<b>Dye-added mulberry diet in relation to silkworm growth, yield, and quality of silkworm cocoons</b>

Background: Textile dyeing is a major environmental pollutant in the fashion industry. Producing naturally colored silk through dietary dye supplementation in silkworms offers a potential eco-friendly alternative. However, the effects of this method on silkworm development, cocoon yield, and silk quality are not fully understood. Aim: This study aimed to evaluate the impact of supplementing mulberry leaves with different dyes on silkworm (Bombyx mori) growth, cocoon yield, and the quality and coloration of silk cocoons. Methods: An experiment was conducted using a completely randomized design with three replicates, each containing 200 fourth-instar silkworms. Three dyes (rhodamine B, Nile blue A, and neutral red) and a control (freshwater) were applied to mulberry leaves. Parameters recorded included larval development duration, larvae and silk gland weight, pupation rate, single cocoon and shell weight, total cocoon yield, filament length, raw silk rate, and silk color. Results: Dye supplementation resulted in visible coloration in larvae, silk glands, and cocoons. Compared to the control, dye treatments caused a reduction of 4%–13% in single cocoon weight and 17.4%–26% in shell weight. Cocoon yield per 200 larvae decreased by 19.3%–29.4%. Among the dyes, neutral red produced the highest yield, while rhodamine yielded the longest silk filament. The dyed cocoons retained distinguishable colors, although lighter than the original dyes, with minor adverse effects on silk quality. Conclusion: Feeding silkworms with dye-supplemented mulberry leaves successfully produced naturally colored silk with minimal negative effects on development and quality. This approach represents a promising, environmentally sustainable method for producing high-value colored silk.