Residual Feed Intake in Beef Cattle Is Associated With Differences in Hepatic mRNA Expression of Fatty Acid, Amino Acid, and Mitochondrial Energy Metabolism Genes

Abstract

We evaluated the mRNA expression of genes involved in hepatic fatty acid, amino acid, and mitochondrial energy metabolism in crossbred beef steers with divergent low and high residual feed intake (RFI). Low-RFI beef steers (n = 8; RFI = - 1.93 kg/d) and high-RFI beef steers (n = 8; RFI = + 2.01kg/d) were selected from a group of 56 growing crossbred beef steers (average BW = 261 ± 18.5 kg) fed a high-forage total mixed ration after a 49-d performance testing period. At the end of the 49-d performance testing period, liver biopsies were collected from the low-RFI and high-RFI beef steers for RNA extraction and cDNA synthesis. The mRNA expression of 84 genes each related to fatty acid metabolism, amino acid metabolism, and mitochondrial energy metabolism were analyzed using pathway-focused PCR-based arrays. The mRNA expression of 8 genes (CRAT, SLC27A5, SLC27A2, ACSBG2, ACADL, ACADSB, ACAA1, and ACAA2) involved fatty acid transport and β-oxidation were upregulated (FC ≥ 2.0, FDR ≤ 0.05) in low-RFI, compared to high-RFI steers. Among those involved in amino acid metabolism, hepatic mRNA expression of a gene encoding for aminoadipate aminotransferase, an enzyme related to lysine degradation, was downregulated (FC = -5.45, FDR = 0.01) in low-RFI steers, whereas those of methionine adenosyltransferase I and aspartate aminotransferase 2, which both link amino acid and lipid metabolism, were upregulated (FC ≥ 2.0, FDR ≤ 0.05). Two mitochondrial energy metabolism genes (UQCRC1 and ATP5G1) involved in ATP synthesis via oxidative phosphorylation were upregulated (FC ≥ 2.0, FDR ≤ 0.05) in low-RFI beef steers, compared to high-RFI beef steers. The results of this study demonstrated that low-RFI beef steers exhibit upregulation of molecular mechanisms related to fatty acid transport, fatty acid β-oxidation, and mitochondrial ATP synthesis, which suggest that low-RFI beef steers have enhanced metabolic capacity to maximize capture of energy and nutrients from feeds consumed.

An across breed, diet and tissue analysis reveals the transcription factor NR1H3 as a key mediator of residual feed intake in beef cattle

“…In addition to its interaction with genes related to immune processes and lipid metabolism, CPNE3 was also interacting with genes involved in energy production and mitochondrial processes. A role for differential mitochondrial functioning towards variation in RFI in beef cattle has been suggested previously [ 2 , 5 , 25 ]. Indeed, the results from the current study further highlight a role for mitochondrial functionality towards variation in RFI.…”

“…Specifically, these included genes of the mitochondrial enzyme complexes ( COX18, NDUFAF7, NDUFS1 ), genes involved in CoA biosynthesis ( PANK1, PANK2, PANK3 ), a mitochondrial transporter protein ( SLC25A15 ); as well as genes involved in mitochondrial regulation ( MIEF1 , EIF2AK3 , ERMP1 ) and the citric acid cycle ( GPAM , IDH1 ). Indeed, SLC25A15, NDUFS1 and GPAM were previously reported as differentially expressed in cattle divergent for RFI [ 15 , 16 , 25 ]. Moreover, IDH1 and SLC25A15 were also present within the breed contrast in the skeletal muscle tissue, suggesting a role for these genes towards RFI irrespective of breed type examined.…”

“…Furthermore, a separate cluster of co-expressed genes pertaining to the diet contrast within the muscle tissue was also enriched for oxidative phosphorylation. Additionally, genes included within this diet-specific cluster were recently reported as differentially expressed in the liver tissue of crossbred beef steers divergent for RFI phenotype [ 25 ]. These included genes encoding the first and second enzyme complexes of the electron transport chain ( NDUFB5 , NDUFA5 , NDUFC1 , NDUFA4 , UQCRH ) as well as a gene encoding a mitochondrial amidinotransferase protein ( GATM ).…”

The mRNA-lncRNA landscape of multiple tissues uncovers key regulators and molecular pathways that underlie heterosis for feed intake and efficiency in laying chickens

“…These findings are consistent with previously reported studies for expression in the rumen epithelium of low RFI steers [ 54 , 55 ] and on the breast muscle of low RFI chickens [ 56 ]. Thus, the decreased levels of expression of OXPHOS-related genes that we observed for ATP5I indicate that crossbred YW may have a lower protein expression of ATP5I than purebred YY, as validated by Western blot, and lower ATP production, which impairs metabolic capacity to capture energy and nutrients from feeds consumed, resulting in higher feed intake [ 57 ]. Therefore, we measured feed intake/efficiency and the expression level of OXPHOS-related genes in parental breed in advance and selected efficient breeds with highly expressed OXPHOS-related genes as maternal parent were expected to improve feed efficiency in the crossbreds.…”

Characterization of rumen microbiome and immune genes expression of crossbred beef steers with divergent residual feed intake phenotypes

“…Liver biopsy procedure was carried out on d 70 as described (Swanson et al, 2000;Taiwo et al, 2022). After excising the skin, liver tissue was extracted using a 14-gauge biopsy needle (TruCore-II Automatic Biopsy Instrument: Angiotech, Lausanne, Switzerland) and during a single puncture, approximately 1g of liver samples were obtained from each of the beef steers.…”