Sericulture has immense economic significance. Separating male and female silkworm pupae for egg production in grainage is a laborious task; hence, sex-limited breeds for cocoon color are advantageous for this process. The major constraint in sex-limited breeds is their low fecundity. Sex-limited female moths lay a lower number of eggs than nonsex-limited breeds. Polyamine, spermidine was shown to improve fecundity in several organisms, including the silkworm, Bombyx mori L. In the present study, cocoon color sex-limited breeds, HTO2SL, APS27SL, and SLFC27, were selected and fed with spermidine to improve fecundity and nutritional efficiency. The fifth-instar silkworm larvae of the selected breeds were subjected to standard rearing conditions with and without spermidine supplementation up to spinning. The spermidine-supplemented sex-limited breeds exhibited a significant increase in fecundity, nutritional indices, and economic parameters compared with the control sex-limited breeds. Among the 3 sex-limited breeds tested, the performance of APS27SL improved significantly.

Graphical Abstract