Effects of functional polysaccharide from silkworm as an immunostimulant on transcriptional profiling and disease resistance in fish

Dietary manipulation to maintain fish health and reduce bacterial infection through the use of immunostimulants has been widely used worldwide. A broad range bioactive substances capable optimising animal found in several insect species, including antimicrobial/antiviral peptides, polysaccharides such as chitin, lauric acid, products honey. Recently, we identified a novel polysaccharide from Bombyx mori, termed silkrose-BM, that can activate innate immunity mammalian RAW264.7 macrophages provide effective protection against vibriosis penaeid prawns. However, efficacy dietary silkrose-BM teleosts remains unclear. Here, investigated effects inclusion Japanese medaka (Oryzias latipes) after they were artificially challenged with Edwardsiella tarda. The survival E. tarda was significantly improved by at concentration 10, 100, 1000 ng/g. RNA-seq analysis performed intestine liver identify changes transcriptional profiling evoked silkrose-BM. group showed 1,194 2,259 differentially expressed genes (DEGs) liver, respectively, when compared control prior infection. Functional enrichment DEGs putative involved Toll-like receptor/nuclear factor ?B pathway, cytokine-cytokine receptor interactions, complement cascade, antimicrobial junctional modification. Taken together, these results suggest an immunostimulant improve immune system resistance edwardsiellosis teleosts.