Short‐term supplementation of gilthead seabream (Sparus aurata) diets withNannochloropsis gaditanamodulates 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 g/kg of the protein provided by plant feedstuffs and 150 g/kg provided by fishmeal was used as control, and three other diets identical to the control were supplemented with 5, 7.5 and 15 g/kg N. gaditana meal and fed to 56.6 g fish for 37 days. 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.

Dietary Supplementation with Omega-6 LC-PUFA-Rich Microalgae Regulates Mucosal Immune Response and Promotes Microbial Diversity in the Zebrafish Gut

“…Studies on the effects of microalga-supplemented diets on the host microbiome are very rare. Previous studies analyzing fish microbiome alterations in response to dietary fatty acid supplementation used mainly omega-3 LC-PUFA-producing microorganisms, such as Schizochytrium [35], and the microalgae Nannochloropsis gaditana [34] and Phaeodactylum tricornutum [33]. This is the first report of the effects of omega-6 LC-PUFA-rich L. incisa on the fish gut microbiome.…”

“…The effects of omega-6 LC-PUFA and, in particular, the omega-6 C20 LC-PUFA (ARA and DGLA) on the general microbiome structure and its outcomes have not been previously addressed. Although a few studies have reported the effects of dietary omega-3 LC-PUFA [33][34][35], the impact of the specific omega-6 LC-PUFA ARA and DGLA on the fish microbiome has not been examined.…”

Chlorella sp. and Nannochloropsis sp. Inclusion in Plant-Based Diets Modulate the Intestine and Liver Antioxidant Mechanisms of European Sea Bass Juveniles

“…To the authors' knowledge, the impact of dietary microalgae on the intestinal antioxidant mechanisms in fish is limited to a study in gilthead sea bream (Sparus aurata) fed practical diets supplemented with 1.5% of Nannochloropsis gaditana (36), where no signs of nutritional regulation of CuZn-and Mn-SOD and CAT were observed at the transcriptional level. Even so, there is crescent evidence that microalgae may be of value to counteract or prevent the impairment of intestinal health generally observed in fish fed aquafeeds rich in PF.…”

Effects of a short pulse administration ofUlva rigidaon innate immune response and intestinal microbiota inSparus auratajuveniles

“…piscicida infection (Nuñez-Díaz et al, 2016) Vizcaíno et al (2016) reported a beneficial effect of replacement of fish meal by 25% of macroalgae U. rigida for 60 days as dietary ingredient in juvenile S. aurata on productive parameters. Furthermore, significant changes in immune system (Cerezuela et al, 2012) and intestinal microbiota (Jorge et al, 2019) of S. aurata have been recorded after short-term (28 and 37 days respectively) supplementation of Phaeodactylum tricornutum and Tetraselmis chuii, and Nannochloropsis gaditana respectively. To our knowledge, there are no previous studies assessing the effects of a short pulse of dietary administration of macroalgae U. rigida on innate immune response and intestinal microbiota in S. aurata.…”