[Show abstract][Hide abstract] ABSTRACT: A total of 80 piglets (7.9 ± 1.0 kg) were used in a feeding experiment with dried oregano. The diets
differed in their oregano content: 0 g, 2 g, 4 g and 8 g oregano/kg feed, corresponding to 0, 23.5,
46.9 and 93.9 mg carvacrol/kg DM. After the experimental period of 5 weeks, 20 piglets of both
extreme feeding groups were slaughtered: 10 animals of the control group and 10 animals of the
group that received 8 g oregano/kg. Ingesta samples of jejunum, caecum and colon were collected
and analyzed by FISH and PCR RFLP to compare the diversity of microbiota. The results showed no
significant changes in microbiota in response to oregano. The patterns of the PCR-RFLP showed a
similarity of 61.8% - 91.8% in both feeding groups. In conclusion, an effect of oregano on the in-
testinal microbiota could not be shown under the methods used.
[Show abstract][Hide abstract] ABSTRACT: Concentrations of zearalenone (ZEN), deoxynivalenol (DON) and their metabolites α-zearalenol (α-ZEL), β-zearalenol (β-ZEL), zearalanone (ZAN), α-zearalanol (α-ZAL), β-zearalanol (β-ZAL) and de-epoxy-deoxynivalenol (de-DON) in serum, liquor and urine of female piglets fed diets containing 0.01, 0.05, 0.08, 0.17 and 0.29 mg ZEN/kg and 0.03, 0.59, 1.27, 2.01 and 4.52 mg DON/kg during 29 days of treatment were analysed. After 1, 3, 8, 15, 22 and 29 days, four piglets per group were slaughtered. The simultaneous determination of all analytes was carried out using a sensitive and selective in-house-validated liquid chromatography tandem mass spectrometry (LC-MS/MS) method after sample preparation with Oasis™ HLB columns. ZEN, α-ZEL, DON and de-DON were detected in serum, whereas in liquor only ZEN, DON and de-DON were found at lower concentrations. In urine, all analytes were detected in considerably higher concentrations as in serum and liquor, whereby α- and β-ZAL could only be detected sporadically. Apart from ZEN in liquor and α- and β-ZAL in urine, the mycotoxin concentrations increased with increasing concentrations of Fusarium toxins in the diet. The toxin intake per kg body weight 3-4 h prior to slaughtering correlated well with the DON and the sum of DON and de-DON concentrations in all three specimens as well as with the ZEN, α-ZEL and the sum of ZEN and metabolite concentrations in urine. Due to the high correlation between the dietary DON concentration and the DON (r = 0.855) and the sum of DON and de-DON (r = 0.870) concentration in serum, the exposure to DON can be evaluated. Moreover, serum levels of these toxins indicative of an exceeding of the guidance value in feed can be established using the corresponding regression equations. Strictly speaking, these relationships are only valid for the experimental conditions of the underlying experiment. For practical application of these relationships, the individual variation needs to be additionally considered. Effects of the duration of toxin exposure within the feeding groups were observed for ZEN, DON and de-DON in all specimens as well as for α-ZEL, β-ZEL and ZAN in urine.
Archives of animal nutrition 10/2014; · 1.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A long-term feeding experiment with dairy cows was performed to investigate the effects of feeding a Fusarium toxin contaminated (FUS) and a background-contaminated control (CON) ration with a mean concentrate feed proportion of 50% during the first 11 weeks after parturition (Groups FUS-50, CON-50, Period 1), and with concentrate feed proportions of 30% or 60% during the remaining 17 weeks (Groups CON-30, CON-60, FUS-30 and FUS-60, Period 2), on zearalenone (ZEN) residue levels in blood serum, milk, urine and bile. ZEN, α-zearalenol (α-ZEL) and β-zearalenol (β-ZEL), zearalanone (ZAL), α-zearalanol (α-ZAL) and β-zearalanol (β-ZAL) were determined by HPLC with fluorescence detection. The ZEN concentrations of the rations fed to Groups CON-50, FUS-50 (Period 1), CON-30, CON-60, FUS-30 and FUS-60 (Period 2) amounted to 53.1, 112.7, 35.0, 24.4, 73.8 and 72.5 µg/kg dry matter, respectively. The concentrations of ZEN, α-ZEL, β-ZEL, ZAN, α-ZAL and β-ZAL in serum, urine and milk were lower than 1, 1, 4, 100, 50 and 200 ng/g, respectively, while ZEN, α-ZEL and β-ZEL were detected in bile. Their levels changed with oral ZEN exposure in the course of the experiment and in a similar direction with concentrate feed proportion (Period 2 only). Thus the proportions of the individual β-ZEL, α-ZEL and ZEN concentrations of their sum varied only in narrow ranges of 68-76%, 6-13% and 12-20%, respectively. Interestingly, the bile concentrations of β-ZEL, α-ZEL and ZEN of Groups CON-60 and FUS-60 amounted to only approximately 50%, 45% and 62%, respectively, of those of Groups CON-30 and FUS-30 despite a similar or even lower ZEN exposure. The results indicate that conversion of ZEN to its detectable metabolites was not changed by different dietary concentrate feed proportions while their absolute levels were decreased. These findings might suggest concentrate feed proportion-dependent and rumen fermentation-mediated alterations in ZEN/metabolite degradation, and/or liver associated alterations in bile formation and turnover.
