Potential role of the tilapia, Oreochromis Niloticus, in controlling the Acute Hepatopancreatic Necrosis Disease (AHPND)

Abstract

Acute hepatopancreatic necrosis disease (AHPND), also called early mortality syndrome (EMS), is a recently emergent shrimp bacterial disease that has resulted in substantial economic losses since 2009. The disease is caused by a pathogenic strain of Vibrio parahaemolyticus. One way to prevent pathogenic V. parahaemolyticus against in shrimp farming is to use tilapia-shrimp polyculture system. The purpose of this study was to determine potential role of the tilapia, Oreochromis Niloticus, in controlling the growth of EMS inducing bacteria Vibrio parahaemolyticus. In this study, 30L fiber tanks were filled with 25L experimental water and used to test four treatments with three replicates each including: tilapia-cultured water and one tilapia; tilapia-cultured water and without tilapia; shrimp-cultured water without the addition of tilapia; and tilapia-cultured water without the addition of tilapia. Water in the experimental tanks of treatment 1-3 were challenged with AHPND+ V. parahaemolyticus at the density of 0.9 x 106 cells/ml for 7 days. The bacterial density in treatment 1 was lower than treatment 2 and 3 at most of time points post challenge. There was a significant difference in the bacteria count among treatments 1-3 at 12 hours and 120 hours of exposure. The results indicated that tilapia can inhibit directly the growth of EMS causing V. parahaemolyticus. There has yet be able to make a conclusion on the antibacterial activity against V. parahaemolyticus of the mucus scrapped from tilapia gill and skin. Keyword: AHPND/EMS Tilapia-shrimp polyculture Vibrio parahaemolyticus Tilapia mucus