author(s)
Shah HA Mahdi, Md. Rokonuzzaman, Md. Aftab Uddin and Md. Kamrul Ahsan

abstract
The present investigation reported the effects of amoxocillin, oxytetracyclin and doxycyclin on physiological parameters, growth and development of the larva and pupa, mortality percentage and different cocoon characteristics of silkworm, Bombyx mori L. at various concentrations. The experimental results showed that the effect of different antibiotics on physiological parameters like food consumption, food utilization and food digestibility of 5^th instar larvae were increased in the treated lines in comparison to the control. The highest food consumption, food utilization and food digestibility of 5^th instar larvae was recorded at 5% doses. Weight of larva and pupa were significantly increased due to different antibiotics application in mulberry leaves and the most effective result was found at 5% doses of amoxicillin, followed the order oxytetracyclin and doxycyclin. In case of larval and pupal duration, it was observed that the duration of larval and pupal period of silkworm, B. mori was significantly decreased and the lowest period has been recorded at 5% doses of amoxocillin. Antibiotics also reduced the larval and pupal mortality percentage at different concentrations. The cocoon characters e.g. cocoon weight, shell weight and shell ratio were significantly increased at different antibiotic concentrations like 2% and 5%. The effectiveness of different antibiotics followed the order amoxocillin > oxytetracyclin > doxycyclin.