Abstract
We evaluated the in vivo regulatory effects of a feed prepared with an extract of the red alga Asparagopsis taxiformis on the immune system of Penaeus monodon. The shrimp were fed with medicated feed containing an effective dose (850 mg kg−1) of algal extract for 28 days. Treated P. monodon exhibited enhanced hemocyte count, phagocytosis, agglutination titer, and bactericidal activity compared to an algae-free control diet. A notable increase in the prophenoloxidase activity was also observed. Algal extract had a clear and positive effect on the immune system of P. monodon, explaining previously observed improvements in shrimp health associated with algal diets.