The effect of conjugated linoleic acid supplements on oxidative and antioxidative status of dairy cows

Dairy cows develop frequently negative energy balance around parturition and in early lactation, resulting in excessive mobilization of body fat and subsequently in increased risk of ketosis and other diseases. Dietary conjugated linoleic acid (CLA) supplements are used in dairy cows mainly for their depressing effect on milk fat content, but are also proposed to have antioxidative properties. As negative energy balance is associated with oxidative stress, which is also assumed to contribute to disease development, the present study was conducted to examine effects of CLA on oxidative and antioxidative status of lactating dairy cows. German Holstein cows (primiparous n=13, multiparous n=32) were divided into 3 dietary treatment groups receiving 100g/d of control fat supplement, containing 87% stearic acid (CON; n=14), 50g/d of control fat supplement and 50g/d of CLA supplement (CLA 50; n=15), or 100g/d of CLA supplement (CLA 100; n=16). The CLA supplement was lipid-encapsulated and contained 12% of trans-10,cis-12 CLA and cis-9,trans-11 CLA each. Supplementation took place between d1 and 182 postpartum; d 182 until 252 postpartum served as a depletion period. Blood was sampled at d -21, 1, 21, 70, 105, 140, 182, 224, and 252 relative to calving. The antioxidative status was determined using the ferric-reducing ability of plasma, α-tocopherol, α-tocopherol-to-cholesterol mass ratio, and retinol. For determination of oxidative status concentrations of hydroperoxides, thiobarbituric acid-reactive substances (TBARS), N'-formylkynurenine, and bityrosine were measured. Mixed models of fixed and random effects with repeated measures were used to evaluate period 1 (d -21 to 140) and 2 (d182-252) separately. Cows showed increased oxidative stress and lipid peroxidation during the periparturient period in terms of increased serum concentrations of hydroperoxides and TBARS, which decreased throughout lactation. During period 1, the supplemented cows had lower TBARS concentrations, which was not detectable in period 2. The other determined parameters were not affected by CLA supplementation. The obtained results show that dietary CLA supplementation in the chosen dosage, formulation, and application period had a marginal antioxidative effect in terms of lipid peroxidation in lactating 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.

Excretion pathways and ruminal disappearance of glyphosate and its degradation product aminomethylphosphonic acid in dairy cows

From 6 balance experiments with total collection of feces and urine, samples were obtained to investigate the excretion pathways of glyphosate (GLY) in lactating dairy cows. Each experiment lasted for 26d. The first 21d served for adaptation to the diet, and during the remaining 5d collection of total feces and urine was conducted. Dry matter intake and milk yield were recorded daily and milk and feed samples were taken during the sampling periods. In 2 of the 6 experiments, at the sampling period for feces and urine, duodenal contents were collected for 5d. Cows were equipped with cannulas at the dorsal sac of the rumen and the proximal duodenum. Duodenal contents were collected every 2h over 5 consecutive days. The daily duodenal dry matter flow was measured by using chromium oxide as a volume marker. All samples (feed, feces, urine, milk and duodenal contents were analyzed for GLY and aminomethylphosphonic acid (AMPA). Overall, across the 6 experiments (n=32) the range of GLY intake was 0.08 to 6.67mg/d. The main proportion (61±11%; ±SD) of consumed GLY was excreted with feces; whereas excretion by urine was 8±3% of GLY intake. Elimination via milk was negligible. The GLY concentrations above the limit of quantification were not detected in any of the milk samples. A potential ruminal degradation of GLY to AMPA was derived from daily duodenal GLY flow. The apparent ruminal disappearance of GLY intake was 36 and 6%. In conclusion, the results of the present study indicate that the gastrointestinal absorption of GLY is of minor importance and fecal excretion represents the major excretion pathway. A degradation of GLY to AMPA by rumen microbes or a possible retention in the body has to be taken into account.

