APPLIED OF TWO COMMERCIAL PROBIOTICS IN GROW-OUT OF RED SNAPPER (Lutjanus johni)  

The constraints of red snapper (Lutjanus johni) culture were high pathogen infection and low growth performance. We developed grow-out technique of red snapper cultured with two commercial probiotics in laboratory scales as a model for grow-out technology of intensive cultured method to farmer. This research consisted of three treatments as follows: control, probiotic A and probiotic B with two replication, respectively. Control treatment used no additional probiotics, probiotic A contains of Bacillus sp. and probiotic B contain of Lactobacillus sporogenes. Probiotics A and B mixed with commercial feed with doses 3 g/kg feed and 15 g/kg feed, respectively. Two hundred of fish used in each treatment (total length 4 cm) and cultured in 3 tons concrete tanks for 60 days. Specific growth rate, biomass and feed convertion ratio of fish group with probiotics B showed better performance compared to others. Artificial infection with Vibrio vulnificus with density of 7.8 x 10⁸cfu/ml showed high survival rate when probiotic B applied during cultured. Fish healthy monitoring of treatment with probiotics showed low pathogen infection in gut compared to control. This research concluded that applying probiotics is necessary during grow-out of red snapper.