Basic studies on the development of a low-cost artificial diet for the silkworms and the establishment of a year-round sericulture system

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The aim of the present study is to establish a year-round sericulture system to carry out a year-round sericulture in Japan, to produce high quality cocoons throughout the year, thereby to activate the sericultural industry in Japan.A new artificial diet was developed which included bean-curd lees, an industrial waste, in place of defatted soy bean powder as much as 50% for the grown silkworm larvae. A new preparation method of mulberry leaf powder with low facility cost, i.e., by drying mulberry leaves in the sun was developed. The required amount of dried mulberry leaf powder, other major raw materials and minor additives such as vitamins and minerals for the preparation of a low-cost artificial diet were established. Two types of a standard table for aseptically rearing silkworms, one for parent silkworm for hybridization, and another for hybrid races, on an artificial diet by twice or three times feedings throughout the larval stages was established. A standard expected results fro … More m a year-round sericulture system were established such as silkworm growth, pupation rate, adult emergence rate, amount of oviposition.Facilities needed for a year-round sericulture system were investigated for two cases. One is to exploit the facilities now in use. The other is to make completely new facilities. A germ-free room and germ-free facilities were evaluated. Machineries for the preparation of an artificial diet was investigated and a new facilities were devised to make a considerable reduction of required labor.A year-round sericulture system to rear silkworms twice a month, and total 24 times per year by the three times feeding method yielded the following results. Required days for larval growth, 24-25 days. Amount of harvested cocoons per one egg case, 32-35kg. Reelability percentage, 60-85%. Raw silk percentage of cocoon, 14.5-16.5%. Length of cocoon filament, 1000-1150m. Size of cocoon filament, approximately 2.2-2.6 deniers. No tendency to become yellowish. Lustrous characteristics. Items of labor and required time for each item of labor, required expenses and production cost were, for the first time, calculated for the year-round sericulture system of three times feedings method throughout the larval instars. Profitability of a plant to produce 100 tons of cocoons per year by using the presently proposed system was evaluated. Less