Effects of monensin and essential oils on immunological, haematological and biochemical parameters of cows during the transition period

Using a model to generate experimental groups with different manifestations of post-partum (p.p.) fat mobilization and ketogenesis, the effects of a dietary and a medical intervention on biochemical and haematological parameters, antibody titre, leucocytes subsets and function of transition cows were examined. In total, 60 German Holstein cows were allocated 6 weeks antepartum (a.p.) to 3 high-body condition score (BCS) groups (BCS 3.95) and 1 low-BCS group (LC, BCS 2.77). High-BCS cows received a monensin controlled-release capsule (HC/MO) or a blend of essential oils (HC/EO) or formed a control group (HC). Parameters were evaluated in 3 periods (day (d) -42 until calving, 1 until 14 days in milk (DIM), 15 until 56 DIM). Over the course of trial, various parameters were influenced by period with greatest variability next to calving. White blood cell count was higher in the HC (8.42 × 10³ /μl) and HC/EO (8.38 × 10³ /μl) groups than in the HC/MO group (6.81 × 10³ /μl) considering the whole trial. Supplementation of monensin decreased aspartate aminotransferase in comparison with the HC group similar to LC treatment. Bilirubin concentration was nearly doubled in all high-BCS cows in period 2. In period 3, essential oils increased γ-glutamyltransferase (80.4 Units/l) in comparison with all other groups and glutamine dehydrogenase (61 Units/l) in comparison with the LC (19 Units/l) and the HC/MO group (18 Units/l). Results suggest that parameters were generally characterized by a high variability around calving. Based on biochemical characteristics, it appeared that the HC cows seemed to have compromised hepatocyte integrity when compared to the LC cows. From the immune parameters investigated, the BVDV antibody response was more pronounced in HC/MO compared to HC/EO.

The effects of a ration change from a total mixed ration to pasture on rumen fermentation, volatile fatty acid absorption characteristics, and morphology of dairy cows

To investigate the effect of the change from a concentrate and silage-based ration (total mixed ration, TMR) to a pasture-based ration, a 10-wk trial (wk 1-10) was performed, including 10 rumen- and duodenum-fistulated German Holstein dairy cows (182±24 d in milk, 23.5±3.5kg of milk/d; mean ± standard deviation). The cows were divided in either a pasture group (PG, n=5) or a confinement group (CG, n=5). The CG stayed on a TMR-based ration (35% corn silage, 35% grass silage, 30% concentrate; dry matter basis), whereas the PG was gradually transitioned from a TMR to a pasture-based ration (wk 1: TMR only; wk 2: 3 h/d on pasture wk 3 and 4: 12 h/d on pasture wk 5-10: pasture only). Ruminal pH, volatile fatty acids (VFA), NH3-N, and lipopolysaccharide (LPS) concentrations were measured in rumen fluid samples collected medially and ventrally on a weekly basis. Ruminal pH was continuously recorded during 1 to 4 consecutive days each week using ruminal pH measuring devices. In wk 1, 5, and 10, rumen contents were evacuated and weighed, papillae were collected from 3 locations in the rumen, and subsequently a VFA absorption test was performed. In the PG, mean rumen pH and molar acetate proportions decreased, and molar butyrate proportions increased continuously over the course of the trial, which can most likely be ascribed to an increased intake of rapidly fermentable carbohydrates. During the first weeks on a full grazing ration (wk 5-7), variation of rumen pH decreased, and in wk 5 a lower rumen content, papillae surface area, and potential for VFA absorption were observed. In wk 8 to 10, variation of rumen pH and total VFA concentrations increased again, and acetate/propionate ratio decreased. In wk-10 rumen content, papillae area and VFA absorption characteristics similar to initial levels were observed. Although continuous rumen pH assessments and LPS concentrations did not reveal an increased risk for subacute rumen acidosis (SARA) during the adaption period, histopathology of rumen papillae and potential for VFA absorption indicated a possible risk for rumen health. An increased risk for SARA was observed in wk 9 and 10 in the PG, but rumen LPS concentrations and histopathology were not adversely affected. Results of the present study suggest that after behavioral and metabolic adaptation to the transition from a TMR to a pasture-based ration, no adverse effects on rumen morphology and absorption capacity occurred, although rumen pH after adaptation to pasture indicated increased risk of SARA.

