Antibacterial activity of sponge associated fungi against vibriosis agents in shrimp and its toxicity to Litopenaeus vannamei

Whiteleg shrimp (Litopenaeus vannamei) is commonly reported to be infected by Vibro spp. which increases the death rate and decreases the productivity. Even though the use of antibiotic is considered effective against the vibriosis, unfortunately, it is prohibited in aquaculture practice. Regarding to this issue, an exploration of biological sources of anti-vibriosis is urgently needed. Our study used sponge associated fungi as source of anti-vibriosis agent. The objectives of this research were to screen the potential of sponge associated fungi against vibriosis agents, to determine the antibacterial activity, to detect the nonribosomal peptide-synthetase (NRPS) gene fragments of potential fungus and to determine the fungal extract lethal concentration (LC50) to L. vannamei. There were 8 from 28 of sponge associated fungi which could be revived. From 8 available strains, Trichoderma asperellum MT02 showed inhibition zone against V. harveyi and V. alginolyticus, while V. parahaemolyticus was inhibited by Trichoderma sp. MT01. Crude extract of T. asperellum MT02 showed antibacterial activity against V. harveyi and V. alginolyticus. The widest inhibition zone was performed against V. alginolyticus at concentration 1000 µg mL-1 with LC50 value of 383.70 µg mL-1. The existence of NRPS gene fragments was detected in T. asperellum MT02