Shape Index Versus Hatchability of Fertile Eggs of Japanese Quail (Coturnix coturnix japonica)

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W. F. DEAN, J. I. PRICE AND L. LEIBOVITZ

potentiated mixture (Ro 5-0013) in chickens. Poultry Sci. 48: 1151-1155. Padanyi, M., B. Toth and I. Weiner, 1967. Studies of the determination of the therapeutic and toxic dose of sulfaquinoxaline in fowls experimentally infected with fowl cholera. Ao. Lapja, 22: 152-156. Price, J. I., E. Dougherty and D. W. Bruner, 1962.

Salmonella infections in white pekin ducks. A short summary of the years 1950-60. Avian Dis. 6: 145-147. Prip, M. and K. M01bak, 1969. On the application of oxytetracycline (terramycin hydrochloride) in the "New Duck Syndrome." Nord. Vet. Med. 21:655-659.

Shape Index Versus Hatchability of Fertile Eggs of Japanese Quail {Coturnix coturnix japonica)

(Received for publication June 21, 1972) ABSTRACT Regression analysis of data from 2,815 fertile Coturnix eggs showed a very highly significant linear regression of hatchability on shape index. Estimates of surface to volume ratios from shape indices produced values fitting the regressed hatchability estimates very closely. Correlation between estimated values was + 0.998 (P < 0.001). POUXTRY SCIENCE 52: 558-562, 1973

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HERE have been several studies of possible relationships between shape of eggs and percent hatchability of fertile eggs. Most of these have concerned chicken eggs, and several have shown no statistically significant relationship between the two observations. Benjamin (1920) measured chicken eggs with micrometers and concluded "—The size, the shape and the color of the egg seem to have no effect on its incubation record." Jull and Haynes (1925), after observing 1,138 chicken eggs with shape indices, (diameter X 100) (length) ranging from 61 to 85 percent, stated "—egg shape, where normal eggs are in-

The investigation reported in this paper (No. 72-5-68) is in connection with a project of the Kentucky Agricultural Experiment Station and is published with approval of the Director.

volved, does not affect hatching quality." Hays and Sumbardo (1927) compared length and diameter with hatchability. Their conclusion: "No relation between physical characteristics of eggs studied and hatchability was disclosed." Hutt (1938) compared egg shape and incidence of malpositions among 1,056 White Leghorn eggs and 956 eggs from heavy breeds and found "—no adequate or consistent evidence that shape of an egg, as measured in this investigation, influences the probability of the contained embryo dying in any malposition." Olsen and Haynes (1949) compared several egg characteristics with hatchability. The classification pertinent to the present investigation was "Misshapen Eggs," defined as "elongated, round or out-of-round eggs." Of 68 fertile eggs so classified 48.9 percent hatched. Control eggs (3,031) hatched 87.2 percent, thus

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D. W. MACLATJRY, W. M. INSKO, JR., J. J. BEGIN AND T. H. JOHNSON Animal Sciences Department, Kentucky Agricultural Experiment Station, Lexington, Kentucky 40506

559

EGG SHAPE INDEX AND HATCHABILITY

breadth (B) X 100 (length L) and the fate of each egg was recorded. A total of 3,406 eggs were set in 5 hatches. Of these 2,815 were fertile and 2,118 hatched. Percent hatchability of fertile eggs by shape indices within hatches and over all hatches is shown in Table 1.

TABLE 1.—Hatchability of fertile eggs of Coturnix quail, classified by shape index and hatch. Shape Index (B X 100) L 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89

Percent Hatchability Hatch Hatch Hatch Hatch Hatch 1 2 3 4 5 100 100 80 70 77 58 69 75 67 77 69 74 50 69 60 54 33 80

100 78 87 72 91 70 70 77 71 75 79 79 83 81 100 50 82

89 100 71 70 83 86 85 67 77 87 67 82 100 67 70

25

67

66 100 75 80 95 80 74 80 85 87 88 77 60 78 100 33 87

100 50 100 62 64 57 86 45 72 80 70 60 76 57 63 57 58

All Hatches 100 57 93 80 73 82 69 68 78 73 75 77 76 65 75 64 50 71 33 54

Tests of the original data produced significant chi-square values among shape index classes within all hatches and within the totals of the hatches combined. Estimation of linear regression of percent hatchability on shape index resulted in negative estimates in all hatches. Three of the 5 estimates differed significantly from zero (P<0.05). The estimate over all hatches differed from zero with very high significance (P < 0.001) indicating that hatchability decreased as shape varied from elongated (index 69) to round (index 89). The rate of decrease in hatchability was 1.6 percent for 1 percent increase in shape index. The observed values and estimated regression for combined hatches are shown in Figure 1. These data do not confirm the observation of Brunson and Godfrey (1952) that hatchability was lower at both extremes of the shape index scale. They also differ from the conclusions of Benjamin (1920), Jull and Haynes (1925), and Hays and Sumbardo (1927) that shape and hatchability were unrelated. The implication derived from this study is that as egg shape approached the shape of a sphere

