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Strain Difference and Initial Quality Relationships to Rate of Interior Egg Quality Decline*
Strain Difference and Initial Quality Relationships to Rate of Interior Egg Quality Decline* JACK L. FRY, J. S. MOORE AND A. W.
O'STEEN
University of Florida, Gainesville, Fla. (Received for publication September 14, 1964)
J
* Florida Agri. Exp. Sta., Journal Series No. 1923.
their analysis has since been questioned. Mueller (1959) reported a highly significant positive correlation coefficient of 0.722 for initial Haugh unit score and seven day Haugh unit loss; these eggs were not, however, held under normal storage conditions. Kidwell et al. (1964) using strains in the Iowa Multiple Unit Random Sample Egg Laying Tests concluded that Haugh unit loss was not genetically determined. This study consists of an evaluation of egg quality data from different commercial strains to give further information on the relationship of initial interior quality and strain differences to interior quality loss. MATERIALS AND METHODS
The eggs for this study were collected quarterly during the laying year from the 24 entries in the 1960-61 Florida Random Sample Egg Laying Test. Pullets were housed at 160 days of age on September 1, 1960; eggs were sampled two months after housing and at 3-month intervals. Initial quality determinations were made on the day following collection. Eggs laid the two succeeding days were stored at approximately 56°F. and 65% relative humidity, and one third were broken out after 7, 14, and 21 days of storage. All observations were made by the method of Kilpatrick et aZ.(1960). Pen means were used in calculating all correlation coefficients reported. Individual egg observations or individual percentages of initial quality were used in the analyses of variance of pen and storage or time differences. Strains are not identified as
649
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on June 26, 2015
OHNSON and Merritt (1955) suggested that, to be economically sound, selection for improved egg quality should have no adverse effects on the egg producing ability of the strain. The reverse is likewise true; yet these two criteria have received major emphasis in both the breeding and advertising of commerical strains of hens. It has been well confirmed that negative genetic correlations exist between albumen quality and egg production (Goodman and Godfrey, 1955; Johnson and Merritt, 1955; and King et al., 1961). This appears to be verified in the industry as it is accepted that there are strain differences in rate of production and in egg quality. A strain that is lower than average in one criterion tends to be higher than average in the other. A recent important area of research is that of the relationship of initial interior quality to the rate of quality decline during storage. Also important is the relationship of interior quality at the beginning of a laying "year," to the rate of decline as the hen ages. Fry (1956) reported a small positive correlation between initial quality and the decline in seven days at three different temperatures. May et al. (1957) found that eggs of high albumen quality declined at a more rapid rate than eggs of lower quality as indicated by a correlation coefficient of 0.358 between original quality and seven day loss of quality. These workers also noted strain differences in the rate of quality decline but the validity of
650
J. L. FRY, J. S. MOORE AND A. W.
O'STEEN
TABLE 1.—Pen mean Ilaugh unit scores and 2nd, 3rd and 4th Quarter percentages of 1st Quarter quality
Pen
1st Quarter
2nd Quarter
3rd Quarter
4th Quarter
H.U. Scores
H.U. Scores % of 1st Qtr.
H.U. Scores % of 1st Qtr.
H.U. Scores % of 1st Qtr.
90.1 93.1 90.9 90.4 79.9 88.1 88.0 88.3 82.2 86.8 87.4 88.7 86.4 82.4 87.8 82.4 86.8 87.7 86.4 88.6 84.2 87.3 88.0 87.3
84.5 87.7 86.5 83.4 77.5 83.1 82.3 82.0 74.9 81.4 81.3 81.2 81.4 77.3 83.7 78.3 83.4 83.7 80.1 84.0 80.2 82.0 84.9 78.6
93.9 94.2 95.2 92.3 97.1 94.3 93.4 92.8 91.1 93.8 93.2 91.6 94.2 93.9 95.1 95.0 96.0 95.4 92.6 94.8 95.2 94.0 96.4 90.1
77.7 80.7 81.4 77.9 72.3 79.1 78.2 76.4 73.3 74.7 76.5 73.6 73.2 73.2 78.3 69.0 79.0 78.0 76.0 79.1 74.0 78.2 76.2 73.9
86.2 86.7 89.5 86.1 90.5 89.7 88.9 86.5 89.2 86.1 87.5 82.9 84.8 88.9 89.2 83.7 91.2 88.9 87.9 89.2 87.9 89.6 86.6 84.6
76.3 81.8 77.7 75.7 71.4 72.0 77.5 76.7 72.2 75.3 74.6 74.3 78.0 72.6 77.8 67.7 77.9 78.8 77.8 78.1 73.9 76.6 77.0 74.7
84.7 87.8 85.5 83.7 89.3 81.7 88.1 86.8 87.7 86.9 85.4 83.8 90.3 88.1 88.6 82.2 89.7 89.8 90.2 88.1 87.7 87.6 87.5 85.5
Average
87.0
81.8
94.0
76.2
87.6
75.6
86.9
such but are in the same order as listed in the Florida Random Sample Egg Laying Test reports (1960-61) or are available from the authors. RESULTS AND DISCUSSION Pen means for Haugh unit scores and percentages of 1st Quarter quality are presented in Table 1 for 1st, 2nd, 3rd and 4th Quarter break-outs. The 2nd, 3rd and 4th Quarter scores were 94.0%, 87.6%, and 8 6.9%, respectively, of 1st Quarter quality.
