Determination of Anti-Infectious Myonecrosis Virus (IMNV) Properties of Cynodon Dactylon in Penaeus Vannamei

Abstract

Infectious   myonecrosis   virus   (IMNV)   is   one   of   the   most pathogenic    viruses    causing    severe    mortality    inPenaeus vannameiin   many countries.   Several   strategies   have   been implemented  to  inhibit  the  presence  of  IMNV  disease.  The present study was carried out to examine the anti-IMNV activity ofCynodon    dactylonpowdered    extract    on    shrimp    byin vivotesting in three systems: indoor tankand cages in raceways and cages in the commercial ponds. TheC. dactylonplant powder mixed  with  shrimp  feed  in  four  different  concentration  which was named as RAV-S A (10 %), RAV-S B (15%), RAV-S C (20 %), and RAV-S  D  (25%).  All  the  four  doses  were  tested  in  the  tank  trial, then the best two doses RAV-S C (20 %), and RAV-S D (25%) from tank trial were tested in cage trials. The best-selected dose RAV-S C (20 %) from cage trial was tested in the cage-pond trial. The shrimp  were  infected  using  sub-lethal  dose  of  IMNV  usingper osmethod of challenge in tank and cage trial. No artificial IMNV infection  made  for  the  cage-pond  test.  The  efficacy  rate  of treatment groups against IMNV in tank level trial was as followed, 20%  survival  in  RAV-S  A  (10  %),  12  %  survival  in  RAV-S  B  (15%), 30 % survival in RAV-S C (20 %), and 30% survival in RAV-S D (25%) and  0  (zero)  %  survival  in  Positive  control.  The  efficacy  rate  of treatment  groups  against  IMNV  in  cage  trial  was  as  followed, 75.2 % survival in RAV-S B (15 %), and 91.1 % survival in RAV-S C (20 %) and 79.6 % survival in Positive control and 99.17 % survival in the negative control. The typical gross sign of IMNV were also monitored  which  was  28.90  %  in  RAV-S  B  (15  %),  and  2.55  %  in RAV-S C (20 %) and 50 % in Positivecontrol and 0 (zero) % in the negative  control.  The  efficacy  rate  of  treatment  groups  against IMNV in the cage-pond trial for RAV-S C (20 %) was 69% survival and 53% survival for the control. The typical gross percentage of treatment RAV-S C (20 %) was 10% whereas control was 46%. The trial     showed     thatCynodon     dactyloncontains     anti-IMNV properties.  The  limitation  is  in  finding  the  right  dose  and appropriate way for inoculation