Real-time quantification of the immune gene expression in rainbow trout fed different forms of probiotic bacteria Lactobacillus rhamnosus

Abstract

Whether it is better to use viable or non-viable probionts in aquaculture is still a matter of debate. In this study, the molecular immunomodulation in rainbow trout Oncorhynchus mykiss induced by viable or killed forms of the probiont Lactobacillus rhamnosus JCM 1136 was investigated. Three forms of this probiont:(1) heat-killed (HK), (2) live spray (LI) and (3) freezedried (FD) were incorporated into a basal (control) diet for rainbow trout O. mykiss. The LI and FD diets are referred to as viable diets. A rearing trial, in triplicate, was conducted for 30 days, with the control and probiotic diets as treatments. The cytokine genes such as the tumour necrosis factor (TNF), transforming growth factor (TGF-b), interferon (IFN) and immune gene Immunoglobulin (Ig) found in tissues from the kidney and spleen were assessed for their expression pattern by real-time polymerase chain reaction. The tested immune genes were up-regulated in the treatment groups, sometimes even in many folds like in the case of the Ig gene. The TNF gene was found to be highly (Po0.05) up-regulated (5000-fold) in groups fed both viable forms (LI, FD). With regard to the TGF-b gene, the spleen of the HK and FD groups showed signi¢cant up-regulation of 20-and 30-folds respectively. The IFN gene was upregulated (Po0.05) in all treatments, but more in the viable diet treatments. Kidney and spleen tissues showed similar expression patterns, i.e. all of these genes were up-regulated more with the viable diets that with the control, and in most cases, the viable diets induced a higher expression of the immune genes than the HK diet.

Dietary probiotic Pediococcus acidilactici MA18/5M modulates the intestinal microbiota and stimulates intestinal immunity in rainbow trout (Oncorhynchus mykiss)

“…Compared to the control fish, increased gene expression levels of the pro-inflammatory cytokines il1 and il8, commonly used as biomarkers for immune regulation, were observed. These findings are in agreement with previous studies which have reported that dietary supplementation with probiotic bacteria increased the expression of pro-inflammatory cytokines (e.g., il1, il8, and tnfα) in fish cells and tissues (Kim & Austin, 2006;Panigrahi et al, 2007;Panigrahi, Viswanath, & Satoh, 2011), including the intestine (Gioacchini et al, 2014;He et al, 2009;Perez-Sanchez et al, 2011;Standen et al, 2013Standen et al, , 2016. Concomitantly, the expression of the antiinflammatory cytokine il10 gene was downregulated.…”

In vitro and in vivo evaluation of lactic acid bacteria of aquatic origin as probiotics for turbot (Scophthalmus maximus L.) farming

“…cremoris SMM69. The up-regulation of these genes has been previously reported in rainbow-trout head-kidney and/or spleen [18,19,46,59], sea bass (Dicentrarchus labrax L.) head-kidney [60], tilapia (Oreochromis niloticus) intestine [47], and Japanese pufferfish (Takifugu rubripes) head-kidney [16] fed with probiotic LAB or using in vitro co-cultures of fish cell lines and probiotic LAB. In spite of the up-regulation of pro-inflammatory cytokines in skin observed in our work, the expression of IL-1b gene was significantly down-regulated in other turbot organs such as head-kidney, spleen, liver or intestine.…”

“…With regard to this, the knowledge of the immunomodulatory properties of probiotics, mainly on mucosa, is essential for their successful application in fish farming [45]. Several studies have described the immunostimulant effect of feeding fish with probiotics [18,19,46,47], but any previous work has described the fishimmune response to the bath administration of probiotics. However, this way of application has been previously used to evaluate the effect of immunostimulant mucosal uptake on the transcription of inflammatory cytokines in rainbow trout fries [48].…”

The study of antioxidant enzymes and immune-related genes expression in common carp (Cyprinus carpio) fingerlings fed different prebiotics

“…() observed enhanced expression of TNF‐α in rainbow trout following dietary administration of a commercial prebiotic mixture. Similarly, when rainbow trout were fed with a probiotics, Lactobacillus rhamnosus , an upregulation in the expression of TNF‐α was also observed (Panigrahi, Viswanath & Satoh, ) suggesting that both probiotics and prebiotics might have the same effects in eliciting immune response in fish as well as in modulating the gut microbiota (Nayak, ).…”