pH or additive concentration was noticed when carcasses scalded at 50 and 52° C. and pH 9.5 were found to be more yellow than those scalded at the same temperature and pH 6.5. The carcasses scalded at the higher temperatures for each pH had more feathers removed. No differences in skin moisture were found. The only effect on skin color due to pH found in these experiments could be attributed to the concentration at which the additive was most effective. The pH must be monitored constantly to maintain a specific concentration. The optimum pH range can be
1292
J. L. HEATH AND C. J. WABECK
determined using p H as a m e a s u r e of additive concentration.
REFERENCES
Vitamin E or Vitamin A Protects Chickens Against E. coli Infectionl ROBERT P . TENGERDY
Department
of
Microbiology
CHERYL F . NOCKELS
Department
of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523 (Received for publication December 10, 1974)
ABSTRACT The supplementation of either vitamin E (300 mg./kg. diet) or vitamin A (60,000 I.U./kg. diet) to a standard chick ration increased the protection of six week old immunized chickens against E coli infection, decreasing mortality from about 40% to 5%. The combination of the two vitamins, however, did not give as much protection as either vitamin alone. Vitamin E or A did not protect chicks from weight loss and severe morbidity due to infection, but slightly increased the rate of recovery. POULTRY SCIENCE 54: 1292-1296, 1975
I
N an earlier publication we have reported the protective effect of dietary supplementation of vitamin E against E. coli infection in young three week old chicks (Heinzerling et al., 1974). Although the protection was closely associated with an increased hemagglutination antibody titer, there was no proof that this antibody had a direct role in protection. The increased antibody production may only be an indication of a general increase in the immune responses of the chicken. A more direct proof for the role of increased immunity in protection is the resistance of immunized birds to reinfection, / 1. This research was supported by a grant from Hoffmann LaRoche, Inc.
such as the case of protection in vaccinated birds. Therefore, in the present study we first infected (immunized) three week old chicks with E. coli, then at six weeks of age reinfected the survivors with a massive dose of E. coli that would kill about 40% of immunized chicks, but 100% of normal chicks. We correlated antibody titers with survival in various dietary groups. The dietary variables included vitamin E and A, alone or in combination. It was reported recently that vitamin A acts as an adjuvant and a steroid antagonist in the immune response (Cohen and Cohen, 1973). We wanted to find out if vitamin A may also have a protective effect similar to vitamin E if supplemented to diets in pharmacological doses, alone or in combination with vitamin E.
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Heath, J. L., and 0. P. Thomas, 1973. The xanthophyll content and color of broiler skin after scalding. Poultry Sci. 52:967-971. Heath, J. L., and O. P. Thomas, 1974. The effect
of feather removal during processing on the xanthophyll content of broiler skin. Poultry Sci. 53: 291295. Lucas, A. M., and P. R. Stettenheim, 1972. Avian Anatomy Integument, Part II, Agriculture Handbook 362, U.S. Government Printing Office, Washington, D.C. Steel, R. F. D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Company, Inc., New York.