Innate immune-stimulating and immune genes up-regulating activities of three types of alginate from Sargassum siliquosum in Pacific white shrimp, Litopenaeus vannamei

• Alginate stimulated immune system and up-regulated immune-related genes expression of Pacific white shrimp.
• The four immune-related genes expression in Pacific white shrimp were up-regulated by alginates.
• The increasing immune system and up-regulating the genes expression by alginates worked synergically and resulted the better performance on growth.

The Total Haemocyte Count (THC), phenoloxidase (PO), Superoxide Dismutase (SOD) activity, Phagocytic Activity/Index and Total Protein Plasma (TPP) were examined after feeding the white shrimp Litopenaeus vannamei with diets supplemented with three different types of alginates (acid, calcium and sodium alginates). Immune–related genes expression was evaluated by quantitative Real Time PCR (qRT-PCR). Results indicated that the immune parameters directly increased according to the doses of alginates and time. The 2.0 g kg−1 of acid and sodium alginate treatments were gave better results. Four immune-related genes expression i.e. LGBP, Toll, Lectin, proPO were up regulated. It is therefore concluded that the supplementation of alginate of Sargassum siliquosum on the diet of L. vannamei enhanced the innate immunity as well as the expression of immune-related genes. It is the first report on the simultaneous evaluation of three alginate types to enhance innate immune parameters and immune-related genes expression in L. vannamei.