IMPACT OF FEEDING LOW MOLECULAR WEIGHT MULBERRY PEPTIDES ON COCOON AND SILK DEVELOPMENT BY BOMBYX MORI L., (BOMBYCIDAE)

摘要

Silk obtained from silkworm, Bombyx mori L., is considered as the only natural animal fiber and the insect depends only on the mulberry leaves at their larval stage. We have isolated and purified low molecular weight (LMW, 0.5-3 KDa) peptide(s) from mulberry leaves (SI cultivar). For peptide isolation, leaves of three maturity stages (young, mature and senescence) were selected on the basis of biochemical and morphological attributes of leaves. Feeding of mulberry leaves supplemented with isolated peptide(s) from 5,h instar larval stage resulted in rapid larval growth and enhanced cocoon shell weight, when compared with control. Highest larval growth rate and cocoon weight was obtained from peptide treatment isolated from young leaves. Scanning electron microscopic study (SEM) revealed that the silk fibers obtained from peptide treated silkworm were smooth in texture and at least two times thicker than untreated counterparts. HPLC analysis indicated that the major peptide peak at mature stages of mulberry leaves was partially fragmented during senescence. Sequence analysis of bioactive peptide revealed the abundance of aromatic and hydrophobic amino acids with antioxidant activity and exhibits striking similarity with molting hormone Bombyxin. Therefore the peptides isolated from mulberry leaves might have an implication in improving sericulture and textile industry.