Project description:A transcriptomic approach was used to evaluate potential interactions between prepartum body condition score (BCS) and feeding management in the weeks before calving on hepatic metabolism during the transition period. Thirty-two mid-lactation grazing dairy cows of mixed age and breed were randomly allocated to one of four treatment groups in a 2 × 2 factorial arrangement: two prepartum BCS categories [4.0 (thin, BCS4) and 5.0 (optimal, BCS5); based on a 10-point scale], and two levels of energy intake during the 3 wk preceding calving (75 and 125% of estimated requirements). Liver samples were obtained at -7, 7, and 28 d relative to parturition and subsequent RNA was hybridized to the Agilent 44K Bovine (V2) Microarray chip. The Dynamic Impact Approach was used for pathway analysis, and Ingenuity Pathway Analysis was used for gene network analysis. The greater number of differentially expressed genes in BCS4 cows in response to prepartum feed allowance indicated that these animals were more responsive to prepartum nutrition management than optimally-conditioned cows. However, independent of prepartum BCS, pathway analysis revealed that prepartal feeding level had a marked effect on carbohydrate, amino acid, lipid, and glycan metabolism. Altered carbohydrate and amino acid metabolism indicated a greater and more prolonged negative energy balance post-calving in BCS5 cows overfed prepartum. This was indicated by opposite effects of pre-calving feeding in in BCS4 compared with BCS5 cows in amino acid, vitamin, and co-factor metabolism. The prepartum feed restriction ameliorated the metabolic adaptation to the new lactation in BCS5 cows, while detrimentally affecting BCS4 cows, which seemed to adapt better when overfed. Moreover, alterations in the glycosaminoglycans synthesis pathway support this idea, indicating better hepatic health status in feed-restricted BCS5 cows and overfed BCS4 animals. IPA network analysis indicated liver damage in feed-restricted thin cows, likely due to metabolic overload. Overall, the data indicate that overfeeding in late-pregnancy should be limited to underconditioned animals, while cow with optimal degree of body condition should be maintained on an energy restricted diet.

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:In high yielding dairy cows the liver undergoes extensive physiological and biochemical changes during the early postpartum period in an effort to re-establish metabolic homeostasis and to counteract the adverse effects of negative energy balance (NEB). These adaptations are likely to be mediated by significant alterations in hepatic gene expression. To gain new insights into these events an EB model was created using differential feeding and milking regimes to produce two groups of cows with either a mild (MNEB) (n=5) or severe NEB (SNEB) (n=6) status. Cows were slaughtered and liver tissues collected on days 6-7 of the first follicular wave postpartum. Using an AffymetrixM-BM-. 23k oligonucleotide bovine array to determine global gene expression in hepatic tissue of these cows, a total of 416 genes (189 up- and 227 down-regulated) were found to be altered by SNEB. Network analysis using Ingenuity Pathway Analysis revealed that SNEB was associated with widespread changes in gene expression classified into 36 gene networks including those associated with lipid metabolism, connective tissue development and function, cell signalling, cell cycle and metabolic diseases. Severe NEB cows displayed reduced expression of transcription activators and signal transducers that regulate the expression of genes and gene networks associated with cell signalling and tissue repair. These alterations are linked with increased expression of abnormal cell cycle and cellular proliferation associated pathways. This study provides new information and insights on the effect of SNEB on gene expression in high yielding Holstein Friesian dairy cows in the early postpartum period. Multiparous Holstein-Friesian cows (n=24) were blocked 2 weeks prior to expected calving date according to parity, body condition score, and previous lactation yield (average lactation 6477M-BM-1354kg) and randomly allocated to mild (MNEB; n=12) or severe (SNEB; n=12) NEB groups. MNEB cows were fed ad lib grass silage and 8 kg day-1 concentrates and milked once daily; SNEB cows were fed 25 kg day-1 silage and 4kg day-1 concentrate and milked three times daily. Measurements of body condition score and EB were used to select cows which showed extremes in EB from each group (MNEB, n=5; SNEB, n=6). Cows were slaughtered on days 6-7 of the first follicular wave after calving (mean number of days post-partum: MNEB mean 13.6 M-BM-1 0.75, range 11M-bM-^@M-^S15; SNEB mean 14.3 M-BM-1 0.56, range 13M-bM-^@M-^S16), based on daily transrectal ultrasonography.The entire liver was removed within 15 to 30 min after slaughter and weighed. Samples weighing approximately 1 g were dissected, rinsed in RNase free phosphate buffer, snap frozen in liquid nitrogen and stored at -80M-BM-:C.

