Nutritional Enhancement of Deoiled Silkworm Pupae through Microbial Fermentation for Sustainable Aquafeed Development

Abstract

This study explores silkworm pupae (SWP), a byproduct of sericulture, as a sustainable protein substitute for fishmeal in aquafeeds. With the rising costs and limited availability of fishmeal, there is an urgent need for alternative ingredients that are both economical and nutritionally adequate. SWP are rich in protein, essential amino acids, and lipids, but challenges such as poor digestibility and anti-nutritional factors limit their direct use. Fermentation has emerged as a promising strategy to improve their feed value. Three diet types were prepared: a control feed without pupae, a diet with deoiled SWP, and a diet with fermented SWP (FSWP). Fishmeal, groundnut oil cake, rice bran, and vitamin–mineral premixes formed the base ingredients, with fishmeal progressively replaced by deoiled or fermented pupae up to 35%. Fermentation of SWP was conducted for 48 hours under microaerophilic conditions using Saccharomyces cerevisiae and Lactobacillus casei to enhance protein bioavailability and reduce anti-nutritional compounds. Proximate composition was assessed following AOAC methods: crude protein by spectrophotometry, lipid by Soxhlet extraction, fiber by acid–alkali hydrolysis, and ash by muffle incineration. All tests were performed in triplicate, and results expressed as mean ± SD. Statistical analysis was conducted using one-way ANOVA with Tukey’s HSD and Duncan’s test (p < 0.05). Results showed that FSWP diets had the highest protein (69.88%) and improved nutrient profiles compared to deoiled SWP and control feeds. These findings indicate that microbial fermentation enhances the nutritional quality of SWP, making FSWP a cost-effective, eco-friendly replacement for fishmeal in aquaculture feed formulations.