Archives of animal nutrition 10/2014; · 1.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Physiological consequences of adaptation to and continued feeding of a high-energetic diet were studied in eight non-pregnant, non-lactating dairy Holstein cows over a period of 16 weeks. The first six weeks served as an adaptation period from the low energetic straw-based diet (3.8 MJ NEL/kg DM) to the high-energetic ration (7.5 MJ NEL/kg DM). Intake of dry matter (DM) increased with dietary energy concentration from 9 to 20 kg/d up to week 9 to 12 and decreased thereafter. The initial live weight (LW) of 550 ± 60 kg was increased linearly and corresponded to an average daily LW gain of 2.3 ± 0.3 kg. Energy balance increased approximately nine-fold to a maximum of 114 MJ NEL/d in week 10. Ruminal fermentation pattern was completely changed from an acetate dominating profile to a propionate based one, which was paralleled by a marked increase in the rumen fluid endotoxin concentration. Unlike blood glucose concentration, which increased continuously, that of cholesterol and triglycerides started to increase after an initial stagnation. In conclusion, both ruminal adaptation to a high-energetic diet and the continued feeding of such a diet induced digestive and metabolic adaptations in non-pregnant, non-lactating cows characterised by a progressing positive energy balance.
Archives of animal nutrition 10/2014; · 1.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The mycotoxin deoxynivalenol (DON) and lipopolysaccharides (LPS) are reported to act synergistically in the animal organism. Thus, we tested the hypothesis that systemic co-exposure of DON and LPS aggravates the impact of the individual toxin on leukocyte counts in vivo and peripheral blood mononuclear cells (PBMC) ex vivo. Growing barrows were fed a standard diet, equipped with permanent venous catheters and infused for 1 h with one of four treatments: control group with physiological saline (CON, n = 8), mycotoxin group (DON, n = 6) with 100 μg/kg body weight (BW) deoxynivalenol, endotoxin group (LPS, n = 6) with 7.5 μg/kg BW Escherichia coli LPS, and co-exposed group (DON + LPS, n = 6) with 100 μg/kg BW DON and 7.5 μg/kg BW LPS. Blood was collected 30 min prior to infusion and 10, 20, 30, 60, 360, 720 and 1440 min after start of infusion for total and differential leukocyte counts. PBMC were isolated from blood drawn at 3 and 24 h and subjected to an ex vivo 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay, either non-stimulated or stimulated with concanavalin A. LPS induced a transient significant leukopenia between 30 and 360 min, owing to a decrease in segmented neutrophils and lymphocytes (time × treatment: p < 0.001). Metabolic activity of stimulated PBMC ex vivo was severely compromised in pigs 3 h after LPS exposure (<50 % of control, p < 0.001), but already regained 80 % of its activity at 24 h, thus showing no difference between treatments. DON alone did not affect leukocytes in vivo or PBMC activity ex vivo and neither aggravated the effect of LPS.
