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Hatchability of Chicken Eggs Exposed to Electromagnetic Fields Prior to Incubation1,2
Hatchability of Chicken Eggs Exposed to Electromagnetic Fields Prior to Incubation 1,2 PATRICIA Y. HESTER, B. B. BOHREN, and IRENA FABIJANSKA 3 Department of Animal Sciences, Purdue University, West Lafayette, Indiana 47907 (Received for publication March 24, 1978)
INTRODUCTION T h e effects of electromagnetic (EMG) fields on biological systems have intrigued scientists for over a c e n t u r y (for a review, see A c e t o et al., 1 9 7 0 ) . Studies p e r f o r m e d on plant a n d animal species have s h o w n t h a t EMG fields can induce b o t h beneficial as well as detrimental effects. For example, t o m a t o e s , apple seeds and apricot seeds e x p o s e d t o EMG fields d e m o n strated such desired characteristics as an increase in ripening t i m e for t h e t o m a t o e s , a decrease in g e r m i n a t i o n t i m e , and an increase in t h e percentage germination for t h e seeds (Boe and Salunkhe, 1 9 6 3 ; Chao and Walker, 1 9 6 7 ) . In contrast, morphological abnormalities occurred in a m p h i b i a n and m a m m a l i a n cells when t r e a t e d with s t r o n g EMG fields (Levengood, 1 9 6 9 ; Malinin et al, 1 9 7 6 ) . Avian species have also been used in studies on EMG energy. F o r example, investigators have shown t h a t t h e migratory p a t t e r n s of birds are affected b y magnetic fields (Larkin a n d Keeton, 1 9 7 6 ; Larkin and Sutherland, 1 9 7 7 ) .
'Journal paper no. 7100 of the Purdue University Agricultural Experiment Station. 2 The use of trade names in this publication does not imply endorsement by the Purdue University Agricultural Experiment Station. 'Warsaw Agricultural University, Faculty of Animal Science, Rakowiecka 26/30, 02-528 Warsaw, Poland. 1978 Poultry Sci 57:1239-1244
These studies suggested t h a t t h e earth's magnetism served as an orientation guide for migrating birds. In additional studies related t o avian species, Krueger et al. ( 1 9 7 5 ) c o n t i n u o u s l y e x p o s e d commercial layers to l o w p o w e r very high frequency ( 2 6 0 MHz) and ultra-high freq u e n c y ( 9 1 5 MHz a n d 2 . 4 3 5 GHz) fields as well as low frequency magnetic (1.4 G) and electric fields ( 1 6 0 0 V / m ) . Although egg p r o d u c t i o n was reduced, t h e eggs collected from t h e electromagnetically-treated hens were n o t affected as indicated b y a n o r m a l sex ratio as well as fertility and hatchability percentages. Direct exposures of EMG energy o n quail and chicken eggs have been studied. M c R e e et al. ( 1 9 7 5 ) e x p o s e d J a p a n e s e quail eggs t o 2.45 GHz microwave radiation for 4 hr per day during t h e first 5 days of i n c u b a t i o n . Hatchability percentages, b o d y weights, and specific hematological p a r a m e t e r s were n o t unlike t h e controls. Van Ummersen ( 1 9 6 3 ) e x p o s e d 4 8 hr chick e m b r y o e s t o a microwave radiation of 2 4 5 0 MHz for 2 8 0 - 3 0 0 min. When t h e chick e m b r y o e s were e x a m i n e d at 96 hr of incubation, abnormalities in t h e growth a n d developm e n t of t h e t r e a t e d e m b r y o e s had occurred. A United States p a t e n t ( 3 , 9 1 0 , 2 3 3 ) issued O c t o ber 7, 1 9 7 5 claimed t h a t chicken eggs e x p o s e d t o EMG energy d e m o n s t r a t e d hatchability percentages which were 5 t o 8% greater t h a n u n t r e a t e d controls. T h e levels of EMG energy used t o d e m o n s t r a t e this increased hatchability ranged from 6 0 t o 1 2 0 G with an e x p o s u r e t i m e of 3 t o 10 sec per egg ( A m b u r n , 1 9 7 6 ) .
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ABSTRACT White Leghorn eggs were exposed to electromagnetic (EMG) fields immediately prior to incubation. The hatchability percentages and body weight means of the chicks at hatch were compared with untreated controls. Data were collected for two different time periods of incubation, 0 to 20.5 and 20.5 to 21.5 days of incubation. In Trial 1, eggs of H&N and Shaver strains were exposed to a 90-gauss EMG field produced by a direct current. In Trial 2, eggs of the Shaver strain were exposed to the following four EMG treatments: 1) direct current, 125 gauss; 2) direct current, 160 gauss; 3) alternating current, 125 gauss; 4) alternating current, 160 gauss. The results of both trials indicated that no significant differences occurred in hatchability between electromagnetically-treated and control eggs. Hatching time and body weights at hatch were also not affected by the treatments in either trial.
