Phytogenics from sage and lemon verbena promote innate immunity and barrier function in the gut of gilthead seabream (Sparus aurata)

Deciphering the dietary immunomodulatory effects of a medicinal plant leaf extract (MPLE) obateined from sage (Salvia officinalis, Lamiaceae) and lemon verbena (Lippia citriodora, Verbenaceae) upon the gut-associated lymphoid tissue (GALT) of gilthead seabream (Sparus aurata). Transcriptomic analysis was conducted in order to determine the differences on gene expression level between these two dietary strategies at gut-specific level. The experimental design included two conditions: (1) fish fed basal diet with no medicinal plant leaf extract (MPLE) added and low fishmeal (FM) content (7%) (control); (2) fish fed 0.1% inclusion of MPLE (10%, ursolic acid, 3% other triterpenic compounds; 2% verbascoside and < 1% polyphenols) from sage (Salvia officinalis, Lamiaceae) and lemon verbena (Lippia citriodora, Verbenaceae). After 92 days of feeding trial, total RNA were extracted invidually from gilthead sea bream (S. aurata) gut fed basal diet or an experimental diet containing 0.1% inclusion. Total RNA samples were grouped into 3 pools (n= 4 fish for each condition). The transcriptomic analysis was done following a reference design using the control diet group as reference.