Reka Tienken

Effects of an energy-dense diet and nicotinic acid supplementation on production and metabolic variables of primiparous or multiparous cows in periparturient period

It is well observed that feeding energy-dense diets in dairy cows during the dry period can cause metabolic imbalances after parturition. Especially dairy cows with high body condition score (BCS) and fed an energy-dense diet were prone to develop production diseases due to metabolic disturbances postpartum. An experiment was conducted to determine the effects of an energy-dense diet and nicotinic acid (NA) on production and metabolic variables of primiparous and multiparous cows in late pregnancy and early lactation which were not pre-selected for high BCS. Thirty-six multiparous and 20 primiparous German Holstein cows with equal body conditions were fed with energy-dense (60% concentrate/40% roughage mixture; HC group) or adequate (30% concentrate/70% roughage mixture; LC group) diets prepartum. After parturition, concentrate proportion was dropped to 30% for all HC and LC groups and was increased to 50% within 16 days for LC and within 24 days for HC cows. In addition, half of the cows per group received 24 g NA supplement per day and cow aimed to attenuate the lipid mobilisation postpartum. Feeding energy-dense diets to late-pregnant dairy cows elevated the dry matter (p < 0.001) and energy intake (p < 0.001) as well as the energy balance (p < 0.001) without affecting the BCS (p = 0.265) during this period. However, this did not result in any metabolic deviation postpartum as the effects of prepartum concentrate feeding were not carried over into postpartum period. Multiparous cows responded more profoundly to energy-dense feeding prepartum compared with primiparous cows, and parity-related differences in the transition from late pregnancy to lactation were obvious pre- and postpartum. The supplementation with 24 g NA did not reveal any effect on energy metabolism. This study clearly showed that energy-dense feeding prepartum did not result in metabolic imbalances postpartum in multiparous and primiparous cows not selected for high BCS. A genetic predisposition for an anabolic metabolic status as indicated by high BCS may be crucial for developing production diseases at the onset of lactation.

Effects of Prepartum Dietary Energy Level and Nicotinic Acid Supplementation on Immunological, Hematological and Biochemical Parameters of Periparturient Dairy Cows Differing in Parity.

Simple Summary Several biological changes occur during the transition from late pregnancy to early lactation which is associated with a high susceptibility of health disorders. Nicotinic acid, as feed additive, is suggested to balance catabolic metabolism of periparturient dairy cows by attenuating lipolysis and impact production performance. This study provides information of the biological changes occurring around parturition with special emphasis on differences between primiparous and multiparous cows. Present results showed that energy-dense feeding prepartum did not result in metabolic imbalances postpartum in dairy cows which were similar in body condition score. Nicotinic acid supplementation did not reveal any effect. Abstract The periparturient period is critical according to health, productivity and profitability. As this period is fundamental for the success of the lactation period, the interest in improving periparturient health by dietary supplements increased in recent years. The present study investigated the effects of feeding nicotinic acid (NA) combined with varying dietary energy densities on immunological, hematological and biochemical parameters of periparturient cows differing in parity. Thirty-six multiparous and 20 primiparous dairy cows were enrolled in the study 42 days before expected parturition date until 100 days postpartum with the half of the cows being supplemented with 24 g of NA/d. After parturition a diet with 30% concentrate was fed to all cows which was followed by different concentrate escalation strategies. Dietary NA supplementation was ceased on day 24 postpartum. Dietary NA increased (P = 0.010) serum nicotinamide concentrations (mean of 3.35 ± 1.65 µg/mL), whereas NA could not be detected. Present data emphasize that periparturient cows are faced with major physiological challenges and that both parity-groups have different prerequisites to adapt to those changes irrespective of NA supplementation. The overfeeding of energy to cows which were similar in body condition score had only minor effects on periparturient immune system function and the metabolism of those cows.

Longitudinal changes in adipose tissue of dairy cows from late pregnancy to lactation. Part 1: The adipokines apelin and resistin and their relationship to receptors linked with lipolysis

