Silkworm (Bombyx mori) has the Capability to Accumulate C20 and C22 Polyunsaturated Fatty Acids

Bombyx mori, an insect with significant economic importance in China contains a large amount of lipids among different developmental stages, especially the pupal stage. Silkworms are fed with a base diet and fish oil supplemented diet, and the fatty acid (FA) compositions of different strains, life stages, and sexes are determined by GC-MS. No C-20 or C-22 polyunsaturated fatty acids (PUFAs) are detected in silkworms fed with the base diet. Females accumulates more unsaturated fatty acids (USFAs) than males in the pupal stage, and the relative amount of USFAs decreases from the wandering stage to the moth stage, especially in females, suggesting that silkworms prefer the utilization of USFAs. In addition, when silkworms are fed with a diet supplemented with fish oil, which contained C-20 and C-22 PUFAs, they accumulates C-20 and C-22 PUFAs in proportion to the concentration of fish oil added to the diet.Practical Applications: Currently, the main dietary source of C20 and C22 PUFAs is marine fish, however, of which the stocks are declining because of environmental pollution and overfishing. Because of its excellent capability to accumulate C20 and C22 PUFAs, silkworm could be developed as a potential new source of these long-chain FAs by transferring Delta 5 and Delta 6 desaturases to silkworm or its primary food, mulberry. The silkworm (Bombyx mori) can accumulate C-20 and C-22 polyunsaturated fatty acids (PUFAs) from diet supplemented with these PUFAs (B). The accumulation efficiency of eicosapentaenoic acid (EPA) in silkworm is particularly outstanding. This capacity may make silkworm a potential new source of C-20 and C-22 PUFAs.