Evaluation of the Links between Lamb Feed Efficiency and Rumen and Plasma Metabolomic Data

Abstract

Feed efficiency is one of the keystones that could help make animal production less costly and more environmentally friendly. Residual feed intake (RFI) is a widely used criterion to measure feed efficiency by regressing intake on the main energy sinks. We investigated rumen and plasma metabolomic data on Romane male lambs that had been genetically selected for either feed efficiency (line rfi−) or inefficiency (line rfi+). These investigations were conducted both during the growth phase under a 100% concentrate diet and later on under a mixed diet to identify differential metabolite expression and to link it to biological phenomena that could explain differences in feed efficiency. Nuclear magnetic resonance (NMR) data were analyzed using partial least squares discriminant analysis (PLS-DA), and correlations between metabolites’ relative concentrations were estimated to identify relationships between them. High levels of plasma citrate and malate were associated with genetically efficient animals, while high levels of amino acids such as L-threonine, L-serine, and L-leucine as well as beta-hydroxyisovalerate were associated with genetically inefficient animals under both diets. The two divergent lines could not be discriminated using rumen metabolites. Based on phenotypic residual feed intake (RFI), efficient and inefficient animals were discriminated using plasma metabolites determined under a 100% concentrate diet, but no discrimination was observed with plasma metabolites under a mixed diet or with rumen metabolites regardless of diet. Plasma amino acids, citrate, and malate were the most discriminant metabolites, suggesting that protein turnover and the mitochondrial production of energy could be the main phenomena that differ between efficient and inefficient Romane lambs.

Some plasma biomarkers of residual feed intake in beef cattle remain consistent regardless of intake level

“…The same trend was also observed for the other two BCAAs, leucine and valine, which tended to differ between RFI phenotypes, regardless of the feeding level (raw P values < 0.10; data not shown). This confirms results reported by others in beef cattle 11,14,16 and growing lambs 34 , showing lower plasma concentrations of BCAAs in efficient RFI individuals. Our findings, even though they did not reach statistical significance after false positive correction, align with previous conclusions obtained in a meta-analysis of genome-wide association studies in beef cattle 18 , where BCAA degradation was identified as the only metabolic pathway associated with RFI.…”

Multiple Omics Find New Cecal Microbial Features Associated with Feed Efficiency in Ducks

“…Feed efficiency is a critical factor in reducing the costs associated with livestock production and enhancing environmental protection (31). RFI serves as a commonly employed metric for assessing feed efficiency.…”

A Review of Studies on Improvement of Sheep Resilience to Climate Change Stresses

“…For example, in meat production, FCR is calculated as the amount of feed required to produce 1 kg of meat. A lower FCR indicates higher feed efficiency [27]. There are different FCR values for different sheep products as shown in Table 1.…”