The transition from pregnancy to lactation is characterized by major changes in glucose and adipose tissue metabolism. Anti- and prolipolytic pathways mediated via the hydroxycarboxylic acid receptors 1 (HCAR1) and 2 (HCAR2) and tumor necrosis factor-α receptor 1 (TNFR1), as well as the adipokines apelin and resistin, are likely involved in regulating these processes. This study aimed to determine the mRNA abundance of the aforementioned receptors in both subcutaneous and visceral adipose tissue, to characterize the adipokine concentrations in serum, and to test the effects of feeding diets with either high or low portions of concentrate and a concomitant niacin supplementation from late gestation to early lactation. Twenty pluriparous German Holstein cows were all kept on the same silage-based diet until d 42 antepartum, when they were allocated to 2 feeding groups: until d 1 antepartum, 10 animals each were assigned to either a high-concentrate (60:40 concentrate-to-roughage ratio) or a low-concentrate diet (30:70). Both groups were further subdivided into a control and a niacin group, the latter receiving 24 g/d of nicotinic acid from d -42 until 24. From d 1 to 24 postpartum, the concentrate portion was increased from 30 to 50% for all cows. Biopsies of subcutaneous (SCAT) and retroperitoneal adipose tissue (RPAT) were taken at d -42, 1, 21, and 100 relative to parturition. Blood samples were drawn along with the biopsies and on d -14, 3, 7, 14, and 42. The concentrations of the adipokines apelin and resistin in serum were measured via ELISA. The mRNA of the 3 receptors in AT was quantified as well as the protein abundance of HCAR2 by Western blot. The feeding regimen did not affect the variables examined. The concentrations of apelin remained fairly constant during the observation period, whereas the resistin concentrations increased toward parturition and decreased to precalving levels within 1 wk after calving. The mRNA abundance of HCAR1, HCAR2, and TNFR1 changed in SCAT and RPAT during the considered time period. For the HCAR2 protein, time-dependent changes were restricted to SCAT. The mRNA abundance of all receptors was greater in RPAT than in SCAT. The tissue-specific correlations observed between the receptors point to a link between these factors and may indicate different regulatory roles in the respective tissues. This study provides insight into the complex metabolic adaptations during the transition period and supports a differential regulation of lipolysis among SCAT and RPAT in dairy cows.

Changes in lipid metabolism and β-adrenergic response of adipose tissues of periparturient dairy cows affected by an energy-dense diet and nicotinic acid supplementation

Dairy cattle will mobilize large amounts of body fat during early lactation as an effect of decreased lipogenesis and increased lipolysis. Regulation of lipid metabolism involves fatty acid synthesis from acetate and β-adrenergic-stimulated phosphorylation of hormone-sensitive lipase (HSL) and perilipin in adipocytes. Although basic mechanisms of mobilizing fat storage in transition cows are understood, we lack a sufficiently detailed understanding to declare the exact regulatory network of these in a broad range of dairy cattle. The objective of the present study was to quantify 1) protein abundance of fatty acid synthase (FAS), 2) extent of phosphorylation of HSL and perilipin in vivo, and 3) β-adrenergic stimulated lipolytic response of adipose tissues in vitro at different stages of the periparturient period. We fed 20 German Holstein cows an energy-dense or an energetically adequate diet prepartum and 0 or 24 g/d nicotinic acid (NA) supplementation. Biopsy samples of subcutaneous and retroperitoneal adipose tissue were obtained at d 42 prepartum (d -42) and at d 1, 21, and 100 postpartum (d +1, d +21, d +100, respectively). To assess β-adrenergic response, tissue samples were incubated with 1 μ isoproterenol for 90 min at 37°C. The NEFA and glycerol release, as well as HSL and perilipin phosphorylation, was measured as indicators of in vitro stimulated lipolysis. In addition, protein expression of FAS and extent of HSL and perilipin phosphorylation were measured in fresh, nonincubated samples. There was no effect of dietary energy density or NA on the observed variables. The extent of HSL and perilipin phosphorylation under isoproterenol stimulation was strongly correlated with the release of NEFA and glycerol, consistent with the functional link between β-adrenergic-stimulated protein phosphorylation and lipolysis. In the nonincubated samples, FAS protein expression was decreased at d +1 and d +21, whereas HSL and perilipin phosphorylation increased from d -42 to d +1 and remained at an increased level throughout the first 100 d of lactation. In vitro lipolytic response was significant in prepartum samples at times when in vivo lipolysis was only minimally activated by phosphorylation. These data extend our understanding of the complex nature of control of lipolysis and lipogenesis in dairy cows and could be useful to the ongoing development of systems biology models of metabolism to help improve our quantitative knowledge of the cow.

Influence of energy level and nicotinic acid supplementation on apoptosis of blood leukocytes of periparturient dairy cows

