Squid (Loligo edulis) ink raw extract as an anti–vibriosis substance in grouper (Epinephelus fuscoguttatus) juvenile culture infected by Vibrio alginolyticus

In mariculture Vibrio alginolyticus is frequently isolated from vibriosis sick grouper, Epinephelus fuscoguttatus. The high mortality of grouper larvae in grouper hatchery as vibriosis cases need a way to overcome with other antibacterial products. Squid ink, as a squid waste product, which contains a variety of bioactive components which are environmentally friendly was used as an anti vibriosis substance. The methods used in this research were: Phase I: extraction of squid ink; Phase 2: Paper Disk Test, Scanning Electronic Microscope (SEM) observation, and GC-MS chromatography test for the active ingredient; Phase 3: in-vivo trials on squid ink extract against V. alginolyticus in tiger grouper juvenile. An experimental method with completely randomized design using three treatment doses of squid ink extract (365.5; 312.5; 265.5 mg L^-1), after preliminary test using Minimum Inhibitory Concentration (MIC), to treat the infected juvenile with V. alginolyticus each with three replications was used. Blood samples were investigated for hematological profile i.e.: erythrocyte, leukocyte, monocyte, lymphocyte, and neutrophile. The conclusion of the research results were squid ink extract can be used as bactericidal for V. algynolyticus at a dose of 265.5 mg L^-1. Squid ink contains 9-octadecenoic acids/oleic acids as an antibacterial agent. The tiger grouper juvenile which was infected with V. alginolyticus reached 100% survival rate after squid ink extraction treatment and gives a highly significant effect to hematological profile.