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HESTER ET AL.
The purpose of this study was to evaluate the claims made by this United States patent description. Specifically, the objectives were to determine if the exposure of chicken eggs to EMG fields immediately prior to incubation would affect the percentage of hatchability, the time of hatch, or the body weights of the chicks at hatching. MATERIALS AND METHODS
After 18 days of incubation, the eggs from each incubation tray were transferred to Jamesway pedigree baskets for hatching. Three baskets were used at each tray level, and each was divided into three hatching compartments with
4
Patent number of magnetic coil is 3,910,233 issued October 7, 1975. 5 Model 505 Gaussmeter, Radio Frequency Laboratory Industries, Inc., Boonton, NJ 07005.
RESULTS AND DISCUSSION Trial 1. The percent hatchability means for the control and treated eggs for the Shaver and H&N strains for the two different incubation periods are presented in Table 1. The means of chick body weights at hatching are shown in Table 2, and the analyses of variance of both variables are shown in Table 3. An EMG field ot 90 gauss appears to have no
Downloaded from http://ps.oxfordjournals.org/ at Florida International University on June 15, 2015
White Leghorn chicken eggs obtained from commercial hatcheries were treated with various levels of EMG energy. The EMG fields were adjusted to specific gauss levels within a 4.5inch magnetic coil 4 through the use of a gaussmeter 5 . Each egg was individually rolled through the magnetic coil with an exposure time of approximately 3 sec. per egg. The eggs were rolled on a plastic packaging material to prevent breakage. For Trial 1, samples of 1232 White Leghorn eggs of the Shaver and H&N strains, respectively, were used. One-haf of the eggs (616) in each of the strains was exposed to an EMG field of 90 gauss produced by a direct current. The remaining eggs (616) of each strain served as untreated controls. Immediately following the administration of the treatment, the eggs were placed in trays for incubation. Two Jamesway 252 incubators with a total of 28 trays or blocks were used. Two samples of 10 eggs representing each of the four strain-treatment combinations were distributed at random within each tray for a total of 80 eggs per tray. Eight extra eggs for each of the eight groups were set in each tray to replace any eggs which were broken during incubation. The position of the eggs in each tray was staggered to provide for more even heat distribution among the eggs within each incubator. Proper dry and wet bulb temperatures were maintained throughout the experiment as recommended by the manufacturer.
two metal dividers. The eight experimental groups and the set of extra eggs were placed in the respective nine compartments using the same randomization scheme as assigned to the incubation trays. The chicks in each hatching basket were counted and weighed at 20.5 and 21.5 days of incubation. The time period between 0 and 20.5 days of incubation will be referred to as incubation period 1 while 20.5 through 21.5 days of incubation will be referred to as incubation period 2. The proportion of eggs set which hatched during each of the incubation periods was expressed as percentage of hatchability. Any chicks which hatched after 21.5 days of incubation were not included in the study. An analysis of variance with a factorial design including a split-plot was employed to determine the significance of any observed differences. Trays and samples were considered to be random variables while all other variables were assumed to be fixed. Trial 2 was similar to Trial 1 except that only the Shaver strain eggs were used and five treatments were compared. These included an untreated control, two types of current, direct and alternating, combined with two levels of EMG energy, 125 gauss and 160 gauss. A total of 3080 eggs was used, i.e. 616 eggs per treatment. Two samples of 10 eggs for each of the five treatments were distributed at random to each of the 28 trays for a total of 100 eggs per tray. An additional 10 eggs representing the 10 respective samples were incubated in each tray to replace any eggs broken during incubation. At 18 days of incubation, the 10 groups of experimental eggs and the set of reserve eggs from each incubator tray were transferred by groups to 11 hatching compartments. The hatching compartments for each tray level were formed from four Jamesway pedigree baskets each divided into three compartments by two metal dividers.
ELECTROMAGNETIC FIELDS ON CHICKEN EGGS
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TABLE 1.—Hatchability means for control and electromagnetically-treated eggs of Shaver and H&N strains at two different incubation periods (Trial 1) Incubation period Strain
Treatment
Shaver
Control EMG»
H&N
Control EMG a
Total
34.5 34.1
36.6 37.3
71.1 71.4
38.2 37.5
43.0 43.2
81.2 80.7
EMG treatment denotes a 90 gauss EMG field produced by a direct current.
TABLE 2 .—Body weight means ± SD at hatch of Shaver and H&N strains of chicks hatched from control and electromagnetically treated eggs (Trial 1) Body weight, g (treatment) Strain
Control
Shaver H&N Means
40.14 35.73 37.94
EMGa 2.72^ 2.06 3.27
40.21 35.35 37.78
Means 2.43 2.16 3.35
40.18 35.54 37.86
2.57 2.11 3.30
EMG treatment denotes a 90 gauss EMG field produced by a direct current. Values expressed as means ± SD.
