The best of both worlds: no apparent trade-off between immunity and reproduction in two group-living African mole-rat species.

Co-operatively breeding mammals often exhibit a female reproductive skew and suppression of the subordinate non-breeding group members. According to evolutionary theory and the immunity-fertility axis, an inverse relationship between reproductive investment and survival (through immunocompetence) is expected. As such, this study investigated if a trade-off between immunocompetence and reproduction arises in two co-operatively breeding African mole-rat species, namely the Damaraland mole-rat (Fukomys damarensis) and common mole-rat (Cryptomys hottentotus hottentotus), which possess female reproductive division of labour. This study also attempted to investigate the relationship between the immune and endocrine systems in Damaraland mole-rats. There was no trade-off between reproduction and immunocompetence in co-operatively breeding African mole-rat species, and in the case of the Damaraland mole-rats, breeding females (BFs) possessed increased immunocompetence compared with non-breeding females (NBFs). Furthermore, the increased levels of progesterone possessed by Damaraland mole-rat BFs compared with NBFs appear to be correlated to increased immunocompetence. In comparison, BF and NBF common mole-rats possess similar immunocompetence. The species-specific differences in the immunity-fertility axis may be due to variations in the strengths of reproductive suppression in each species. This article is part of the theme issue 'Evolutionary ecology of inequality'.

Active Control of Alfvén Eigenmodes by Externally Applied 3D Magnetic Perturbations.

The suppression and excitation of Alfvén eigenmodes have been experimentally obtained, for the first time, by means of externally applied 3D perturbative fields with different spatial spectra in a tokamak plasma. The applied perturbation causes an internal fast-ion redistribution that modifies the phase-space gradients responsible for driving the modes, determining, ultimately their existence. Hybrid kinetic-magnetohydrodynamic simulations reveal an edge resonant transport layer activated by the 3D perturbative field as the responsible mechanism for the fast-ion redistribution. The results presented here may help to control fast-ion driven Alfvénic instabilities in future burning plasmas with a significant fusion born alpha particle population.

The endocrine control of reproductive suppression in an aseasonally breeding social subterranean rodent, the Mahali mole-rat (Cryptomys hottentotus mahali).

Cooperative behaviour, sociality and reproductive suppression in African mole-rats have been extensively studied. Nevertheless, endocrine correlates of some species of social mole-rats have been neglected, and these species may hold the key to understanding the behavioural and physiological complexity that allows the maintenance of social groups in African mole-rats. In this study, we investigated endocrine correlates implicated in the suppression of reproduction and cooperative behaviours, namely glucocorticoids (a stress-related indicator) through faecal glucocorticoid metabolites (fGCMs), plasma testosterone (an indicator of aggression) and plasma prolactin in the Mahali mole-rat (Cryptomys hottentotus mahali) across reproductive classes (breeding females and males, non-breeding females and males) and season (wet and dry). Breeders possessed higher levels of testosterone than non-breeders. In reproductively suppressed non-breeding females, fGCMs were significantly higher than in breeders. Furthermore, an adrenocorticotropic hormone stimulation test (ACTH challenge test) on both male and female non-breeders revealed that female non-breeders show a more significant response to the ACTH challenge than males. At the same time, plasma prolactin levels were equally elevated to similar levels in breeding and non-breeding females. Chronically high levels of prolactin and fGCM are reported to cause reproductive suppression and promote cooperative behaviours in non-breeding animals. Furthermore, there was a negative relationship between plasma prolactin and progesterone in non-breeding females. However, during the wet season, a relaxation of suppression occurs through reduced prolactin which corresponds with elevated levels of plasma progesterone in non-breeding females. Therefore, prolactin is hypothesised to be the primary hormone controlling reproductive suppression and cooperative behaviours in non-breeding females. This study provides new endocrine findings for the maintenance of social suppression in the genus Cryptomys.

Accuracy of H. pylori fecal antigen test using fecal immunochemical test (FIT).

