Project description:The current situation of rising demand for animal products and sustainable resource usage, improving nutrient utilization efficiency in dairy cows is an important task. Understanding the biology of feed efficiency in dairy cows enables for the development of markers that may be used to identify and choose the best animals for animal production. Thus in this study, ten Holstein cows were evaluated for feed efficiency and adipose tissue samples from five high efficient and five low efficient dairy cows were collected for protein extraction, digestion and data were analyzed for differential abundant proteins enriched in feed efficiency pathways. Among the identified peptides, we found 110 DAPs and two protein networks significantly related to feed efficiency. Among the relative mRNA expression of genes involved in energy metabolism including transcription/translation (STAT2, DDX39A and RBM39) or protein transport (ITGAV), only RBM39 showed significant decrease in high efficient dairy cows. The findings presented here confirmed the Transferrin upregulated in pathways including acute phase response signaling, LXR/RXR activation, FXR/RXR activation of high efficient dairy cows supporting that these pathways are related to feed efficiency in dairy cows.
Project description:In this study, we investigated the molecular regulatory mechanisms of milk protein production in dairy cows by studying the miRNAomes of five key metabolic tissues involved in protein synthesis and metabolism from dairy cows fed high- and low-quality diets. In total, 340, 338, 337, 330, and 328 miRNAs were expressed in the rumen, duodenum, jejunum, liver, and mammary gland tissues, respectively. Some miRNAs were highly correlated with feed and nitrogen efficiency, with target genes involved in transportation and phosphorylation of amino acid (AA). Additionally, low-quality forage diets (corn stover and rice straw) influenced the expression of feed and nitrogen efficiency-associated miRNAs such as miR-99b in rumen, miR-2336 in duodenum, miR-652 in jejunum, miR-1 in liver, and miR-181a in mammary gland. Ruminal miR-21-3p and liver miR-2285f were predicted to regulate AA transportation by targeting ATP1A2 and SLC7A8, respectively. Furthermore, bovine-specific miRNAs regulated the proliferation and morphology of rumen epithelium, as well as the metabolism of liver lipids and branched-chain AAs, revealing bovine-specific mechanisms. Our results suggest that miRNAs expressed in these five tissues play roles in regulating transportation of AA for downstream milk production, which is an important mechanism that may be associated with low milk protein under lowquality forage feed.
Project description:An accumulation of over a decade of research in cattle has shown that genetic selection for decreased residual feed intake (RFI), defined as the difference between an animal’s actual feed intake and its expected feed intake, is a viable option for improving feed efficiency and reducing the feed requirements of herds, thereby improving the profitability of cattle producers. Hormonal regulation is one of the most important factors in feed intake. To determine the relationship between hormones and feed efficiency, we performed gene expression profiling of hormonal regulation in whole blood of Chinese Holstein cattle with low and high RFI coefficients. 857 differential expression genes (from 24683 genes) were found. Among these, 415 genes were up-regulated and 442 genes were down-regulated in the low RFI group. The gene ontology (GO) search revealed 6 significant terms and 64 genes associated with hormonal regulation, and the Kyoto Encyclopedia of Genes and Genomes (KEGG) selected the adipocytokine signaling pathway, insulin signaling pathway. In conclusion, the study indicated that the molecular expression of genes associated with hormonal regulation differs in dairy cows, depending on their RFI coefficients, and that these differences may be related to the molecular regulation of the leptin-NPY and insulin signaling pathways.
Project description:We performed single-cell RNA-sequencing on the rumen epithelium of dairy cows to construct an epithelial single-cell map of the rumen.
Project description:Climate change affects the duration and intensity of heat waves during summer months and jeopardizes animal health and welfare. High ambient temperatures cause heat stress in dairy cows resulting in a reduction of milk yield, feed intake, and alterations in gut barrier function. The objectives of this study were to investigate the mucosal amino acid, glucose and lactate metabolism, as well as the proteomic response of the small intestine in heat stressed (HS) Holstein dairy cows. Cows of the HS group (n = 5) were exposed for 4 days to 28°C (THI = 76) in a climate chamber. Percentage decrease in daily ad libitum intake of HS cows was calculated to provide isocaloric energy intake to pair-fed control cows kept at 15°C (THI = 60) for 4 days. The metabolite, mRNA and proteomic analyses revealed that HS induced incorrect protein folding, cellular destabilization, increased proteolytic degradation and protein kinase inhibitor activity, reduced glycolysis, and activation of NF-κB signaling, uronate cycling, pentose phosphate pathway, fatty acid and amino acid catabolism, mitochondrial respiration, ATPase activity and the antioxidative defence system. Our results highlight adaptive metabolic and immune mechanisms attempting to maintain the biological function in the small intestine of heat-stressed dairy cows.