Project description:Over-conditioning is a risk factor for upregulated pre- and postpartum fat mobilization. Therefore, we hypothesized that over-conditioning at the end of pregnancy leads to the accumulation of lipids in the liver and modifications of the hepatic gene expression pattern. The aim of this study was to evaluate the effect of over- versus normal-conditioning on the hepatic transcriptomic profile of dairy cows at the end of pregnancy. Ten dry multiparous Holstein cows were euthanized two weeks before expected calving. Body condition score (BCS) and backfat thickness (BFT) were evaluated, and blood samples for nonesterified fatty acids (NEFA) were taken before euthanasia. After euthanasia, liver biopsy samples were collected for further assessment of total lipids and RNA sequencing. Five cows were classified as normal-conditioned (BCS = 2.5–3.5) and five as over-conditioned (BCS = 3.75–5). Regression models confirmed that normal-conditioned cows had lower BCS [3.17 ± 0.10 (least square mean ± SE)], BFT (1.29 ± 0.29 cm), and serum NEFA (0.16 ± 0.04 mmol/L) in comparison to over-conditioned cows (4.35 ± 0.21, 3.14 ± 0.43 cm, and 0.38 ± 0.07 mmol/L for BCS, BFT, and NEFA, respectively). Total liver lipid percentage tended to be lower in normal- than over-conditioned cows (4.63 ± 0.40% and 6.06 ± 0.44%, respectively). In comparison to the mean liver lipid percentage of the normal and over conditioned cows, one over-conditioned cow had a relatively low (5.21%) and one normal-conditioned cow had a relatively high (6.07%) liver lipid percentage. Differentially expressed genes (DEGs) analysis (edgeR quasi-likelihood method) showed that normal-conditioned presented two upregulated and five downregulated genes in comparison to over-conditioned cows. Linear discriminant analysis effects size revealed 23 DEG between normal- versus over-conditioned cows. Notably, the liver of normal-conditioned cows had upregulated genes associated with liver functionality (albumin, selenoprotein P, and insulin-like growth factor binding protein 1 and 2). On the other hand, over-conditioned cows had upregulated genes associated with the acute phase response (complement C3, hemopexin, and lipopolysaccharide-binding protein). High basal lipolysis in over-conditioned cows at the end of pregnancy increases liver lipid content and alters the hepatic gene expression pattern to a pro-inflammatory state.

Project description:As polyphenols are exerting a broad spectrum of metabolic effects, we hypothesize that feeding of GSGME might influence other metabolic pathways in the liver which could account for the positive effects of GSGME observed in cows during early lactation. In order to investigate this hypothesis, we used using a genome-wide transcript profiling technique to explore changes in the hepatic transcriptome of cows supplemented with GSGME during the transition period. Transcriptomic analysis of the liver revealed 207 differentially expressed transcripts (fold change > 1.3 or < -1.3, P < 0.05), from which 156 (155 mRNAs, 1 miRNA) were up- and 51 (43 mRNAs, 8 miRNAs) were down-regulated, between cows fed GSGME and control cows. Gene set enrichment analysis of the 155 up-regulated mRNAs showed that the most enriched gene ontology (GO) biological process terms were dealing with cell cycle regulation, such as M phase, cell cycle phase, mitotic cell phase and microtubule cytoskeleton and the most enriched KEGG database pathways were p53 signaling and cell cycle. Functional analysis of the 43 down-regulated mRNAs revealed that 13 genes (XBP1, HSPA5, HERPUD1, DNAJC5G, CALR, PDIA4, DNAJB11, PHLDA1, PPP1R3C, GADD45B, BAG3, HYOU1, MANF) are involved in ER stress-induced UPR. Moreover, several of the down-regulated mRNAs, like CXCL14 and CCL3L1L and the acute phase protein SAA4, play an important role in inflammatory processes. Accordingly, protein folding, response to unfolded protein, response to protein stimulus, unfolded protein binding, chemokine activity, chemokine receptor binding and heat shock protein binding were identified as one of the most enriched GO biological process and molecular function terms assigned to the down-regulated genes. In line with the transcriptomics data the plasma concentrations of the acute phase proteins SAA and haptoglobin were reduced in cows fed GSGME compared to control cows. Collectively, our findings from transcriptome analysis of down-regulated mRNAs and functional analysis of mRNAs targeted by the up-regulated mir-376c clearly indicate that GSGME is able to inhibit inflammatory processes and ER stress in the liver of dairy cows during early lactation. Moreover, our findings indicate that at least some of the GSGME effects on the hepatic transcriptome of dairy cows are mediated by miRNA-mRNA interactions.

Dataset Information

Hepatic proteomics of transition dairy cows

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