RESEARCH NOTES
affecting length of the upper beak and of the long bones. Genetics, 26: 426-439. Landauer, W., 1951. The hatchability of chicken eggs as influenced by environment and heredity.
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Storrs Agric. Exp. Sta. Bull. No. 262. Taylor, L. W., 1949. Fertility and Hatchability of Chicken and Turkey Eggs. John Wiley and Sons, New York.
BLOOD GLUTATHIONE LEVELS AND EGG PRODUCTION IN INBRED LINES OF CHICKENS 1 ENSEL C. STUTTS, W. E. BRILES AND H. 0. KTJNKEL
(Received for publication February 27, 1956)
The blood levels of soluble sulfhydryl compounds—expressed as reduced glutathione—have been determined for a number of mature inbred White Leghorn females using the nitroprusside method of Grunert and Phillips (1951). Significant individual and line differences in blood glutathione levels have been observed in birds of inbred lines 22, 23, and 24 (Stutts etal., 1956). A consideration of the data revealed that the glutathione levels determined on March 17, 1955, in 76 individually caged females in lines 22, 23, 24, and the 22X24 crossline were significantly and negatively correlated (r=—0.34, p<0.01) with the number of eggs produced during the month of March. Considering the egg production and glutathione levels of the 54 birds from inbred lines 22, 23, and 24 only, the correlation was —0.37 (p<0.01). Only 44 of the line 22, 23, and 24 females survived throughout the following two months. However, for the survivors, a highly significant correlation ( — 0.42) was found between the glutathione levels and the egg production during the 75 days following the glutathione analyses. Including the data on the line 1 Supported in part by a grant-in-aid from the Pioneer Hi-Bred Com Company, Des Moines, Iowa, to the Texas Agricultural Experiment Station.
22X24 cross birds reduced the correlation to —0.27, but it remains significant statistically (p<0.05). These are gross correlations, and line differences are such that they would contribute appreciably to the magnitude of these values. On a within-line basis, the correlations were negative but did not reach a point of statistical significance. The glutathione levels measured for 25 females of lines 22, 23, and 24 at a second determination on March 26, were found also to be significantly and negatively correlated (— 0.43, p < 0.05) with the number of eggs produced during the 66 days following the sampling of the blood. Expressing the glutathione on a per-unit-of-redcell basis, such as by the glutathionehemoglobin ratio, results in correlations of increased magnitude. This is evident more within lines than for the gross correlation (Table 1). On the within-line basis the glutathione-hemoglobin ratio appeared to be more indicative of egg production than glutathione alone, increasing the coefficient of determination from 9.7% to 23%. Analyses of variance indicated that in the birds used there were significant differences between lines with respect to both average egg production (p<0.05) and glutathione concentration (p<0.01).
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Departments of Biochemistry and Nutrition and of Poultry Husbandry, Texas Agricultural Experiment Station, College Station, Texas
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RESEARCH NOTES
TABLE 1.—Correlations between egg production, and blood glutathione (GSH) or the blood glutathionehemoglobin ratio (GSH/Hb) Line
No. birds
22 23 24
9 7 9
Gross Correlation 22+23+24 Within-line Correlation 22+23+24
- „ .eggs _ Lrb±1 -0.495 -0.320 -0.422
No. birds
GSH/Hbeggsi
9 5 8
-0.562 -0.938* -0.626
25
-0.434*
22
-0.454»
25
-0.312
22
-0.480*
Number of eggs produced from March 26 through M a y 31, 1955. * Significant a t 0.05 level of probability
Considering both sets of glutathione analyses, the test females with the lowest average glutathione level (line 23) had the highest average egg production; line 24 birds were intermediate in both values; while birds of line 22 had the highest mean glutathione level and produced fewer eggs per bird (Table 2). A similar relationship was found to exist also between egg production and the glutathione-hemoglobin ratio. Such a relationship is exactly as expected from the negative within-line correlations described above. The small numbers involved, the extent of inbreeding in the birds (an average inbreeding coefficient of approximately 50%), and the fact that the glutathione analyses were made after the birds had begun to lay, prevent a clear interpretation
T;„„ L lne
No. birds
22
16 9 17 8 11 5
Date A,r„ n m Avg. of GSH ?^,g: ^ n GSH/Hb No. eggs determi- ( m |;V U 0 (mg./gm.) through nation ""••' 5/31/55 3/17/55 3/26/55 3/17/55 3/26/55 3/17/55 3/26/55
31.8 39.2 27.9 34.9 23.2 24.0
4.82
16.6 18.3 26.1 21.3 29.6 22.6
of these observations. Yet the relatively large negative correlations, especially with the glutathione-hemoglobin ratios, indicate a definite relationship between the glutathione level and egg production in these inbred lines of chickens. The line differences between males of the same lines have been found to be essentially the same as those observed in the females (Stutts el al., 1956) and indicate a hereditary basis for part of the variation in glutathione concentration in the erythrocytes. This suggests that there may be a genetic correlation between glutathione concentration and egg production. REFERENCES Grunert, R. R., and P. H. Philips, 1951. A modification of the nitroprusside method of analysis for glutathione. Arch. Biochem. 30: 217-225. Stutts, E. C , W. Johnson, W. E. Briles and H. O. Kunkel, 1956. Variation in reduced glutathione in the bloods of inbred lines of chickens. Proc. Soc. Exp. Biol. Med. 91: 60-63.
NEWS AND NOTES (Continued from page 723) mended Beaudette for "long, industrious, and fruitful labors to enlarge man's knowledge of avian diseases." BACK ISSUES OF POULTRY SCIENCE Issues Wanted—D. R. Clandinin, Division of Poultry Husbandry, Department of Animal Science, University of Alberta, Edmonton, Alberta, Canada —Volume 13, No. 1. A.P.A. NOTES In the recent biennial election of the American Poultry Association, the following officers were
elected: President—B. F. Ricketts, Zanesville, Ohio; Vice-President—O. H. Knuth, Indianapolis, Ind.; Directors—H. Atkins, Davenport, Iowa; W. W. Bunnell, Farmington, Conn.; M. B. Cosby, Smithville, Ont., Can.; L. W. Crouch, Great Falls, Mont.; J. F. Feek, Cincinnati, Ohio; J. G. Kuhlmann, Colorado Springs, Colo.; K. McNish, Bristol, Tenn.; W. L. Mullaney, Buffalo, N. Y.; L. H. Ritzhaupt, Guthrie, Okla.;'A. M. StodeljVanNuys., Calif.; H. E. Upton, White Rock, B.C., Can.; and E. W. Wilson, Atlanta, Ga. C. T. Driessen, P.O. Box 337, Great Falls, Mont., is Secretary.
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1
TABLE 2.—Average glutathione (GSH) levels and subsequent egg production of line 22,23 and 24 females