TABLE 3.—Analyses of variance of hatchability and body weight means of Trial 1 Mean squares
Source
df
Hatchability
Block or tray (B) Treatment (T) B X T Strain (S) B X S TX S B XT X S Samples (S')/(B X T X S)
27 1 27 1 27 1 27 112
.75 .00 .90 26.52" .72 .06 .68 .92
I n c u b a t i o n period ( H ) a H X B H X T H X B X T HX S H X B X S H XT X S H X B X TX S H X S 7 ( S X T X B)
1 27 1 27 1 27 1 27 112
17.68 67.23** .27 7.60 1.88 4.00 .00 4.69 4.68
Applies only to hatchability analysis. **P<.01.
Body weight means 7.47 1.25 4.99 1205.05** 4.36 2.87 3.17 6.09
Expected mean squares
( o j + og')/n (a 2 + a g ' ) / n (ol +
<°s
(°l
+ + + + + +
a g T + 280x aBT 2o|jS + 560s 2a2BS CTgTS + 280XS okTS
a n s ' ) / n + 4 CT HB + 1 1 2 0 H a2HS')/n + 4a2HB + a f ^ O / n + 2af4BT + 560HT + c2HS0/n + 2 a 2 H B T
<<* + <<* +
K
(°e (ae
+
(ae + + + (o| +
<°J (4
CT HS')/n + 4 o H B S + 1 1 2 * H S ofeO/n + 4a2HBS afjgO/n + 2 < J | J B T S + 5 6 0 H T S o2HS')/n + 2 a | j B T S afjsO/n
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a
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HESTER ET AL.
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TABLE 4.—Hatchability means (%) for control and electromagnetically-treated at two different incubation periods (Trial 2)
eggs
Treatments a periods
0
DC-125
DC-160
AC-125
AC-160
I 11 Total
36.6 40.7 77.3
37.9 44.1 82.0
34.5 47.0 81.5
38.2 43.6 81.8
38.2 41.6 79.8
effect on either hatchability or on chick weight. The only significant differences for main effects were between strains with the Shaver strain demonstrating a significantly lower hatchability but larger chick weight. This strain difference in hatchability and chick weight can possibly be attributed to egg size. Large eggs have lower hatchability and larger chick weights when compared with smaller eggs (Coles, 1956). It was obvious through visual inspection that the eggs of the Shaver strain were larger than those of the H&N strain. The only significant interaction was between incubation periods and trays in the analysis for hatchability percentages (Table 3). This effect might have been small if trays were truly random, but in this case the trays included two incubators, one of which hatched faster than the other. Additionally, since the hatchability percentages were analyzed at two different incubation periods, a large percentage of hatchability in incubation period 1 would automatically mean a small percentage of hatchability in
TABLE 5.—Body weight means ± SD of chicks hatched from control and electromagneticallytreated eggs (Trial 2) Treatments3-
Body weight (g)
0 DC-125 DC-160 AC-125 AC-160
37.97 37.94 38.09 38.34 38.19
1.07 b 1.19 .85 1.01 .99
Treatments 0, DC-125, DC-160, AC-125, and AC160 represent untreated controls, direct current — 125 gauss, direct current — 160 gauss, alternating current — 125 gauss, and alternating current — 160 gauss, respecively. Values expressed as means ± SD.
incubation period 2 which was exactly what happened with one of the incubators of this trial. These results led to an automatic negative correlation between the incubation periods which, coupled with the differences in the rate of hatchability between incubators, led to the large and significant interaction between incubation periods and trays. It is still reasonable to conclude that the interaction of incubation periods with treatments and strains was unimportant because even if their mean squares were tested by the sampling error, as they would be if tray effects were fixed, they would not be significant. Trial 2. The hatchability percentages for control and electromagnetically-treated eggs at two different incubation periods are shown in Table 4. The body weight means of chicks at hatching are presented in Table 5, and the analyses of variance of both variables are shown in Table 6. Both levels of EMG energy utilized in this trial, regardless of the type of current, resulted in hatchability percentages which were not significantly different from the controls. All treated eggs did show a numerical increase in total hatchability percentages. However, the orthogonal comparison between control and treated eggs provided an F value still below the 5% level of significance. The greatest difference in hatchability (4.7%) occurred between control eggs and those eggs treated with an EMG energy level of 125 gauss produced by a direct current (Table 4). Significant differences were apparent between incubation periods with a greater percentage of the eggs hatching during incubation period 2. Again, as a result of the negative correlation between incubation periods 1 and 2, the interaction of incubation period with tray, and with tray and treatment were also significant. However, the more meaningful
Downloaded from http://ps.oxfordjournals.org/ at Florida International University on June 15, 2015
Treatments 0, DC-125, DC-160, AC-125, and AC-160 represent untreated controls, direct current — 125 gauss, direct current — 160 gauss, alternating current — 125 gauss, and alternating current — 160 gauss, respectively.
