The frequency effect of synbiotic supplementation diet to control the co-infection disease of Infectious Myonecrosis Virus and Vibrio harveyi

Abstract

One of the obstacles in intensive shrimp culture is the high frequency of disease. The diseases that most often attack are bacterial, viral and infection by bacterial and viral at the same time (co-infection). Co-infection disease can accelerate and increase mortality. One of the alternative to prevent the diseases is synbiotics, because synbiotics could increase the shrimp immune response and resistance to diseases. This study aimed to evaluated the frequency effect of synbiotic supplementation diet to control the co-infection disease of IMNV and V. harveyi. The frequencies applied in this study were daily, once in three days and once a week supplementation. The synbiotics used in this study is the combination between the probiotics SKT-b and prebiotic is the derivate of oligosaccharide from sweet potato starch (Ipomoea batatas L). Several stages of this study consisted of prebiotic preparation (making the sweet potato starch, oligosaccharide extraction with ethanol 70%, the determination of total dissolved solid and oligosaccharide test with HPLC), probiotic preparation, IMNV stock preparation and V. harveyi preparation, 1 dosage synbiotics (1% probiotic with 2 % prebiotic) in vivo test during 30 days and challenged test. The growth performance were the daily growth rate and feed conversion ratio. The number of bacteria in shrimp intestine observed at the end of synbiotics treatment consisted of the total viable bacterial count, presumptive vibrio counts and the presumptive SKT-bR counts. Immune responses observed before and after challenge test were total hemocyte count, the numbers of hemocytes (hyaline cells and granular cells), phenoloxidase activity and respiratory burst activity. Shrimp resistance observed was the shrimp survival against co-infection by IMNV and V. harveyi for seven days. PCR test using Nugen IMNV diagnostic kits for IMNV confirmation and streak plate method on TCBS containing rif media for V. harveyi confirmation. The result of oligosaccharide extraction with 5% TPT used in this study consist of 1,115% inulin; 1,015% FOS and 1,488% GOS. Supplementation of synbiotics diet during 30 days were increase the number of bacteria in shrimp intestine and improve growth performance (LPH and FCR) and shrimp resistance against co-infestion IMNV and V. harveyi. Synbiotics treatment significantly increase THC value and PO activity than controls (before challenge test). Generally, daily supplementation of synbiotics showed better resistance against co-infection IMNV and V. harveyi and better growth performance than control. Daily supplementation of synbiotics given the best result in LPH was 8,12±0,12% and FCR was 1,11±0,08. Total hemocyte count value was 6,40x106±0,85 cell/ml and phenoloxidase was 1,07±0,15. Moreover, daily supplementation of synbiotics given the best shrimp resistance against co-infection by IMNV and V. harveyi with the survival value was 93,33±5,77% compared with positive control was 46,67±11,57%.