The Prevention of Streptococcal Disease on Nila (Oreochromis niloticus) with Whole Cell β-haemolytic and Non-haemolytic Type Streptococcus agalactiae Vaccine

Abstract

This research aimed to know the effectiveness of a Streptococcus agalactiae vaccine to prevent Streptococcosis caused by S. agalactiae on Nila (Oreochromis niloticus). The vaccine was prevared prom whole cell β-haemolytic type, nonhaemolytic type and bivalen (mixture of 50% of β-haemolytic and 50% nonhaemolytic whole cell). Vaccinated trial was done through intra peritonial (ip) injection into fish having mean weight of 15 g. Control positif nila were injected with PBS. Vaccinated fish challenged by IP injection 106 colony forming unit (CFU)/fish of β-haemolytic, 105 CFU/fish of non-haemolytic, and 105,5 CFU/fish of bivalen (β-haemolytic and non-haemolytic) S. agalactiae. Fish vaccinated with whole cell β-haemolytic had a relative percent survival (RPS) of 67% when challenged with β-haemolytic and 50% challenged with nonhaemolytic. A RPS of 63% from fish vaccinated with whole cell non-haemolytic challenged with non-haemolytic and 63% challenged with β-haemolytic. Whereas nila vaccinated with bivalen had a RPS of 64% challenged with bivalen, 74% challenged with β-haemolytic, and 68% challenged with non-haemolytic of S. agalactiae. The conclution is vaccination S. agalactiae bivalen have highest protection against S. agalactiae infection.