ELECTROMAGNETIC FIELDS ON CHICKEN EGGS
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TABLE 6.—Analyses of variance of hatchability and body weight means of Trial 2 Mean squares
df
Source
27 4 108 140
Incubation period (H) a HX B H XT H XBXT H X S'/(B X T)
1 27 4 108 140
1.15 1.07 .75 .88
55.95* 8.94'* 3.68 10.40** 1.06
Body weight means 1.62 1.49 1.01 .99
Expected mean squares
( a | + a | ' ) / n + Og T + 284>x ( a | + ag')/n + CTgT (o% + a|.)/n (o\ + a^s'Vn + l O a ^ g + 28O0H / n + 1 0 < J H B ( a | + a^gO/n + 2 a | j B T + 5 6 0 H T ( a | + a|j S ')/n + 2 a ^ B T (a\ + a J HS -)/n
Applies only to hatchability analysis. *P«.05; **P«.01.
interaction beween incubation period and treatm e n t was nonsignificant, indicating t h a t t h e increase in p e r c e n t hatchability b e t w e e n t h e t w o incubation periods did n o t differ a m o n g treatments. Body weight means of Shaver chicks h a t c h e d from t r e a t e d eggs did n o t differ significantly from chicks h a t c h e d from u n t r e a t e d eggs (Table 5). Many environmental factors influence t h e hatchability of eggs. F o r this reason, maint e n a n c e of p r o p e r i n c u b a t o r conditions is necessary for maximizing t h e efficiency a n d profits of hatcheries. It is well k n o w n t h a t t e m p e r a t u r e and h u m i d i t y affect b o t h hatchability and hatching t i m e (Landauer, 1948). Additionally, p h o t o a c c e l e r a t i o n of e m b r y o n i c d e v e l o p m e n t occurs in t h e presence of light during incubation (Walter and Voitle, 1972). T h e influence of EMG fields on hatchability and hatching time of chicken eggs had n o t been previously considered. EMG fields are considered as an additional natural environmental factor since all living organisms are exposed t o .3 to .6 gauss EMG fields a t sea level (Aceto et al., 1 9 7 0 ) . In this s t u d y , EMG energy ranging from 9 0 t o 1 6 0 gauss "utilizing either direct or alternating curr e n t failed t o have any influence on hatchability, hatching time, or t h e b o d y weights of t h e chicks at h a t c h . ACKNOWLEDGEMENTS T h e a u t h o r s wish t o express their appreciation t o Micro-Magnetics C o m p a n y of Sterling
Heights, MI for t h e financial s u p p o r t of this work.
REFERENCES Aceto, H., Jr., C. A. Tobias, and I. L. Silver, 1970. Some studies on the biological effects of magnetic fields. IEEE Trans. Magnetics 6 : 3 6 8 - 3 7 3 . Amburn, R. D., 1976. Method of magnetically treating eggs and animal semen. United States Patent 3,991,714. Boe, A. A., and D. K. Salunkhe, 1963. Effects of magnetic fields on tomato ripening. Nature 199:91-92. Chao, L., and D. R. Walker, 1967. Effects of a magnetic field on the germination of apple, apricot, and peach seeds. Hort. Sci. 2:152—153. Coles, R., 1956. The influence of the hens egg weight on hatching. Poultry Sci. 35:817-822. Krueger, W. F., A. J. Giarola, J. W. Bradley, and A. Shrekenhamer, 1975. Effects of electromagnetic fields on fecundity in the chicken. Ann. N. Y. Acad. Sci. 247:391-400. Landauer, W., 1948. The hatchability of chicken eggs as influenced by environment and heredity. Connecticut (Storrs) Agr. Exp. Sta. Bull. 262. Larkin, R. P., and P. J. Sutherland, 1977. Migrating birds respond to project Seafarer's electromagnetic field. Science 195:777-779. Larkin, T. S., and W. T. Keeton, 1976. Bar magnets mask the effect of normal magnetic disturbances on pigeon orientation. J. Comp. Physiol. 110:227-231. Levengood, W. C , 1969. A new teratogenic agent applied to amphibian embryos. J. Embryol. Exp. Morph. 2 1 : 2 3 - 3 1 . Malinin, G. I., W. D. Gregory, L. Morelli, V. K. Sharma, and J. C. Houck, 1976. Evidence of morphological and physiological transformation of mammalian cells by strong magnetic fields. Sci-
Downloaded from http://ps.oxfordjournals.org/ at Florida International University on June 15, 2015
Block or tray (B) Treatment (T) BXT Sample (S')/(B X T)
Hatchability
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HESTER ET AL.
ence 194:844-846. McRee, D. 1., P. E. Hamrick, J. Zinkl, P. Thaxton, and C. R. Parkhurst, 1975. Some effects of exposure of the Japanese quail embryo to 2.45-GHz microwave radiaton. Ann. N. Y. Acad. Sci. 247:377-390. Van Ummerson, C. A., 1963. An experimental study of developmental abnormalities induced in the
chick embryo by exposure to radio frequency waves. Ph.D. dissertation. Tufts University, Medford, MA. Walter, J. H., and R. A. Voitle, 1972. Effects of photoperiod during incubation on embryonic and post-embryonic development of broilers. Poultry Sci. 51:1122-1126.
