An aqueous extract from Sargassum sp. enhances the immune response and resistance against Streptococcus iniae in the Asian sea bass (Lates calcarifer Bloch)

摘要: The effects of the hot water extract from Sargassum sp. on growth performance, immune responses, oxidative stress, and resistance Asian sea bass (Lates calcarifer) to Streptococcus iniae were investigated. Four groups fish fed basal diet containing at 0, 0.5, 1.0, 2.0 g kg−1 for 30 days. Thereafter, each group divided into equal halves. first half was injected intraperitoneally with 0.85 % NaCl, second S. (2 × 103 cfu fish−1). At end 30 days feeding trial, there no significant differences in final body weight, weight gain, feed conversion ratio, hepatosomatic index among four groups. Plasma protein, total immunoglobulin (Ig), lysozyme messenger RNA (mRNA) levels diets 1.0 extract, however, became increased a non-dose-dependent manner. When exposed bacteria, 24 h, significantly (p < 0.05) higher hematocrit, red blood cell white cell, Ig, serum than those control diet, highest survival rate also observed this group. In addition, receiving seaweed able suppress lipid peroxidation especially 24-h post challenge. These findings thus suggested that can be used as an immunostimulant bass.