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No Flavor Changes in Chicken Broilers Fed Monensin1
No Flavor Changes in Chicken Broilers Fed Monensinl MARCIA M O H L E R , SHARON KLINGER, G A L E SHEMWELL, D . E . PRATT AND W . J. STADELMAN
Food Science Institute, Purdue University, West Lafayette, Indiana 47907 (Received for publication March 4, 1975)
POULTRY SCIENCE 54: 1697-1700, 1975
INTRODUCTION
T
HE efficiency of monensin as an anticoccidial compound has been well documented. Shumard et al. (1970) found weight gain and feed efficiency of treated infected birds to be comparable to those of non-infected control birds. Monensin-medicated birds did at least as well and in some cases better than broilers treated with other coccidiostats tested by Reid et al. (1972) with respect to live weight, feed conversion, mortality rates, and lesion scores. Hurst et al. (1974) found that monensin and roxarsone did not affect the utilization of sodium and that the growth rate and feed efficiency were essentially the same for monensin and roxarsone control birds on the same sodium chloride level.
In a study of chicken flavor, Lineweaver and Pippen (1961), attributed the most important flavor component to muscle meat rather than fat, skin or bones. Kazeniac (1961) found flavor to be a complex blend of different compounds. Flavor and aroma of chicken broth were affected by both pH and application of different amounts of heat. The objective of this study was to determine if Coban R 45 premix would result in
1. Journal Paper No. 5811, Purdue Agricultural Experiment Station, West Lafayette, Indiana 47907.
a detectable change in flavor of broilers when fed so the monensin activity was 110 grams per ton. PROCEDURE Broiler chickens were grown under commercial conditions in two lots. One group of broilers was maintained as non-medicated controls, and the other group was fed monensin, 110 grams per ton, as supplied by a Coban R premix. The birds fed monensin for 61 days were subjected to a 72-hour withdrawal period prior to slaughter. Then at 64 days of age all broilers were processed using commercial methods, identified as to medication program, packaged, frozen, and delivered to the foods laboratories. A taste panel of ten persons was selected after six training sessions from an original group of 16 persons. On any single day eight of the selected panelists were utilized to evaluate the flavor of the chicken. The tasting procedure followed was a duo-trio test (A.S.T.M., 1968; and Peryam and Schwartz, 1950). In this test, each panelist was given a 5 to 10 gram sample of the test meat. The panelist was also given two additional samples. One of these was the same as the first, and the other was from the alternate source material, and the panelist was asked to identify the sample that was the same as the first sample presented. With the duo-trio test ran-
1697
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 6, 2015
ABSTRACT A study was conducted to compare flavor of control broilers with others that had been fed an anticoccidial agent, monensin, at 110 grams per ton for 61 days with a 72-hour withdrawal prior to slaughter. A total of 42 birds from each treatment group were compared using a duo-trio test with white meat, dark meat and liver. Extra livers from each treatment group were used. Comparisons were made with the products served hot immediately after cooking in a pressure deep fat fryer, and with the fried products chilled and reheated. No change in flavor was detected as a result of including the anticoccidial agent in the diet of broilers.
1698
MOHLER, KLINGER, SHEMWELL, PRATT AND STADELMAN
ture of 163° C. was used. Livers were heated for 4 minutes and other parts for 9-1/2 minutes. In order to generate steam when cooking livers, several ribs and backs were placed in the cooker for the short cook. The heated oil was changed in the cooker at frequent intervals so that no detectable offflavor was imparted to the chicken from the cooking oil. Three chickens and four livers from each of the two groups were prepared for each tasting session. For the first seven sessions, the cooking was accomplished just prior to serving to the panel. For the next seven tasting sessions, the chicken was cooked about 4 hours prior to tasting. It was chilled and reheated to about 60° C. just prior to serving to the panel. Chi square analysis was used to test significance of differences observed.
TABLE 1.—Summary of duo-trio test on flavor of chicken parts White No. Served fresh cooked Served reheated
56 56
Sum
112
Correct
Liver
Dark Correct
No.
29 56 56 28 57 112 Total N == 336 Correct == 174
No.