Downloaded from http://ps.oxfordjournals.org/ at Florida International University on June 15, 2015
INTRODUCTION T h e effects of electromagnetic (EMG) fields on biological systems have intrigued scientists for over a c e n t u r y (for a review, see A c e t o et al., 1 9 7 0 ) . Studies p e r f o r m e d on plant a n d animal species have s h o w n t h a t EMG fields can induce b o t h beneficial as well as detrimental effects. For example, t o m a t o e s , apple seeds and apricot seeds e x p o s e d t o EMG fields d e m o n strated such desired characteristics as an increase in ripening t i m e for t h e t o m a t o e s , a decrease in g e r m i n a t i o n t i m e , and an increase in t h e percentage germination for t h e seeds (Boe and Salunkhe, 1 9 6 3 ; Chao and Walker, 1 9 6 7 ) . In contrast, morphological abnormalities occurred in a m p h i b i a n and m a m m a l i a n cells when t r e a t e d with s t r o n g EMG fields (Levengood, 1 9 6 9 ; Malinin et al, 1 9 7 6 ) . Avian species have also been used in studies on EMG energy. F o r example, investigators have shown t h a t t h e migratory p a t t e r n s of birds are affected b y magnetic fields (Larkin a n d Keeton, 1 9 7 6 ; Larkin and Sutherland, 1 9 7 7 ) .
'Journal paper no. 7100 of the Purdue University Agricultural Experiment Station. 2 The use of trade names in this publication does not imply endorsement by the Purdue University Agricultural Experiment Station. 'Warsaw Agricultural University, Faculty of Animal Science, Rakowiecka 26/30, 02-528 Warsaw, Poland. 1978 Poultry Sci 57:1239-1244
These studies suggested t h a t t h e earth's magnetism served as an orientation guide for migrating birds. In additional studies related t o avian species, Krueger et al. ( 1 9 7 5 ) c o n t i n u o u s l y e x p o s e d commercial layers to l o w p o w e r very high frequency ( 2 6 0 MHz) and ultra-high freq u e n c y ( 9 1 5 MHz a n d 2 . 4 3 5 GHz) fields as well as low frequency magnetic (1.4 G) and electric fields ( 1 6 0 0 V / m ) . Although egg p r o d u c t i o n was reduced, t h e eggs collected from t h e electromagnetically-treated hens were n o t affected as indicated b y a n o r m a l sex ratio as well as fertility and hatchability percentages. Direct exposures of EMG energy o n quail and chicken eggs have been studied. M c R e e et al. ( 1 9 7 5 ) e x p o s e d J a p a n e s e quail eggs t o 2.45 GHz microwave radiation for 4 hr per day during t h e first 5 days of i n c u b a t i o n . Hatchability percentages, b o d y weights, and specific hematological p a r a m e t e r s were n o t unlike t h e controls. Van Ummersen ( 1 9 6 3 ) e x p o s e d 4 8 hr chick e m b r y o e s t o a microwave radiation of 2 4 5 0 MHz for 2 8 0 - 3 0 0 min. When t h e chick e m b r y o e s were e x a m i n e d at 96 hr of incubation, abnormalities in t h e growth a n d developm e n t of t h e t r e a t e d e m b r y o e s had occurred. A United States p a t e n t ( 3 , 9 1 0 , 2 3 3 ) issued O c t o ber 7, 1 9 7 5 claimed t h a t chicken eggs e x p o s e d t o EMG energy d e m o n s t r a t e d hatchability percentages which were 5 t o 8% greater t h a n u n t r e a t e d controls. T h e levels of EMG energy used t o d e m o n s t r a t e this increased hatchability ranged from 6 0 t o 1 2 0 G with an e x p o s u r e t i m e of 3 t o 10 sec per egg ( A m b u r n , 1 9 7 6 ) .
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Downloaded from http://ps.oxfordjournals.org/ at Florida International University on June 15, 2015
ABSTRACT White Leghorn eggs were exposed to electromagnetic (EMG) fields immediately prior to incubation. The hatchability percentages and body weight means of the chicks at hatch were compared with untreated controls. Data were collected for two different time periods of incubation, 0 to 20.5 and 20.5 to 21.5 days of incubation. In Trial 1, eggs of H&N and Shaver strains were exposed to a 90-gauss EMG field produced by a direct current. In Trial 2, eggs of the Shaver strain were exposed to the following four EMG treatments: 1) direct current, 125 gauss; 2) direct current, 160 gauss; 3) alternating current, 125 gauss; 4) alternating current, 160 gauss. The results of both trials indicated that no significant differences occurred in hatchability between electromagnetically-treated and control eggs. Hatching time and body weights at hatch were also not affected by the treatments in either trial.
