Dietary supplementation of Durvillaea potatorum fucoidan enhances the immune responses and improves survival of juvenile black tiger shrimp Penaeus monodon against white spot syndrome virus and acute hepatopancreatic necrosis disease

Abstract

The use of natural immunostimulants as alternatives to antibiotics has gained attention in aquaculture to mitigate disease impacts. In this study, we evaluated fucoidan extracted from giant bull kelp (<i>Durvillaea potatorum</i>) as a dietary additive in black tiger shrimp (<i>Penaeus monodon</i>). Four experimental diets containing increasing levels of fucoidan (0, 1.0, 2.5, and 5.0 g kg⁻¹ diet) were tested for their effects on growth, non-specific immune parameters, and survival against white spot syndrome virus (WSSV) and acute hepatopancreatic necrosis disease (AHPND)-causing <i>Vibrio parahaemolyticus</i>. After 30 days of feeding, fucoidan supplementation did not adversely affect shrimp growth or culture survival, even at the highest inclusion level (5 g kg⁻¹). Non-specific immunological indices, including total hemocyte count (THC), differential hemocyte count (DHC), phenoloxidase (PO) activity, plasma total protein (PTP), and plasma agglutination titer (PAT), were enhanced by fucoidan supplementation, with improvements observed even at 1 g kg⁻¹ relative to the control group. Activation of non-specific immunity translated into increased resistance against WSSV and AHPND, with the highest survival recorded in shrimp fed 5 g kg⁻¹ fucoidan, followed by 2.5 g kg⁻¹. In comparison, similar survival rates against WSSV and AHPND were observed in the unsupplemented control and 1 g kg⁻¹ fucoidan. Overall, this study demonstrates that dietary inclusion of <i>D. potatorum</i> fucoidan at 5 g kg⁻¹ effectively enhances immune responses and disease resistance in <i>P. monodon</i> without negatively impacting growth performance, highlighting its potential as a functional feed additive in shrimp aquaculture.