Action of proteases of the nematophagous fungi Pochonia chlamydosporia on Ascaris suum eggs of collared peccary (Pecari tajacu)

Among the parasites of domestic and wild swine, Ascaris suum stands out; a nematode that can lead to growth retardation and reduction in weight gain due to its action, especially in young animals. The objective of this study was to test the ovicidal action of proteases from Pochonia chlamydosporia (VC4) on A. suum eggs in an assay with Petri dishes. The fungus P. chlamydosporia (VC4) was grown in Erlenmeyers flasks with 50 ml of liquid minimal media supplemented with 0.2% gelatin for production of enzymes. In the present assay, 500 eggs were poured into Petri dishes of 4.5 cm in diameter and 5 ml of VC4 proteases were added in each Petri dish and incubated at 26°C in the dark for 14 days. After this period, the number of embryonated and destroyed A. suum eggs present in each plate from treated and control groups was counted. Significant difference (p <0.01) was found between the number of eggs from treated group compared to the control group. At the end of the experiment, the proteases of P. chlamydosporia (VC4) demonstrated efficacy in reducing embryonated eggs on the plates of the treated group (78.7%) compared to the control group (83.7%). The results presented in this study demonstrate that proteases of P. chlamydosporia (VC4) were effective in the destruction of A. suum eggs and therefore could be used as biological control of this nematode. Key words: Nematophagous fungi, Pochonia chlamydosporia, protease, Pecari tajacu, Ascaris suum.