Enhancements of non-specific immune response in Mugil cephlus by using seaweed extract protection against Vibrio alginolyticus (BRTR07)

Abstract

Objective: To focus on the growth rate and feed utilization of fish by using trash fish feeds supplement with marine seaweeds. Methods: Selected seaweed was extracted using hot-water and its extract was mixed with trash fish feed at different concentrations (0.5%, 1% and 2% for 1-30 days) and the non- specific immune response in fish was studied and challenged with Vibrio alginolyticus at 1 × 10 6 CFU/fish. The hot-water extract of seaweeds was analysed by gas chromatography-mass spectrometry. Results: The average body weight (5.320 ± 0.018), percent weight gain (227.66 ± 0.28), specific growth rate (2.080 ± 0.015), hepatosomatic index (1.197 ± 0.00) and viscerosomatic index (4.421 ± 0.150) were significantly increased in the fish feed with seaweed containing 5% of Sargassum wightii (S. wightii) when compared with other seaweeds and control diet. Hot- water extract of S. wightii (1%) was significantly enhanced the immune response in fish when compared with other diets (0.5% and 2%). S. wightii showed good immunostimulation properties. Gas chromatography-mass spectrometry result showed that the hot-water extract of S. wightii seaweed contained fatty acids. Conclusions: Trash fish feed will reduce the production cost and also provide evidence that aqueous leaf extract of S. wightii (1%) was added to a formulated fish diet which could activate the non-specific immune response and disease resistance against Vibrio alginolyticus in Mugil