Effect of TiO sub(2) Nanoparticles on the Reproduction of Silkworm

Silkworm (Bombyx mori) is an important economic insect and the model insect of Lepidoptera. Because of its high fecundity and short reproduction cycle, it has been widely used in reproduction and development research. The high concentrations of titanium dioxide nanoparticles (TiO sub(2) NPs) show reproductive toxicity, while low concentrations of TiO sub(2) NPs have been used as feed additive and demonstrated significant biological activities. However, whether the low concentrations of TiO sub(2) NPs affect the reproduction of B. mori has not been reported. In this study, the growth and development of gonad of B. mori fed with a low concentration of TiO sub(2) NPs (5 mg/L) were investigated by assessing egg production and expression of reproduction-related genes. The results showed that the low concentration of TiO sub(2) NPs resulted in faster development of the ovaries and testes and more gamete differentiation and formation, with an average increase of 51 eggs per insect and 0.3410 super(-4) g per egg after the feeding. The expressions of several reproduction-related genes were upregulated, such as the yolk-development-related genes Ovo-781 and vitellogenin (Vg) were increased by 5.33- and 6.77-folds, respectively. This study shows that TiO sub(2) NPs feeding at low concentration can enhance the reproduction of B. mori, and these results are useful in developing new methods to improve fecundity in B. mori and providing new clues for its broad biological applications.