Correlation coefficients for 1st Quarter quality and 2nd, 3rd and 4th Quarter percentage of 1st Quarter quality were —.149, — .171 and —.203, respectively. Significant negative correlations would have indicated that hens which produce higher quality eggs at the beginning of the year decrease in quality more rapidly with increasing age than hens with a lower initial quality. Table 2 shows highly significant differences among pens and among quarters of the year for both Haugh unit scores and
TABLE 2.—Analyses of variance of Haugh unit scores and percentages of 1st Quarter quality % of 1st Qtr.
Haugh Unit Score Source Time Pen (TXP) Error Total
d.f.
SS
F
d.f.
SS
F
3 23 69 2,832 2,927
63,286 21,862 3,884 142,966 231,998
417.70** 1.88** 1.11™
2 23 46 2,003 2,074
21,404 5,158 3,381 143,054 172,997
150.73** 3.15** 1.04M
** Significant at .01 level. ns Nonsignificant.
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on June 26, 2015
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
651
INTERIOR EGG QUALITY DECLINE T A B L E 3.—Correlation coefficients of egg quality characteristics 2nd Quarter
1st Quarter Initial H.U. 7 day decline 14 day decline 21 day decline 7 to 14 day decline 14 to 21 day decline 7 to 21 day decline
Initial H.U.
7-day decline
-.257 -.316 + .128
+ .542** + .234 -.208 -.341 -.579**
— — —
-.234 + .101 -.049
3rd Quarter
7-day decline
Initial H.U.
—
-.064 + .522** + .614**
-.210 + .067 -.724** + .325 -.668"
— — — •
for stored eggs. 4th Quarter
7-day decline -.344 + .036 -.808** + .300 -.592"
— — —
Initial H.U.
7-day decline
+ .522" + .236 + .501*
— — —
+ .251 + .229 -.650** -.052 -.733**
* Significant at .05 level. ** Significant at . 01 level. Ail correlations not otherwise indicated are nonsignificant.
{% of initial Initial Quality 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter
87.0 81.8 76.2 75.6
quality)
7-day %
H.U. H.U. H.U. H.U.
86.5 88.0 89.1 87.7
14-day % 21-day % 79.5 80.6 85.9 80.8
76.8 79.2 81.0 78.0
percentages of 1st quarter Haugh unit score. Correlation coefficients for eggs stored 7, 14 and 21 days are listed in Table 3 by sampling periods. In three of the four periods the initial quality was negatively though nonsignificantly correlated with 7day quality and in the fourth period a significant positive correlation was found. At 21 days of storage the quality was positively correlated in three test periods, two of which were significant; for the other period a small negative correlation was noted. In most cases the 7-day decline was positively correlated with 14-day and 21day quality; this is to be expected since the 7-day decline is a major part of the 14day and 21-day decline. Decline at 7 days of storage was nega-
T A B L E 5.—Analyses oj variance of storage studies data (% of initial 2nd Quarter
1st Quarter
quality) 4th Quarter
3rd Quarter
Source Storage time Pen (TXP) Error Total
d.l.
SS
F
d.f.
