Efikasi Vaksinasi Booster Streptococcus agalactiae terhadap Tingkat Kelangsungan Hidup dan Respons Imun Benih Ikan Nila (Oreochromis niloticus)

Abstract

Serangan penyakit Streptokokosis akibat bakteri Streptococcus agalactiae menjadi penghambat peningkatan produksi ikan nila (Oreochromis niloticus). Penurunan proteksi vaksinasi tunggal seiring waktu mendasari pentingnya vaksinasi ulang (booster). Penelitian ini bertujuan menguji efikasi vaksinasi dua kali booster S. agalactiae melalui injeksi terhadap respons imun dan kelangsungan hidup ikan nila (O. niloticus). Metode eksperimental menggunakan Rancangan Acak Lengkap (RAL) dengan lima perlakuan dan tiga ulangan meliputi kontrol negatif (KN), kontrol positif (KP), vaksinasi tunggal (V), vaksinasi satu kali booster (VB), dan vaksinasi dua kali booster (VDB). Ikan nila berbobot 20,00±1,1 g divaksinasi dan booster kemudian diuji tantang setiap 14 hari menggunakan S. agalactiae tanpa pengulangan individu melalui injeksi intraperitoneal. Perlakuan VDB menghasilkan respons imun dan nilai kelangsungan hidu p relatif tertinggi sebesar 87,50±10,83% diikuti oleh perlakuan VB sebesar 68,75±10,83% dan perlakuan V sebesar 56,25±10,83%. Vaksinasi dua kali booster efektif meningkatkan kelangsungan hidup dan memperpanjang masa proteksi ikan nila terhadap infeksi S. agalactiae.

Streptococcosis caused by Streptococcus agalactiae is a major constraint to increasing Nile tilapia (Oreochromis niloticus) production. The decline in protection from primary vaccination over time highlights the importance of booster vaccination strategies. This study aimed to evaluate the efficacy of a double booster vaccination of S. agalactiae administered via injection on immune response and survival of nile tilapia (O. niloticus). An experimental method using a Completely Randomized Design (CRD) was applied with five treatments and three replications, consisting of a negative control (KN), positive control (KP), single vaccination (V), one booster vaccination (VB), and double booster vaccination (VDB). Nile tilapia with a body weight of 20,00±1,1 g were vaccinated and boosted, then challenged every 14 days using S. agalactiae without individual reuse through intraperitoneal injection. The VDB treatment showed the best immune response and level of protection, and the highest relative survival rate of 87,50±10,83% followed by the VB treatment at 68,75±10,83% and the V treatment at 56.25±10.83%. Double booster vaccination effectively improved survival and extended the protective period of Nile tilapia against S. agalactiae infection.