Research on Survival Rate and Cadmium Content in Body of Tenebrio molitor Linnaeus Fed on Rice Contained Cadmium
After Tenebrio molitor Linnaeus takes rice with cadmium,the larva cadmium content is related to the safe utilization of this resource insect and paddy products.The third-instar larvae of Tenebrio molitor Linnaeus were fed with natural cadmium-containing rice with a cadmium content of 0.25,0.40,0.79 and 1.10 mg/kg to deter-mine their survival rate within 30 days.The cadmium content of the corresponding worm body,worm slough and jeju-num of Tenebrio molitor larvae after feeding was determined by comparing the above natural cadmium-containing rice with the cadmium-containing rice with the cadmium contents were adjusted to 0.20,0.40,0.80 and 1.20 mg/kg.And the biological accumulation factor(BAF value)of pollutants in corresponding worms was calculated.The results indicated that there was no significant difference between the survival rate of the third-instar larvae of Tenebrio molitor Linnaeus fed with natural cadmium-containing rice with cadmium content of 0.25 mg/kg and 0.40 mg/kg for 30 days and the survival rate of the third-instar larvae fed with natural cadmium-containing rice with cadmium content of 0.79 mg/kg and 1.10 mg/kg for 30 days.At this time,survival rate was over 87%.The cadmium content in larvae fed with natural harvested rice contained cadmium at 0.25 mg/kg and modulated rice with cadmium at 0.20 mg/kg was increased by 10 times compared with that of the larvae fed with the control sam-ple in the first 10 d.The cadmium content in worm body increased significantly with the increasing of cadmium content in the diets and feeding duration.The cadmium content in third instar larvae reached 1.03 and 1.73 mg/kg after they were fed the natural harvested rice contained cadmium at 1.10 mg/kg and modulated sample con-tained cadmium at 1.20 mg/kg through 30 d.The results indicated that the cadmium accumulation was obvious in surviving larvae.The BAF value decreased with the increasing of cadmium content in the samples.Most of the cad-mium was accumulated in worm body and a few existed in molts.No cadmium was discharged through excretion pathway.There was no significant difference in the larvae survival rate who fed rice contained cadmium at 0.40 mg/kg.Most individuals(the survival rate was above 87%)of the larvae could still survive,develop,molt and grow,etc.,after feeding with the natural harvested rice contained cadmium at 1.10 mg/kg.Cadmium fed into the worm body was not discharged through excretion way and can be minished through molting partly.The cadmium ac-cumulation in T.molitor who fed on modulated rice contained cadmium was higher than that fed on the rice con-tained cadmium naturally.
Tenebrio molitorrice contained cadmiumsurvivecadmium content in worm bodyBAF value