Maternal immunity of tilapia broodstock vaccinated with polyvalent vaccine and resistance of their offspring against Streptococcus agalactiae

摘要: This study aimed to examine the use of Streptococcus agalactiae polyvalent vaccine in tilapia broodstock and effect maternal immunity resistance on their offspring against S. agalactiae strain. The was injected with at a dose 10⁸ CFU per fish 2nd gonadal maturity until spawning. Challenge test carried out 5, 10, 15 20 days after hatching using NK₁, N₁₇O, N₁₄G, N₃M, N₄M strain respectively combination them. We observed immunological parameters broodstock, eggs larvae relative cent survival (RPS) challenged pathogenic S. agalactiae. results showed that leukocytes, phagocytic activity, respiratory burst, lysozyme activity antibody levels vaccinated had higher level compared unvaccinated broodstock. high recombination activating gene 1 (RAG1) were also from Larvae produced when variety RPS value more than 50% hatching. In conclusion, administrated could enhance protect