2 23 46 1,655 1,726
29,158 5,896 3,247 118,986 157,287
202.49" 3.55" .99us — —
2 23 46 1,473 1,544
* Significant at . 05 level. ** Significant at .01 level. Nonsignificant,
n8
SS 23,037 3,907 4,539 126,786 158,269
F 133.93" 1.98" 1.15 n 3 — —
d.f. 2 23 46 1,295 1,366
SS 15,199 3,265 7,432 140,660 166,556
F 69.72" \.ity>s 1.49* — —
d.f.
SS
F
2 23 46 1,054 1,125
18,650 6,921 11,227 148,371 185,169
66.13** 2.13" 1.73** — —
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on June 26, 2015
tively correlated with 7 to 14 day decline, three of these correlations being significant (P < .01). For all four sampling periods the 7 day decline was negatively and highly significantly correlated with 7 to 21 day decline indicating a significant balancing out of total decline. The average initial quality and the percentage of decline for the different storage times for each Quarterly sampling period are presented in Table 4. The storage temperature during the 3rd Quarter period was slightly lower than the other periods and may have had some effect on the percent decline. The decline during the first 7 days is by far larger than the second or third seven day periods. Analyses of variance for the storage studies are given in Table 5. Storage time effects were highly significant in all periods. Pen differences were significant (P < .01) in the 1st, 2nd, and 4th Quarters and approached significance in the 3rd. The interaction of storage time X pen was significant (P < .05) in the 3rd Quarter
T A B L E 4.—Decline in quality with storage
652
J. L. FRY, J. S. MOORE AND A. W.
and at the .01 level in the 4th Quarter. The significant differences in quality decline of entries in the Random Sample Test suggest the consideration of rate of quality decline during storage, in addition to initial quality, as a criterion for selection of breeding stock. SUMMARY
REFERENCES Fry, J. L., 1956. Management and holding conditions as they affect the interior quality of eggs. M.S. Thesis, Okla. State Univ., Stillwater. Goodman, B. L., and G. F. Godfrey, 195S. Genetic, phenotypic and environmental correlations between some egg quality traits and egg production and hatchability. Poultry Sci. 34: 1197. Johnson, A. S., and E. S. Merritt, 1955. Heritability of albumen height and specific gravity of eggs from White Leghorns and Barred Rocks and the correlations of these traits with egg production. Poultry Sci. 34: 578-587. Kidwell, M. G., A. W. Nordskog and R. H. Forsythe, 1964. Variation among commercial strains of chickens in loss of egg albumen quality. Poultry Sci. 43 : 38-42. Kilpatrick, L., A. W. Brant and H. L. Shrader, 1960. Equipment and methods for measuring egg quality. U.S.D.A., AMS-246. King, S. C , J. D. Mitchell, W. H. Kyle and W. J. Stadelman, 1961. Egg quality genetic variation and covariation. Poultry Sci. 40: 965-975. May, K. N., F. J. Schmidt and W. J. Stadelman, 1957. Strain variation in albumen quality of hen's eggs. Poultry Sci. 36: 1376-1379. Mueller, W. J., 1959. Factors affecting the quality loss in egg albumen during storage. Poultry Sci. 38: 843-846.
The Characterization of a Growth Inhibitor of Glandless Cottonseed CHARLES JOHNSTON AND A. B. WATTS Department of Poultry Science, Louisiana State University, Baton Rouge, Louisiana (Received for publication September 21, 1964)
A S PART of a feeding test designed to •*• *• evaluate the nutritional value of glandless cottonseed, which is essentially free of gossypol, the authors (1961) found that the nutritional value of the meals for the chick could be greatly improved by heating the flaked seed kernels in the presence of added water prior to extraction of the oil with commercial hexane or by ex-
tracting the oil from the seed with a homogenous mixed solvent composed of hexane, acetone, and water. These findings have since been confirmed by Hill (1964) with the chick and by Gyorgy (1963) using the rat as the experimental animal. Since these meals contained only traces of gossypol (0.00 percent free and 0.02 percent total), the likelihood that the observed change
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on June 26, 2015
Eggs were sampled quarterly during the laying year from entries in the Florida Random Sample Egg Laying Test (1960-61). Storage studies were conducted each period. Highly significant differences among pens and among quarters of the year were observed for both Haugh unit scores and percentages of 1st Quarter Haugh unit score. The 2nd, 3rd and 4th Quarter Haugh unit scores were 94.0%, 87.6% and 86.9%, respectively, of 1st Quarter quality. Decline in quality during the first 7 days of storage was greater than either the 7 to 14 or 14 to 21 day decline. Pens differed significantly (P < .01) in their rate of quality decline during storage in three of the four collection periods.