BACKGROUND: Gastric and colorectal cancer (CRC) are both one of the most common cancers worldwide. In many countries fecal immunochemical tests (FIT)-based CRC screening has been implemented. We investigated if FIT can also be applied for detection of H. pylori, the main risk factor for gastric cancer. METHODS: This prospective study included participants over 18 years of age referred for urea breath test (UBT). Patients were excluded if they had used antibiotics/bismuth in the past 4 weeks, or a proton pomp inhibitor (PPI) in the past 2 weeks. Participants underwent UBT, ELISA stool antigen test in standard feces tube (SAT), ELISA stool antigen test in FIT tube (Hp-FIT), and blood sampling, and completed a questionnaire on user friendliness. UBT results were used as reference. RESULTS: A total of 182 patients were included (37.4% male, median age 52.4 years (IQR 22.4)). Of these, 60 (33.0%) tested H. pylori positive. SAT and Hp-FIT showed comparable overall accuracy 71.1% (95%CI 63.2-78.3) vs. 77.6% (95%CI 70.4-83.8), respectively (p = 0.97). Sensitivity of SAT was 91.8% (95%CI 80.4-97.7) versus 94.2% (95%CI 84.1-98.9) of Hp-FIT (p = 0.98). Serology scored low with an overall accuracy of 49.7% (95%CI 41.7-57.7). Hp-FIT showed the highest overall user convenience. CONCLUSIONS: FIT can be used with high accuracy and sensitivity for diagnosis of H. pylori and is rated as the most convenient test. Non-invasive Hp-FIT test is highly promising for combined upper and lower gastrointestinal (pre-) cancerous screening. Further research should investigate the clinical implications, benefits and cost-effectiveness of such an approach.

Elucidating key plant growth-promoting (PGPR) traits in Burkholderia sp. Nafp2/4-1b (=SARCC-3049) using gnotobiotic assays and whole-genome-sequence analysis.

Burkholderia sp. Nafp2/4-1b (=SARCC-3049) is a plant growth-promoting rhizobacteria (PGPR) initially isolated from the rhizosphere of pristine grassland in South Africa, and its ability to enhance growth was previously evaluated on maize (Zea mays L.). Here, the bacterium was tested with the aim of investigating its role in improving the nodulation and growth of the forage legume lucerne (Medicago sativa L.) when it is co-inoculated with the rhizobial symbionts of this legume in the glasshouse. When the co-inoculation resulted in a statistically significant (P = 0·05) increase in the number of nodules and improved plant biomass compared with single inoculation, we sequenced and analysed its genome to gain a better understanding of the genetic determinants responsible for the observed PGPR traits. The Illumina HiSeq 2500-sequenced genome resulted in 92 scaffolds, with an N50 of 322 407 bp, a total draft genome size of 7 788 045 bp and GC content of 66·2%. Analysis of the genome sequence confirmed the presence of a number of essential genes that code for various PGPR traits. The main plant beneficial genes associated with PGPR traits in Burkholderia sp. Nafp2/4-1b include pyoverdine siderophores biosynthesis gene (PvdF); acdS that codes for 1-aminocyclopropane-1-carboxylate (ACC) deaminase; the tryptophan synthase genes involved in auxin biosynthesis (TSA1, TSB1) and the pqqABCDE operon related to phosphate solubilization. This study generated valuable information on the potential of the PGPR Burkholderia sp. strain Nafp2/4-1b as an effective commercial inoculant, which warrants further formulation and field application studies before developing it into a low cost, environmentally safe and effective biofertilizer.

Preparation, analysis, and application of coated glass targets for the Wendelstein 7-X laser blow-off system.

Coated glass targets are a key component of the Wendelstein 7-X laser blow-off system that is used for impurity transport studies. The preparation and analysis of these glass targets as well as their performance is examined in this paper. The glass targets have a high laser damage threshold and are coated via physical vapor deposition with µm thick films. In addition, nm-thin layers of Ti are used as an interface layer for improved ablation efficiency and reduced coating stress. Hence, the metallic or ceramic coating has a lateral homogeneity within 2% and contaminants less than 5%, being optimal for laser ablation processing. With this method, a short (few ms) and well defined pulse of impurities with about 1017 particles can be injected close to the last closed flux surface of Wendelstein 7-X. In particular, a significant amount of atoms with a velocity of about 1 km/s enters the plasma within 1 ms. The atoms are followed by a negligible concentration of slower clusters and macro-particles. This qualifies the use of the targets and applied laser settings for impurity transport studies with the laser blow-off system in Wendelstein 7-X.

Recrystallization as the governing mechanism of ion track formation.