[Show abstract][Hide abstract] ABSTRACT: A rising atmospheric CO2 concentration might affect the nutritional value of feedstuffs. Only little information about the effects of elevated CO2 on C4 plants, such as maize, is known. Therefore, the present study investigated the effects of atmospheric CO2 enrichment on the nutritional value of maize grains (cv. “Romario”), which were grown at two different atmospheric CO2 concentrations (ambient CO2: 380 ppm (AMBI) and enriched CO2: 550 ppm (FACE)) in 2008. The nutrient composition of the maize grains was analysed and two digestibility studies with pigs (trial 1) and broilers (trial 2), and an in sacco degradability study with cows (trial 3) were performed. Regarding the chemical composition of nutrients, a significant CO2 effect on sugar concentration was observed. The grain sugar concentration increased significantly under CO2 enrichment from 19.9 to 24.8 g kg−1 DM. There were no major effects of the CO2 concentration on the other analysed nutrients and amino acids. Different results were calculated in both digestibility studies and in the in sacco experiment. The digestibility of the ether extract (EE), organic matter (OM) and the metabolisable energy (ME) for pigs were significantly increased for diet maize grown under FACE conditions. In broiler chickens, the digestibility of crude protein (CP) of the diet containing maize grain cultivated under enriched atmospheric CO2 concentration was significantly increased from 912 g kg−1 to 927 g kg−1 as well as EE, which rose from 914 g kg−1 to 924 g kg−1. The degradability CP and neutral detergent fiber (aNDFom) in the in sacco degradability study were significantly influenced by the CO2 treatment. In both cases, the effective degradability declined significantly from about 730 to 619 g kg−1 (CP) and from 865 to 617 g kg−1 (aNDFom) under FACE conditions at a passage rate of 0.05 h−1. It is concluded that the content of crude nutrients of maize grain cultivated under elevated CO2 did not change, but the digestibility of some nutrients was significantly increased in trials with pigs and broiler chickens and the CP and aNDFom in sacco degradability was significantly decreased.
Animal Feed Science and Technology 10/2014; · 1.61 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Early lactating cows mobilize adipose tissue (AT) to provide energy for milk yield and maintenance and are susceptible to metabolic disorders and impaired immune response. Conjugated linoleic acids (CLA), mainly the trans-10, cis-12 isomer, reduce milk fat synthesis and may attenuate negative energy balance. Circulating glucocorticoids (GC) are increased during parturition in dairy cows and mediate differentiating and anti-inflammatory effects via glucocorticoid (GR) and mineralocorticoid receptors (MR) in the presence of the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1). Activated GC are the main ligands for both receptors in AT; therefore, we hypothesized that tissue-specific GC metabolism is effected by varying amounts of GR, MR and 11βHSD1 and/or their localization within AT depots. Furthermore, the lipolytic and antilipogenic effects of CLA might influence the GC/GR/MR system in AT. Therefore, we aimed to localize GR and MR as well as the expression pattern and activity of 11βHSD1 in different AT depots during early lactation in dairy cows and to identify potential effects of CLA. Primiparous German Holstein cows were divided into a control (CON) and a CLA group. From day 1 post-partum (p.p.) until sample collection, the CLA group was fed with 100 g/d CLA (contains 10 g each of the cis-9, trans-11 and the trans-10, cis-12-CLA isomers). CON cows (n = 5 each) were slaughtered on day 1, 42 and 105 p.p., while CLA cows (n = 5 each) were slaughtered on day 42 and 105 p.p. Subcutaneous fat from tailhead, withers and sternum, and visceral fat from omental, mesenteric and retroperitoneal depots were sampled. The localization of GR and 11βHSD1 in mature adipocytes – being already differentiated – indicates that GC promote other effects via GR than differentiation. Moreover, MR were observed in the stromal vascular cell fraction and positively related to the pre-adipocyte marker Pref-1. However, only marginal CLA effects were observed in this study.