Correct
28 20
56 56
34 35
48
112
69*
*(P < .05). TABLE 2.—Summary of duo-trio test on flavor of chicken parts by panelists White
Dark
Liver
Sum
Panelist
H1
R2
H
R
H
R
H
R
Total
1 2 3 4 5 6 7 8 9 10
3/73 3/6 4/6 2/7 3/6 1/3 3/6 3/4 4/6 3/5
4/7 1/6 5/7 4/7 4/7 4/7 3/7 3/6 0/1 0/1
6/7 3/6 3/6 3/7 3/6 1/3 2/6 1/4 4/6 2/5
1/7 2/6 2/7 3/7 2/7 2/7 3/7 4/6 0/1 1/1
4/7 2/6 3/6 5/7 3/6 3/3 5/6 4/4 3/6 2/5
4/7 3/6 7/7 4/7 4/7 4/7 4/7 4/6 1/1 0/1
13/21 8/18 10/18 10/21 9/18 5/9 10/18 8/12 11/18 7/15
9/21 6/18 14/21 11/21 10/21 10/21 10/21 11/18 1/3 1/3
22/42 14/36 24/39 21/42 19/39 15/30 20/39 19/30 12/21 8/18
29/56
28/56
28/56
20/56
34/56
35/56
91/168
83/168
174/336
Total
'H = Served hot, freshly cooked. 2 R = Served hot after cooling and reheating. 3 Number of correct identifications/Number of samples tasted.
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 6, 2015
dom selection will give fifty percent correct responses. At each sitting, each panelist evaluated a sample of white meat, dark meat and of liver served on separate trays. In preparing the chickens for the taste test, they were removed from frozen storage, placed in a 2° C. refrigerated room with forced air movement and held for 48 hours. About an hour prior to cooking the thawed birds were cut up into 2 wings, 2 thighs, 2 drumsticks, 2 halves (longitudinal) of breast, a neck, a rib cage, and a back. Livers had been separately packaged in polyethylene bags. All parts were dusted with general purpose flour and held for a few minutes prior to cooking. Cooking was accomplished in a PHT pressure deep fat fryer. This unit develops 9 psig pressure from steam resulting from water lost from the meat in the deep fat. A fat tempera-
1699
MONENSIN AND BROILER FLAVOR
TABLE 3.—Summary of correct identifications of duo-trio test on flavor of chicken parts by dates Served Fresh Cooked White
1/28 1/30 2/1 2/4 2/6 2/8 2/11
4/81 2/8 6/8 3/8 7/8 2/8 5/8
29/56 Sum Served Reheated 2/13 2/15 2/18 2/20 2/22 2/25 2/27 Sum Total
Dark 3/8 5/8 7/8 3/8 3/8 4/8 3/8
Liver
Total
6/8 7/8 7/8 1/8 5/8 3/8 5/8
13/24 14/24 20/24* 7/24 15/24 9/24 13/24
28/56
34/56
91/168
5/8 3/8 3/8 3/8 2/8 2/8 2/8
6/8 4/8 5/8 7/8 4/8 5/8 4/8
14/24 10/24 14/24 14/24 11/24 11/24 9/24
3/8 3/8 6/8 4/8 5/8 4/8 3/8 28/56 57/112
20/56 48/112
35/56 69/112
83/168 174/336
*(P < 0.05). 'Number of correct identifications/number of samples tasted. TABLE 4.—Preference of correct responses for either treatment group Reheated 2
Hot'
Monensin Control Monensin Control White Dark Liver Total
14/28 3 12/20 16/35
14/28 8/20 19/35
16/29 16/28 15/34
13/29 12/28 19/34
42/83
41/83
47/91
44/91
•Served hot, freshly cooked. 2 Served hot after cooling and reheating. 3 Number of correct identifications/number of samples tasted. RESULTS The summary of the 112 tastings each of white meat, dark meat and liver are summarized in Table 1. No Significant differences in flavor were detected for either white or dark meat whether served freshly cooked or reheated. By chi square analysis, the combined value for liver indicated that panelists could differentiate between the two groups.
