ORGAN CONTENT AND FECAL EXCRETION OF CADMIUM IN MALE AND FEMALE RATS CONSUMING VARIABLE AMOUNTS OF NATURALLY-OCCURRING CADMIUM IN CONFECTIONERY SUNFLOWER KERNELS (HELIANTHUS-ANNUUS L.)

Sunflowers (Helianthus annuus L.) tend to remove cadmium (Cd)from the soil and deposit it in their seeds. The availability of Cd in sunflowe r kernels for absorption and deposition in animal tissues was studied using a 15-week feeding trial with both male and female rats begun at weanling age. Diets included (I) purified basal diet with no sunflower kernels (85 mu g Cd/kg), (2) basal diet containing 20% ground low-Cd sunflower kernels (120 mu g Cd/kg), (3) basal diet containing 20% grou nd high-Cd sunflower kernels (195 mu g Cd/kg), and (4) basal diet cont aining 20% ground low-Cd sunflower kernels plus Cd chloride (175 mu g Cd/kg). In a second experiment, adult rats were fed sunflower kernels that contained an endogenous or exogenous label of Cd-109. Cd availabi lity was assessed by measuring Cd-109 excretion in feces and by measur ing the amount of label accumulated in liver and kidney. Results were as follows: (I) Although all diets were of similar nutrient compositio n, female rats that consumed diets containing 20% ground sunflower ker nels gained significantly (P < 0.02) more weight than those without ke rnels in their diets. Increased weight was not the result of increased feed intake. (2) Increasing Cd intake twofold as a result of feeding sunflower kernels significantly (P < 0.001) increased the body burden (total liver plus kidney content) of Cd from 1.6 to 4.0 nmol in female s and from 4.0 to 7.0 nmol in males. (3) The availability of Cd from s unflower kernels labeled endogenously with Cd-109 was not different (P > 0.1) than kernels labeled exogenously: 12% versus15%, respectively. Eight days after dosing, total liver Cd-109,vas 1% of the initial dos e; at 20 days it was only 0.3%. The corresponding amounts in kidney we re 0.1% 8 days after dosing and 0.2% 20 days after dosing. The amount of label in liver and kidney was not affected by the method of labelin g the kernels. This study clearly shows that Cd from sunflower kernels is available for absorption and accumulation in tissues of the rat, a lthough in very small concentrations. Published by Elsevier Science In c. 1998.