[Show abstract][Hide abstract] ABSTRACT: Scope: Procyanidins are amongst the most abundant polyphenols in the human diet and they are reported to exhibit several beneficial health effects. However the knowledge about their metabolic fate is rather limited. To investigate the systemic absorption and metabolism of dietary procyanidin B4 a kinetic study using pigs as model system has been performed.Methods and results: After oral application of a single-dose of 10 mg/kg body weight procyanidin B4, urine and plasma were collected over a period of 48 h. Procyanidin B4 and its possible metabolites were analyzed in physiological samples using high-performance liquid chromatography tandem mass spectrometry and gas chromatography mass spectrometry. Procyanidin B4 was detected as intact molecule in urine as well as in plasma. Maximum reached plasma concentration of procyanidin B4 (cmax) was 2.13 ng/mL (3.68 nM) and mean total urinary excretion related to the administered dose was 0.008 ± 0.003%. In addition to that the monomeric structural units catechin and epicatechin were determined as degradation products. Furthermore methylated and conjugated monomeric metabolites were identified. Monomeric metabolites were identified to be the major fraction occurring in the systemic circulation. The analysis of phenolic acids did not show an increase of these possible further metabolites.Conclusion: After oral administration procyanidin B4 is absorbed as intact molecule and it is excreted in urine. In addition it is degraded to the monomeric subunits which are then further metabolized to methylated and glucuronidated conjugates in pigs.This article is protected by copyright. All rights reserved
Molecular Nutrition & Food Research 09/2014; · 4.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: α-Tocopherol is absorbed in the small intestine and transported to the liver from where it is secreted into the systemic circulation. Hepatic vitamin E-binding proteins and metabolizing enzymes control vitamin E concentrations. We hypothesized that hepatic gene expression of vitamin E-binding proteins and the rate-limiting metabolic enzyme cytochrome P450 4F2 (CYP4F2) will change in dairy cows that are faced with high need for vitamin E with the onset of lactation. Liver biopsies and blood samples were taken from 10 German Holstein cows on days -21, 1, 21, 70, and 105 relative to calving. The mRNA abundance of α-tocopherol transfer protein (TPP), α-tocopherol associated protein (TAP), and CYP4F2 was quantified by real-time RT-PCR. Serum concentrations of α-tocopherol were quantified by HPLC. The mRNA abundance of TTP, which specifically binds α-tocopherol and facilitates its secretion via lipoproteins, increased from d -21 to d 105; d 105 values were higher than on the other days. The mRNA encoding TAP, a ligand-dependent transcriptional activator, followed a similar pattern to that observed for TTP. Expression of CYP4F2 mRNA, the enzyme that catalyzes the hydroxylation of the phytyl side chain of tocopherols, remained unchanged. Serum α-tocopherol increased post partum in line with the observed increase in TTP mRNA. Increasing mRNA expression of TPP with days in milk indicates improved hepatic release of vitamin E into circulation to support target tissues; this was indeed reflected by increasing serum α-tocopherol concentrations. The functional consequences of increasing TAP remain to be elucidated.
65th Annual Meeting of the EAAP, Copenhagen – Denmark; 08/2014
[Show abstract][Hide abstract] ABSTRACT: In the present study, the potential for carry-over of deoxynivalenol (DON) into eggs and DON residues in plasma and bile of laying hens of different genetic backgrounds after long-term feeding trial was investigated. A total of 80, 23-week-old laying hens were assigned to a feeding trial with two diets, a control diet and a Fusarium toxin-contaminated diet (FUS) (0.4 and 9.9 mg DON kg(-1), respectively). In the 60th week of hen's life, 10 eggs from each group were collected. In the 70th week of hen's life, all hens were slaughtered and samples of blood and bile were collected. The samples were analysed by liquid chromatography tandem mass spectrometry (LC-MS/MS) for DON and de-epoxy-DON. DON was only detected in samples of hens which fed the FUS diet while none of the samples analysed had detectable levels of de-epoxy-DON. In plasma and bile samples, DON levels ranged from 0.2 to 0.6 ng ml(-1) and from 1.8 to 4.1 ng ml(-1), respectively. DON levels in egg yolk and albumen ranged between 0.0-0.46 ng g(-1) and 0.0-0.35 ng g(-1), respectively, corresponding to carry-over rates of DON into eggs from 0.0 to 0.000016. Moreover, no differences in DON levels or carry-over rates were noticed between the two tested breeds. These results show that very low levels of DON were transferred into eggs and indicate that although eggs could contribute to human exposure to DON, the levels are very low and insignificant.
