author(s)
Sebrin J Islam, Prasenjit Manna, Balagopalan Unni and Jatin Kailta

abstract
Oxidative stress leads to imbalance between the production of free radicals and antioxidant defense mechanism. Muga silkworm being reared outdoor is subjected to heavy metal pollution. The present study focuses on the potential capacity of larvae in terms of growth and antioxidant enzyme activity fed with heavy metals (Cd, Pb, Mn & Zn) stressed leaves in vitro condition. Heavy metal accumulation in pupa was correlated with body weight and instar duration and its effect on silk thread was studied. The body weight and instar duration was significantly varied in high dose of Cd and Pb, indicating that metal pollution prevented silkworm from achieving better growth. Effect of heavy metal on the antioxidant enzyme activity (Glutathione-S-transferase, superoxide dismutase, catalase) showed significant difference than control. Groups were compared by One-way ANOVA using Student Neumann Keul test. Present study suggests that activity of antioxidant enzymes in the larvae varies with respect to time and concentration of heavy metal ions.