At the Fisheries Research Institute Shingu Experiment Station in Shingu City, Wakayama Prefecture, Kinki University, fertilized eggs were imported from Germany and artificially hatched, and Siberian sturgeon was fed a compound feed containing female hormones. succeeded in.
It takes a long time to cultivate and produce caviar from sturgeon, and since half of the sturgeon are male, it is costly to distinguish between male and female.Kinki University has been working on the development of all-female technology in order to improve the efficiency of caviar production.
In this study, 4 fry of Siberian sturgeon 150 months after hatching were fed a compound feed mixed with female hormones for 6 months, and then bred with a normal compound feed until the 22nd month.Forty-five fish were randomly selected from these, and the shape of the gonads was observed with a stereomicroscope, and the individual with confirmed egg cells was identified as a female.In the individuals in which no egg cells could be confirmed, the tissue sections of the gonads were stained and the eggs were confirmed. As a result, egg cells were confirmed in all 45 fish.
Normally, in order to select males, one sturgeon about 3 years old is taken out of the pond, an incision is made in the abdomen, and the color and shape of the gonads are visually confirmed to distinguish between males and females.In addition, it is necessary to suture the incision with a surgical needle and thread and return it to the pond.By making all females, this step can be omitted, the labor of producers is expected to be reduced, and the production cost of caviar produced from cultured sturgeon can be reduced.If the production cost is reduced by this, it is considered that the selling price of caviar can be reduced, and it is expected that the caviar will be provided to consumers at a lower price.
In the future, Kinki University will develop a feed containing plant estrogen, a food-derived ingredient that replaces female hormones, with the aim of achieving total femaleization.If all female sturgeon caviar becomes available, it is expected that it will be commercialized and that fry and fertilized eggs will be supplied nationwide as all female seedlings.