The periparturient period of dairy cows is accompanied by an immunosuppression that leaves the animal more susceptible to infections and metabolic disorders. Non-esterified fatty acids (NEFA) and beta-hydroxybutyrate (BHB) which peak shortly after parturition due to lipolysis are known to impair immune cell functions. Niacin with its well-known anti-lipolytic effect may have the ability to ameliorate this situation. Additionally, niacin shows also anti-inflammatory effects that may be beneficial to the immune status of the cow. To address this 29 multiparous and 18 primiparous German Holstein cows were subjected to four different feeding groups. They were fed either a ration with a high concentrate proportion of 60% (HC), or a low concentrate proportion of 30% (LC). After parturition both concentrate levels were reduced to 30% and increased again to 50% either within 16days (LC-group) or within 24days (HC-group). Half of the animals received either 24g per day of nicotinic acid from 42days prepartum until 24days postpartum (LC-NA, HC-NA) or no supplement (LC-CON, HC-CON). Apoptosis in polymorphonuclear leukocytes (PMN) and peripheral blood mononuclear cells (PBMC) was examined with an Annexin V and propidium iodide (PI) based fluorescence flow cytometry assay and distinguished into early apoptotic (Annexin V positive and PI negative) and late apoptotic (Annexin V and PI positive) cells. Additionally, the pro-apoptotic gene BAX, the effector caspase CASP3, and the anti-apoptotic genes BCL2 and BCL-xL, as well as the NFκB subunit RELA were quantified by real-time PCR in blood leukocytes. All variables showed time dependencies that were mainly related to parturition (p<0.01). Early apoptotic PBMC were significantly affected by concentrate level showing higher numbers of apoptotic cells in the HC groups (p=0.029). PBMC were characterized by a more pronounced apoptosis than PMN and seemed to be more susceptible to the changes that occur around parturition. The genes BAX and CASP3 were positively correlated (0.631) and their peak preceded the apoptotic peak around parturition in the blood leukocytes. The LC animals showed a decrease in BCL2 expression before parturition, whereas the HC animals showed a continuous increase in BCL2 mRNA abundance (p=0.059). RELA correlated stronger with the pro-apoptotic genes (0.715 and 0.650 with BAX and CASP3 respectively) and its expression was higher in primiparous than in multiparous cows (p=0.011). Nicotinic acid supplementation did show some influence in increasing numbers of early apoptotic PMN and late apoptotic PBMC between 42 and 100 DIM.

Associations between Forkhead Box O1 (FoxO1) Expression and Indicators of Hepatic Glucose Production in Transition Dairy Cows Supplemented with Dietary Nicotinic Acid.

Forkhead box protein O1 (FoxO1) is a transcription factor which promotes hepatic glucose production (HGP) by up-regulating the transcription of gluconeogenic enzymes in monogastric species. The activity of FoxO1 is inhibited by insulin-induced phosphorylation. The aims of the present study were to find associations between FoxO1 expression and variables associated with HGP as affected by feeding regimen in dairy cows during the transition period. Twenty one healthy German Holstein cows were allocated to four groups (LC-CON, HC-CON, LC-NA with 5 cows/group and HC-NA with 6 cows/group, respectively). Cows received 0 (LC-CON and HC-CON) or 24 (LC-NA and HC-NA) g/d nicotinic acid with high (HC) or low (LC) concentrate proportion from -42 days (-41.8 + 4.8; mean + standard deviation) relative to expected calving date (d-42) to d24. Liver biopsy was taken at d-42, 1, 21, and 100. The total protein expression of FoxO1 (tFoxO1) and the extent of phosphorylation of FoxO1 at serine 256 (pFoxO1) were analysed semiquantitatively by Western Blotting. The expression of hepatic mRNA of FoxO1 and seven genes associated with HGP was measured by real-time RT-PCR. Mixed model and Pearson’s correlation were used for statistical evaluation with the level of significance at P<0.05. No dietary effect was observed either on feed intake, energy balance, or on the concentration of blood metabolites. Neither time nor diet affected the expression of FoxO1 total protein and mRNA. A NA × concentrate interaction was found in pFoxO1. However, no corresponding dietary effect was found in the mRNA expression of investigated genes. Different patterns of correlations between FoxO1-related variables and investigated indicators for HGP were found at d21 and 100. The results indicated that the regulation of HGP did not take place on the levels of mRNA and protein expression and the phosphorylation of FoxO1 in dairy cows in early lactation.

Longitudinal changes in adipose tissue of dairy cows from late pregnancy to lactation. Part 2: The SIRT-PPARGC1A axis and its relationship with the adiponectin system