ACKNOWLEDGMENT This work was supported in part by a grant from Eli Lilly Company, Indianapolis, Indiana. REFERENCES A.S.T.M., 1968. Manual on Sensory Testing Methods. Publication STP 434. Hurst, R. E., E. J. Day and B. C. Dilworth, 1974. The effects of monensin and sodium chloride on broiler performance. Poultry Sci. 53: 434-436. Kazeniac, S. J., 1961. Chicken flavor. Proceedings
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 6, 2015
Date
As cooking of livers was so rapid, any size variation would result in a difference in degree of cooking which could influence flavor differences. The results as reported by individual panelists are listed in Table 2. The data show rather well that as a group the ten members of the panel could not detect differences between the treatments whether it was freshly cooked or reheated. However, panelist 3 differentiated all of the reheated livers correctly, and panelists 6 and 8 identified the correct sample in the fresh cooked livers in all samples tasted. While these individual sets of observations are statistically significant, the numbers are too small to be of practical significance especially when these panelists' observations in total are observed. Table 3 lists the numbers of correct identifications of unknown samples by days. One of the fourteen days was significant at the five percent level of probability. This is undoubtedly a random occurrence, as on the following tasting session the number of correct identifications was the least for all days. To aid in understanding whether or not flavor differences were of real meaning, the panelists were asked to indicate their preference. Only those preferences that were associated with a correct identification were counted. The results are summarized in Table 4. No significant differences in preference were found.
1700
MOHLER, KLINGER, SHEMWELL, PRATT AND STADELMAN
Flavor Chemistry Symposium, Campbell Soup Company, Camden, NJ. pp. 37-55. Lineweaver, H., and E. L. Pippen, 1961. Chicken flavor. Proceedings Flavor Chemistry Symposium, Campbell Soup Company, Camden, NJ. pp 21-36. Peryam, D. R., and V. W. Schwartz, 1950. Measurement of sensory differences. Food Technol. 4: 390-395.
Reid, W. M., L. Kowalski and J. Rice, 1972. Anticoccidial activity of monensin in floor-pen experiments. Poultry Sci. 51: 139-146. Shumard, R. F., M. E. Callender and W. M. Reid, 1970. Monensin, a new anticoccidial agent. Proc. XlVth World Poultry Congress, Madrid, Spain, pp. 613-615.
D. L. ZARTMAN
Dairy Department, New Mexico State University, Las Cruces, New Mexico 88003 (Received for publication March 7, 1975)
ABSTRACT Dark Cornish and White Leghorn hens were divided into a virgin group and a group inseminated with semen that had been irradiated with 5,000 r. of X rays. Two replicate trials were performed, one during winter and the second during summer. Two parthenogenetic embryos were found among 1,417 virgin eggs incubated for 24 hours. No other development was seen in eggs from this group. The three chicks produced by the inseminated group were not gynogenetic. Their heterozygous coloration showed them to be normal fertilization products. Fertility of 1,500 eggs was only about 5% and survival was almost nil for eggs from hens artificially inseminated with semen irradiated at 5,000 r. Most embryonic development consisted of membranous growth with occasional blood cells. The frequency of detectable embryonic development in abortive eggs was half as great after seven days incubation compared to the frequency after only 24 hours incubation. POULTRY SCIENCE 54: 1700-1703, 1975
INTRODUCTION
I
N view of increased costs of production and impending food shortages in the world market, a full-fledged attempt at increasing efficiency and total animal production is timely. A means of doing this is through production of single-sex populations and more accurate control of genotypes of breeding animals. Artificial gynogenesis would be a means of accomplishing these objectives if it could be regularly and consistently produced. This was the objective of this experiment. Encouragement came from the successes of Stalker (1956), Carson (1967), Olsen and Buss (1967) and Olsen et al. (1968) in increas-
ing substantially the incidence of natural parthenogenesis in Drosophila species, turkeys and chickens through selection. The idea of inducing gynogenesis comes from the works of Amoroso and Parkes (1947), Briggs et al. (1951) and Edwards (1954), who treated spermatozoa of rabbits, frogs and mice with high dosages of X rays. Varying degrees of induced parthenogenesis resulted but viability was poor in rabbits and mice. Chickens were chosen as a model animal for this experiment because of the simplicity of semen acquisition and deposition and, moreover, the complete collectibility of eggs and easily observable progressions of embryonic development. MATERIALS AND METHODS
