Effects of oligo-porphyran on immunological parameters related to immunoregulation and growth in RAW264.7 macrophages and zebrafish model.

Many carbohydrate compounds derived from marine seaweeds possess immune-enhancing activities. In recent years, the effect of dietary addition of marine polysaccharides on fish has been widely evaluated. Here, we studied the immunoregulation potential of oligo-porphyran (OP) through LPS-induced RAW264.7 cells and zebrafish model. Surprisingly, we found that OP had an excellent anti-inflammatory effect with a dose-dependent manner in vitro. OP administration effectively reduced LPS-induced NO release and inflammatory cytokine production in RAW264.7 cells. Notably, we also found that dietary OP to zebrafish exerted positive effect on intestinal immunity through regulating immune factor content and gut microbiota. Besides, dietary OP could also maintain steadiness of intestinal morphology of zebrafish, enhance the intestinal digestive enzyme activity, and promote the accumulation of crude protein and crude fat in zebrafish. These findings indicated that OP supplementation in diet could promote growth, improve immunity, and regulate intestinal flora, which made OP a promising aquatic candidate additive. [ABSTRACT FROM AUTHOR]