We investigated the 1-deoxynojirimycin (1-DNJ) content of extracts from silkworm larvae at each developmental stage within three silkworm varieties. We also compared the content of the following polyhydroxylated alkaloids in the silkworm extracts: 1-DNJ, fagomine, and 1,4-dideoxy-1,4-imino-d-arabinitol (DAB). In addition, we evaluated the glucose-lowering effects of silkworm extract powder in db/db mice. The 1-DNJ content was the highest in Yeonnokjam 5 th instar 3 rd d larvae and Hansaengjam 5 th instar 3 rd d larvae, which contained 18.4 mg/100 g dry weight and 18.3 mg/100 g dry weight, respectively. The 5 th instar 3 rd d larvae exhibited a higher content of 1-DNJ than that of 5 th instar 5th d larvae among all varieties. The glucose-lowering effects of silkworm extracts and Yeonnokjam powder were tested on db/db mice, and the blood glucose levels were found to decrease significantly in the YR70 group. Silkworm extracts (180 mg/kg, 90 mg/kg, 45 mg/kg, and 22.5 mg/kg) and acarbose (50 mg/kg) were administered orally for 4 wk. Changes in water intake were not statistically significant between control and silkworm extract-treated groups. Compared to the control group, blood glucose levels in the silkworm extract powder-treated group decreased in the 22.5 mg/kg/d group after being administered for 4 wk. This decrease was statistically significant. Furthermore, biochemical changes in the AST(Aspartate aminotransferase), ALT(Alanine aminotransferase), TCHO(Total Cholesterol), TG(Triglyceride), LDL(Low density lipoprotein), and HDL(High density lipoprotein) levels in blood were not observed. However, statistically significant decreases in blood GLU in the 22.5 mg/kg/d group compared to that of the control group occurred. In addition, the epididymal fat weight of the silkworm extract powder-treated group decreased significantly in both the 22.5 mg/kg/d group and 180 mg/kg/d group compared to that of the control group, but there were no statistically significant changes in perirenal fat weight. These results demonstrate that silkworm extracts inhibit changes in blood glucose levels in model diabetic mice. Measurement of fasting blood glucose levelsFasting blood glucose levels were measured after the animals fasted for 3 h for 4 wk. The db/db mice were obtained from Japan SLC, Inc (Japan), and animals at 6 wk of age were used.Blood glucose levels were determined in mouse blood samples from the tail vein using a glucose analyzer (Accu-Chek Active;Roche Diagnostics GmbH, Germany). Blood glucose levels were determined in blood samples from the tail vein at 0 min (prior to maltose administration), 30 min, 60 min, 90 min, and 120 min after maltose administration for glucose tolerance tests. Administration of silkworm extracts to db/db miceMale C57BL/KSJ-(db/db) mice (6 wk old) were purchased from Japan SLC, Inc (Japan). They were housed in a conventional state with the appropriate temperature (23°C ± 3°C) and humidity (55% ± 15%) under a 12-h light/12-h dark cycle with free access to food and water. All groups were fed a s...

This study was conducted to confirm the mass production of male pupae and sex-limited larval marking variety as a host for synnemata production of Isaria tenupes in RDA(Rural Development Administration). Silkworm pupation, infection rate and synnemate formation of I.tenuipes were examined. Among the silkworm varieties tested, male Hansaengjam showed the highest pupation rate at 98.7%. I. tenuipes infection rate of larvae of newly-exuviated 5th instar silkworm was 83.7~90.4% in the spring rearing season and 91.7~96.6% in the autumn rearing season. Synnemata production of I. tenuipes was execellent in female Yangwonjam with an incidence rate of 99.5% followed by male Yangwonjam(99.5%) and Baegokjam(99.4%)