👤 James K Drackley

We determined the effect of prepartum plane of energy intake on liver function and metabolism pre- and postpartum by combining in vivo and in vitro data with mRNA expression data. A subset of multiparous prepartal Holsteins (n = 18) from a previously conducted experiment consumed 1 of 3 amounts of dietary energy intake, relative to their requirements. A diet formulated to allow consumption of ≥150% of net energy requirements during the far-off dry period and the close-up dry period was fed for ad libitum intake (150E) or in restricted amounts so that cows consumed 80% of requirements for energy (80E). A second diet was formulated to include wheat straw (26.1% of dry matter) to limit energy intake to 100% of NRC (2001) requirements for energy when fed ad libitum during the far-off period (100E). In the close-up period, 100E was fed the 150E diet for ad libitum intake. Expression of mRNA for genes related to fatty acid oxidation (PPARA, CPT1A, ACOX1) was greater for 100E cows than 150E cows on d 14 postpartum. These expression patterns were related to in vitro data for conversion of palmitate to CO Show less

The objective of the study was to evaluate the effect of overfeeding a moderate energy diet and a 2,4-thiazolidinedione (TZD) injection on blood and hepatic tissue biomarkers of lipid metabolism, oxidative stress, and inflammation as it relates to insulin sensitivity. Fourteen dry non-pregnant cows were fed a control (CON) diet to meet 100% of NRC requirements for 3 wk, after which half of the cows were assigned to a moderate-energy diet (OVE) and half of the cows continued on CON for 6 wk. All cows received an intravenous injection of 4 mg TZD/kg of body weight (BW) daily from 2 wk after initiation of dietary treatments and for 2 additional week. Compared with CON cows and before TZD treatment, the OVE cows had lower concentration of total protein, urea and albumin over time. The concentration of cholesterol and tocopherol was greater after 2 wk of TZD regardless of diet. Before and after TZD, the OVE cows had greater concentrations of AST/GOT, while concentrations of paraoxonase, total protein, globulin, myeloperoxidase, and haptoglobin were lower compared with CON cows. Regardless of diet, TZD administration increased the concentration of ceruloplasmin, ROMt, cholesterol, tocopherol, total protein, globulin, myeloperoxidase and beta-carotene. In contrast, the concentration of haptoglobin decreased at the end of TZD injection regardless of diet. Prior to TZD injection, the mRNA expression of Based on molecular and blood data, administration of TZD enhanced some aspects of insulin sensitivity while causing contradictory results in terms of inflammation and oxidative stress. The bovine liver is TZD-responsive and level of dietary energy can modify the effects of TZD. Because insulin sensitizers have been proposed as useful tools to manage dairy cows during the transition period, further studies are required to investigate the potential hepatotoxicity effect of TZD (or similar compounds) in dairy cattle. Show less

Objectives were to determine adipose tissue mRNA expression of peroxisome proliferator-activated receptor (PPAR)γ co-regulators, target enzymes and transcription regulators, inflammation-related genes, and adipokines in response to dietary long-chain fatty acids (LCFA). From -21 through 10 d relative to parturition cows were fed no supplemental LCFA (control), saturated LCFA (SFAT; mainly 16:0 and 18:0), or fish oil (FO). Lipid was fed at 250 g/d prepartum or approximately 1.5 to 1.9% of the previous day's dry matter intake postpartum. Transcript profiling of 35 genes via quantitative PCR was conducted on biopsies (n=5 cows/diet) collected at -14 and 11 d from parturition. Despite lower dry matter intake with FO, pre- and postpartal blood nonesterified fatty acids, β-hydroxybutyrate, and liver triacylglycerol were unaffected by treatment but increased after calving regardless of diet. Prepartal expression of adipogenic/lipogenic transcription regulators [CEBPA, CEBPB, RXRA, KLF5, and MLXIPL (formerly ChREBP)] and co-regulators (CARM1, EP300, NCOA1, MED1, NCOR2, and NRIP1) was upregulated by FO and SFAT versus control, whereas most enzymes involved in lipogenesis/triacylglycerol synthesis (FASN, SCD, DGAT2, and LPIN1) had greater expression only with FO. Expression of most adipogenic/lipogenic genes decreased after parturition, but feeding SFAT led to sustained upregulation of CEBPA, CEBPB, RXRA, several PPAR-co-activators, and DGAT2 and SCD, suggesting maintenance of a pro-adipogenic/pro-lipogenic state with SFAT. The co-activator CREBBP was greater in cows fed lipid and did not decrease after parturition, suggesting ligand activation of PPARγ. The greater peripartal expression of NFKB1 and TBK1 due to dietary lipid was suggestive of a local inflammatory response. At amounts fed prepartum, both FO and SFAT were effective in upregulating the adipose tissue PPARγ-gene network. In contrast, only SFAT led to sustaining that response. Overall, the observed expression patterns are suggestive of an adipogenic regulatory mechanism particularly responsive to SFAT. Show less