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HESTER ET AL.
The purpose of this study was to evaluate the claims made by this United States patent description. Specifically, the objectives were to determine if the exposure of chicken eggs to EMG fields immediately prior to incubation would affect the percentage of hatchability, the time of hatch, or the body weights of the chicks at hatching. MATERIALS AND METHODS
After 18 days of incubation, the eggs from each incubation tray were transferred to Jamesway pedigree baskets for hatching. Three baskets were used at each tray level, and each was divided into three hatching compartments with
4
Patent number of magnetic coil is 3,910,233 issued October 7, 1975. 5 Model 505 Gaussmeter, Radio Frequency Laboratory Industries, Inc., Boonton, NJ 07005.
RESULTS AND DISCUSSION Trial 1. The percent hatchability means for the control and treated eggs for the Shaver and H&N strains for the two different incubation periods are presented in Table 1. The means of chick body weights at hatching are shown in Table 2, and the analyses of variance of both variables are shown in Table 3. An EMG field ot 90 gauss appears to have no
Downloaded from http://ps.oxfordjournals.org/ at Florida International University on June 15, 2015
White Leghorn chicken eggs obtained from commercial hatcheries were treated with various levels of EMG energy. The EMG fields were adjusted to specific gauss levels within a 4.5inch magnetic coil 4 through the use of a gaussmeter 5 . Each egg was individually rolled through the magnetic coil with an exposure time of approximately 3 sec. per egg. The eggs were rolled on a plastic packaging material to prevent breakage. For Trial 1, samples of 1232 White Leghorn eggs of the Shaver and H&N strains, respectively, were used. One-haf of the eggs (616) in each of the strains was exposed to an EMG field of 90 gauss produced by a direct current. The remaining eggs (616) of each strain served as untreated controls. Immediately following the administration of the treatment, the eggs were placed in trays for incubation. Two Jamesway 252 incubators with a total of 28 trays or blocks were used. Two samples of 10 eggs representing each of the four strain-treatment combinations were distributed at random within each tray for a total of 80 eggs per tray. Eight extra eggs for each of the eight groups were set in each tray to replace any eggs which were broken during incubation. The position of the eggs in each tray was staggered to provide for more even heat distribution among the eggs within each incubator. Proper dry and wet bulb temperatures were maintained throughout the experiment as recommended by the manufacturer.
two metal dividers. The eight experimental groups and the set of extra eggs were placed in the respective nine compartments using the same randomization scheme as assigned to the incubation trays. The chicks in each hatching basket were counted and weighed at 20.5 and 21.5 days of incubation. The time period between 0 and 20.5 days of incubation will be referred to as incubation period 1 while 20.5 through 21.5 days of incubation will be referred to as incubation period 2. The proportion of eggs set which hatched during each of the incubation periods was expressed as percentage of hatchability. Any chicks which hatched after 21.5 days of incubation were not included in the study. An analysis of variance with a factorial design including a split-plot was employed to determine the significance of any observed differences. Trays and samples were considered to be random variables while all other variables were assumed to be fixed. Trial 2 was similar to Trial 1 except that only the Shaver strain eggs were used and five treatments were compared. These included an untreated control, two types of current, direct and alternating, combined with two levels of EMG energy, 125 gauss and 160 gauss. A total of 3080 eggs was used, i.e. 616 eggs per treatment. Two samples of 10 eggs for each of the five treatments were distributed at random to each of the 28 trays for a total of 100 eggs per tray. An additional 10 eggs representing the 10 respective samples were incubated in each tray to replace any eggs broken during incubation. At 18 days of incubation, the 10 groups of experimental eggs and the set of reserve eggs from each incubator tray were transferred by groups to 11 hatching compartments. The hatching compartments for each tray level were formed from four Jamesway pedigree baskets each divided into three compartments by two metal dividers.
ELECTROMAGNETIC FIELDS ON CHICKEN EGGS
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TABLE 1.—Hatchability means for control and electromagnetically-treated eggs of Shaver and H&N strains at two different incubation periods (Trial 1) Incubation period Strain
Treatment
Shaver
Control EMG»
H&N
Control EMG a
Total
34.5 34.1
36.6 37.3
71.1 71.4
38.2 37.5
43.0 43.2
81.2 80.7
EMG treatment denotes a 90 gauss EMG field produced by a direct current.
TABLE 2 .—Body weight means ± SD at hatch of Shaver and H&N strains of chicks hatched from control and electromagnetically treated eggs (Trial 1) Body weight, g (treatment) Strain
Control
Shaver H&N Means
40.14 35.73 37.94
EMGa 2.72^ 2.06 3.27
40.21 35.35 37.78
Means 2.43 2.16 3.35
40.18 35.54 37.86
2.57 2.11 3.30
EMG treatment denotes a 90 gauss EMG field produced by a direct current. Values expressed as means ± SD.
