The Ability to Digest Cellulose Can Significantly Improve the Growth and Development of Silkworms

Cellulose is essential in the growth and development of herbivores. However, its limited utilization by herbivores is a key factor restricting their feed conversion rates. Cellulase can hydrolyze cellulose into glucose, and the addition of exogenous cellulase preparations to feed is an effective method for improving the cellulose utilization rate of ruminants. Nevertheless, the decomposition efficiency of exogenous cellulase is unstable and susceptible to various external factors. In this study, the endoglucanase III gene from Apriona germari (AgEGase III) was introduced into silkworms to investigate whether transgenic silkworms with cellulose-digesting capabilities outperformed normal silkworms in terms of growth, reproduction, and economic traits. The results show that the transgenic silkworms exhibited increased body size, weight, feeding efficiency, and digestibility compared to the wild-type silkworms. The cocoon weight, shell weight, cocoon-shell ratio, and pupa weight were notably elevated by 11%, 37%, 23%, and 9%, respectively. Additionally, the egg weight and egg-laying quantity of the female moth were also significantly increased compared to those of the wild type. Furthermore, feeding transgenic silkworms with an artificial feed containing additional cellulose demonstrated their ability to digest and utilize cellulose, leading to improved growth and development. This study offers theoretical support for the development of transgenic ruminant species that express cellulolytic enzymes.