Abnormal context-reward associations in an immune-mediated neurodevelopmental mouse model with relevance to schizophrenia

Impairments in central reward processing constitute an important aspect of the negative symptoms of schizophrenia. Despite its clinical relevance, the etiology of deficient reward processing in schizophrenia remains largely unknown. Here, we used an epidemiologically informed mouse model of schizophrenia to explore the effects of prenatal immune activation on reward-related functions. The model is based on maternal administration of the viral mimic PolyI:C and has been developed in relation to the epidemiological evidence demonstrating enhanced risk of schizophrenia and related disorders following prenatal maternal infection. We show that prenatal immune activation induces selective deficits in the expression (but not acquisition) of conditioned place preference for a natural reward (sucrose) without changing hedonic or neophobic responses to the reward. On the other hand, prenatal immune activation led to enhanced place preference for the psychostimulant drug cocaine, while it attenuated the locomotor reaction to the drug. The prenatal exposure did not alter negative reinforcement learning as assessed using a contextual fear conditioning paradigm. Our findings suggest that the nature of reward-related abnormalities following prenatal immune challenge depends on the specificity of the reward (natural reward vs drug of abuse) as well as on the valence domain (positive vs negative reinforcement learning). Moreover, our data indicate that reward abnormalities emerging in prenatally immune-challenged offspring may, at least in part, stem from an inability to retrieve previously established context-reward associations and to integrate such information for appropriate goal-directed behavior.

How strict is galactose restriction in adults with galactosaemia? International practice

Dietary management of 418 adult patients with galactosaemia (from 39 centres/12 countries) was compared. All centres advised lactose restriction, 6 restricted galactose from galactosides ± fruits and vegetables and 12 offal. 38% (n=15) relaxed diet by: 1) allowing traces of lactose in manufactured foods (n=13) or 2) giving fruits, vegetables and galactosides (n=2). Only 15% (n=6) calculated dietary galactose. 32% of patients were lost to dietetic follow-up. In adult galactosaemia, there is limited diet relaxation.

Practices in prescribing protein substitutes for PKU in Europe: No uniformity of approach

BACKGROUND

There appears little consensus concerning protein requirements in phenylketonuria (PKU).

METHODS

A questionnaire completed by 63 European and Turkish IMD centres from 18 countries collected data on prescribed total protein intake (natural/intact protein and phenylalanine-free protein substitute [PS]) by age, administration frequency and method, monitoring, and type of protein substitute. Data were analysed by European region using descriptive statistics.

RESULTS

The amount of total protein (from PS and natural/intact protein) varied according to the European region. Higher median amounts of total protein were prescribed in infants and children in Northern Europe (n=24 centres) (infants <1 year, >2-3g/kg/day; 1-3 years of age, >2-3 g/kg/day; 4-10 years of age, >1.5-2.5 g/kg/day) and Southern Europe (n=10 centres) (infants <1 year, 2.5 g/kg/day, 1-3 years of age, 2 g/kg/day; 4-10 years of age, 1.5-2 g/kg/day), than by Eastern Europe (n=4 centres) (infants <1 year, 2.5 g/kg/day, 1-3 years of age, >2-2.5 g/kg/day; 4-10 years of age, >1.5-2 g/kg/day) and with Western Europe (n=25 centres) giving the least (infants <1 year, >2-2.5 g/kg/day, 1-3 years of age, 1.5-2 g/kg/day; 4-10 years of age, 1-1.5 g/kg/day). Total protein prescription was similar in patients aged >10 years (1-1.5 g/kg/day) and maternal patients (1-1.5 g/kg/day).

CONCLUSIONS

The amounts of total protein prescribed varied between European countries and appeared to be influenced by geographical region. In PKU, all gave higher than the recommended 2007 WHO/FAO/UNU safe levels of protein intake for the general population.