Archives of animal nutrition 08/2014; · 1.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Telomeres are short and repetitive sequences of the chromosomes which shorten with every cell-division. Therefore telomere length (TL) is considered as a biological marker for aging and cell proliferation depending on the tissue type. Increasing oxidative stress in response to nutrient surplus, e.g. in overconditioned dairy cows at the onset of lactation, accelerates telomere attrition. Adipose tissue (AT) is mobilized in early lactating cows to cope with the nutrient demands for milk synthesis. The different AT depots are divided into visceral (vc) and subcutaneous (sc) depots which exhibit different metabolic functions and cellular composition. We hypothesized that TL shortening within AT is depot specific in overconditioned cows due to different metabolic activities of sc and vcAT. Herein, we aimed to characterize the TL in seven different fat depots after rapid, diet-induced fat accumulation in cows. Eight German Holstein cows (non-lactating, non-pregnant, age: 4-6 years) were gradually adapted to a high-energy ration by increasing the portion of concentrate in the ration from 0 to 60% of daily dry matter intake within 6 wk. Animals were fed the 60% diets for further 10 wk and were then slaughtered; tissue samples from scAT (sternum, withers and tailhead) and vcAT (pericardial, mesenterial, omental and retroperitoneal) were collected and snap frozen for further analyses. After isolation of genomic DNA, a multiplex quantitative PCR was used to analyze the relative quantity of telomere (qT) products compared with ß-globin products which served as reference gene to estimate TL in AT. Differences between qT in the single AT depots were analyzed using the Student’s t-test (SPSS; mean ± SEM). Mesenterial AT exhibited 1.3-fold lower qT compared to omental (59.1 ± 7.4; P= 0.01) and pericardial (57.7 ± 7.9; P= 0.004) depots and 1.2-fold lower qT than retroperitoneal (53.5 ± 4.9; P= 0.01) AT. In scAT depots, fat from withers displayed 1.3-fold higher qT values than sternum (47.3 ± 3.5; P=0.005) AT and 1.1-fold higher qT compared to tailhead (54.1 ± 8.2; P=0.05) fat. Although vcAT is known to have a higher metabolic activity than scAT in dairy cows, we did not observe any differences in TL when comparing all sc versus all vcAT. Depot specific differences of TL might nevertheless be a hint to depot specific roles.
ADSA ASAS CSAS Joint Annual Meeting, Kansas City, Missouri, USA; 07/2014
[Show abstract][Hide abstract] ABSTRACT: In dairy cows, adipose tissue (AT) is mobilized during early lactation to meet the increased energy demands through lactation. Overconditioned cows are more prone to metabolic disorders during this period than lean cows. Just like in other tissues, mitochondria are the main site of energy production within AT. Different energy demands may lead to changes of mitochondrial DNA (mtDNA), which reflects the abundance of mitochondria in a cell. Different bovine AT depots differentiated into visceral (vc) and subcutaneous (sc) regions, might present different mtDNA contents, due to diverse metabolic functions. Therefore, we aimed to compare the number of mtDNA copies per cell between various sc and vcAT depots from overconditioned cows. Eight non-lactating, non-pregnant German Holstein cows (Age: 4 – 6 years) received diets with increasing proportions of concentrate feed during the first 6 weeks of the trial until 60% were reached. This diet was maintained for 10 weeks and cows had an average body weight (BW) gain of 243 ± 33.3 kg within this period. Animals were slaughtered at the end of the experiment and tissue samples from sc (sternum, withers and tailhead) and vc (mesenterial, omental and retroperitoneal) AT were collected and snap frozen for genomic DNA isolation. The number of mtDNA copies/cell was quantified by multiplex quantitative PCR using ß-globin as reference gene. Data (mean ± SEM) were analyzed using Mann-Whitney-U-test and the Spearman ( correlation coefficient (SPSS). The number of mtDNA copies/cell was 2.6-fold higher in all vc compared to all sc (P< 0.001) AT. Retroperitoneal AT exhibits greatest mtDNA copies/cell (3488 ± 190) compared to all other AT depots. The mtDNA copy number/cell in mesenterial and omental AT were 3058 ± 405 and 2921 ± 235, respectively. In tailhead and sternum AT mtDNA copy number/cell was 3-fold and in withers AT 2-fold lower compared to retroperitoneal. Different amounts of mtDNA copies/cell might reflect individual energy demands and metabolic functions in different sc and vcAT depots. In this study, mtDNA was isolated from whole AT including both adipocytes and the cells belonging to the stromal vascular cell fraction (SVF). Therefore, lower values of mtDNA copies in scAT might be due to an increased SVF, which contains significantly less mtDNA copy numbers. Higher amounts of mtDNA copies per cell in vcAT compared to scAT are in accordance to the higher metabolic activity of vcAT, particularly the retroperitoneal AT depot.