Response of dielectric crystals: MgO, Al2O3 and Y3Al5O12 (YAG) to irradiation with 167 MeV Xe ions decelerating in the electronic stopping regime is studied. Comprehensive simulations demonstrated that despite similar ion energy losses and the initial excitation kinetics of the electronic systems and lattices, significant differences occur among final structures of ion tracks in these materials, supported by experiments. No ion tracks appeared in MgO, whereas discontinuous distorted crystalline tracks of ~2 nm in diameter were observed in Al2O3 and continuous amorphous tracks were detected in YAG. These track structures in Al2O3 and YAG were confirmed by high resolution TEM data. The simulations enabled us to identify recrystallization as the dominant mechanism governing formation of detected tracks in these oxides. We analyzed effects of the viscosity in molten state, lattice structure and difference in the kinetics of metallic and oxygen sublattices at the crystallization surface on damage recovery in tracks.

Guideline versus non-guideline based management of rectal cancer in octogenarians.

PURPOSE: The number of octogenarians with rectal adenocarcinoma is growing. Current guidelines seem difficult to apply on octogenarians which may result in non-adherence. The aim of this retrospective cohort study is to give insight in occurrence of treatment-related complications, hospitalisations and survival among octogenarians treated according to guidelines versus octogenarians treated otherwise. METHODS: 108 octogenarians with rectal adenocarcinoma were identified by screening of medical records. 22 patients were excluded for treatment process analysis because of stage IV disease or unknown stage. Baseline characteristics, diagnostic process, received treatment, motivation for deviation from guidelines, complications, hospitalisations and date of death were documented. Patients were divided in two groups depending on adherence to treatment guidelines. Differences in baseline characteristics, treatment-related complications and survival between both groups were evaluated. RESULTS: Diagnosis and treatment according to guidelines occurred in 95 and 54% of the patients, respectively. When documented, patient's preference and comorbidities were major reasons to deviate from guidelines. 66% of patients who were treated according to guidelines experienced complications versus 34% of those treated otherwise (p = 0.02). After adjustment for differences in age and polypharmacy, this association was not significant. Patients treated according to the guideline had better survival 18 months after diagnosis (80 versus 56%, p = 0.02). CONCLUSIONS: Treating octogenarians with rectal cancer according to guidelines seem to lead to better overall survival, but may lead to a high risk of complications. This may jeopardise quality of life. More and prospective studies in octogenarians with rectal cancer are needed to customize guidelines for these patients.

A randomised comparison of two faecal immunochemical tests in population-based colorectal cancer screening.

OBJECTIVE: Colorectal cancer screening programmes are implemented worldwide; many are based on faecal immunochemical testing (FIT). The aim of this study was to evaluate two frequently used FITs on participation, usability, positivity rate and diagnostic yield in population-based FIT screening. DESIGN: Comparison of two FITs was performed in a fourth round population-based FIT-screening cohort. Randomly selected individuals aged 50-74 were invited for FIT screening and were randomly allocated to receive an OC -Sensor (Eiken, Japan) or faecal occult blood (FOB)-Gold (Sentinel, Italy) test (March-December 2014). A cut-off of 10 µg haemoglobin (Hb)/g faeces (ie, 50 ng Hb/mL buffer for OC-Sensor and 59 ng Hb for FOB-Gold) was used for both FITs. RESULTS: In total, 19 291 eligible invitees were included (median age 61, IQR 57-67; 48% males): 9669 invitees received OC-Sensor and 9622 FOB-Gold; both tests were returned by 63% of invitees (p=0.96). Tests were non-analysable in 0.7% of participants using OC-Sensor vs 2.0% using FOB-Gold (p<0.001). Positivity rate was 7.9% for OC-Sensor, and 6.5% for FOB-Gold (p=0.002). There was no significant difference in diagnostic yield of advanced neoplasia (1.4% for OC-Sensor vs 1.2% for FOB-Gold; p=0.15) or positive predictive value (PPV; 31% vs 32%; p=0.80). When comparing both tests at the same positivity rate instead of cut-off, they yielded similar PPV and detection rates. CONCLUSIONS: The OC-Sensor and FOB-Gold were equally acceptable to a screening population. However, FOB-Gold was prone to more non-analysable tests. Comparison between FIT brands is usually done at the same Hb stool concentration. Our findings imply that for a fair comparison on diagnostic yield between FIT's positivity rate rather than Hb concentration should be used. TRIAL REGISTRATION NUMBER: NTR5385; Results.