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indicating an influence of shape on ability to hatch. Skoglund (1951) divided chicken eggs into 3 classifications: long and narrow (index under 69), normal (index 69-77), and short and round (index over 77). His resulting hatchability among over 32,000 eggs in a commercial hatchery showed normal eggs hatching 2 percent better than extremes. Among nearly 8,000 eggs in Delaware Experiment Station incubators there was a trend toward lower hatchability with higher index, but the range was only 1.4 percent. Brunson and Godfrey (1952) found that extreme shapes among 1,282 Broad Breasted Bronze turkey eggs did not hatch as well as those with intermediate indices. In a group with shape indices ranging from 60 to 82 "—eggs within the range of 65 to 78 hatched 10.0 percent better than the combined group of the extremes." The investigation reported here is concerned with hatchability of fertile eggs of Coturnix quail with shape indices ranging from 69 to 89. After gathering from mass-mated pens consisting of 30 females and 10 males, egg breadth and length were measured, and the eggs were numbered for identification and stored at approximately 14.0 degrees C. Eggs were set at weekly intervals. Incubation conditions and subsequent handling of unhatched eggs were as described in Insko et al. (1971). Shape index was calculated as

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MACLAURY, INSKO, BEGIN AND JOHNSON

Romanoff and Romanoff (1949) consider the egg as a prolate spheroid for which volume V equals xLB 2

= 0.5236 LB 2 .

They quote compensating coefficients k, used in the equation V =

69

71

73

75

77

79

81

83

85

87

FIG. 1. Observed hatchability, regressed-hatchability and modified surface/volume ratio related to shape index in Coturnix quail.

(index 100) hatchability decreased. Index 100 is the point at which egg shape would change from resemblance to a prolate spheroid (egg shape) to that of an oblate spheroid (doorknob shape). Shape index may indicate a relationship in the physical conditions of incubation which would influence hatchability. A strong possibility would be the ratio of shell surface to volume of egg, which would be related to heat transfer in the incubator. The following derivation resulted in surface to volume (S/V) ratios which fitted very closely the regression line of percent hatchability on shape index. As defined above I =

B

(6)

ranging from 0.85 to 1.0046 to reduce errors in observation in various individual investigations. The same authors, starting with the concept that surface area equals the two-thirds power of the volume, give the general equation in which surface area S equals k

(TTLB 2 ) 2 ' 3

6

— = kV 2/3 ,

with k taking values ranging from 4.63 to 5.07 in various individual investigations. Since we are concerned here with the ratio S/V, we do not use specific values of the constant but start with S = kV 2 ' 3

and

V

k(irLB 2 )

Substituting, kTT / V =

IL IL L X X — 6 V 100 100

= ( — L3I2) \60,000 /

X 100 Then

Transposing B =

IL

S

100

V~

where I = shape index of egg B = breadth of egg and L = length of egg

kV 2 ' 3

V "

V1'3 k

/ T Y/3 2 3 ( ) i ' \60,000/

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SHAPE INDEX sMgAOTHX 100

k(7rLB2)

561

EGG SHAPE INDEX AND HATCHABILITY

With our interest in the variation of the ratio S/V with variation in I, we hold L constant and combine all constants, making k

= K

60,000,

and S V

K p/s

TABLE 2.—Estimated values of hatchability of fertile eggs regressed on shape index and of Surface/ Volume ratio estimated from shape index for Coturnix quail eggs. Shape Index B X 100 j

L

Adjusted S/V ratio 3438.577 117 65

S/V =

85.88 84.28 82.69 81.10 79.50 77.91 76.31 74.71 73.12 71.52 69.93 68.33 66.74 65.14 63.55 61.95 60.35 58.75 57.16 55.56 53.97

I2/3

86.78 84.74 82.85 81.00 79.18 77.39 75.75 74.02 72.33 70.66 69.12 67.52 66.03 64.57 63.04 61.63 60.24 58.87 57.52 56.19 54.88