O'STEEN
O'STEEN
University of Florida, Gainesville, Fla. (Received for publication September 14, 1964)
J
* Florida Agri. Exp. Sta., Journal Series No. 1923.
their analysis has since been questioned. Mueller (1959) reported a highly significant positive correlation coefficient of 0.722 for initial Haugh unit score and seven day Haugh unit loss; these eggs were not, however, held under normal storage conditions. Kidwell et al. (1964) using strains in the Iowa Multiple Unit Random Sample Egg Laying Tests concluded that Haugh unit loss was not genetically determined. This study consists of an evaluation of egg quality data from different commercial strains to give further information on the relationship of initial interior quality and strain differences to interior quality loss. MATERIALS AND METHODS
The eggs for this study were collected quarterly during the laying year from the 24 entries in the 1960-61 Florida Random Sample Egg Laying Test. Pullets were housed at 160 days of age on September 1, 1960; eggs were sampled two months after housing and at 3-month intervals. Initial quality determinations were made on the day following collection. Eggs laid the two succeeding days were stored at approximately 56°F. and 65% relative humidity, and one third were broken out after 7, 14, and 21 days of storage. All observations were made by the method of Kilpatrick et aZ.(1960). Pen means were used in calculating all correlation coefficients reported. Individual egg observations or individual percentages of initial quality were used in the analyses of variance of pen and storage or time differences. Strains are not identified as
649
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on June 26, 2015
OHNSON and Merritt (1955) suggested that, to be economically sound, selection for improved egg quality should have no adverse effects on the egg producing ability of the strain. The reverse is likewise true; yet these two criteria have received major emphasis in both the breeding and advertising of commerical strains of hens. It has been well confirmed that negative genetic correlations exist between albumen quality and egg production (Goodman and Godfrey, 1955; Johnson and Merritt, 1955; and King et al., 1961). This appears to be verified in the industry as it is accepted that there are strain differences in rate of production and in egg quality. A strain that is lower than average in one criterion tends to be higher than average in the other. A recent important area of research is that of the relationship of initial interior quality to the rate of quality decline during storage. Also important is the relationship of interior quality at the beginning of a laying "year," to the rate of decline as the hen ages. Fry (1956) reported a small positive correlation between initial quality and the decline in seven days at three different temperatures. May et al. (1957) found that eggs of high albumen quality declined at a more rapid rate than eggs of lower quality as indicated by a correlation coefficient of 0.358 between original quality and seven day loss of quality. These workers also noted strain differences in the rate of quality decline but the validity of
650
J. L. FRY, J. S. MOORE AND A. W.
O'STEEN
TABLE 1.—Pen mean Ilaugh unit scores and 2nd, 3rd and 4th Quarter percentages of 1st Quarter quality
Pen
1st Quarter
2nd Quarter
3rd Quarter
4th Quarter
H.U. Scores
H.U. Scores % of 1st Qtr.
H.U. Scores % of 1st Qtr.
H.U. Scores % of 1st Qtr.
90.1 93.1 90.9 90.4 79.9 88.1 88.0 88.3 82.2 86.8 87.4 88.7 86.4 82.4 87.8 82.4 86.8 87.7 86.4 88.6 84.2 87.3 88.0 87.3
84.5 87.7 86.5 83.4 77.5 83.1 82.3 82.0 74.9 81.4 81.3 81.2 81.4 77.3 83.7 78.3 83.4 83.7 80.1 84.0 80.2 82.0 84.9 78.6
93.9 94.2 95.2 92.3 97.1 94.3 93.4 92.8 91.1 93.8 93.2 91.6 94.2 93.9 95.1 95.0 96.0 95.4 92.6 94.8 95.2 94.0 96.4 90.1
77.7 80.7 81.4 77.9 72.3 79.1 78.2 76.4 73.3 74.7 76.5 73.6 73.2 73.2 78.3 69.0 79.0 78.0 76.0 79.1 74.0 78.2 76.2 73.9
86.2 86.7 89.5 86.1 90.5 89.7 88.9 86.5 89.2 86.1 87.5 82.9 84.8 88.9 89.2 83.7 91.2 88.9 87.9 89.2 87.9 89.6 86.6 84.6
76.3 81.8 77.7 75.7 71.4 72.0 77.5 76.7 72.2 75.3 74.6 74.3 78.0 72.6 77.8 67.7 77.9 78.8 77.8 78.1 73.9 76.6 77.0 74.7
84.7 87.8 85.5 83.7 89.3 81.7 88.1 86.8 87.7 86.9 85.4 83.8 90.3 88.1 88.6 82.2 89.7 89.8 90.2 88.1 87.7 87.6 87.5 85.5
Average
87.0
81.8
94.0
76.2
87.6
75.6
86.9
such but are in the same order as listed in the Florida Random Sample Egg Laying Test reports (1960-61) or are available from the authors. RESULTS AND DISCUSSION Pen means for Haugh unit scores and percentages of 1st Quarter quality are presented in Table 1 for 1st, 2nd, 3rd and 4th Quarter break-outs. The 2nd, 3rd and 4th Quarter scores were 94.0%, 87.6%, and 8 6.9%, respectively, of 1st Quarter quality.