Effects of Fusarium mycotoxins in rations with different concentrate proportions on serum haptoglobin and hepatocellular integrity in lactating dairy cows

It was hypothesized that long-term intake of a diet contaminated with deoxynivalenol (DON) and differing in the proportion of concentrate might affect hepatocellular integrity and function as well as biomarkers of systemic inflammation in lactating dairy cows. In Period 1 (11 weeks), 26 lactating German Holstein cows (13 primiparous and 13 pluriparous, 31 days in milk, 522 kg body weight, on average) were divided into two groups and fed diets (50% concentrate) with (MYC, n = 12; on average 5.3 mg DON/kg DM) or without (CON, n = 14) DON contaminations. In Period 2 (16 weeks), each group was further divided into two groups to test whether elevated concentrate proportion as additional burden might enhance the toxicity of DON. The cows in MYC60 (n = 6; 4.6 mg DON/kg DM) and CON60 (n = 7) received the diet with 60% concentrate, while cows in MYC30 (n = 6; 4.4 mg DON/kg DM) and CON30 (n = 7) received the diet with 30% concentrate. Blood samples were taken in biweekly intervals for activities of aspartate amino transferase (AST), glutamate dehydrogenase (GLDH) and gamma-glutamyl transferase as well as for concentration of total bilirubin and haptoglobin. Biopsies from liver were collected in week 27 for morphological analyses. No DON effect was found for the variables assessed in blood. The diet with 60% concentrate led to higher activities of AST and GLDH in Period 2. No morphological change was found by both light and electron microscopic analyses of liver samples. Results indicated that long-term intake of DON-contaminated diet over 27 weeks led to neither relevant damages of hepatocytes nor systemic inflammatory responses in lactating dairy cows, even if the dietary concentrate proportion was increased to 60%.

Simultaneous determination of zearalenone, deoxynivalenol and their metabolites in bovine urine as biomarkers of exposure

A feeding trial with 30 dairy cows which were fed rations with three different concentrations of zearalenone (ZEA) and deoxynivalenol (DON) contaminated maize was carried out to examine the ZEA and DON concentration in urine. German Holstein cows (n=30) were divided into three groups (n=10 in each) which received diets with following toxin concentrations: CON (0.02 mg ZEA and 0.07 mg DON, per kg dry matter (DM)), FUS-50 (0.33 mg ZEA and 2.62 mg DON, per kg DM), FUS-100 (0.66 mg ZEA and 5.24 mg DON, per kg DM). For urine analysis, a reliable, cost-efficient and sensitive method for simultaneous determination of ZEA, DON and their metabolites was developed. The method comprises a solid phase extraction clean-up on Oasis HLB cartridges followed by LC-MS/MS measurement. ZEA, α-zearalenol, β-zearalenol, DON and de-epoxydeoxynivalenol (DOM) could be detected in the urine samples of the feeding trial. Thereby, DON was almost completely metabolised to DOM (83-98%) independent of the DON exposure. Moreover, conjugated toxins were the major urinary metabolites based on results of the analysis with β-glucuronidase treated and untreated samples. Furthermore, relationships between toxin intake and urinary toxin concentration could be established. In conclusion, increased urine toxin concentrations may hint on toxin exposure through the diets and thus the mycotoxins ZEA and DON and their detected metabolites could be used as biomarkers of exposure.

Using rumen probes to examine effects of conjugated linoleic acids and dietary concentrate proportion on rumen pH and rumen temperature of periparturient dairy cows