ADSA ASAS CSAS Joint Annual Meeting, Kansas City, Missouri, USA; 07/2014
[Show abstract][Hide abstract] ABSTRACT: With the onset of lactation, overconditioned cows mobilize more body tissue than thin cows and are prone to develop metabolic disorders. The metabolic stress in cows with higher body condition score (BCS) prior to calving and greater loss of BCS after calving comprises oxidative stress. Increased production of reactive oxygen metabolites may damage cells and accelerate telomere shortening which serves as biological marker for age and stress-related conditions. Herein we aimed to investigate the telomere length (TL) in subcutaneous adipose tissue (AT) during exemplarily induced excessive fat accumulation in cows. We hypothesized that TL is associated with the production of derivates of reactive oxygen metabolites (dROM), as indicator for oxidative stress, in overconditioned cows. Eight non-lactating, non-pregnant German Holstein cows (4 – 6 years) received diets with increasing concentrate feed proportions (0 to 60% of the total daily dry matter intake) during the first 6 weeks of the experiment which was maintained for 9 weeks. The BCS (5-point scale) increased from 2.3 ± 0.12 to 4.57 ± 0.14 and the average body weight (BW) gain was 243 ± 33.3 kg. Blood samples were taken monthly for photometric quantification of dROM in serum using N,N,diethyl-1,4-phenylendiamine as chromogen. Subcutaneous AT from tailhead was collected at the beginning and of the experiment and after 15 weeks. Samples were snap frozen for isolation of genomic DNA. A multiplex quantitative PCR was used to analyze the relative quantity of telomere (qT) products compared with ß-globin products which served as reference gene to estimate TL in AT. Data (mean ± SEM) for TL, BCS and BW as well as for dROM were evaluated using repeated measurement ANOVA or non-parametric tests, respectively. Correlations were calculated using the Spearman (and Pearson (r) correlation coefficient. Relative qT decreased throughout the experiment (51.8 ± 3.26 to 43.6 ± 1.76; P = 0.01) whereas dROM increased more than 2-fold (P = 0.003). Shorter TL were correlated with BCS (r = -0.586, P = 0.017), BW (r = -0.653, P = 0.008) and dROM (= -0.596, P = 0.015). Increasing dROM indicating oxidative stress were observed in overconditioned cows. Fat accumulation was accompanied by reduced TL in bovine AT. Shortening of telomeres might indicate fibrosis and would thus result in AT dysfunction which might compromise the adaptive capability of AT to the needs of lactation in overconditioned cows.
ADSA ASAS CSAS Joint Annual Meeting, Kansas City, Missouri, USA; 07/2014
[Show abstract][Hide abstract] ABSTRACT: In the transition period, overconditioned cows usually have more problems to adapt to the needs of lactation than leaner cows and are thus more prone to health problems. The mitochondrial DNA (mtDNA) copy number reflects the abundance of mitochondria in a cell and may change under different energy requirements and physiological conditions. Increased metabolic demands as well as increased mtDNA copies per cell are associated with elevated oxidative stress. However, the association between oxidative stress through excessive fat accumulation and mtDNA copy numbers in bovine adipose tissue (AT), being considered as a major contributor to systemic oxidative stress, has not been investigated so far. We hypothesized that the mtDNA copy number in AT will increase concomitant with oxidative stress (assessed by quantifying the derivates of reactive oxygen species (dROM)) during fat accretion in cows. Eight non-lactating, non-pregnant pluriparous German Holstein cows (Age: 4 - 6 years) were fed diets with increasing portions of concentrate feed during the first 6 weeks of the experiment until 60% were reached, which was maintained for 9 weeks. Within this period cows had an average body weight (BW) gain of 243 ± 33.3 kg. Blood samples were collected monthly and dROM were photometrically quantified in serum using N,N,diethyl-1,4-phenylendiamine as chromogen. Biopsies from the subcutaneous tailhead AT were taken every 8 weeks and immediately snap frozen for genomic DNA isolation. The number of mtDNA copies/cell was measured by a multiplex quantitative PCR using ß-globin as reference gene. Data (mean ± SEM) for mtDNA copies and dROM as well as for BW were analyzed using non-parametric tests or repeated measurement ANOVA, respectively. Correlations were calculated using the Spearman (correlation coefficient. Throughout the fat accumulation period mtDNA copies/cell and dROM increased 4-fold (329 ± 57.5 to 1385 ± 160; P= 0.002) and 2.5-fold (49.9 ± 9.24 to 125 ± 16.0 μg H2O2 equivalents/mL; P=0.003), respectively. We observed a positive correlation between mtDNA copy numbers and BW (= 0.596, P= 0.003) and dROM (=0.550, P= 0.005). Increased mtDNA copies in AT might be an adaptation in response to oxidative stress that evolves from excessive fat accumulation in overconditioned cows. It is known, that mtDNA copy numbers increase as a compensatory response mechanism to mtDNA damage. Therefore, increased numbers of mitochondria and thus increased numbers of mtDNA copies per cell might then amplify the production of ROM leading to further mtDNA damage.
