Effects of Schizochytrium and micro-minerals on immune, antioxidant, inflammatory and lipid-metabolism status of Micropterus salmoides fed high- and low-fishmeal diets

Habte-Michael Habte-Tsion,Waldemar Rossi,Vikas Kumar,Gagan D Kolimadu,Keith Filer

doi:10.1038/s41598-020-64286-9

Habte-Michael Habte-Tsion, Waldemar Rossi + Show 3 more

Open Access

https://doi.org/10.1038/s41598-020-64286-9

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Abstract

A 12-week factorial experiment was conducted to investigate the interactive effects of dietary algal meal (Schizochytrium sp., AM) and micro-minerals (MM, either organic [OM] or inorganic [IM]) on the immune and antioxidant status, and the expression of hepatic genes involved in the regulation of antioxidants, inflammatory cytokines, lipid metabolism, and organ growth of largemouth bass (LMB; Micropterus salmoides) fed high-and low-fishmeal (FM) diets. For this purpose, two sets of six iso-nitrogenous (42% crude protein) and iso-lipidic (12% lipid) diets, such as high (35%) and low (10%) FM diets were formulated. Within each FM level, AM was used to replace 50% or 100% of fish oil (FO), or without AM (FO control) and supplemented with either OM or IM (Fe, Zn, Mn, Cu, and Se). Diets were fed to juvenile LMB (initial weight, 25.87 ± 0.08 g) to near satiation twice daily. The results indicated that FO replacement by dietary AM did not change the levels of most biochemical (ALB, AMY, TP and GLOB), antioxidants (SOD, GPx and GSH), and immune (IgM and lysozyme) parameters in LMB, except ALP and CAT. MM affected only hepatic GSH, with lower values in fish fed the OM diets. FM influenced the levels of ALP, AMY, GLOB, IgM, and MDA (P < 0.05). A three-way interactive effect (P = 0.016) was found on IgM only, with lower levels in fish fed diet 12 (low-FM, AM100, OM). Subsequently, the relative expressions of hepatic antioxidants (Cu/Zn-SOD and GPx-4), inflammatory cytokines (TNF-α and TGF-β1), lipid metabolism (FASN and CYP7A1), and organ growth (IGF-I) related genes were affected by the dietary treatments, with interactions being present in Cu/Zn-SOD, TNF-α, TGF-β1, FASN and IGF-I. Overall, dietary AM could be used as an alternative to FO in low-FM diets without compromising the health of LMB, especially when it is supplemented with MM.

Highlights

IntroductionAlgae have been recognized as an alternative source of fatty acids (especially eicosapentaenoic acid [EPA], docosahexaenoic acid [DHA], and arachidonic acid [ARA]) for use in aquafeeds[1]
Algae have been recognized as an alternative source of fatty acids for use in aquafeeds[1]
The results of this study indicated that dietary algal meal (AM) could completely replace fish oil (FO) and improve/ maintain the immune, antioxidant, anti-inflammatory, and lipid metabolism capacity of Largemouth bass (LMB)

Summary

Introduction

Algae have been recognized as an alternative source of fatty acids (especially eicosapentaenoic acid [EPA], docosahexaenoic acid [DHA], and arachidonic acid [ARA]) for use in aquafeeds[1]. There are few reports on the health/ immunonutrition studies for LMB18–29 and to the best of our knowledge, there is no report about the potential interactive effects of FM, algal meal (AM), and MM (organic minerals [OM] vs inorganic minerals [IM]) on the growth, health, and signaling molecules involved in antioxidant and inflammatory cytokines responses or lipid metabolism and organ growth of LMB. We designed this study to investigate the interactive effects of dietary FM, AM and MM (OM vs IM) including Fe, Zn, Mn, Cu and Se, on the biochemical, immune, antioxidant and inflammatory cytokines status of juvenile LMB fed high- and low-FM diets. Nutrigenomics was used to investigate the relationship between the nutrients (FM, AM and MM) and target genes involved in antioxidant and inflammatory responses and in lipid metabolism and organ growth

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