Toxicological evaluation of morning glory seed: subchronic 90-day feeding study.

Diets containing 0.8, 2.53 and 8.0% field variety morning glory seed were fed to male and female rats (20 per group) in a 90-day subchronic feeding study. Gross clinical observations, body weight, and feed and water intake were recorded weekly. At 90 days, all surviving rats were autopsied, organs were weighed, and blood chemistry analyses, haematology, and bone-marrow evaluation for evidence of clastogenic effects were performed. Tissues from control (0% seed) and high-dose (8.0% seed) rats were examined histologically. Effects of morning glory seed were noted mainly in the high-dose group of both sexes. These included increases in mortality, feed consumption (on a body-weight basis), water consumption, serum alkaline phosphatase and potassium, white blood cell count, and brain and liver weights (as a percentage of body weight); body-weight gain and serum glucose were decreased. Significant changes seen in high-dose females alone were: increased haemoglobin, serum constituents (urea nitrogen, glutamic-pyruvic transaminase, glutamic-oxaloacetic transaminase, and ornithine carbamyl transferase), and organ weights (heart, kidney, spleen and pancreas as a percentage of body weight), and decreases in serum albumin, total protein, albumin:globulin ratio, and calcium. Significant changes occurring in high-dose males alone were: increased testicular weight (as a percentage of body weight), increased serum phosphorus, and decreased serum cholesterol. Liver degeneration in the high-dose females was greater than that in the controls. Mortality at 8.0% seed in the diet was 40% in males and 10% in females. At 0.8% seed, the only parameter that differed significantly from that of the controls was a final body-weight reduction in females without a corresponding reduction in feed consumption.

Toxicological evaluation of sicklepod and black nightshade seeds in short-term feeding studies in rats.

Nutritionally complete diets containing sicklepod or black nightshade seed at 1, 2, 4, 8, 16 and 32% were fed to groups of three to five male Sprague-Dawley rats in a series of short-term (8-9 days) toxicity studies. Gross clinical observations, body weights and feed and water intake data were recorded. Clinical chemistry analyses, haematology, histology and bone-marrow evaluation for evidence of clastogenic effects were performed. In addition, groups of five female rats were fed sicklepod seed at the same dosages to compare effects on body weight and feed and water consumption. For sicklepod, all of the animals fed diet containing 32% seed and one (female) fed diet containing 16% seed died by day 8. Body-weight gain and feed and water consumption were decreased with increasing doses of sicklepod seed. Other effects of sicklepod seed included: testicular hypospermia at dosages of 8% or greater, and bone-marrow depletion, reduced numbers of polychromatic erythrocytes in the bone marrow, increased neutrophil:lymphocyte ratio, and red nasal discharge at 16%. Black nightshade seed was relatively non-toxic compared with the sicklepod. The principal adverse effects of black nightshade were decreased body-weight gain and feed consumption, which occurred during the first 3 days of the study in animals fed 32% seed.

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.

Toxicological evaluation of jimson weed (Datura stramonium) seed.

Diets containing 0.5, 1.58 and 5.0% jimson weed seed were fed to male and female rats (20/group) in a 90-day subchronic feeding study. The alkaloid content was 2.71 mg atropine and 0.66 mg scopolamine/g of seed. Gross clinical observations, body weights and feed and water intakes were recorded weekly. Tear production and pupil dilation measurements were made throughout the study. At 90 days, all of the animals were autopsied and clinical-chemistry analyses, complete haematology and bone-marrow evaluation for evidence of clastogenic effects were performed. Tissues from control (0% seed) and high-dose animals were examined histologically. The principal effects of jimson weed seed were: decreased body-weight gain, serum albumin and serum calcium; increased liver and testes weights (as a percentage of body weight), serum alkaline phosphatase and blood urea nitrogen. Female rats showed more marked responses to jimson weed seed than did males. In addition to the effects seen in both sexes, the females developed decreased serum total protein and cholesterol, and increased serum glutamic-pyruvic transaminase and chloride, red blood cell count, haemoglobin concentration and packed red cell volume. No histological lesions were associated with ingestion of jimson weed seed at 5.0%. It is concluded that jimson weed seed at concentrations of 0.5% or more in the diet produced adverse physiological changes in rats.

Safety of trypsin inhibitors in the diet: effects on the rat pancreas of long-term feeding of soy flour and soy protein isolate.

The effects on the pancreas of chronic dietary exposure to defatted soy flour and soy protein isolate have been studied in two two-year feeding trials in rats. Emphasis was placed on detecting changes that might accompany low levels of dietary trypsin inhibitor (TI) as might be found in edible grade soy products and on studying the influence of protein nutrition. The major pathological findings in the pancreas were nodular hyperplasia (NH), consisting of foci of hyperplastic acinar cells often grossly visible by six months, and the benign neoplastic lesion, acinar adenoma (AA), which developed more slowly. In the first feeding trial, the objectives were to obtain the dose-response relationship of pancreatic pathology to dietary TI provided by raw and heated soy flour and to study the nutritional interaction of protein level which was varied from 10% to 30% using casein supplementation. Also, the responses to raw and heated soy protein isolate were compared to determine whether the removal of more than 50% of the constituents found in soy flour would alter the development of pancreatic lesions. In the second trial, the effect of unusually low levels of TI in raw and heat-treated soy protein isolate, prepared through a salt extraction process and fed at 10% and 30% protein in the diet, was investigated. The incidence of both NH and AA was positively related to the TI content of the diet. The probit transformation of the percent incidence of AA was linearly related to the log of TI/g protein in the diet. A single curve best described the response to 20% and 30% protein, with a slope that was distinctly greater than that for 10% protein. The intersection of the two curves near the TI concentration of edible grade soy flour predicts that protein level in the diet can be expected to have essentially no effect on the incidence of AA when TI activity is in this range. But, for proteins containing greater concentrations of TI, increasing the level of protein in the diet will increase the incidence of pancreatic pathology, while for proteins with quite low levels of TI, increasing the protein in the diet above 10% will have a protective effect.(ABSTRACT TRUNCATED AT 400 WORDS)

Pancreatic response in rats and mice to trypsin inhibitors from soy and potato after short- and long-term dietary exposure.

The effects on the pancreas of chronic (95 wk) dietary exposure to protease inhibitors from soy and potato were compared in rats and mice. Soy and potato trypsin inhibitor (TI) concentrates were prepared from defatted raw soy flour and potato juice, respectively, by selective precipitation and ultrafiltration. Animals were fed a diet in which casein supplied approximately 20% protein. Each concentrate (less than 1% of the diet) was added to provide 100 and 200 mg of trypsin inhibitor activity per 100 g of diet. In short-term (28 d) experiments in rats, both sources of TI decreased the apparent nutritional quality of casein and produced pancreatic hypertrophy consistent with a hormonally mediated feedback mechanism for pancreatic adaptation to diet that is interactive with the nutritional status of the animal. After long-term feeding (95 wk), soy and potato TI produced dose-related pancreatic pathology in rats consisting of nodular hyperplasia and acinar adenoma, which was typical of that associated with raw soy flour. Although mice responded similarly to rats to soy TI in short-term (28-d) feeding experiments, they were resistant to the formation of these lesions following long-term feeding. This considerable species variation in propensity to develop preneoplastic and neoplastic lesions of the pancreas is not predicted by the short-term hypertrophic and hyperplastic response of the pancreas to TI.