Correlation coefficients for 1st Quarter quality and 2nd, 3rd and 4th Quarter percentage of 1st Quarter quality were —.149, — .171 and —.203, respectively. Significant negative correlations would have indicated that hens which produce higher quality eggs at the beginning of the year decrease in quality more rapidly with increasing age than hens with a lower initial quality. Table 2 shows highly significant differences among pens and among quarters of the year for both Haugh unit scores and
TABLE 2.—Analyses of variance of Haugh unit scores and percentages of 1st Quarter quality % of 1st Qtr.
Haugh Unit Score Source Time Pen (TXP) Error Total
d.f.
SS
F
d.f.
SS
F
3 23 69 2,832 2,927
63,286 21,862 3,884 142,966 231,998
417.70** 1.88** 1.11™
2 23 46 2,003 2,074
21,404 5,158 3,381 143,054 172,997
150.73** 3.15** 1.04M
** Significant at .01 level. ns Nonsignificant.
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on June 26, 2015
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
651
INTERIOR EGG QUALITY DECLINE T A B L E 3.—Correlation coefficients of egg quality characteristics 2nd Quarter
1st Quarter Initial H.U. 7 day decline 14 day decline 21 day decline 7 to 14 day decline 14 to 21 day decline 7 to 21 day decline
Initial H.U.
7-day decline
-.257 -.316 + .128
+ .542** + .234 -.208 -.341 -.579**
— — —
-.234 + .101 -.049
3rd Quarter
7-day decline
Initial H.U.
—
-.064 + .522** + .614**
-.210 + .067 -.724** + .325 -.668"
— — — •
for stored eggs. 4th Quarter
7-day decline -.344 + .036 -.808** + .300 -.592"
— — —
Initial H.U.
7-day decline
+ .522" + .236 + .501*
— — —
+ .251 + .229 -.650** -.052 -.733**
* Significant at .05 level. ** Significant at . 01 level. Ail correlations not otherwise indicated are nonsignificant.
{% of initial Initial Quality 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter
87.0 81.8 76.2 75.6
quality)
7-day %
H.U. H.U. H.U. H.U.
86.5 88.0 89.1 87.7
14-day % 21-day % 79.5 80.6 85.9 80.8
76.8 79.2 81.0 78.0
percentages of 1st quarter Haugh unit score. Correlation coefficients for eggs stored 7, 14 and 21 days are listed in Table 3 by sampling periods. In three of the four periods the initial quality was negatively though nonsignificantly correlated with 7day quality and in the fourth period a significant positive correlation was found. At 21 days of storage the quality was positively correlated in three test periods, two of which were significant; for the other period a small negative correlation was noted. In most cases the 7-day decline was positively correlated with 14-day and 21day quality; this is to be expected since the 7-day decline is a major part of the 14day and 21-day decline. Decline at 7 days of storage was nega-
T A B L E 5.—Analyses oj variance of storage studies data (% of initial 2nd Quarter
1st Quarter
quality) 4th Quarter
3rd Quarter
Source Storage time Pen (TXP) Error Total
d.l.
SS
F
d.f.
2 23 46 1,655 1,726
29,158 5,896 3,247 118,986 157,287
202.49" 3.55" .99us — —
2 23 46 1,473 1,544
* Significant at . 05 level. ** Significant at .01 level. Nonsignificant,
n8
SS 23,037 3,907 4,539 126,786 158,269
F 133.93" 1.98" 1.15 n 3 — —
d.f. 2 23 46 1,295 1,366
SS 15,199 3,265 7,432 140,660 166,556
F 69.72" \.ity>s 1.49* — —
d.f.
