A Microbial Feed Additive Abates Intestinal Inflammation in Atlantic Salmon

Abstract

The efficacy of a microbial feed additive (Bactocell®) in countering intestinal inflammation in Atlantic salmon was examined in this study. Fish were fed either the additive-coated feed (probiotic) or feed without it (control). After an initial 3-week feeding, an inflammatory condition was induced by anally intubating all the fish with oxazolone. The fish were offered the feeds for 3 more weeks. Distal intestine from the groups was obtained at 4 h, 24 h, and 3 weeks, after oxazolone treatment. Inflammatory responses were prominent in both groups at 24 h, documented by changes in intestinal micromorphology, expression of inflammation-related genes, and intestinal proteome. The control group was characterized by edema, widening of intestinal villi and lamina propria, infiltration of granulocytes and lymphocytes, and higher expression of genes related to inflammatory responses, mul1b, il1b, tnfa, ifng, compared to the probiotic group or other time points of the control group. Further, the protein expression in the probiotic group at 24 h after inducing inflammation revealed five differentially regulated proteins – Calr, Psma5, Trp1, Ctsb, and Naga. At 3 weeks after intubation, the inflammatory responses subsided in the probiotic group. The findings provide evidence that the microbial additive contributes to intestinal homeostasis in Atlantic salmon.

Dietary Yeast Cell Wall Extract Alters the Proteome of the Skin Mucous Barrier in Atlantic Salmon (Salmo salar): Increased Abundance and Expression of a Calreticulin-Like Protein

“…Secondly, in medaka Oryzias melastigma , calreticulin protein levels were decreased in gill after treatment with brevetoxin-1, a fish toxin associated with toxic algal blooms [58]. In a recent study, calreticulin was over expressed in the proteome of the distal intestine of Atlantic salmon 24 h after inducing inflammation [59]. Up-regulation of three isoforms of calreticulin was recorded in the channel catfish Ictalurus punctatus after iron-dextran treatment and/or bacterial challenge [60].…”

Defatted Biomass of the Microalga, Desmodesmus sp., Can Replace Fishmeal in the Feeds for Atlantic salmon

“…The processing and sectioning techniques of the distal intestinal samples (n = 6 fish) are described in Vasanth et al (2015).…”

“…The cDNA was synthesized as described by Vasanth et al (2015). The obtained cDNA was 30-fold diluted and used in qPCR.…”

“…The various steps such as protein extraction, two-dimensional electrophoresis and capturing of the gel images are described previously (Vasanth et al, 2015).…”

“…IL-17D is important in local immune responses and repair of tissues after structural damage (Starnes et al, 2002). il17a and tfgb were upregulated in the intestine of Atlantic salmon during the early and/or late inflammatory stages (Marjara et al, 2012), and il1b was reduced after recovery from inflammation (Vasanth et al, 2015). Oral intubation of 10 mg of A. platensis suspension per carp (C. carpio) increased the phagocytic activity, superoxide anion production, il1b and tnfa, but decreased il10 in head kidney leukocytes (Watanuki et al, 2006).…”