Synthesis, characterization and multifunctional properties of plasmonic Ag-TiO2 nanocomposites.

We report on the synthesis of multifunctional Ag-TiO2 nanocomposites and their optical, physio-chemical, surface enhanced Raman scattering (SERS) and antibacterial properties. A series of Ag-TiO2 nanocomposites were synthesized by sol-gel technique and characterized by x-ray diffraction, scanning and transmission electron microscopy, energy-dispersed x-ray analysis, photoluminescence, UV-vis, x-ray photoelectron and Raman spectroscopy and Brunauer-Emmett-Teller method. The Ag nanoparticles (NPs) (7-20 nm) were found to be uniformly distributed around and strongly attached to TiO2 NPs. The novel optical responses of the nanocomposites are due to the strong electric field from the localized surface plasmon (LSP) excitation of the Ag NPs and decreased recombination of photo-induced electrons and holes at Ag-TiO2 interface providing potential materials for photocatalysis. The nanocomposites show enhancement in the SERS signals of methyl orange (MO) molecules with increasing Ag content attributed to the long-range electromagnetic enhancement from the excited LSP of the Ag NPs. To further understand the SERS activity, molecular mechanics and molecular dynamics simulations were used to study the geometries and SERS enhancement of MO adsorbed onto Ag-TiO2 respectively. Simulation results indicate that number of ligands (MO) that adsorb onto the Ag NPs as well as binding energy per ligand increases with increasing NP density and molecule-to-surface orientation is mainly flat resulting in strong bond strength between MO and Ag NP surface and enhanced SERS signals. The antimicrobial activity of the Ag-TiO2 nanocomposites was tested against the bacterium Staphylococcus aureus and enhanced antibacterial effect was observed with increasing Ag content explained by contact killing action mechanism. These results foresee promising applications of the plasmonic metal-semiconductor based nano-biocomposites for both chemical and biological samples.

The role of neutral and ionized oxygen defects in the emission of tin oxide nanocrystals for near white light application.

Tin oxide (SnO2) nanocrystals (NCs) based phosphor was synthesized by a green chemistry microwave-assisted hydrothermal method at different reactor pressures. The x-ray diffraction analysis showed that a single rutile SnO2 phase with a tetragonal lattice structure was formed. The photoluminescence emission was measured for He-Cd laser excitation at 325 nm and it showed a broad band emission from 400 to 800 nm for all the synthesized reactor pressures. The broad emission spectra were due to the creation of various oxygen and tin defects as confirmed by x-ray photoelectron spectroscopy data. The origin of the emission in the SnO2 NCs is discussed with the help of an energy band diagram. Analysis suggests that the visible emission of SnO2 NCs is due to a transition of an electron from a level close to the conduction band edge to a deeply trapped hole in the SnO2 NCs. The NCs were found to be suitable for warm near white light emission device applications.

Diet effects on urine composition of cattle and N2O emissions.

Ruminant production contributes to emissions of nitrogen (N) to the environment, principally ammonia (NH3), nitrous oxide (N2O) and di-nitrogen (N2) to air, nitrate (NO3 -) to groundwater and particulate N to surface waters. Variation in dietary N intake will particularly affect excretion of urinary N, which is much more vulnerable to losses than is faecal N. Our objective is to review dietary effects on the level and form of N excreted in cattle urine, as well as its consequences for emissions of N2O. The quantity of N excreted in urine varies widely. Urinary N excretion, in particular that of urea N, is decreased upon reduction of dietary N intake or an increase in the supply of energy to the rumen microorganisms and to the host animal itself. Most of the N in urine (from 50% to well over 90%) is present in the form of urea. Other nitrogenous components include purine derivatives (PD), hippuric acid, creatine and creatinine. Excretion of PD is related to rumen microbial protein synthesis, and that of hippuric acid to dietary concentration of degradable phenolic acids. The N concentration of cattle urine ranges from 3 to 20 g/l. High-dietary mineral levels increase urine volume and lead to reduced urinary N concentration as well as reduced urea concentration in plasma and milk. In lactating dairy cattle, variation in urine volume affects the relationship between milk urea and urinary N excretion, which hampers the use of milk urea as an accurate indicator of urinary N excretion. Following its deposition in pastures or in animal houses, ubiquitous microorganisms in soil and waters transform urinary N components into ammonium (NH4 +), and thereafter into NO3 - and ultimately in N2 accompanied with the release of N2O. Urinary hippuric acid, creatine and creatinine decompose more slowly than urea. Hippuric acid may act as a natural inhibitor of N2O emissions, but inhibition conditions have not been defined properly yet. Environmental and soil conditions at the site of urine deposition or manure application strongly influence N2O release. Major dietary strategies to mitigating N2O emission from cattle operations include reducing dietary N content or increasing energy content, and increasing dietary mineral content to increase urine volume. For further reduction of N2O emission, an integrated animal nutrition and excreta management approach is required.

