5-aminolevulinic Acid's Effects on Immune-related Gene Expression and Acute Hepatopancreatic Necrosis Disease (AHPND) Protection in Pacific White Shrimp Litopenaeus vannamei

5-aminolevulinic acid (5-ALA) is an endogenous non-protein amino acid that is widely used in medicine, pharmacy products, agriculture, and aquaculture. In this study, the aim is to investigate the effects of 5-ALA on feeding Pacific white shrimp (Litopenaeus vannamei) with a diet supplemented with 5-ALA on their growth performance, immune responses, and resistance to acute hepatopan-creatic necrosis disease (AHPND) caused by Vibrio paraheamolyticus. Shrimp were fed with different diets, including a commercial diet (control) and diets supplemented with 15 ppm (ALA15) and 30 ppm (ALA30) of 5-ALA for 15 and 30 days before bacteria challenge. Anti-lipopolysaccharide factor, crustin, and penaeidin3 immune genes had significantly increased expression level after 15 and 30 days of feeding with 5-ALA. The mortality rate of L. vannamei fed with 5-ALA for 15 and 30 days significantly decreased after V. parahaemolyticus infection. These results indicated that the diet supplemented with 5-ALA enhanced the innate immune response and consequently shrimp's pathogen tolerance. Thus, 5-ALA can be used as immunostimulant additive for Pacific white shrimp cultivation.