Project description:Steer small intestine transcriptome Evaluation of the naturally occurring transcriptome variation among beef steers with divergent gain and feed intake phenotypes.
Project description:The transcriptome of 189 samples across four tissues from 48 beef steers with varied feed efficiency were generated using Illumina HiSeq4000
Project description:Steer liver transcriptome Evaluation of the naturally occurring transcriptome variation in liver among beef steers with divergent gain and feed intake phenotypes.
Project description:Steer spleen transcriptome Evaluation of the naturally occurring transcriptome variation in the spleen among beef steers with divergent gain and feed intake phenotypes.
Project description:Steer mesenteric fat transcriptome. Evaluation of the naturally occurring transcriptome variation in mesenteric fat among beef steers with divergent gain and feed intake phenotypes.
Project description:We functionally analyzed the rumen epithelial transcriptomes from low- and high- feed efficient beef steers to identify differences that might contribute to variation in feed efficiency.
Project description:Neotyphodium coenophialum is an endophytic fungus that infects most tall fescue (Festuca arundinacea) pastures that are commonly used in animal grazing systems in the United States. Beef cattle grazing such pastures are impaired in health and production performance, resulting in a large economic loss in US food-animal production systems. Based on the clinical symptoms and laboratory analyses of blood, it was hypothesized that such affected cattle display liver-specific changes in the expression of gene transcripts that are associated with the metabolic enzymes and transporters critical for beef health and performance. Microarray analysis using the GeneChip Bovine Genome Array (Affymetrix, Inc., Santa Clara, CA) was conducted to determine if grazing endophyte-infected tall fescue pastures affects the liver gene expression profiles of growing beef steers. Nineteen steers were assigned to graze either a low toxic endophyte tall fescue-mixed grass (LE treatment, 5.7 ha, n = 9) or a high toxic endophyte infected tall fescue (HE treatment, 5.7 ha, n = 10) pasture located in the University of Kentucky Agricultural Research Center. All steers had ad libitum access to fresh water and an industry standard mineral-vitamin supplement. 88 days grazing on pasture. Approximately 2 g of tissue from the right lobe of the liver of each steer were collected for RNA extraction and microarray analysis.
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:Neotyphodium coenophialum is an endophytic fungus that infects most tall fescue (Festuca arundinacea) pastures that are commonly used in animal grazing systems in the United States. Beef cattle grazing such pastures are impaired in health and production performance, resulting in a large economic loss in US food-animal production systems. Based on clinical and biochemical blood analyte profiles, hepatic targeted gene and protein analyses, and hepatic transcriptomic profiling, microarray analysis using the WT Btau 4.0 Array (version 1.0, Affymetrix, Inc., Santa Clara, CA) was conducted to determine if grazing endophyte-infected tall fescue pastures affects pituitary gene expression profiles of growing beef steers. The specific overall hypothesis tested was that grazing high endophyte-infected pasture would alter the pituitary genomic expression profiles of the same growing steers, especially genes involved in production and secretion of prolactin, growth hormone, thyroid stimulating hormone, and adrenocorticotropic hormone. Sixteen steers were assigned to graze either a low toxic endophyte tall fescue-mixed grass (LE treatment, 5.7 ha, n = 8) or a high toxic endophyte infected tall fescue (HE treatment, 5.7 ha, n = 8) pasture located in the University of Kentucky Agricultural Research Center. All steers had ad libitum access to fresh water, an industry standard mineral-vitamin supplement, and grazed respective pastures for 89 to 105 days. Whole pituitaries were collected for RNA extraction and microarray analysis.
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.