Spirulina water extract and Lactobacillus bulgaricus FNCC-0041, Streptococcus thermophilus FNCC-0040 secretion as immunostimulants in gnotobiotic Artemia challenge tests against pathogenic Vibrio parahaemolyticus, V. vulnificus, and V. harveyi

Abstract

Spirulina water extract (SWE) has a good potency as an immunostimulant. Lactobacillus bulgaricus & Streptococcus thermophilus are lactic acid bacteria (LAB) that produce exopolysaccharide exudate. Vibriosis is a common infectious disease for aquatic cultivans caused by Vibrio spp. This study determines the ability of SWE in combination with L. bulgaricus & S. thermophilus as immunostimulant (Artemia challenge test) assay against Vibrio parahaemolyticus, V. vulnificus, and V. harveyi. Factorial Design with two factors namely SWE doses (0, 300, 600, and 900 ppb) and Vibrio spp. treatment (non-Vibrio spp., Vibrio harveyi (Vh), Vibrio parahaemolyticus (Vp), Vibrio vulnificus (Vv), Vh-Vp, Vv-Vp, Vp-Vh, and Vp-Vv-Vh) were applicated. SWE was diluted and LAB at a concentration of 108 cell/mL were fermented in three days at 30°C. Ten newly hatched Artemia nauplii were enriched with fermented and non-fermented SWE for one hour, then challenged with 108 cell/mL Vibrio spp. The survival of Artemia was recorded every 6 hours. Results showed that the survival rate of Artemia enriched with 300 ppb concentration of SWE and LAB was significant than control (p<0.05). It is concluded that there is a positive effect on the bioencapsulation of the minimum concentration of SWE and LAB secretion to accelerate Artemia's immune response.