Abstract: 【Aim】High-fat diet has been proven to induce various diseases such as hyperlipidemia, posing a threat to human health. This study investigated the effects of high-fat diet on the growth and development, economic traits, lipid metabolism and immune function of Bombyx mori by adding soybean oil to mulberry leaves, to evaluate the feasibility of using B. mori to construct a hyperlipidemia disease model for human health research. 【Methods】 The day-0 4th instar and day-0 5th instar larvae of B. mori were fed with high-fat diets (mulberry leaves treated with 0.5%, 1.0% and 2.0% soybean oil, respectively) until maturity. The body weight of various day-old larvae and the cocoon layer rate were measured. The triglyceride contents in the fat body and serum of the 5th instar larvae of B. mori fed with the mulberry leaves treated with 0.5% soybeal oil were detected using a triglyceride test kit. Oil red O staining was used to observe the morphological changes and average optical density values of lipid droplets. Real-time fluorescence quantitative PCR was used to analyze the transcription levels of eight immune-related genes (BmCecD2, BmCecA, BmCecB, BmCecE, BmCec-CBM2-2, BmSpz1, BmDual and BmKayak) in the 5th instar larval fat bodies. 【Results】Compared with the control group (fed with regular mulberry leaves), high-fat diet (nulberry leaves treated with 0.5%, 1.0% and 2.0% soybean oil, respectively) significantly inhibited the body weight gain of B. mori larvae and significantly reduced the cocoon layer rate. Compared with the control, a high-lipid diet (mulbery leaves treated with 0.5% soybean oil) significantly increased the triglyceride content in the fat body and serum of the 5th instar larvae of B. mori, resulted in abnormal morphology of fat body and accumulation of lipid droplets, and significantly down-regulated the expression levels of the tested eight innate immune-related genes in the fat body of the 5th instar larvae. Among them, the expression levels of BmCecE, BmDual and BmKayak were down-regulated by more than 90%.【Conclusion】The high-fat diet leads to slow growth, delayed development, decreased economic traits, disrupted lipid metabolism and weakened immune regulatory function in B. mori. Among them, the increase in triglyceride content is similar to the physiological and pathological characteristics of human hyperlipidemia. This study provides a theoretical basis for constructing disease models using insects.

Key words: Bombyx mori, high-fat diet, growth and development, economic traits, triglyceride, innate immunity