Dietary 5-aminolevulinic acid enhances adenosine triphosphate production, ecdysis and immune response in Pacific white shrimp, Litopenaeus vannamei (Boone)

Previous studies have shown that 5-aminolevulinic acid (5-ALA), a precursor of haem, can enhance haem synthesis and the activity of haemoproteins. Here, we investigated the effects of dietary 5-ALA on Pacific white shrimp, Litopenaeus vannamei (Boone). Dietary groups included basal diet (BD, control) and BD plus 15, 30 and 60 ppm 5-ALA (ALA15, ALA30 and ALA60 respectively). Hepatopancreas adenosine triphosphate (ATP) levels increased with increasing 5-ALA concentration (ALA60 p < 0.05) after 2 weeks of feeding. 5-aminolevulinic acid diets significantly increased the expression of ecdysis-related genes: nuclear receptor E75 and chitinase 4 (ALA15, ALA30, ALA60), cytochrome P450 Shade (ALA60), chitinase 1 (ALA60) and chitinase 3 (ALA15, ALA60). Catalase (CAT) and prophenoloxidase gene expression levels were also significantly higher in ALA60 after 12 weeks of feeding. Six hours after L. vannamei were exposed to Vibrio parahaemolyticus, total haemocyte count (ALA60) and gene expression levels of CAT (ALA30, ALA60) were significantly higher in 5-ALA groups compared to the control. 5-aminolevulinic acid diets also increased survival of L. vannamei following V. parahaemolyticus immersion challenge. These results suggest that supplementing L. vannamei diets with 5-ALA can enhance ATP production, immune response against V. parahaemolyticus, total haemocyte count and expression of some immune-related genes. 5-aminolevulinic acid can also induce ecdysis-related gene expressions, without adversely affecting growth.