TABLE 3.—Analyses of variance of hatchability and body weight means of Trial 1 Mean squares
Source
df
Hatchability
Block or tray (B) Treatment (T) B X T Strain (S) B X S TX S B XT X S Samples (S')/(B X T X S)
27 1 27 1 27 1 27 112
.75 .00 .90 26.52" .72 .06 .68 .92
I n c u b a t i o n period ( H ) a H X B H X T H X B X T HX S H X B X S H XT X S H X B X TX S H X S 7 ( S X T X B)
1 27 1 27 1 27 1 27 112
17.68 67.23** .27 7.60 1.88 4.00 .00 4.69 4.68
Applies only to hatchability analysis. **P<.01.
Body weight means 7.47 1.25 4.99 1205.05** 4.36 2.87 3.17 6.09
Expected mean squares
( o j + og')/n (a 2 + a g ' ) / n (ol +
<°s
(°l
+ + + + + +
a g T + 280x aBT 2o|jS + 560s 2a2BS CTgTS + 280XS okTS
a n s ' ) / n + 4 CT HB + 1 1 2 0 H a2HS')/n + 4a2HB + a f ^ O / n + 2af4BT + 560HT + c2HS0/n + 2 a 2 H B T
<<* + <<* +
K
(°e (ae
+
(ae + + + (o| +
<°J (4
CT HS')/n + 4 o H B S + 1 1 2 * H S ofeO/n + 4a2HBS afjgO/n + 2 < J | J B T S + 5 6 0 H T S o2HS')/n + 2 a | j B T S afjsO/n
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a
II
HESTER ET AL.
1242
TABLE 4.—Hatchability means (%) for control and electromagnetically-treated at two different incubation periods (Trial 2)
eggs
Treatments a periods
0
DC-125
DC-160
AC-125
AC-160
I 11 Total
36.6 40.7 77.3
37.9 44.1 82.0
34.5 47.0 81.5
38.2 43.6 81.8
38.2 41.6 79.8
effect on either hatchability or on chick weight. The only significant differences for main effects were between strains with the Shaver strain demonstrating a significantly lower hatchability but larger chick weight. This strain difference in hatchability and chick weight can possibly be attributed to egg size. Large eggs have lower hatchability and larger chick weights when compared with smaller eggs (Coles, 1956). It was obvious through visual inspection that the eggs of the Shaver strain were larger than those of the H&N strain. The only significant interaction was between incubation periods and trays in the analysis for hatchability percentages (Table 3). This effect might have been small if trays were truly random, but in this case the trays included two incubators, one of which hatched faster than the other. Additionally, since the hatchability percentages were analyzed at two different incubation periods, a large percentage of hatchability in incubation period 1 would automatically mean a small percentage of hatchability in
TABLE 5.—Body weight means ± SD of chicks hatched from control and electromagneticallytreated eggs (Trial 2) Treatments3-
Body weight (g)
0 DC-125 DC-160 AC-125 AC-160
37.97 37.94 38.09 38.34 38.19
1.07 b 1.19 .85 1.01 .99
Treatments 0, DC-125, DC-160, AC-125, and AC160 represent untreated controls, direct current — 125 gauss, direct current — 160 gauss, alternating current — 125 gauss, and alternating current — 160 gauss, respecively. Values expressed as means ± SD.
incubation period 2 which was exactly what happened with one of the incubators of this trial. These results led to an automatic negative correlation between the incubation periods which, coupled with the differences in the rate of hatchability between incubators, led to the large and significant interaction between incubation periods and trays. It is still reasonable to conclude that the interaction of incubation periods with treatments and strains was unimportant because even if their mean squares were tested by the sampling error, as they would be if tray effects were fixed, they would not be significant. Trial 2. The hatchability percentages for control and electromagnetically-treated eggs at two different incubation periods are shown in Table 4. The body weight means of chicks at hatching are presented in Table 5, and the analyses of variance of both variables are shown in Table 6. Both levels of EMG energy utilized in this trial, regardless of the type of current, resulted in hatchability percentages which were not significantly different from the controls. All treated eggs did show a numerical increase in total hatchability percentages. However, the orthogonal comparison between control and treated eggs provided an F value still below the 5% level of significance. The greatest difference in hatchability (4.7%) occurred between control eggs and those eggs treated with an EMG energy level of 125 gauss produced by a direct current (Table 4). Significant differences were apparent between incubation periods with a greater percentage of the eggs hatching during incubation period 2. Again, as a result of the negative correlation between incubation periods 1 and 2, the interaction of incubation period with tray, and with tray and treatment were also significant. However, the more meaningful
Downloaded from http://ps.oxfordjournals.org/ at Florida International University on June 15, 2015
Treatments 0, DC-125, DC-160, AC-125, and AC-160 represent untreated controls, direct current — 125 gauss, direct current — 160 gauss, alternating current — 125 gauss, and alternating current — 160 gauss, respectively.
