Effect of Staphylococcus aureus Infection on Biochemical and Antioxidant Activities of Fifth Instar Silkworm Larvae (Bombyx mori L.)

Abstract

In the present study silkworm used as a model animal for evaluating the pathogenicity of Staphylococcus aureus. The fifth instar silkworm larvae was used and infected by intrahaemocoelic injection of bacterial sample. The haemolymph was collected from the infected and control group larvae at 6, 12, 18 and 24 hours of post infection and stored at -4°C in eppendorf tubes to use. Lipid peroxidation, phenol oxidase and acid phosphatase activity were estimated in the haemolymph of control and infected group. This indicated that there was a gradual increase in lipid peroxidation, phenol oxidase and acid phosphatase activities in infected group when compared with control group. The antioxidant enzyme activities were estimated in the haemolymph of control and infected group. We found that the antioxidant enzyme activities were decreased after 24 hours of infection with S. aureus. The silk glands were removed and the wet weight was measured, the wet weight of the silk glands was decreased on the 24 hours of infection when compared with control group.