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

Abstract

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.