Sanshi-Konchu Biotec
Online ISSN : 1884-7943
Print ISSN : 1881-0551
ISSN-L : 1881-0551
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Displaying 1-3 of 3 articles from this issue
  • Chikara HIRAYAMA
    2024 Volume 93 Issue 2_3 Pages 2_3_085-2_3_091
    Published: 2024
    Released on J-STAGE: January 25, 2025
    JOURNAL FREE ACCESS

     Mulberry leaf powder is the most expensive among the ingredients in the artificial diets of the silkworm, yet it is essential for the growth of normal silkworm strains. In an effort to reduce the cost of artificial diets, green coffee bean extract was considered as the substitute for mulberry leaf powder. The analysis using HPLC revealed that commercial green coffee bean extracts contain more than 20% chlorogenic acid (5-CQA), a feeding stimulant of the silkworm identified from mulberry leaves. Test diets, with defatted soybean meal and corn meal as the main ingredients and varying amounts of green coffee bean extract, were fed to larvae of the normal silkworm strains during the 4th instar. As a result, diets containing more than 0.3% green coffee bean extract were found to be sufficient for larval growth. Based on these findings, a diet for grown silkworms (4th and 5th instar larvae) was developed. The growth performances of silkworm larvae fed the diet was comparable to that of larvae fed a regular commercial diet, suggesting the potential of green coffee bean extracts as a useful and cost-effective feed ingredient for the silkworm.

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  • Saori OISHI, Takeshi FUJII, Wataru KOJIMA, Katsuhiko ITO, Yukio ISHIKA ...
    2024 Volume 93 Issue 2_3 Pages 2_3_093-2_3_103
    Published: 2024
    Released on J-STAGE: January 25, 2025
    JOURNAL FREE ACCESS

     Ameiotic and meiotic parthenogenesis induced by carbonated water was investigated using ovarian eggs of the silkworm, Bombyx mori. We used B. mori females in which the red egg gene locus is heterozygous (+/re) in order to facilitate detection of parthenogenesis via egg pigmentation. More than 80% of the ovarian eggs from virgin females exhibited parthenogenesis when maintained at 17゚C for 1 day, soaked in carbonated water for 1 h at 17゚C, and subsequently maintained at 17゚C or 3 days. When ovarian eggs were soaked in carbonated water adjusted to different pH values, parthenogenesis was significantly increased in the acidic pH range where CO2 bubbles were generated in the water. Because eggs soaked in acidified non-carbonated mineral water exhibited a significantly lower induction rate, CO2 gas in carbonated water, rather than hydrogen ions, was suggested to play more important role in parthenogenesis induction. Sealing the front pole, back pole, lateral side, whole part, and no part of ovarian eggs with nail varnish (topcoat) to inhibit CO2 diffusion into the eggs resulted in 79.1%, 93.1%, 82.4%, 0%, and 84.4% egg parthenogenesis, respectively. These findings suggest that gaseous CO2 from carbonated water, penetrating eggs via unspecified surface areas, induces ameiotic parthenogenesis. In general, the hatchability of parthenogenetic eggs was very low. We hypothesize that embryonic lethality arises from haploid cells in parthenogenetic embryos.

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