ELECTROMAGNETIC FIELDS ON CHICKEN EGGS
1243
TABLE 6.—Analyses of variance of hatchability and body weight means of Trial 2 Mean squares
df
Source
27 4 108 140
Incubation period (H) a HX B H XT H XBXT H X S'/(B X T)
1 27 4 108 140
1.15 1.07 .75 .88
55.95* 8.94'* 3.68 10.40** 1.06
Body weight means 1.62 1.49 1.01 .99
Expected mean squares
( a | + a | ' ) / n + Og T + 284>x ( a | + ag')/n + CTgT (o% + a|.)/n (o\ + a^s'Vn + l O a ^ g + 28O0H
Applies only to hatchability analysis. *P«.05; **P«.01.
interaction beween incubation period and treatm e n t was nonsignificant, indicating t h a t t h e increase in p e r c e n t hatchability b e t w e e n t h e t w o incubation periods did n o t differ a m o n g treatments. Body weight means of Shaver chicks h a t c h e d from t r e a t e d eggs did n o t differ significantly from chicks h a t c h e d from u n t r e a t e d eggs (Table 5). Many environmental factors influence t h e hatchability of eggs. F o r this reason, maint e n a n c e of p r o p e r i n c u b a t o r conditions is necessary for maximizing t h e efficiency a n d profits of hatcheries. It is well k n o w n t h a t t e m p e r a t u r e and h u m i d i t y affect b o t h hatchability and hatching t i m e (Landauer, 1948). Additionally, p h o t o a c c e l e r a t i o n of e m b r y o n i c d e v e l o p m e n t occurs in t h e presence of light during incubation (Walter and Voitle, 1972). T h e influence of EMG fields on hatchability and hatching time of chicken eggs had n o t been previously considered. EMG fields are considered as an additional natural environmental factor since all living organisms are exposed t o .3 to .6 gauss EMG fields a t sea level (Aceto et al., 1 9 7 0 ) . In this s t u d y , EMG energy ranging from 9 0 t o 1 6 0 gauss "utilizing either direct or alternating curr e n t failed t o have any influence on hatchability, hatching time, or t h e b o d y weights of t h e chicks at h a t c h . ACKNOWLEDGEMENTS T h e a u t h o r s wish t o express their appreciation t o Micro-Magnetics C o m p a n y of Sterling
Heights, MI for t h e financial s u p p o r t of this work.
REFERENCES Aceto, H., Jr., C. A. Tobias, and I. L. Silver, 1970. Some studies on the biological effects of magnetic fields. IEEE Trans. Magnetics 6 : 3 6 8 - 3 7 3 . Amburn, R. D., 1976. Method of magnetically treating eggs and animal semen. United States Patent 3,991,714. Boe, A. A., and D. K. Salunkhe, 1963. Effects of magnetic fields on tomato ripening. Nature 199:91-92. Chao, L., and D. R. Walker, 1967. Effects of a magnetic field on the germination of apple, apricot, and peach seeds. Hort. Sci. 2:152—153. Coles, R., 1956. The influence of the hens egg weight on hatching. Poultry Sci. 35:817-822. Krueger, W. F., A. J. Giarola, J. W. Bradley, and A. Shrekenhamer, 1975. Effects of electromagnetic fields on fecundity in the chicken. Ann. N. Y. Acad. Sci. 247:391-400. Landauer, W., 1948. The hatchability of chicken eggs as influenced by environment and heredity. Connecticut (Storrs) Agr. Exp. Sta. Bull. 262. Larkin, R. P., and P. J. Sutherland, 1977. Migrating birds respond to project Seafarer's electromagnetic field. Science 195:777-779. Larkin, T. S., and W. T. Keeton, 1976. Bar magnets mask the effect of normal magnetic disturbances on pigeon orientation. J. Comp. Physiol. 110:227-231. Levengood, W. C , 1969. A new teratogenic agent applied to amphibian embryos. J. Embryol. Exp. Morph. 2 1 : 2 3 - 3 1 . Malinin, G. I., W. D. Gregory, L. Morelli, V. K. Sharma, and J. C. Houck, 1976. Evidence of morphological and physiological transformation of mammalian cells by strong magnetic fields. Sci-
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Block or tray (B) Treatment (T) BXT Sample (S')/(B X T)
Hatchability
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HESTER ET AL.
ence 194:844-846. McRee, D. 1., P. E. Hamrick, J. Zinkl, P. Thaxton, and C. R. Parkhurst, 1975. Some effects of exposure of the Japanese quail embryo to 2.45-GHz microwave radiaton. Ann. N. Y. Acad. Sci. 247:377-390. Van Ummerson, C. A., 1963. An experimental study of developmental abnormalities induced in the
chick embryo by exposure to radio frequency waves. Ph.D. dissertation. Tufts University, Medford, MA. Walter, J. H., and R. A. Voitle, 1972. Effects of photoperiod during incubation on embryonic and post-embryonic development of broilers. Poultry Sci. 51:1122-1126.
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