Dietary effects of linseed on fatty acid composition of milk and on liver, adipose and mammary gland metabolism of periparturient dairy cows.

During the transition period in dairy cows, drastic adaptations within and between key tissues and cell types occur in a coordinated manner to support late gestation, the synthesis of large quantities of milk and metabolic homoeostasis. The start of lactation coincides with an increase of triacylglycerols in the liver, which has been associated with several economically important diseases in dairy cows (i.e. hepatic lipidiosis, mastitis). The polyunsaturated fatty acids have been used to improve liver metabolism and immune function in the mammary gland. Therefore, the effects of dietary linseed supplementation on milk quality and liver, adipose and mammary gland metabolism of periparturient dairy cows were studied in 14 cows that were randomly assigned to control or linseed supplementation. Animals were treated from 3 weeks antepartum until 6 weeks post-partum. Linseed did not modify dry matter intake, but increased milk yield and lactose yield, and decreased milk fat concentration, which coincided with lower proportion of C16 and higher proportions of stearic acid, conjugated linoleic acid and α-linolenic acid in milk fat. Linseed supplementation did not significantly change the expression of key lipid metabolism genes in liver and adipose tissues, except of glucose transporter 2 (GLUT2) in liver, which was increased in cows supplemented with linseed, suggesting that more glucose was secreted and probably available for lactose synthesis compared with cows fed control diet. Large adaptations of transcription occurred in the mammary gland when dairy cows were supplemented with linseed. The main affected functional modules were related to energy metabolism, cell proliferation and remodelling, as well as the immune system response.

Precore and core promoter mutants are associated with higher HBeAg seroconversion but low disease remission rates in HBV patients treated with nucleos(t)ide analogues.

HBeAg seroconversion in HBV patients is considered an important event. We determined precore (PC) and base core promoter (BCP) mutations in 137 HBeAg-positive nucleos(t)ide analogues (NA) treated patients by INNO-LiPA HBV PreCore assay (Innogenetics). The majority of patients with nongenotype A had PC/BCP mutants present at baseline (P = 0.02). During 29 months of therapy, 45 patients achieved HBeAg seroconversion. Probability of HBeAg seroconversion was higher in patients with PC and/or BCP mutants (P = 0.01). After HBeAg seroconversion, patients with BCP mutants had more HBeAg relapse (P = 0.07), and PC mutants less often achieved HBV DNA < 2000 IU/mL (P = 0.07).

Effects of short- and long-chain fatty acids on the expression of stearoyl-CoA desaturase and other lipogenic genes in bovine mammary epithelial cells.