ADSA ASAS CSAS Joint Annual Meetings, Kansas City, Missouri, USA; 07/2014
[Show abstract][Hide abstract] ABSTRACT: Abstract Text:
Chemerin (RARRES2) is involved in adipogenesis and in mediating fat mobilization in mature adipocytes, exerting its effects via its receptor ChemR23. In humans, circulating chemerin levels are regulated by the energy intake. We hypothesized that the expression of RARRES2 or ChemR23 in subcutaneous (SC) and retroperitoneal (RP) adipose tissue (AT) of dairy cattle will change throughout the transition period and will be affected by different portions of concentrate in the diet. Twenty pluriparous German Holstein cows were divided into a high-concentrate group (HC, n=10) receiving a diet with 60% and a low-concentrate group (LC, n=10) receiving a diet with 30% concentrate on DM basis from d 1 until d 21 post partum. The SCAT from tail head and RPAT were biopsied at d −21, 1 and 21 relative to calving. RARRES2 and ChemR23 mRNA abundance were quantified by qPCR. The statistical analyses were performed with SPSS 21.0 (P<0.05).
The mRNA abundances of both genes were not different between the HC versus the LC group neither in SCAT nor in RPAT, thus, groups were pooled for further analyses. In both tissues RARRES2 and ChemR23 mRNA expression were time-dependent, i.e. less RARRES2 and ChemR23 mRNA was observed ante partum than post partum in both AT (P<0.05). When comparing both AT depots within the individual sampling times, RPAT had 1.33-fold higher RARRES2 mRNA abundance than SCAT on d 1 (P=0.004), whereas no differences between both depots were seen on d -21 and 21. For ChemR23, RPAT and SCAT did not differ at any time point. In conclusion, the different concentrate portion and the difference in energy balance (Δ=18.5 MJ/d in the third week of lactation) between HC vs. LC group were apparently not relevant for the expression of RARRES2 or ChemR23. Considering time-related differences we observed that RARRES2 and its receptor are regulated in a likewise manner in bovine AT. Due to their functions, the higher mRNA abundances of RARRES2 and its receptor in both AT after parturition may reflect the paracrine/autocrine involvement of RARRES2 in stimulation of lipolysis to provide non-esterified fatty acids as energy source to other peripheral tissues.
Chemerin, Adipose tissue, Transition period
[Show abstract][Hide abstract] ABSTRACT: Abstract Text:
The mRNA expression of adiponectin (ADIPOQ) and its receptors ADIPOR1/2 in adipose tissue (AT) decreases with the onset of lactation in dairy cows; the serum concentrations of ADIPOQ have also been demonstrated to drop during the lactation-induced negative energy balance (NEB) but not during feed-restriction induced NEB at later stages of lactation (Singh et al., 2014, doi:10.3168/jds.2013-7598). As to whether the extent of NEB during the lactation-induced NEB may affect ADIPOQ system was not known and we thus hypothesized that the ADIPOQ system will be affected by feeding different portions of concentrate in the diet throughout the transition period, and that visceral (VC) and subcutaneous (SCAT) respond concordantly. Twenty pluriparous German Holstein cows were fed with rations containing either 60% (HC) or 30% (LC) concentrate (DM basis, n=10 per group) from d 1-21 postpartum. The SCAT (tail head) and RPAT were biopsied at d −21, 1 and 21 relative to parturition. Blood samples were collected weekly. ADIPOQ and AdipoR1/2 mRNA abundances were quantified by qPCR, and serum ADIPOQ by ELISA. The statistical analyses were performed using SPSS 21.0 (P<0.05).
