Fish Waste Alchemy: Innate and Acquired Immunity Assessment Followed Vaccinated against Kocuriasis and Investigate the Function of Low Molecular Weight Peptides of Kilka Fish Stick-water As Both Immunostimulant and Adjuvant in Farmed Rainbow Trout

Abstract

Investigation of the immunogenicity of Caspian sea sprat stick-water, rich in hydrolysate protein was set as the aim of this study. Therefore, peptides below 3 kilo Daltons were isolated, and then the concentration of low molecular peptides (μg/μl) was measured. Kocuria rhisophila bacterium, which is known as one of the pathogenic agents of rainbow trout reared, was formalin- killed to make its vaccine with concentration of 2×109 CFU/ml in Tris-Buffered Saline. Eight treatments with 3 repetitions, consist of 240 individuals were considered. Three treatments were injected by concentrations of 10, 25, and 50 mg/body weight of stick-water containing low molecular peptides. In one treatment, bacterin was injected alone; in the three treatments, bacterin was injected along with doses of 10, 25, and 50 mg/body weight of the stick-water. In addition, Tris-Buffered Saline was injected into the control treatment. Next, to measure immunity, innate immunity factors were examined. Finally, in order to check the specific immunity, the challenge was done by immersion with a concentration of 1.2 x 108 CFU/ml of Kocuria rhizophila, after 14 days, the blood bacteremia test of all treatments was performed. According to the results, stick-water containing low molecule peptides was immunogenic in low doses.