This results in an equation relating shape . index I to the ratio of surface area to volume S/V without the use of the absolute quantities of length and breadth. A value of K can be chosen which will Extrapolated Points 100.00 36.42 42.00 make the range of S/V values equal the 60.15 100.00 62.79 100.00 range of regressed hatchability values. Subtracting another constant will place the S/V values at the same level as the hatchability values. The equation derived in this study the values estimated for S/V and the linear regression of percent hatchfrom the indices is: ability oh shape index were close. Estimated correlation between the two was 3438.577 S 117.65. +0.998 and was very highly significant J2/3 V (P < 0.001). From this it would seem The estimated values are shown in Table that the ratio of surface area to volume, 2 and are plotted in Figure 1. Included in possibly as an indicator or rate of heat Table 2 are extrapolated estimates for transfer, is closely related to hatchability 100 percent hatchability and shape index of Coturnix quail eggs. 100. When S/V and hatchability are 100, index by S/V is 62.79 and by hatchability is 60.15. When shape index is 100, hatchability is estimated to be 36.42 percent and S/V to be 42.00. Thus, while the S/V regression is curvilinear and the hatchability regression is linear the difference in estimates of shape index when S/V and hatchability are 100 percent is 2.64. When shape index is 100 the difference between estimated hatchability and estimated S/V is 5.58 percent. Over the range of shape index observed

ACKNOWLEDGMENT

Assisting in measurement or computation were Karen Skees, LuAnne Wright, Paula Whitehead, Kathi Malone, Sandi Lewis and Marian Conrad. REFERENCES Benjamin, E. W., 1920. A study of selections for size, shape, and color of hens' eggs. Cornell University. . Agr. Exp. Sta. Memoir 31. Branson, C. C , and G. F. Godfrey, 1952. The effect of some egg characteristics upon the hatchability of Broad Breasted Bronze turkey eggs. Poultry Sci. 31: 909. Hays, F. A., and A. H,- Sumbardo, 1927. Physical

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69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89

Percent Hatchability H = 195.98 -1.5956 I

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MACLAURY, INSKO, BEGIN AND JOHNSON

characters of eggs in relation to hatchability. Poultry Sri. 6: 196-200. Hutt, F. B., 1938. Embryonic mortality in the fowl. VII. On the relation of malpositions to the size and shape of eggs. Poultry Sci. 17:345-352. Insko, W. M., Jr., D. W. MacLaury, J. J. Begin and T. H. Johnson, 1971. The relationship of egg weight to hatchability of Coturnix eggs. Poultry Sci. 50:297-298. Jull, M. A., and S. Haynes, 1925. Shape and weight of eggs in relation to their hatching quality. J.

Agr. Res. 31: 685-694. Olsen, M. W., and S. K. Haynes, 1949. Egg characteristics which influence hatchability. Poultry Sci. 28:198-201. Romanoff, A. L., and A. J. Romanoff, 1949. The Avian Egg. John Wiley and Sons, Inc., New York. Skoglund, W. C , 1951. The relationship between egg shape and hatchability in meat type strains of New Hampshires. Delaware Agr. Exp. Sta. Tech. Bui. 287.

YTJKIO AKIBA AND TATSURO MATSUMOTO Department of Animal Science, Faculty of Agriculture, Tohoku University, Sendai, Japan (Received for publication June 22, 1972) ABSTRACT Thyroid function of chicks after withdrawal of goitrin, a goitrogen in rapeseed, from the diet following 21 days feeding was investigated. Increased thyroid weight (about 4 times that of the control) and thyroidal 131I uptake (about 2.7 times that of the control) induced by 21 days feeding of 0.05% goitrin were decreased gradually after withdrawal of goitrin. Other synthesizing steps of thyroid hormone in the gland, such as iodination of tyrosines and coupling of iodotyrosines and synthesizing of thyroxine, and plasma level of thyroid hormone were completely recovered within 2 days af terwithdrawal of goitrin. Distinct rebound phenomena were observed in circulating level of thyroid hormone and synthesis of thyroxine in the gland after the withdrawal. These results suggest that depression in metabolism of thyroid hormone induced by administration of goitrin may be restored in a relatively short time after withdrawal of goitrin, despite hypertrophy of thyroid gland which persist for relatively longer time. POULTRY SCIENCE 52: 562-567, 1973

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HAT the thyroid gland is enlarged and metabolism of thyroid hormone biosynthesis is depressed by feeding of rapeseed meal to an animal is well known (Turner, 1946; Bell, 1957; Manns and Bowland, 1963; and Manns et al., 1963). A main goitrogen, (—)-5-vinyl-2-oxazolidinethione (goitrin), among many goitrogens in rapeseed has been reported. Thyroid enlargement and inhibition in biosynthesis of thyroid hormone were induced by administration of goitrin in rats and chicks (Krusius and Peltola, 1966; Langer, 1966; Clandinin et al., 1966; and

Akiba and Matsumoto, 1971). However, changes of thyroid function after withdrawal of rapeseed meal or goitrin has not been reported. The object of the experiment reported herein is to investigate changes in thyroid function after withdrawal of goitrin in chicks. MATERIALS AND METHODS

Day-old Single Comb White Leghorn chicks were fed an experimental diet containing 0.05% goitrin, which was replaced after 21 days with a diet containing

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Thyroid Function of Chicks after Withdrawal of (—)-5-Vinyl-2-oxazolidinethione, a Goitrogen in Rapeseed