Common and diet-specific metabolic pathways underlying residual feed intake in fattening Charolais yearling bulls

Ezequiel Jorge-Smeding,Gonzalo Cantalapiedra-Hijar,Muriel Bonnet,Sébastien Taussat,Gilles Renand,Isabelle Ortigues-Marty,Benoit Graulet

doi:10.1038/s41598-021-03678-x

Abstract

Residual feed intake (RFI) is one of the preferred traits for feed efficiency animal breeding. However, RFI measurement is expensive and time-consuming and animal ranking may depend on the nature of the diets. We aimed to explore RFI plasma biomarkers and to unravel the underlying metabolic pathways in yearling bulls fed either a corn-silage diet rich in starch (corn diet) or a grass-silage diet rich in fiber (grass diet). Forty-eight extreme RFI animals (Low-RFI, n = 24, versus High-RFI, n = 24, balanced per diet) were selected from a population of 364 Charolais bulls and their plasma was subjected to a targeted LC-MS metabolomic approach together with classical metabolite and hormonal plasma analyses. Greater lean body mass and nitrogen use efficiency, and lower protein turnover were identified as common mechanisms underlying RFI irrespective of the diet. On the other hand, greater adiposity and plasma concentrations of branched-chain amino acids (BCAA) together with lower insulin sensitivity in High-RFI animals were only observed with corn diet. Conversely, greater plasma concentrations of BCAA and total triglycerides, but similar insulin concentrations were noted in efficient RFI cattle with grass diet. Our data suggest that there are diet-specific mechanisms explaining RFI differences in fattening Charolais yearling bulls.

Highlights

In a growing world’s human population the efficient use of natural resources becomes a crucial issue for sustainable livestock systems
Starch intake differed between Residual feed intake (RFI) groups in a different way according to the diet (RFI × Diet; P < 0.01) as it was lower for Low- than High-RFI animals only in the corn silage diet (Table 1)
In agreement with what was observed for starch intake, the net portal appearance for glucose differed between RFI groups in a diet-dependent manner (RFI × Diet; P < 0.01) as it was lower for Low- than High-RFI animals only in the corn diet (Table 1)

Summary

Introduction

In a growing world’s human population the efficient use of natural resources becomes a crucial issue for sustainable livestock systems. As for any other feed efficiency trait, RFI determination is expensive and time-consuming, needing at least 6 weeks of individual daily feed intake and body weight gain recording[5]. For this reason, research aimed at exploring biological markers of RFI has become of scientific interest in the last years as a way to find easier and cheaper strategies for identifying individuals with superior feed efficiency. This could mean that biological mechanisms underlying RFI, and the associated biomarkers, might differ depending on the nature of the diet and to the type of absorbed nutrients This is a crucial issue if RFI selection programs are to be applied in beef cattle systems where a wide variety of feeding conditions exists. To the best of our knowledge, our study presents the largest experimental set up for exploring RFI biomarkers in fattening bulls through a targeted metabolomic approach

Objectives

Methods

Results

Discussion

Conclusion