The NEB was more negative in LC than in HC animals (Δ=18.5 MJ/d, third week of lactation). Effects of diet were limited to ADIPOQ in SCAT, with 4.1-fold lower mRNA abundance in LC than in HC at d 21 (P<0.02). With the exception of AdipoR2 mRNA in RPAT, we detected time-related changes in SC and RPAT with higher abundances ante partum (P<0.05) for all target mRNAs, and for ADIPOQ in serum. AdipoR2 mRNA abundance in RPAT was highest at d 1. Irrespective of time, ADIPOQ and AdipoR2 expression was higher in RPAT than in SCAT (P<0.05), whereas AdipoR1 mRNA abundance was not different between both tissues. ADIPOQ and AdipoR1 mRNA abundance were positively correlated in SCAT (r=0.461, P<0.01) and RPAT (r=0.745, P<0.01). AdipoR1 and AdipoR2 were correlated in SCAT (r=0.422, P<0.01). The lower ADIPOQ mRNA abundance in SCAT of the LC group points to greater responsiveness towards dietary effects in this depot; however, this was apparently not reflected in serum ADIPOQ indicating that other fat depots might compensate the decrease. The observed time-related changes in SCAT and of serum ADIPOQ confirm earlier reports, whereas the likewise regulation in RPAT for ADIPOQ and AdipoR1 has not been previously investigated in cows. The correlation between ADIPOQ and AdipoR1 mRNA abundances points to a co-regulation of both genes in AT.
[Show abstract][Hide abstract] ABSTRACT: The aim of the experiment was to determine the impact of heat stress on nutrient digestibility and nitrogen balance in sheep fed silages differing in fibre quality. The digestibility trial was conducted at three different ambient temperatures (15°C, 25°C and 35°C for 24 h/d). The tested brown-midrib maize (Bm) silage had a higher nutrient digestibility, except for ether extract (EE) and a higher metabolisable energy (ME) content than the control maize (Con) silage. Nitrogen (N) excretion with faeces was higher but N excretion with urine was lower for sheep fed Bm silage, subsequently N balance did not differ between the two silages. Temperature had no effect on nutrient digestibility, except for crude protein (CP), but N excretion with urine was lower at elevated temperatures. A diet by temperature interaction was found for dry matter (DM) and organic matter (OM) digestibility. When the ambient temperature increased from 15°C to 25°C, the DM and OM digestibility increased in animals fed Con silage, but decreased in animals fed Bm silage. Concomitantly, ME estimated from digestible nutrients was higher for Bm than for Con at 15°C, but no differences were found at 25°C and 35°C. Effects of diet by temperature interaction, furthermore, were observed for EE and CP digestibility. Therefore, forage quality has to be considered when feeding heat-stressed animals.
Archives of animal nutrition 07/2014; · 1.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The present study investigates effects of rising atmospheric CO2 concentration on protein composition of maize, wheat and barley grain, especially on the fractions prolamins and glutelins. Cereals were grown at different atmospheric CO2 concentrations to simulate future climate conditions. Influences of two nitrogen fertilization levels were studied for wheat and barley. Enriched CO2 caused an increase of globulin and B-hordein of barley. In maize, the content of globulin, α-zein and LMW polymers decreased, whereas total glutelin, zein, δ-zein and HMW polymers rose. Different N supplies resulted in variations of barley sub fractions and wheat globulin. Other environmental influences showed effects on the content of nearly all fractions and sub fractions. Variations in starch-protein bodies caused by different CO2 treatments could be visualized by scanning electron microscopy. In conclusion, climate change would have impacts on structural composition of proteins and consequently on the nutritional value of cereals.
Journal of agricultural and food chemistry. 06/2014;
[Show abstract][Hide abstract] ABSTRACT: As the term "masked mycotoxins" encompasses only conjugated mycotoxins generated by plants and no other possible forms of mycotoxins and their modifications, we hereby propose for all these forms a systematic definition consisting of four hierarchic levels. The highest level differentiates the free and unmodified forms of mycotoxins from those being matrix-associated and from those being modified in their chemical structure. The following lower levels further differentiate, in particular, "modified mycotoxins" into "biologically modified" and "chemically modified" with all variations of metabolites of the former and dividing the latter into "thermally formed" and "non-thermally formed" ones. To harmonize future scientific wording and subsequent legislation, we suggest that the term "modified mycotoxins" should be used in the future and the term "masked mycotoxins" to be kept for the fraction of biologically modified mycotoxins that were conjugated by plants.