1. Journal article 551, Agricultural Experiment Station, New Mexico State University, Las Cruces, New Mexico 88003.
Chickens. Single Comb White Leghorn (hereafter called S.C.W.L.) and Dark Cornish
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 6, 2015
Attempted Induction of Gynogenesis in Chickensl
Food Science Institute, Purdue University, West Lafayette, Indiana 47907 (Received for publication March 4, 1975)
POULTRY SCIENCE 54: 1697-1700, 1975
INTRODUCTION
T
HE efficiency of monensin as an anticoccidial compound has been well documented. Shumard et al. (1970) found weight gain and feed efficiency of treated infected birds to be comparable to those of non-infected control birds. Monensin-medicated birds did at least as well and in some cases better than broilers treated with other coccidiostats tested by Reid et al. (1972) with respect to live weight, feed conversion, mortality rates, and lesion scores. Hurst et al. (1974) found that monensin and roxarsone did not affect the utilization of sodium and that the growth rate and feed efficiency were essentially the same for monensin and roxarsone control birds on the same sodium chloride level.
In a study of chicken flavor, Lineweaver and Pippen (1961), attributed the most important flavor component to muscle meat rather than fat, skin or bones. Kazeniac (1961) found flavor to be a complex blend of different compounds. Flavor and aroma of chicken broth were affected by both pH and application of different amounts of heat. The objective of this study was to determine if Coban R 45 premix would result in
1. Journal Paper No. 5811, Purdue Agricultural Experiment Station, West Lafayette, Indiana 47907.
a detectable change in flavor of broilers when fed so the monensin activity was 110 grams per ton. PROCEDURE Broiler chickens were grown under commercial conditions in two lots. One group of broilers was maintained as non-medicated controls, and the other group was fed monensin, 110 grams per ton, as supplied by a Coban R premix. The birds fed monensin for 61 days were subjected to a 72-hour withdrawal period prior to slaughter. Then at 64 days of age all broilers were processed using commercial methods, identified as to medication program, packaged, frozen, and delivered to the foods laboratories. A taste panel of ten persons was selected after six training sessions from an original group of 16 persons. On any single day eight of the selected panelists were utilized to evaluate the flavor of the chicken. The tasting procedure followed was a duo-trio test (A.S.T.M., 1968; and Peryam and Schwartz, 1950). In this test, each panelist was given a 5 to 10 gram sample of the test meat. The panelist was also given two additional samples. One of these was the same as the first, and the other was from the alternate source material, and the panelist was asked to identify the sample that was the same as the first sample presented. With the duo-trio test ran-
1697
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 6, 2015
ABSTRACT A study was conducted to compare flavor of control broilers with others that had been fed an anticoccidial agent, monensin, at 110 grams per ton for 61 days with a 72-hour withdrawal prior to slaughter. A total of 42 birds from each treatment group were compared using a duo-trio test with white meat, dark meat and liver. Extra livers from each treatment group were used. Comparisons were made with the products served hot immediately after cooking in a pressure deep fat fryer, and with the fried products chilled and reheated. No change in flavor was detected as a result of including the anticoccidial agent in the diet of broilers.
1698
MOHLER, KLINGER, SHEMWELL, PRATT AND STADELMAN
ture of 163° C. was used. Livers were heated for 4 minutes and other parts for 9-1/2 minutes. In order to generate steam when cooking livers, several ribs and backs were placed in the cooker for the short cook. The heated oil was changed in the cooker at frequent intervals so that no detectable offflavor was imparted to the chicken from the cooking oil. Three chickens and four livers from each of the two groups were prepared for each tasting session. For the first seven sessions, the cooking was accomplished just prior to serving to the panel. For the next seven tasting sessions, the chicken was cooked about 4 hours prior to tasting. It was chilled and reheated to about 60° C. just prior to serving to the panel. Chi square analysis was used to test significance of differences observed.
TABLE 1.—Summary of duo-trio test on flavor of chicken parts White No. Served fresh cooked Served reheated
56 56
Sum
112
Correct
Liver
Dark Correct
No.
29 56 56 28 57 112 Total N == 336 Correct == 174
No.
