Evaluation of the immunoprotective effect of dietary Fucoidan and Laminarin on Juvenile Blunt Snout Bream (Megalobrama amblycephala)

Megalobrama amblycephala is one of the important farmed economic fish in China. However, it is susceptible to the threat of disease, especially sepsis caused by Aeromonas hydrophila infection. Although antibiotics have a certain degree of effectiveness in disease prevention, the abuse of antibiotics will lead to increased bacterial resistance and affect the safety of aquatic products. Therefore, it is of great significance to develop green immune preparations with biosafety advantages. As feed additives, fucoidan and laminarin are widely used in livestock and poultry breeding. However, their application in freshwater fish like Megalobrama amblycephala is still limited. Therefore, this experiment took the M. amblycephala as the experimental object and added 0, 250 mg/kg and 1000 mg/kg of fucoidan and 250 mg/kg and 1000 mg/kg of laminarin to the diet. A. hydrophila infection experiments were carried out after 8 weeks of breeding. After infection of 0, 6, 24, and 72 hours, intestines, hepatopancreas, kidneys, and gill tissue of the juvenile M. amblycephala were sampled to be used for non-specific immunoassay.