Interactive effects of dietary lipid and phenotypic feed efficiency on the expression of nuclear and mitochondrial genes involved in the mitochondrial electron transport chain in rainbow trout.

Rodrigue Yossa,Jonathan Eya,Ann Gannam,Vitalis Ukwuaba

doi:10.3390/ijms16047682

Abstract

A 2 × 3 factorial study was conducted to evaluate the effects of dietary lipid level on the expression of mitochondrial and nuclear genes involved in electron transport chain in all-female rainbow trout Oncorhynchus mykiss. Three practical diets with a fixed crude protein content of 40%, formulated to contain 10% (40/10), 20% (40/20) and 30% (40/30) dietary lipid, were fed to apparent satiety to triplicate groups of either low-feed efficient (F120; 217.66 ± 2.24 g initial average mass) or high-feed efficient (F136; 205.47 ± 1.27 g) full-sib families of fish, twice per day, for 90 days. At the end of the experiment, the results showed that there is an interactive effect of the dietary lipid levels and the phenotypic feed efficiency (growth rate and feed efficiency) on the expression of the mitochondrial genes nd1 (NADH dehydrogenase subunit 1), cytb (Cytochrome b), cox1 (Cytochrome c oxidase subunits 1), cox2 (Cytochrome c oxidase subunits 2) and atp6 (ATP synthase subunit 6) and nuclear genes ucp2α (uncoupling proteins 2 alpha), ucp2β (uncoupling proteins 2 beta), pparα (peroxisome proliferator-activated receptor alpha), pparβ (peroxisome proliferatoractivated receptor beta) and ppargc1α (proliferator-activated receptor gamma coactivator 1 alpha) in fish liver, intestine and muscle, except on ppargc1α in the muscle which was affected by the diet and the family separately. Also, the results revealed that the expression of mitochondrial genes is associated with that of nuclear genes involved in electron transport chain in fish liver, intestine and muscle. Furthermore, this work showed that the expression of mitochondrial genes parallels with the expression of genes encoding uncoupling proteins (UCP) in the liver and the intestine of rainbow trout. This study for the first time presents the molecular basis of the effects of dietary lipid level on mitochondrial and nuclear genes involved in mitochondrial electron transport chain in fish.

Highlights

Fish oil (FO) is the main source of lipid used in fish nutrition, especially for carnivorous species.Many favorable attributes contribute to this extensive use of FO in aquaculture; FO is the best source of digestible energy, is readily accepted by the farmed fish, contains essential fatty acids, does not affect flesh composition and taste of cultured-fish, and, as a lipid, can spare protein utilization to varying degrees [1,2,3]
The objective of the present study was to investigate the effect of graded dietary lipid levels on the expression of mitochondrial and nuclear genes involved in mitochondrial electron transport chain in low-feed efficiency (FE) and high-FE families of rainbow trout fed a diet contained 40% dietary protein
The F136 fish fed diet 40/10 showed a higher nd1 expression than F136 fish fed diet 40/30, whereas the lowest nd1 expression was observed in F120 fish fed diet 40/10; there was no significant difference in nd1 expression between the F136 fish fed diet 40/10 and the group comprising the F120 fish fed diets 40/20 and 40/30, and between the F136 fish fed diets 40/20 and 40/30

Summary

Introduction

Fish oil (FO) is the main source of lipid used in fish nutrition, especially for carnivorous species.Many favorable attributes contribute to this extensive use of FO in aquaculture; FO is the best source of digestible energy, is readily accepted (palatable) by the farmed fish, contains essential fatty acids, does not affect flesh composition and taste of cultured-fish, and, as a lipid, can spare protein utilization to varying degrees [1,2,3]. Several genetic selection programs have been developed in order to select and produce families of poultry and livestock species [6] as well as fish species [7,8,9,10,11] that show improved feed efficiency (FE), with high feed efficient (HFE) fish having higher body weight gain than low feed efficient (LFE) fish, at the same feed intake In broiler nutrition, such improved phenotypic FE has contributed to the optimization of the nutrients (ingredients) used in diet formulation, and has been related to an improvement in mitochondrial function [6,12,13,14]. Genetic variation has been reported in feed consumption, growth and feed efficiency, and improved growth and FE were associated to mitochondrial function in channel catfish Ictalurus punctatus [15,16] and rainbow trout

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Conclusion