Correct
28 20
56 56
34 35
48
112
69*
*(P < .05). TABLE 2.—Summary of duo-trio test on flavor of chicken parts by panelists White
Dark
Liver
Sum
Panelist
H1
R2
H
R
H
R
H
R
Total
1 2 3 4 5 6 7 8 9 10
3/73 3/6 4/6 2/7 3/6 1/3 3/6 3/4 4/6 3/5
4/7 1/6 5/7 4/7 4/7 4/7 3/7 3/6 0/1 0/1
6/7 3/6 3/6 3/7 3/6 1/3 2/6 1/4 4/6 2/5
1/7 2/6 2/7 3/7 2/7 2/7 3/7 4/6 0/1 1/1
4/7 2/6 3/6 5/7 3/6 3/3 5/6 4/4 3/6 2/5
4/7 3/6 7/7 4/7 4/7 4/7 4/7 4/6 1/1 0/1
13/21 8/18 10/18 10/21 9/18 5/9 10/18 8/12 11/18 7/15
9/21 6/18 14/21 11/21 10/21 10/21 10/21 11/18 1/3 1/3
22/42 14/36 24/39 21/42 19/39 15/30 20/39 19/30 12/21 8/18
29/56
28/56
28/56
20/56
34/56
35/56
91/168
83/168
174/336
Total
'H = Served hot, freshly cooked. 2 R = Served hot after cooling and reheating. 3 Number of correct identifications/Number of samples tasted.
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 6, 2015
dom selection will give fifty percent correct responses. At each sitting, each panelist evaluated a sample of white meat, dark meat and of liver served on separate trays. In preparing the chickens for the taste test, they were removed from frozen storage, placed in a 2° C. refrigerated room with forced air movement and held for 48 hours. About an hour prior to cooking the thawed birds were cut up into 2 wings, 2 thighs, 2 drumsticks, 2 halves (longitudinal) of breast, a neck, a rib cage, and a back. Livers had been separately packaged in polyethylene bags. All parts were dusted with general purpose flour and held for a few minutes prior to cooking. Cooking was accomplished in a PHT pressure deep fat fryer. This unit develops 9 psig pressure from steam resulting from water lost from the meat in the deep fat. A fat tempera-
1699
MONENSIN AND BROILER FLAVOR
TABLE 3.—Summary of correct identifications of duo-trio test on flavor of chicken parts by dates Served Fresh Cooked White
1/28 1/30 2/1 2/4 2/6 2/8 2/11
4/81 2/8 6/8 3/8 7/8 2/8 5/8
29/56 Sum Served Reheated 2/13 2/15 2/18 2/20 2/22 2/25 2/27 Sum Total
Dark 3/8 5/8 7/8 3/8 3/8 4/8 3/8
Liver
Total
6/8 7/8 7/8 1/8 5/8 3/8 5/8
13/24 14/24 20/24* 7/24 15/24 9/24 13/24
28/56
34/56
91/168
5/8 3/8 3/8 3/8 2/8 2/8 2/8
6/8 4/8 5/8 7/8 4/8 5/8 4/8
14/24 10/24 14/24 14/24 11/24 11/24 9/24
3/8 3/8 6/8 4/8 5/8 4/8 3/8 28/56 57/112
20/56 48/112
35/56 69/112
83/168 174/336
*(P < 0.05). 'Number of correct identifications/number of samples tasted. TABLE 4.—Preference of correct responses for either treatment group Reheated 2
Hot'
Monensin Control Monensin Control White Dark Liver Total
14/28 3 12/20 16/35
14/28 8/20 19/35
16/29 16/28 15/34
13/29 12/28 19/34
42/83
41/83
47/91
44/91
•Served hot, freshly cooked. 2 Served hot after cooling and reheating. 3 Number of correct identifications/number of samples tasted. RESULTS The summary of the 112 tastings each of white meat, dark meat and liver are summarized in Table 1. No Significant differences in flavor were detected for either white or dark meat whether served freshly cooked or reheated. By chi square analysis, the combined value for liver indicated that panelists could differentiate between the two groups.