Stearoyl-CoA desaturase (SCD) in the bovine mammary gland introduces a cis-double bond at the Δ9 position in a wide range of fatty acids (FA). Several long-chain polyunsaturated fatty acids (PUFA) inhibit expression of SCD, but information on the effect of short-chain fatty acids on mammary SCD expression is scarce. We used a bovine mammary cell line (MAC-T) to assess the effect of acetic acid (Ac) and ß-hydroxybutyric acid (BHBA) in comparison with the effect of various long-chain fatty acids on the mRNA expression of the lipogenic enzymes SCD, acetyl-CoA carboxylase (ACACA), fatty acid synthase (FASN) and their associated gene regulatory proteins sterol regulatory element binding transcription factor 1 (SREBF1), insulin-induced gene 1 protein (INSIG1) and peroxisome proliferator-activated receptor alpha (PPARA)and peroxisome proliferator-activated receptor delta (PPARD) by quantitative real-time PCR. MAC-T cells were treated for 12 h without FA additions (CON) or with either 5 mM Ac, 5 mM BHBA, a combination of 5 mM Ac + 5 mM BHBA, 100 µM C16:0, 100 µM C18:0, 100 µM C18:1 cis-9, 100 µM C18:1 trans-11, 100 µM C18:2 cis-9,12 or 100 µM C18:3 cis-9,12,15. Compared with control, mRNA expression of SCD1 was increased by Ac (+61%) and reduced by C18:1 cis-9 (-61%), C18:2 cis-9,12 (-84%) and C18:3 cis-9,12,15 (-88%). In contrast to native bovine mammary gland tissue, MAC-T cells did not express SCD5. Expression of ACACA was increased by Ac (+44%) and reduced by C18:2 cis-9,12 (-48%) and C18:3 cis-9,12,15 (-49%). Compared with control, FASN expression was not significantly affected by the treatments. The mRNA level of SREBF1 was not affected by Ac or BHBA, but was reduced by C18:1 cis-9 (-44%), C18:1 trans-11 (-42%), C18:2 cis-9,12 (-62%) and C18:3 cis-9,12,15 (-68%) compared with control. Expression of INSIG1 was downregulated by C18:0 (-37%), C18:1 cis-9 (-63%), C18:1 trans-11 (-53%), C18:2 cis-9,12 (-81%) and C18:3 cis-9,12,15 (-91%). Both PPARA and PPARD expression were not significantly affected by the treatments. Our results show that Ac upregulated mRNA expression of SCD1 and ACACA in MAC-T cells. The opposite effect of the PUFA C18:2 cis-9,12 and C18:3 cis-9,12,15 on the these genes and the failure of Ac to mimic the PUFA-inhibited SREBF1 and INSIG1 mRNA expression, suggest that Ac can stimulate mammary lipogenesis via a transcriptional regulatory mechanism different from PUFA.

Sensitive detection of hepatocellular injury in chronic hepatitis C patients with circulating hepatocyte-derived microRNA-122.

As chronic hepatitis C patients with progressive disease can present themselves with normal ALT levels, more sensitive biomarkers are needed. MicroRNAs are newly discovered small noncoding RNAs that are stable and detectable in the circulation. We aimed to investigate the association between hepatocyte-derived microRNAs in serum and liver injury in patients with chronic hepatitis C. The hepatocyte-derived miR-122 and miR-192 were analysed in sera of 102 chronic HCV-infected patients and 24 healthy controls. Serum levels of miR-122 and miR-192 correlated strongly with ALT (R = 0.67 and R = 0.65, respectively, P < 0.001 for both). Median levels of miR-122 and miR-192 in HCV-infected patients were 23 times and 8 times higher as in healthy controls (P < 0.001 for both). Even within the HCV-infected patients with a normal ALT (n = 38), the levels of miR-122 and miR-192 were 12 times and 4 times higher compared with healthy controls (P < 0.001 for both). Multivariate logistic regression analyses showed that only miR-122 was a significant predictor of the presence of chronic HCV infection (P = 0.026). Importantly, miR-122 was also superior in discriminating chronic HCV-infected patients with a normal ALT from healthy controls compared with the ALT level (AUC = 0.97 vs AUC = 0.78, P = 0.007). In conclusion, our study confirmed that liver injury is associated with high levels of hepatocyte-derived microRNAs in circulation and demonstrated that in particular miR-122 is a sensitive marker to distinguish chronic hepatitis C patients from healthy controls. More sensitive blood markers would benefit especially those patients with minor levels of hepatocellular injury, who are not identified by current screening with ALT testing.

Comparison between stearoyl-CoA desaturase expression in milk somatic cells and in mammary tissue of lactating dairy cows.

Stearoyl-CoA desaturase (SCD) is an important enzyme in the bovine mammary gland, where it inserts a cis-double bond at the Δ9 position in a wide range of fatty acids. Investigating SCD expression in the bovine mammary gland generally requires invasive biopsy to obtain mammary tissue. The aim of this study was to evaluate the use of milk somatic cells as a non-invasive alternative to biopsy for measuring mammary SCD expression in dairy cows. Both milk somatic cells and mammary tissue were collected from 14 Holstein-Friesian cows and used for analysis of SCD expression by real-time PCR. The SCD5 mRNA levels in mammary tissue compared with SCD1 were low, and for several milk somatic cell samples, SCD5 expression was even below the limit of detection. A significant relationship was found between SCD1 expression in milk somatic cells and in mammary tissue. In addition, SCD1 expression in milk somatic cells was significantly related to Δ9-desaturase indices in milk, which are commonly used as an indicator of SCD1 activity within the mammary gland. Our study showed that milk somatic cells can be used as a source of mRNA to study SCD1 expression in dairy cows, offering a non-invasive alternative to mammary tissue samples obtained by biopsy.

