Long-Term Storage Procedure for Silkworm Fertilized Egg

Under patent application 2003-057940, 2003-11-01

Long-Term Storage of Fertilized Silkworm Eggs

A method for preserving silkworm fertilized eggs for 2 years was developed. After subjecting 60-day-old eggs to high temperature protection for 20 days, they were stored at -2.5oC for 370 days. Then, the eggs went through a method of protection at 5oC for 90 days, with middle care at 10-15oC for 9 days and re-refrigeration for another 120 days at 0oC.

Allows Breeding in Two-Year Cycle

In order to achieve system preservation of one voltinism silkworm and two voltinism silkworm, it is necessary to breed once a year. For this reason, a great amount of time and labor is required. In order to attain labor-saving system preservation, the system-saving method which allows breeding in a 2-year cycle is the most effective. Therefore, the development of a long-term saving method for fertilized ovum had become necessary.

After performing high temperature (25oC) protection on the eggs for 2 months, they passed through four stages (20oC, 15oC, 10oC, and 5oC) for 10 days, and at 0oC for 5 days each, then refrigerated for 368 days at -2.5oC . In order to achieve activation of the embryo, after protecting the eggs for 90 days at 5oC and performing middle care (10oC for 2 days; 15oC for 4 days), these were re-refrigerated for 120 days at 0oC.

Shortened Period from High-Temperature Protection to Refrigeration

The biggest difference of this newly-developed method from the existing double refrigerating method is the shortened period from high temperature protection to refrigeration, with minimal energy consumption. Temperature change and middle repair frequencies under storage were also reduced in comparison with the prolonged cold storage test of previous reports. The storage process has also been simplified, and the work made easier.

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