Project description:RNA sequencing (RNA-Seq) was performed on rumen papillae from 16 steers with variation in gain and feed intake. Sixteen rumen papillae samples were sequenced by Cofactor Genomics (St.Louis, MO).
Project description:The objective of this study was to characterize the mRNA expression profile in rumen epithelium from Holstein dairy cows fed high or low concentrate dits.
Project description:In dairy cows, administration of high dosages of niacin (NA) was found to cause anti-lipolytic effects, which are mediated by the NA receptor hydroxyl-carboxylic acid receptor 2 (HCAR2) in white adipose tissue (WAT), and thereby to an altered hepatic lipid metabolism. However, almost no attention has been paid to possible direct effects of NA in cattle liver, despite showing that HCAR2 is expressed also in the liver of cattle and is even more abundant than in WAT. Due to this, we hypothesized that feeding of rumen-protected NA to dairy cows influences critical metabolic and/or signaling pathways in the liver through inducing changes in the hepatic transcriptome. In order to identify these pathways, we applied genome-wide transcript profiling in liver biopsies obtained at 1 wk postpartum (p.p.) from dairy cows of a recent study (Zeitz et al., 2018) which were fed a total mixed ration without (control group) or with rumen-protected NA from 21 d before calving until 3 wk p.p. Hepatic transcript profiling revealed that a total of 487 transcripts were differentially expressed [filter criteria fold change (FC) > 1.2 or FC < -1.2 and P < 0.05] in the liver at 1 wk p.p. between cows fed NA and control cows. Substantially more transcripts were down-regulated (n = 338), while only 149 transcripts were up-regulated by NA in the liver of cows. Gene set enrichment analysis (GSEA) for the up-regulated transcripts revealed that the most enriched gene ontology (GO) biological process terms were exclusively related to immune processes, such as leukocyte differentiation, immune system process, leukocyte differentiation, activation of immune response and acute inflammatory response. In line with this, the plasma concentration of the acute phase protein haptoglobin tended to be increased in dairy cows fed rumen-protected NA compared to control cows (P < 0.1). GSEA of the down-regulated transcripts showed that the most enriched biological process terms were related to metabolic processes, such as cellular metabolic process, small molecule metabolic process, lipid catabolic process, organic cyclic compound metabolic process, small molecule biosynthetic process and cellular lipid catabolic process. In conclusion, hepatic transcriptome analysis shows that rumen-protected NA induces genes which are involved mainly in immune processes including acute phase response and stress response in dairy cows at wk 1 p.p. These findings indicate that supplementation of rumen-protected NA to dairy cows in the periparturient period may induce or amplify the systemic inflammation-like condition which is typically observed in the liver of high-yielding dairy cows in the p.p. period.
Project description:Heat stress (HS) has become a major challenge in the dairy industry around the world. Although numerous measures have been taken to alleviate the HS impact on milk production, the cellular level response to HS remains unclear in dairy cows. The objective of this study was to dissect functional alterations based on transcriptomic dynamics in the liver of cows under HS. Dairy cows exposed to HS exhibited both decreased feed intake and milk yield. Through liver transcriptomic analysis, differentially expressed genes were identified among three experimental conditions, including heat stress (HS), pair-fed (PF), and thermoneutral (TN) groups. We observed the upregulation of protein folding and inflammation-related genes in the HS group, while the mitochondrial genes were downregulated. Gene functional enrichment also revealed that mitochondria function and oxidative phosphorylation were dysregulated under HS. The liver transcriptome analysis generated a comprehensive gene expression regulation network upon HS in lactating dairy cows. Overall, this study provides novel insights into molecular and metabolic changes of cows conditioned under HS. Our results could facilitate the development of efficient biomarkers to mitigate the negative effect of HS on dairy cow health and productivity.
Project description:The severity of negative energy balance (NEB) in high-producing dairy cows has a high incidence among health diseases. The periparturient period is crucial for the health status and reproductive performance of dairy cows. During this period, dairy cows experience a transition from a pregnant, non-lactating state to a non-pregnant, lactating state. At the beginning of lactation, the energy needs for milk production are higher than the available energy consumed from feed intake, resulting in a negative energy balance (NEB)]. While in a NEB, cows mobilise their reserves from adipose tissue, resulting in elevated plasma concentrations of non-esterified fatty acids (NEFAs), which are used as a fuel source by peripheral tissues and the mammary gland for milk fat synthesis. Thus, white adipose tissue is one of the main tissue involved in the energy production during this transition period. So the objectives of our study were to dentify mRNA differentially expressed in white adipose before and after calving in dairy cow fed with low (LE) and high (HE) energy diet.