However, none of the changes could definitely be ascribed to radiation. Sections of bone examined by Lisco at ANL indicated no detectable pathological changes.
3.5
EGG PRODUCTION IN CHICKENS
In birds extraordinary demands are made on the calcium metabolism in the production of
egg shells. It was, therefore, of particular interest to observe, during the process of egg production, the metabolism of those internally deposited radioelements that are metabolically
similar to calcium.
Forty-four days after detonation, a group of hens from Rongelap began laying eggs for the
first time since their collection. During the next month and a half, 319 eggs were laid by 13
hens. All the eggs were normal except for two eggs from one hen which were laid without
shells. The shells were complete, smooth and of normal shape. The weights of the eggs ranged
from 30 to 64 g, but those from a given hen were of uniform weight. In 14 eggs studied, the
shell and membranes weighed an average of 13.6 per cent of the whole egg weight, and the ashed
shell weighed 6.8 per cent of the whole egg weight. These values are within the normal range
for eggs of domestic hens.
The gross beta and gammaactivities of the shell, albumen, and yolk were measured in the
first 50 eggs obtained, and the gammaactivity of the shell was measured in the remainderof
the eggs. An increasing amount of gammaactivity appeared in the shells of the first few eggs
laid by each hen. The maximum gammaactivity was usually noted in about the eighth egg laid.
After the activity reached a maximum value, the subsequent eggs in the series showed a general
decline in activity. An example of this phenomenonis illustrated in Fig. 3.8.
The highest gammaactivity found in a single egg shell was 66,300 counts/min, measured
at 60 days postdetonation (Fig. 3.8). For a gamma energy of approximately 1 Mev, this figure
corresponds to 0.07 uc. The yolks and albumens had much less activity than the shells, as was
anticipated. The average distribution of gammaactivity in the eggs is given in Table 3.5.
The results of the radiochemical analysis of two eggs are presented in Table 3.6.
The alkaline earths are the principal fission products deposited in the shell. In the albumen and yolk the beta activity contributed by the alkaline earths was only a little greater than
that associated with the rare earths.
The pattern of deposition of the radioactivity within the egg was also studied by means of
autoradiographs. A series of 50 eggs was hard boiled and sectioned, and autoradiographs were
prepared of the cut surfaces. Only four of the yolks of these 50 eggs were sufficiently radioactive to produce autoradiographs (see Fig. 3.9). There is a correlation between the rings of
radioactivity in the yolk and those of pigment.
The amountof activity removed from the body of the chicken through egg laying is very
much greater than the amount excreted in the urine and feces during the period of this study.
Egg production in the chicken represents a unique form of natural decontamination.
3.6
FERTILITY AND HATCHABILITY STUDIES IN CHICKENS
Fertility studies on the contaminated chickens were begun three and one half months post-
detonation, with the mating of hens and roosters and the incubation of the eggs obtained. In the
first clutch of 20 eggs, four were hatched. One of the chicks had the crippling slipped-tendon
condition, congenital perosis, which is not uncommon. Radioanalysis of the chick tissues indicated that only a barely detectable amount of radioactive material was transferred to the chick,
although the mother hen had at this time an appreciable contamination.
In another hatch six months postdetonation, 65 eggs were incubated. Of these, 28 were
infertile, 3 fertile ones were opened prematurely, 11 developed complete embryosbutfailed to
hatch, and 23 live chicks were hatched, one of which had congenital perosis. The latter chick
and six normal ones were sacrificed and their tissues radioanalyzed. Again, only barely detectable amountsof internally deposited activity were found. The remaining baby chicks are
being raised and observed for possible long-term effects. At the present time all the chicks
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