Toxicological and nutritional evaluation of velvetleaf seed: subchronic 90-day feeding study and protein efficiency ratio assay.

Velvetleaf seed, a common weed contaminant in grain, was fed to male and female rats (20 per group) in a 90-day subchronic feeding study. Diets contained 0, 2.5, 5.0 or 10.0% seed. Gross clinical observations, body weights, and feed and water intake data were recorded weekly. After 91-93 days, all of the animals were autopsied, organ weights were obtained, and clinical chemistry analyses, haematology and bone-marrow evaluation for evidence of clastogenic effects were performed. Tissues from control (0% seed) and high-dose animals were examined histologically. Few effects from velvetleaf seed in the diet were noted. Body-weight gain, water consumption, organ weights, bone marrow, and haematology measurements were similar to those of control rats. Male rats fed 2.5 or 10% seed consumed less feed/kg body weight than did the controls. For males fed 10% seed, the alkaline phosphatase concentration and albumin:globulin ratio were significantly increased compared with the 0% control values. For females fed 10% seed, serum glucose and cholesterol values were decreased compared with those for groups fed 0 or 2.5% seed. No histopathology was associated with ingestion of 10% velvetleaf seed. The protein quality (protein efficiency ratio) of velvetleaf seed, although lower than that of casein, was higher than values reported in the literature for corn, wheat and soya.