Intestinal Explant Cultures from Gilthead Seabream (Sparus aurata, L.) Allowed the Determination of Mucosal Sensitivity to Bacterial Pathogens and the Impact of a Plant Protein Diet

Abstract

The interaction between diet and intestinal health has been widely discussed, although in vivo approaches have reported limitations. The intestine explant culture system developed provides an advantage since it reduces the number of experimental fish and increases the time of incubation compared to similar methods, becoming a valuable tool in the study of the interactions between pathogenic bacteria, rearing conditions, or dietary components and fish gut immune response. The objective of this study was to determine the influence of the total substitution of fish meal by plants on the immune intestinal status of seabream using an ex vivo bacterial challenge. For this aim, two growth stages of fish were assayed (12 g): phase I (90 days), up to 68 g, and phase II (305 days), up to 250 g. Additionally, in phase II, the effects of long term and short term exposure (15 days) to a plant protein (PP) diet were determined. PP diet altered the mucosal immune homeostasis, the younger fish being more sensitive, and the intestine from fish fed short-term plant diets showed a higher immune response than with long-term feeding. Vibrio alginolyticus (V. alginolyticus) triggered the highest immune and inflammatory response, while COX-2 expression was significantly induced by Photobacterium damselae subsp. Piscicida (P. damselae subsp. Piscicida), showing a positive high correlation between the pro-inflammatory genes encoding interleukin 1β (IL1-β), interleukin 6 (IL-6) and cyclooxygenase 2(COX-2).

Medical Image Recognition Technology in the Effect of Substituting Soybean Meal for Fish Meal on the Diversity of Intestinal Microflora in Channa argus

“…Healthy gastrointestinal tract is very important for overall health, and animal health depends on the intake of nutrients, the balance of digestive juice (acid and enzyme), and the important role of microorganisms in the digestive system [ 20 ]. The research on promoting microecology in aquatic animals is still in its infancy, but its importance has been recognized and related research has been carried out [ 21 , 22 ].…”

Gut Associated Lymphoid Tissue (GALT) primary cells and stable cell lines as predictive models for intestinal health in rainbow trout (Oncorhynchus mykiss)

“…However, due to feeding trials using many fish to study just one ingredient, complementary methods have since been developed to identify the mechanisms of action of functional ingredients, which could be especially useful at the early stages of characterization of new products. To examine direct tissue responses several techniques have been developed using explant ( 19 ), primary cell cultures ( 20 ) or cell lines ( 21 ).…”

The Effects of Short-Chain Fatty Acids in Gut Immune and Oxidative Responses of European Sea Bass (Dicentrarchus labrax): An Ex Vivo Approach

“…Among these functions, physical and immunological defense against pathogenic microorganisms is one of the most important [7]. The intestinal epithelial cells are essential for mucosal immunity and are involved in the production of antimicrobial peptides, chemokines, cytokines, and immunoglobulins that help fish defend against infections [8,9].…”

“…However, the lack of adequate in vitro systems to study and understand the physiological processes that occur at the intestine level of several fish species has prompted scientists to find new ways to study these interactions [22]. Thus, innovative systems, like the use of explants (non-disaggregated tissue or organ fragments that have been taken from an organism), are being tested to study the interactions between the host and different compounds or bacteria [9,23].…”