The Variation of the VTG Level in the Process of Sexual Maturity of the Female Fish of Odontobutis potamophila

The female fishes of Odontobutis potamophila in the experiment were used as the research object, which were in the gonadal development stage Ⅲ to stage Ⅴ. The levels of ⅤTG in the serum, liver and ovary of Odontobutis potamophila were performed by an indirect method, measuring the alkali-labile phosphorus content of the lipid-free protein fraction. The levels of phosphorus can reflect the VTG levels indirectly. In the experiment, the phosphorus levels in serum, liver and ovary of Odontobutis potamophila were measured by the chemical response with the aqueous trichloroacetic acid (TCA). The results showed that the VTG level in the liver increased at first, and then decreased, the highest level was at stage Ⅳ, which was (39.91±3.80) mg·g-1. At the stage Ⅲ and stage Ⅳ, the synthesis of VTG was very active. The level of VTG in the serum increased gradually, the VTG level from (15.45±1.77) mg·mL-1 at the stage Ⅲ increased to (33.31±5.57) mg·mL-1 at the stage Ⅴ. The level of VTG in the ovary also increased gradually, during the stage Ⅲ to stage Ⅳ, the growth was faster, which is the most important stage of the deposition of VTG, the highest level was (422.25±29.98) mg·g-1 at the stage Ⅴ. The results indicated that the active synthesis and highly-efficient transport of VTG can lay the foundation of its vast deposits, and would assure the nutritional requirements of embryonic development and subsequent development.