Efficacy of inactive bivalent and trivalent Streptococcus agalactiae bacteria (biotype 1 & 2) vaccines on tilapia, Oreochromis niloticus

Taukhid Taukhid,Desy Sugiani,Tuti Sumiati,Septyan Andriyanto,Angela M Lusiastuti,Achmad Suhermanto

doi:10.1051/e3sconf/202132202014

Abstract

Streptococcosis is a significant fish disease impacting tilapia culture in Indonesia, causing losses estimated up to IDR 15.0 billion annually. This study aims to assess the efficacy of bivalent and trivalent vaccines containing Streptococcus agalactiae bacteria on tilapia. The formula of the bivalent vaccine contains 75% of S01-196-16 and 25% of N14G isolates (v/v). Trivalent vaccine contains 30%, 35%, and 35% of N14G, NP1050, and SG01-16 isolates (v/v), respectively. A challenge test assessed the efficacy of the vaccines, and it was carried out at 30, 90, and 150 days post-vaccination by artificially infection at LD60. Selected bacteria isolate to be appointed in the challenge test are N14G (biotype 2) and S01-196-16 (biotype 1). Relative Percentage of Survival (RPS) was used as the main indicator of vaccine efficacy. The results revealed that the highest RPS of a bivalent vaccine against S. agalactiae (S01-196-16) was achieved at the first challenge (61.84%), and trivalent vaccine against S. agalactiae (N14G) and S. agalactiae (S01-196-16) was achieved at the first challenge (61.53% and 76.20%, respectively). Bivalent and trivalent S. agalactiae bacteria vaccines are promising “tools” to control streptococcosis on tilapia.

Highlights

Tilapia (Oreochromis niloticus) is the second most predominant aquaculture species globally after carp, and it was known as a relatively cheaper aquatic animal protein supply for millions of families
This study aims to assess the efficacy of in-active bivalent and trivalent vaccines, containing Streptococcus agalactiae bacteria on tilapia (Oreochromis niloticus)
It could be assumed that the fish population used in this study was specific pathogen-free (SPF) against S. agalactiae infection

Summary

Introduction

Tilapia (Oreochromis niloticus) is the second most predominant aquaculture species globally after carp, and it was known as a relatively cheaper aquatic animal protein supply for millions of families. The fish are fast-growing, tolerate a wide range of ecological zone conditions, and are more resistant to diseases compared to other cultured species [1]. In an intensive aquaculture system where the fish is stocked at high densities, the fish is under biological stress conditions and prone to various pathogens infections. Fish disease outbreaks in aquaculture are mainly associated with stressful conditions due to biological, physical, and chemical stress factors such as overcrowding, malnutrition, poor water quality, and improper health management strategies [4,5,6,7]

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