SS
F
2 23 46 1,054 1,125
18,650 6,921 11,227 148,371 185,169
66.13** 2.13" 1.73** — —
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on June 26, 2015
tively correlated with 7 to 14 day decline, three of these correlations being significant (P < .01). For all four sampling periods the 7 day decline was negatively and highly significantly correlated with 7 to 21 day decline indicating a significant balancing out of total decline. The average initial quality and the percentage of decline for the different storage times for each Quarterly sampling period are presented in Table 4. The storage temperature during the 3rd Quarter period was slightly lower than the other periods and may have had some effect on the percent decline. The decline during the first 7 days is by far larger than the second or third seven day periods. Analyses of variance for the storage studies are given in Table 5. Storage time effects were highly significant in all periods. Pen differences were significant (P < .01) in the 1st, 2nd, and 4th Quarters and approached significance in the 3rd. The interaction of storage time X pen was significant (P < .05) in the 3rd Quarter
T A B L E 4.—Decline in quality with storage
652
J. L. FRY, J. S. MOORE AND A. W.
and at the .01 level in the 4th Quarter. The significant differences in quality decline of entries in the Random Sample Test suggest the consideration of rate of quality decline during storage, in addition to initial quality, as a criterion for selection of breeding stock. SUMMARY
REFERENCES Fry, J. L., 1956. Management and holding conditions as they affect the interior quality of eggs. M.S. Thesis, Okla. State Univ., Stillwater. Goodman, B. L., and G. F. Godfrey, 195S. Genetic, phenotypic and environmental correlations between some egg quality traits and egg production and hatchability. Poultry Sci. 34: 1197. Johnson, A. S., and E. S. Merritt, 1955. Heritability of albumen height and specific gravity of eggs from White Leghorns and Barred Rocks and the correlations of these traits with egg production. Poultry Sci. 34: 578-587. Kidwell, M. G., A. W. Nordskog and R. H. Forsythe, 1964. Variation among commercial strains of chickens in loss of egg albumen quality. Poultry Sci. 43 : 38-42. Kilpatrick, L., A. W. Brant and H. L. Shrader, 1960. Equipment and methods for measuring egg quality. U.S.D.A., AMS-246. King, S. C , J. D. Mitchell, W. H. Kyle and W. J. Stadelman, 1961. Egg quality genetic variation and covariation. Poultry Sci. 40: 965-975. May, K. N., F. J. Schmidt and W. J. Stadelman, 1957. Strain variation in albumen quality of hen's eggs. Poultry Sci. 36: 1376-1379. Mueller, W. J., 1959. Factors affecting the quality loss in egg albumen during storage. Poultry Sci. 38: 843-846.
The Characterization of a Growth Inhibitor of Glandless Cottonseed CHARLES JOHNSTON AND A. B. WATTS Department of Poultry Science, Louisiana State University, Baton Rouge, Louisiana (Received for publication September 21, 1964)
A S PART of a feeding test designed to •*• *• evaluate the nutritional value of glandless cottonseed, which is essentially free of gossypol, the authors (1961) found that the nutritional value of the meals for the chick could be greatly improved by heating the flaked seed kernels in the presence of added water prior to extraction of the oil with commercial hexane or by ex-
tracting the oil from the seed with a homogenous mixed solvent composed of hexane, acetone, and water. These findings have since been confirmed by Hill (1964) with the chick and by Gyorgy (1963) using the rat as the experimental animal. Since these meals contained only traces of gossypol (0.00 percent free and 0.02 percent total), the likelihood that the observed change
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on June 26, 2015
Eggs were sampled quarterly during the laying year from entries in the Florida Random Sample Egg Laying Test (1960-61). Storage studies were conducted each period. Highly significant differences among pens and among quarters of the year were observed for both Haugh unit scores and percentages of 1st Quarter Haugh unit score. The 2nd, 3rd and 4th Quarter Haugh unit scores were 94.0%, 87.6% and 86.9%, respectively, of 1st Quarter quality. Decline in quality during the first 7 days of storage was greater than either the 7 to 14 or 14 to 21 day decline. Pens differed significantly (P < .01) in their rate of quality decline during storage in three of the four collection periods.
O'STEEN