The transition period in dairy cows is characterized by major changes in glucose and adipose tissue metabolism. The Sirtuin-1 (SIRT1) PPARγ co-activator 1α (PPARGC1A) axis might be related to the adiponectin (ADIPOQ) system to orchestrate the regulation of these processes. We aimed to assess the mRNA abundance of the aforementioned components in one visceral and one subcutaneous fat depot, together with the ADIPOQ concentrations in serum of dairy cows from late gestation to early lactation. In addition, the effect of 2 diets differing in energy density was tested. Twenty pluriparous German Holstein cows were all kept on the same silage-based diet until d 42 antepartum. From then on until d 1 antepartum, 10 animals each were assigned to either high-concentrate (60:40 concentrate:roughage) or low-concentrate (30:70) diets. Both groups were further subdivided into a control and a niacin group, the latter receiving 24 g/d nicotinic acid from d -42 until d 24. From d 1 postpartum (p.p.) to d 24 p.p., the concentrate portion was increased from 30 to 50% for all cows. Biopsies of subcutaneous (SCAT) and retroperitoneal adipose tissue (RPAT) were taken at d -42, 1, 21, and 100 relative to parturition. Blood samples were drawn along with the biopsies as well as on d -21, -14, -7, -3, 1, 3, 7, 14, 21, 28, 35, 42, 63, 82, and 100 relative to calving. Quantification of target mRNA was done using quantitative PCR and serum ADIPOQ concentration was measured via ELISA. The feeding regimen did not affect the variables examined. Serum ADIPOQ concentrations decreased toward parturition, returned to precalving levels within 1 wk after parturition, and remained on a constant level until the end of the experiment. The mRNA abundance of SIRT1, PPARGC1A, NAMPT, and the ADIPOQ receptors 1 (ADIPOR1) and 2 (ADIPOR2) changed in SCAT and RPAT during the considered time period. Comparing SCAT and RPAT, the mRNA of SIRT1, ADIPOR1, and ADIPOR2 were more abundant in RPAT, whereas PPARGC1A and NAMPT were expressed more highly in SCAT. The protein abundance of SIRT1 tended to increase from d -42 to 21. At d 21 we detected more PPARGC1A protein in the low-concentrate group as compared with the high-concentrate group. The correlations observed point to a link between these factors and might hint to a functional role of the variables in the regulation of glucose metabolism. This study substantiates the existence of the SIRT1-PPARGC1A-axis and indicates a functional relationship between SIRT1 and ADIPOR1 in bovine adipose tissue.

Effects of energy supply and nicotinic acid supplementation on phagocytosis and ROS production of blood immune cells of periparturient primi- and pluriparous dairy cows

Effects of energy supply and nicotinic acid (NA) supplementation on the phagocytic activity of polymorphonuclear leukocytes (PMN) and peripheral blood mononuclear cells (PBMC), and on ROS production in PMN of periparturient cows differing in parity were examined. 29 pluriparous and 18 primiparous cows were allocated to four different feeding groups from 42days prepartum until 100days postpartum. They were fed either a ration with a low concentrate proportion of 30% (LC) or a high concentrate proportion of 60% (HC). After parturition all animals received 30% concentrate which was increased to 50% either within 16 (LC) or within 24days (HC). The different concentrate feeding strategies aimed at triggering differences in postpartum lipolysis. Half of the animals per group were supplemented with 24g per day of NA from 42days prepartum until 24days postpartum. All investigated parameters varied significantly over time compared to parturition (p<0.05). Numbers of phagocytosing PMN and PBMC increased in the course of the experiment, whereas the amount of engulfed bacteria per cell decreased between 42 and 11days prepartum. Percentage of basal ROS producing PMN decreased strongly before parturition and reached initial values only at 28days in milk again. Mean fluorescence intensity (MFI) in these ROS producing cells, however, increased before parturition. Oxidative burst stimulation in PMN was reduced around parturition but the amount of ROS produced in the stimulated cells was increased. Pluriparous cows exhibited higher numbers of basal ROS producing PMN and phagocytic PBMC. NA supplementation influenced phagocytosis in blood leukocytes.

Relative Bioavailability of Niacin Supplements for Dairy Cows: Effects of Rumen Protection and of Feed Processing

The present study aimed to examine the effective systemic bioavailability of niacin— with particular focus on its galenic form—and feed processing. Experiment 1 was conducted with 35 dairy cows to investigate the effects of various doses of oral supplemented nicotinic acid (NA) either in differing galenic forms (non-rumen protected (nRP) vs. rumen protected form (RP)) on serum niacin concentrations. Experiment 2 was designed as a pharmacokinetic study examining the serum niacin kinetics over 24 h after giving a single oral bolus of 24 g nRP or RP NA admixed in either pelleted or ground concentrate. In both experiments, only the niacin vitamer nicotinamide (NAM) was detected. Results of experiment 1 showed that both galenic forms at a dose of 24 g/cow daily elevated NAM concentrations at the beginning of the experiment. Despite a daily supplementation, NAM concentrations decreased continuously towards the end of the experiment which was more steeply in nRP NA (p = 0.03). On experimental day 21, NAM concentrations were higher when feeding RP NA (p = 0.03) and the highest dose (24 g/day and cow) (p < 0.01). Results of experiment 2 indicated that nRP and RP were characterized by similar pharmacokinetic profiles resulting in similar areas under the curves as a net result of the kinetic counterbalancing alterations. Pelleting seemed not to influence the relative bioavailability.