Project description:Growing and finishing phases are two important animal production stages, which differ fundamentally in compositional growth. However, the physiological mechanisms altered concomitantly with the shift in whole-body compositional gain as cattle fatten (growing vs. finished steers), are poorly understood. Microarray analysis using the Bovine Gene 1.0 ST Array was conducted to determine shifts in hepatic genomic expression profiles of growing vs. finishing beef steers. The specific overall hypothesis tested was that genes involved in amino acid, carbohydrate and lipid metabolism, antioxidant capacity and immune responses were differentially expressed in growing vs. finishing steers.
Project description:The biological mechanisms associated with the residual feed intake in ruminants have been harnessed immensely via transcriptome analysis of liver and ruminal epithelium, however, this concept has not been fully explored using whole blood. We applied whole blood transcriptome analysis and gene set enrichment analysis to identify key pathways associated with divergent selection for low or high RFI in beef cattle. A group of 56 crossbred beef steers (average BW = 261.3 ± 18.5 kg) were adapted to a high-forage total mixed ration in a confinement dry lot equipped with GrowSafe intake nodes for period of 49 d to determine their residual feed intake (RFI). After RFI determination, weekly whole blood samples were collected three times from beef steers with the lowest RFI (most efficient; low-RFI; n = 8) and highest RFI (least efficient; high-RFI; n = 8). Prior to RNA extraction, whole blood samples collected were composited for each steer. Sequencing was performed on an Illumina NextSeq2000 equipped with a P3 flow. Gene set enrichment analysis (GSEA) was used to analyze differentially expressed gene sets and pathways between the two groups of steers. Results of GSEA revealed pathways associated with metabolism of proteins, cellular responses to external stimuli, stress, and heat stress were differentially inhibited (false discovery rate (FDR) < 0.05) in high-RFI compared to low-RFI beef cattle, while pathways associated with binding and uptake of ligands by scavenger receptors, scavenging of heme from plasma, and erythrocytes release/take up oxygen were differentially enriched (FDR < 0.05) in high-RFI, relative to low-RFI beef cattle. Taken together, our results revealed that beef steers divergently selected for low or high RFI revealed differential expressions of genes related to protein metabolism and stress responsiveness.
Project description:The objective of our study was to assess the effect of rumen-protected niacin supplementation on the overall transcriptomics profile of liver tissue on growing Angus × Simmental steers and heifers. Consequently, the vasodilatory, detoxifying, and immune suppressor effects of niacin were evaluated in hepatocytes. After a 30-day supplementation period with rumen-protected niacin on normal weaned beef calves, we observed a significant list of benefits at the liver transcriptome level. Several metabolic pathways revealed positive effects of administration of rumen-protected niacin; for example, a decrease in lipolysis, apoptosis, inflammatory responses, atherosclerosis, oxidative stress, fibrosis, and vasodilation-related pathways. Therefore, results from this study could potentially promote supplementation of rumen-protected niacin on beef cattle backgrounding operations or new arrivals to a feedlot, especially during the acclimation period when the health status of growing beef cattle is usually compromised.
Project description:MicroRNAs (miRNAs) are short non-coding RNAs that post-transcriptionally regulate expression of mRNAs in many biological pathways. Here we report comprehensive miRNAs profiles by next-gen deep sequencing in Angus cattle divergently selected for residual feed intake (RFI) and identify miRNAs related to feed efficiency in beef cattle Results: Two microRNA libraries were constructed from pooled RNA extracted from livers of low and high RFI cattle, and sequenced by Illumina genome analyser. In total, 23,628,103 high quality short sequence reads were obtained and more than half of these reads were matched to the bovine genome (UMD 3.1). We identified 305 known bovine miRNAs (miRBase v.19). Bta-miR-143, bta-miR-30, bta-miR-122, bta-miR-378 and bta-let-7 were the top five most abundant miRNAs families expressed in liver, representing more than 63% of expressed miRNAs. We also identified 52 homologous miRNAs and 10 novel putative bovine-specific miRNAs, based on precursor sequence and the secondary structure and utilizing the miRBase (version 19). We compared the miRNAs profile between high and low RFI animals and ranked the most differentially expressed bovine known miRNAs. Bovine miR-143 was the most abundant miRNA in the bovine liver and comprised 20% of total expressed mapped miRNAs. The most highly expressed miRNA in liver of mice and humans, miR-122, was the third most abundant in our cattle liver samples. We also identified 10 putative novel bovine-specific miRNA candidates. Differentially expressed miRNAs between high and low RFI cattle were identified with 18 miRNAs being up-regulated and 7 other miRNAs down-regulated in low RFI cattle Conclusions: Our study has identified comprehensive miRNAs expressed in bovine liver. Some of the expressed miRNAs are novel in cattle. The differentially expressed miRNAs between high and low RFI give some insights into liver miRNAs regulating physiological pathways underlying residual feed intake in bovine
Project description:miRNA profiling of bovine satellite cells (BSC) differentiated into myotubes (6th day of in vitro differentiation). BSC isolated from m. semitendinosus of beef (Hereford & Limousine) and dairy (Holstein-Friesian) cattle. Goal was to determine differences in miRNA expresion during in vitro myogenesis in beef vs dairy cattle used as a control.
Project description:The objective of this study was to corroborate the findings of previous BRD-associated transcriptome experiments, utilizing multiple independent populations of high-risk beef cattle.
2022-03-02 | GSE179536 | GEO
Project description:residual feed intake of beef cattle
Project description:Creatine pyruvate (CrPyr) is a new multifunctional nutrient that can provide both pyruvate and creatine. It has been shown to relieve the heat stress of beef cattle by improving antioxidant activity and rumen microbial protein synthesis, but the mechanism of CrPyr influencing rumen fermentation remains unclear. This study aimed to use metaproteomics technologies to investigate the bacterial protein function in rumen fluid samples taken from heat-stressed beef cattle treated with or without 60 g/d CrPyr.