Effects of exposure to clothianidin on the reproductive system of male quails.

Clothianidin (CTD) is a neonicotinoid developed in the 1990s as an insecticide having selective toxicity, but it was later found to cause reproductive abnormalities in rats through oxidative stress. There is an attempt to preserve endangered animals, including the Japanese crested ibis, in Japan. However, there is a concern that neonicotinoid affects the reproduction of this bird, since it is used in its habitat. CTD toxicity in the birds is poorly understood, so we investigated whether or not the daily oral administration of CTD has any deleterious effects on the reproductive functions of mature male quails as experimental animals. The animals were randomly divided into four groups of 6 or 7 quails each, treated orally with 0, 0.02, 1 or 50 mg CTD/kg body weight (Control, CTD0.02, CTD1 and CTD50). After that the males bred with untreated females to estimate the egg weights, and rates of fertilization and normal development, the testes, liver and spleen were examined histologically. Vacuolization and the number of germ cells having fragmented DNA in seminiferous tubules, and the number and size of vacuoles in hepatocytes increased dose-dependently. There were no significant differences in egg weights and fertilization rates between the groups, but some eggs of the CTD1 and CTD50 groups failed to develop, and embryonic length decreased dose-dependently. Thus, it was found that CTD affected the reproduction of the male quail through the fragmentation of germ cells and the inhibition or delay of embryonic development.

Metabolic effects of D-psicose in rats: studies on faecal and urinary excretion and caecal fermentation.

D-psicose (D -ribo-2-hexulose), a C-3 epimer of D-fructose, is one of the "rare sugars" present in small quantities in commercial carbohydrate complex or agricultural products. We investigated the absorption and excretion of D-psicose when orally administrated (5g/kg body weight) to Wistar rats, and the fermentation of D-psicose was measured as caecal short-chain fatty acids (SCFAs) when fed to rats in controlled diets (0, 10, 20 and 30%). Urinary and faecal excretions of D-psicose over the 24 h, following a single oral administration, were 11-15% of dosage for the former and 8-13% of dosage for the latter. Serum D-psicose concentration and D-psicose in the contents of stomach and small intestines decreased progressively after administration. D-psicose in caecum contents was detected after 3h and 7h administration, but not after 1h. Rats fed on D-psicose diets showed short-chain fatty acid production with caecal hypertrophy. These results suggest that D-psicose is partly absorbable in the digestive tract and is excreted into urine and faeces. As with other poorly absorbed dietary carbohydrates, D-psicose is fermented in the caecum by intestinal microflora.

D-psicose is a rare sugar that provides no energy to growing rats.

D-Psicose (D-ribo-2-hexulose), a C-3 epimer of D-fructose, is present in small quantities in commercial carbohydrate complexes and agricultural products. We have previously reported that D-psicose supplements in diets suppressed hepatic lipogenic enzyme activity The lower fat accumulation in rats fed D-psicose may be due to lower lipogenesis in the liver. The present study examined the energy available in D-psicose for rat growth. Male Wistar rats received 7 g daily of a basal diet to which fixed amounts of sucrose, D-fructose, or D-psicose (0.5-2.0 g) were added for 20 d. Body weight gain and body energy gain increased with increases in sucrose and D-fructose, but not with D-psicose. One gram of sucrose, D-fructose, and D-psicose produced a net energy gain of 2.29, 1.76, and 0.007 kcal, respectively. The efficiency of energy deposition from D-psicose was 0.3% that of sucrose. The energy value of D-psicose was effectively zero. These results suggest that D-psicose is a rare sugar providing zero energy that may be useful in sweeteners for obese people as an aid for weight reduction.

Effects of oral acute administration and subchronic feeding of several levels of D-psicose in rats.

The effects of oral acute administration and subchronic (34 d) feeding of several levels of D-psicose, a C3-epimer of D-fructose, were studied in rats. In the acute administration test, five groups of eight male Wistar rats (3 wk old) were orally given D-psicose in doses of 8, 11, 14, 17, and 20 g/kg. Three rats receiving 14 g/kg, three rats receiving 17 g/kg and eight rats receiving 20 g/kg of D-psicose died within 2 d after administration. The calculated LD50 values were 16.3 g/kg by the Behrens-Karber method and 15.8 g/kg by the Litchfield-Wilcoxon method. In the subcronic feeding test, eight groups of seven male Wistar rats (3 wk old) were fed diets containing 0 (control), 10, 20, 30, and 40% for 34 d. One rat fed 30% D-psicose diet and five rats fed 40% D-psicose diet died during the experimental period. Body weight gain, food intake and food efficiency were more extensively suppressed by the higher D-psicose diets. The weights of heart, spleen and abdominal adipose tissue were smaller in the order of dietary D-psicose concentration. Cecal weight increased with increasing D-psicose concentration in the diets. Cecal hypertrophy was observed in rats fed 10-40% D-psicose diets. These results suggest that D-psicose differs in nutritional characteristics from D-glucose or D-fructose. The feeding of diets extremely high in D-psicose seems to be harmful to the intestinal tract.