Challenges in the nutrition and management of herbivores in the temperate zone.

The expected higher global demand for animal proteins and the competition for starch and sugars between food, fuel and feed seem to favour herbivores that convert solar energy captured in fibrous plants into animal products. However, the required higher production level of herbivores questions the sustainability of this conversion. An increase in herbivore production can be achieved by increasing the number of animals associated with the increasing demand of plant biomass or by improving the efficiency with which plant biomass is converted into meat and milk. The potential to increase food production by cattle, the main food-producing herbivore in the temperate zones outside China, was considered in three production systems: grassland-based, mixed rain-fed and mixed irrigated systems. The potential to increase plant biomass production in grassland-based systems seems limited, unless fertiliser is imported in large quantities and crop production is increased, sacrificing valuable, high-quality grasslands, which often conflicts with sustainable production methods. Also, in mixed systems with high inputs of fertiliser or water, improvements in plant biomass production seem marginal and the main challenges for these systems are in breeding high-quality plant biomass at lower levels of fertiliser and the use of new co-products from food processing and bio-based economies. Consequently, the main challenge in herbivore nutrition management is to improve the efficiency of plant biomass utilisation. Stocking rate management along with seasonal variation in the grazing capacity of grasslands and moderate use of fertiliser may increase meat production in grassland-based systems by 400%. Improving plant biomass utilisation in the more industrialised mixed rain-fed systems seems possible by better feed storage technologies and for dairy cattle by improving animal health and lifetime production level. Managing the transition period seems crucial to achieve more sustainable mixed rain-fed and mixed irrigated dairy production systems. Whether sustainable production methods will be implemented also depends on macro-economic conditions and awareness of regional and global environmental concerns.

Effect of rumen-protected choline supplementation on liver and adipose gene expression during the transition period in dairy cattle.

We previously reported that supplementation of rumen-protected choline (RPC) reduces the hepatic triacylglycerol concentration in periparturient dairy cows during early lactation. Here, we investigated the effect of RPC on the transcript levels of lipid metabolism-related genes in liver and adipose tissue biopsies, taken at wk -3, 1, 3, and 6 after calving, to elucidate the mechanisms underlying this RPC-induced reduction of hepatic lipidosis. Sixteen multiparous cows were blocked into 8 pairs and randomly allocated to either 1 of 2 treatments, with or without RPC. Treatments were applied from 3 wk before to 6 wk after calving. Both groups received a basal diet and concentrate mixture. One group received RPC supplementation, resulting in an intake of 14.4 g of choline per day, whereas controls received an isoenergetic mixture of palm oil and additional soybean meal. Liver and adipose tissue biopsies were taken at wk -3, 1, 3, and 6 to determine the mRNA abundance of 18 key genes involved in liver and adipose tissue lipid and energy metabolism. Milk samples were collected in wk 1, 2, 3, and 6 postpartum for analysis of milk fatty acid (FA) composition. The RPC-induced reduction in hepatic lipidosis could not be attributed to altered lipolysis in adipose tissue, as no treatment effect was observed on the expression of peroxisome proliferator-activated receptor γ, lipoprotein lipase, or FA synthase in adipose tissue, or on the milk FA composition. Rumen-protected choline supplementation increased the expression of FA transport protein 5 and carnitine transporter SLC22A5 in the liver, suggesting an increase in the capacity of FA uptake and intracellular transport, but no treatment effect was observed on carnitine palmitoyl transferase 1A, transporting long-chain FA into mitochondria. In the same organ, RPC appeared to promote apolipoprotein B-containing lipoprotein assembly, as shown by elevated microsomal triglyceride transfer protein expression and apolipoprotein B100 expression. Cows supplemented with RPC displayed elevated levels of glucose transporter 2 mRNA and a reduced peak in pyruvate carboxylase mRNA immediately after calving, showing that supplementation also resulted in improved carbohydrate metabolism. The results from this study suggest that RPC supplementation reduces liver triacylglycerol by improved FA processing and very-low-density lipoprotein synthesis, and RPC also benefits hepatic carbohydrate metabolism.