Dietary supplementation with sulfated polysaccharides from Gracilaria birdiae promotes a delayed immunostimulation in marine shrimp challenged by the white spot syndrome virus

Immune system stimulation by dietary supplementation has been widely explored in aquaculture as an effective practice in increasing shrimp resistance against infectious diseases. Given the recurring impacts of white spot syndrome virus (WSSV) on shrimp farming worldwide, the search for immunostimulant compounds is of urgent importance. This study investigated the effect of a diet supplemented with sulfated polysaccharides (SP) from the red seaweed Gracilaria birdiae on the immune response of Pacific white shrimp (Litopenaeus vannamei) challenged with a non-lethal dose of WSSV. The health status and immunocompetence of infected shrimp were monitored by assessing multiple immune parameters in hemolymph. Dietary supplementation with SP from G. birdiae (32days) was able to promote a delayed immunostimulation by enhancing the agglutinating capacity and PO activity and an increase in the survival of L. vannamei challenged with a non-lethal dose of WSSV. Our findings support the potential application of this marine seaweed in shrimp farming and contribute to a better understanding of the effects of immunostimulants on shrimp immune and physiological responses.