Impact on silk synthesis resulting from whey protein supplementation and hydration in silkworm diet, Bombyx mori (Lepidoptera: Bombycidae)

The silkworm Bombyx mori L. converts plant protein into silk. In silk producing countries mulberry leaves are primarily used to feed silkworms, however, recent studies have shown that nutritional supplements in the diet improved the morphological parameters of larvae and cocoons. In the current paper we investigated the effects of whey protein dissolved in water on the larval development of B. mori, cocoon production, mechanical properties of silk threads, silk gland morphology, and mRNA expression of the L-fibroin and sericin-1 genes. The results showed that whey protein supplementation did not affect larval development, and the histological structure of the silk glands remained intact. The water group and whey protein 10% group yielded the highest efficiency of silk protein synthesis. Mechanical testing of silk threads demonstrated that supplementation with whey protein did not affect the quality. The groups fed with whey protein supplements showed similar expression of L-fibroin gene, and higher expression of the sericin-1 gene. Our findings suggest that whey protein does not adversely affect the silk glands and could serve as a basis to produce artificial food for the silkworm.