Effect of Muscardine and Flacherie diseases on the free amino acid profile of Bombyx mori L. larvae during seed and commercial rearing seasons

Muscardine infection led to the complete disappearance of arginine, cysteic acid, methionine-sulphoxide, and threonine in silkworm larvae during both seed and commercial rearing seasons. Flacherie infection caused the total absence of cysteic acid, cysteine, methionine-sulphoxide, and threonine in both seasons. In healthy (control) larvae, asparagine, glutamic acid, and leucine were present in high concentrations. Under Muscardine stress, asparagine, cysteic acid, cysteine, glutamic acid, lysine, leucine, and valine were reduced to trace levels. Flacherie infection reduced α-alanine, cysteine, glycine, and lysine to trace amounts. Comparative analysis clearly indicates that Flacherie exerts a more severe pathological impact on the free amino acid composition of Bombyx mori larvae than Muscardine. The commercial crop season offers comparatively better nutritional and environmental conditions for larval development than the seed crop season.