The study aimed to examine the influence of supplemented conjugated linoleic acids (CLA) to periparturient cows receiving different concentrate proportions antepartum on rumen pH (RpH) and rumen temperature (RT). Twenty pregnant German Holstein cows were equipped with rumen probes for continuous RpH and RT measurement in a frequency of 15 min to investigate effects of dietary concentrate and CLA around parturition and the impact of parturition itself on RpH and RT. Cows had ad libitum access to partial mixed rations, 3 weeks prior to calving until day 7 post-partum. Antepartum, cows received 100 g/day control fat (CON) or CLA supplement, either in low (20%; CON-20, CLA-20) or high concentrate diet (60%; CON-60, CLA-60). Post-partum, concentrate proportion was adjusted to 50% while fat supplementation continued. Compared with adapted feeding, high concentrate proportions antepartum tended to increase DMI and reduced RpH. Groups CON-60 and CLA-60 spent more than 4 h per day below RpH 5.6 during late pregnancy, indicating the presence of subacute rumen acidosis (SARA). The RT remained unaffected antepartum. Before calving, cows spent less time below RpH 5.6 and SARA could be detected in each group post-partum. Mean RpH increased slightly antepartum, whereas few hours before parturition a sharp decrease in RpH could be observed, accompanied with increased RT. Overall, it seems that CLA supplementation influences RpH and RT. Bearing in mind that rumen parameters fluctuate during day and herd level must be known, rumen probes for continuous RpH and RT measurement could be a useful management tool for animal health surveillance and may also help to predict parturition.

2 SPECIFIC FATTY ACID FOLLOW-UP REVEALS RUMEN-PROTECTED FAT SUPPLEMENTATION EFFECTS ON BOVINE OOCYTE QUALITY AND EMBRYO DEVELOPMENT

Information on how supplementation of high-yield dairy cows with rumen-protected fat affects fertility in cattle herds is scarce. Here, Holstein-Friesian heifers (n = 84) received a supplement consisting of either rumen-protected conjugated linoleic acid (CLA; cis-9,trans-11-CLA and trans-10,cis-12-CLA) or stearic acid 18 : 0 (SA) on top of an isocaloric grass silage diet. Two supplementation doses were used (100 and 200 g d–1). Blood and follicular fluid were collected at the start and end of the supplementation period for analysis of cholesterol, insulin-like growth factor (IGF), and nonesterified fatty acids (NEFA), and for fatty acid profiling. Although cholesterol, IGF, and NEFA levels did not differ among experimental groups, lipid profiles in blood and follicular fluid were affected in a dose-dependent manner by both supplements. After 45 days of supplementation, oocytes were collected by ovum pick-up (OPU). The mRNA relative abundance of target genes (IGF1r, GJA1, FASN, SREBP1, and SCAP) was analysed in single in vitro- (24 h IVM) and in vivo-matured (collected by OPU 20 h after GnRH injection) oocytes and in vitro-produced blastocysts (Day 8) by qPCR (n = 6/group). Lipid profiling of individual oocytes from the CLA-supplemented (n = 37) and the SA-supplemented (n = 50) was performed by desorption electrospray ionization mass spectrometry (DESI-MS). Oocytes from the CLA-supplemented (n = 413) and the SA-supplemented (n = 350) groups were used for assessing maturation and blastocysts development rates. In immature oocytes, CLA supplementation led to an increase of triacylglycerol 52 : 3 [TAG (52 : 3)] and TAG (52 : 2), squalene, palmitic acid 16 : 0, and oleic acid 18 : 1, and decreased abundance of TAG (56 : 3), TAG (50 : 2) and TAG (48 : 1). In vitro-matured oocytes showed different lipid profiles, with increased abundances of TAG (52 : 3), and TAG (52 : 2) as well as phosphatidylinositol 34 : 1 [Plo (34 : 1)], whereas phosphatidylglycerol (34 : 1) [PG (34 : 1)] and palmitic acid 16 : 0 were less abundant in in vitro-matured oocytes. SCAP was significantly down-regulated in in vitro-matured oocytes from supplemented heifers compared with their in vivo-matured counterparts. Maturation (CLA = 74% v. SA = 67%) and blastocyst rates (CLA = 22.4% v. SA = 12.7%) were different among experimental groups. One-way ANOVA and the Tukey-Kramer test were applied for a multiple comparison of means (P-value ≤ 0.05 was considered as statistically significant). In conclusion, we demonstrate here that fatty acid monitoring along different compartments (i.e. blood system, follicular fluid, and intra-oocyte) after rumen-protected fat supplementation of dairy heifer diet reveals nutritional footprints on oocyte quality and embryo development. These results demonstrate the close relationship between nutrition and cattle herd's fertility and, at the same time, support the role of the bovine model for understanding nutritional-dependent fertility impairments.