ACKNOWLEDGMENT This work was supported in part by a grant from Eli Lilly Company, Indianapolis, Indiana. REFERENCES A.S.T.M., 1968. Manual on Sensory Testing Methods. Publication STP 434. Hurst, R. E., E. J. Day and B. C. Dilworth, 1974. The effects of monensin and sodium chloride on broiler performance. Poultry Sci. 53: 434-436. Kazeniac, S. J., 1961. Chicken flavor. Proceedings
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 6, 2015
Date
As cooking of livers was so rapid, any size variation would result in a difference in degree of cooking which could influence flavor differences. The results as reported by individual panelists are listed in Table 2. The data show rather well that as a group the ten members of the panel could not detect differences between the treatments whether it was freshly cooked or reheated. However, panelist 3 differentiated all of the reheated livers correctly, and panelists 6 and 8 identified the correct sample in the fresh cooked livers in all samples tasted. While these individual sets of observations are statistically significant, the numbers are too small to be of practical significance especially when these panelists' observations in total are observed. Table 3 lists the numbers of correct identifications of unknown samples by days. One of the fourteen days was significant at the five percent level of probability. This is undoubtedly a random occurrence, as on the following tasting session the number of correct identifications was the least for all days. To aid in understanding whether or not flavor differences were of real meaning, the panelists were asked to indicate their preference. Only those preferences that were associated with a correct identification were counted. The results are summarized in Table 4. No significant differences in preference were found.
1700
MOHLER, KLINGER, SHEMWELL, PRATT AND STADELMAN
Flavor Chemistry Symposium, Campbell Soup Company, Camden, NJ. pp. 37-55. Lineweaver, H., and E. L. Pippen, 1961. Chicken flavor. Proceedings Flavor Chemistry Symposium, Campbell Soup Company, Camden, NJ. pp 21-36. Peryam, D. R., and V. W. Schwartz, 1950. Measurement of sensory differences. Food Technol. 4: 390-395.
Reid, W. M., L. Kowalski and J. Rice, 1972. Anticoccidial activity of monensin in floor-pen experiments. Poultry Sci. 51: 139-146. Shumard, R. F., M. E. Callender and W. M. Reid, 1970. Monensin, a new anticoccidial agent. Proc. XlVth World Poultry Congress, Madrid, Spain, pp. 613-615.
D. L. ZARTMAN
Dairy Department, New Mexico State University, Las Cruces, New Mexico 88003 (Received for publication March 7, 1975)
ABSTRACT Dark Cornish and White Leghorn hens were divided into a virgin group and a group inseminated with semen that had been irradiated with 5,000 r. of X rays. Two replicate trials were performed, one during winter and the second during summer. Two parthenogenetic embryos were found among 1,417 virgin eggs incubated for 24 hours. No other development was seen in eggs from this group. The three chicks produced by the inseminated group were not gynogenetic. Their heterozygous coloration showed them to be normal fertilization products. Fertility of 1,500 eggs was only about 5% and survival was almost nil for eggs from hens artificially inseminated with semen irradiated at 5,000 r. Most embryonic development consisted of membranous growth with occasional blood cells. The frequency of detectable embryonic development in abortive eggs was half as great after seven days incubation compared to the frequency after only 24 hours incubation. POULTRY SCIENCE 54: 1700-1703, 1975
INTRODUCTION
I
N view of increased costs of production and impending food shortages in the world market, a full-fledged attempt at increasing efficiency and total animal production is timely. A means of doing this is through production of single-sex populations and more accurate control of genotypes of breeding animals. Artificial gynogenesis would be a means of accomplishing these objectives if it could be regularly and consistently produced. This was the objective of this experiment. Encouragement came from the successes of Stalker (1956), Carson (1967), Olsen and Buss (1967) and Olsen et al. (1968) in increas-
ing substantially the incidence of natural parthenogenesis in Drosophila species, turkeys and chickens through selection. The idea of inducing gynogenesis comes from the works of Amoroso and Parkes (1947), Briggs et al. (1951) and Edwards (1954), who treated spermatozoa of rabbits, frogs and mice with high dosages of X rays. Varying degrees of induced parthenogenesis resulted but viability was poor in rabbits and mice. Chickens were chosen as a model animal for this experiment because of the simplicity of semen acquisition and deposition and, moreover, the complete collectibility of eggs and easily observable progressions of embryonic development. MATERIALS AND METHODS
1. Journal article 551, Agricultural Experiment Station, New Mexico State University, Las Cruces, New Mexico 88003.
Chickens. Single Comb White Leghorn (hereafter called S.C.W.L.) and Dark Cornish
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 6, 2015
Attempted Induction of Gynogenesis in Chickensl