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