Complex study of the physiological role of cadmium. II. Effect of cadmium load on the cadmium content of eggs.
The possibility of "cadmium (Cd) contamination" of eggs and the dynamics of Cd accumulation were studied. A total of 40 (4 x 10) Japanese quails weighing 155-200 g, being at the middle phase of egg production and kept on batteries in a climatized animal house were used. The birds were fed a standard quail layer diet and drank tap-water ad libitum. With the exception of the control group (Cd-0), the diet of the other three groups was supplemented with Cd sulphate homogeneously mixed in the diet so that it contained 75 mg (Cd-75), 150 mg (Cd-150) and 300 mg (Cd-300) per kg. During the 37-day feeding trial the quails' behaviour, health status and daily egg production were monitored and the birds were weighed weekly. The egg production of the experimental groups, particularly of those exposed to a high Cd load, rapidly decreased: at the highest Cd load (300 ppm) egg production completely ceased at days 10-11 of the trial. The total Cd content of the eggs rose already from the 3rd day of the feeding trial and by day 10 it reached a value of 0.777 mg/kg dry matter in the eggs of quails of group Cd-75. This was about five times the value measured in the control quails' eggs (0.165 mg/kg dry matter). The Cd content of the egg-white and egg-yolk (maximum values: 0.212 and 0.107 mg/kg dry matter) also increased to about 2 or 3 times that measured in the control eggs. The Cd content of eggs reached the peak in the 2nd week of the feeding trial, then started to decrease, and in the 3rd and 4th weeks not even the eggs laid by quails exposed to a high Cd load contained more Cd than about twice the concentration measured in the controls' eggs. The elucidation of this hitherto not studied process requires further investigations. The phenomenon may be due to a lack of the protein necessary for Cd transport and to the impairment of Cd absorption and of the excretory activity of the oviduct. The higher Cd concentrations measured in the egg were accompanied by markedly elevated Fe, K and S values. In the egg samples collected in the 4th week a substantial reduction in Ca and P concentration was observed. As regards the mineral elements measured in the egg-shell, a significant negative correlation was established between the concentration of Cd and those of Zn, Mg and Ca.(ABSTRACT TRUNCATED AT 400 WORDS)
Bokori
J
J
Department of Animal Nutrition, University of Veterinary Science, Budapest, Hungary.
Fekete
S
S
Kádár
I
I
Albert
M
M
D000818:Animals; D001842:Bone and Bones / Q000187:drug effects / Q000473:pathology; D002104:Cadmium / Q000032:analysis / Q000378:metabolism* / Q000633:toxicity*; D003370:Coturnix / Q000502:physiology*; D004531:Eggs / Q000032:analysis / Q000592:standards; D005260:Female; D006304:Health Status; D008099:Liver / Q000187:drug effects / Q000473:pathology; D010053:Ovary / Q000187:drug effects; D010057:Oviducts / Q000187:drug effects; D010058:Oviposition / Q000187:drug effects
D002104:Cadmium