Aquaculture Nutrition | 2019
Short‐term supplementation of gilthead seabream (Sparus aurata) diets with Nannochloropsis gaditana modulates intestinal microbiota without affecting intestinal morphology and function
Abstract
Nannochloropsis gaditana was tested as functional ingredient in low fishmeal diets for gilthead seabream juveniles, and its short‐term effects were evaluated in terms of intestinal morphology, digestive function, intestinal immunological and oxidative status, and intestinal microbiota. A diet with 850\xa0g/kg of the protein provided by plant feedstuffs and 150\xa0g/kg provided by fishmeal was used as control, and three other diets identical to the control were supplemented with 5, 7.5 and 15\xa0g/kg N.\xa0gaditana meal and fed to 56.6\xa0g fish for 37\xa0days. At the end of this period, intestinal mucosa integrity and digestive capacity (luminal enzyme activity and absorption) were not altered by dietary microalgae supplementation. Intestinal transcript levels of key markers of inflammation (IL‐1β and TNF‐α) and of key enzymes involved in redox homeostasis (CuZnSOD, MnSOD and catalase) were also similar across experimental groups. However, microbiota richness increased with dietary supplementation of microalgae, and such modulation requires further investigation, particularly regarding its potential effects on disease resistance at short and long term.