Nutrigenomics and immune function in fish: new insights from omics technologies

Samuel A.M Martin,Elżbieta Król

doi:10.1016/j.dci.2017.02.024

Samuel A.M Martin, Elżbieta Król

Open Access

https://doi.org/10.1016/j.dci.2017.02.024

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Abstract

The interplay between nutrition and immune system is well recognised, however the true integration of research between nutrition, animal energy status and immune function is still far from clear. In fish nutrition, especially for species maintained in aquaculture, formulated feeds are significantly different from the natural diet with recent changes in nutrient sources, especially with protein and oil sources now being predominated by terrestrial derived ingredients. Additionally, many feeds are now incorporated to health management and termed functional feeds, which are believed to improve fish health, reduce disease outbreaks and/or improve post-infection recovery. Using new omics technologies, including transcriptomics (microarray and RNA-seq) and proteomics, the impacts of nutrition on the immune system is becoming clearer. By using molecular pathway enrichment analysis, modules of genes can indicate how both local (intestinal) and systemic immune function are being altered. Although great progress has been made to define the changes in host immune function, understanding the interplay between fish nutrition, intestinal microbiome and immune system is only just beginning to emerge.

Highlights

Both energy and nutrients consumed with food are essential for maintaining optimal immune function (Chandra, 1997)
Comparison and sampling Fish fasted for 4 weeks and control non-fasted fish were injected with pathogen or PBS, sampled 24 h post-infection Fish fed fish meal (FM)-CR vs soybean meal (SBM) vs control FM (54 d) Fish fasted for 7 d vs control non-fasted fish Fish fasted for 7 d vs control non-fasted fish
Functional feeds are defined as feeds which are supplemented to enhance the health benefits to the fish, with the additives being beyond the basal requirements of the fish for normal growth and health

Summary

Introduction

Both energy and nutrients consumed with food are essential for maintaining optimal immune function (Chandra, 1997). Outbreaks of fish diseases commonly occur when fish are stressed due to a variety of factors associated with the aquaculture environment and management procedures such as high stocking densities, transport or handling Such stress may induce a variety of physiological responses grouped broadly as primary (release of adrenal catecholamines and corticosteroids) and secondary, which include changes in energy metabolism and hydromineral balance, coupled with alterations in cardiovascular, respiratory and immune functions (Barton, 2002). Due to the extensive interplay between innate and adaptive immunities, both these systems are according to the human studies sensitive and responsive to nutritional deficiencies, with the most consistent abnormalities seen in cell-mediated immunity, complement system, phagocyte function, cytokine production, mucosal secretory antibody response and antibody affinity (Marcos et al, 2003). There are advances being made using other technologies for deeper understanding of gene regulation including non-coding RNAs, epigenetics and metabolomics, at the time of writing this review, these approaches have not been used to examine the relationship between nutrition and immune function and will not be covered here

Overview of genomic resources for aquaculture

Fasting

Functional feeds

Findings

Use of plant materials to replace marine ingredients