Fatty acid digestion, synthesis and metabolism in broiler chickens and pigs

The impact of variation in the composition of dietary fat on digestion, metabolism and synthesis of fatty acids was studied in broiler chickens and in pigs. In young broiler chickens, digestion of unsaturated fatty acids was substantially higher compared with that of saturated fatty acids. Positional distribution appeared important. Particularly digestion of saturated fatty acids, e.g. palmitic acid (C16:0), esterified at the sn-1 and -3 position of the glycerol backbone was lower (51%) compared with that observed at the sn-2 position (90%). Based on these observations, an equation was developed predicting the digestion of dietary fat sources in broiler chickens and pigs, taking fatty acid composition, the positioning, and the proportion of free fatty acids into account. The deposition of fat, especially of monounsaturated fatty acids in body tissues, increased in broilers by feeding saturated fats in comparison with unsaturated fats caused by both a reduced ß-oxidation and an increased rate of de novo synthesis of fatty acids. In a feeding trial with pigs, starch, saturated and unsaturated fatty acid sources were compared at similar intakes of net energy. Growth performance and backfat thickness were unaffected by dietary energy source. Intramuscular fat content, however, tended to be increased in starch fed pigs when compared with pigs fed the saturated fatty acid source. To study the interactions between dietary linoleic acid (LA; C18:2 n-6) and -linolenic acid (ALA; C18:3 n-3) and their impact on the synthesis of long-chain polyunsaturated fatty acids (LC-PUFA) in both the n-3 and n-6 chains, a trial was designed in which identical increments in the intake of ALA and LA were fed to growing pigs. Generally, dietary LA inhibited the synthesis of n-3 LC-PUFA in the liver. Dietary ALA increased the content of eicosapentaenoic acid (EPA; C20:5 n-3) but decreased that of docosahexaenoic acid (DHA; C22:6 n-3) in the liver. DHA levels in brain were hardly affected by both dietary LA and ALA. It was concluded that in addition to Δ6 desaturase, elongase 2 might be a rate-limiting enzyme in the formation of DHA. The impact of these findings on the potential of contribution of feeding LA and ALA to pigs to meet human dietary requirements for LC-PUFA by meat products was investigated by analysing the fatty acid composition of muscle and fat tissues. It appeared impossible to attain substantial improvements in tissue DHA contents by feeding different combinations of LA and ALA. However, EPA of intramuscular fat can be increased by feeding ALA, particularly when restricting LA intake. In addition, docosapentaenoic acid (DPA; C22:5 n-3) was increased in both muscle and backfat by dietary ALA. DPA might have comparable biological effects as EPA. The potential of meat products to supply DPA in food is considerable and therefore of interest. </p

Gate-tunable band structure of the LaAlO3_3-SrTiO3_3 interface

The 2-dimensional electron system at the interface between LaAlO$_{3}$ and SrTiO$_{3}$ has several unique properties that can be tuned by an externally applied gate voltage. In this work, we show that this gate-tunability extends to the effective band structure of the system. We combine a magnetotransport study on top-gated Hall bars with self-consistent Schr\"odinger-Poisson calculations and observe a Lifshitz transition at a density of $2.9\times10^{13}$ cm$^{-2}$. Above the transition, the carrier density of one of the conducting bands decreases with increasing gate voltage. This surprising decrease is accurately reproduced in the calculations if electronic correlations are included. These results provide a clear, intuitive picture of the physics governing the electronic structure at complex oxide interfaces.Comment: 14 pages, 4 figure

Near-field intensity pattern at the output of silica-based graded-index multimode fibers under selective excitation with a single-mode fiber

Abstract: Selective excitation of graded-index multimode fibers (GIMMFs) with a single-mode fiber (SMF) has gained increased interest for telecommunication applications. It has been proposed as a way to enhance the transmission bandwidth of GI-MMF links and/or create parallel communication channels over the same GI-MMF. Although the effect of SMF excitation on the transmission bandwidth has been investigated, its impact on the near-field intensity pattern at the output face of the GI-MMF has not been systematically addressed. We have carried out an analysis of the near-field intensity pattern at the output face of silica-based GI-MMFs excited by a radially offset SMF. Simulation results exhibit all of the features displayed by experimental ones. It turns out that differential mode attenuation and delay, full intra-group mode mixing, and small deviations in the refractive index profile of the GI-MMF do not affect the overall shape of the near-field intensity, which is determined by the radial offset of the input SMF. This can be exploited in mode group diversity multiplexing links. The effect of defects in the refractive index profile, such as a central dip or peak, is also examined

Correlation between Superconductivity, Band Filling and Electron Confinement at the LaAlO3_{3}-SrTiO3_{3} Interface

By combined top- and backgating, we explore the correlation of superconductivity with band filling and electron confinement at the LaAlO$_3$-SrTiO$_3$ interface. We find that the top- and backgate voltages have distinctly different effects on the superconducting critical temperature, implying that the confining potential well has a profound effect on superconductivity. We investigate the origin of this behavior by comparing the gate-dependence of $T_c$ to the corresponding evolution of the band filling with gate voltage. For several backgate voltages, we observe maximum $T_c$ to consistently coincide with a kink in tuning the band filling for high topgate voltage. Self-consistent Schr\"odinger-Poisson calculations relate this kink to a Lifshitz transition of the second $d_{xy}$ subband. These results establish a major role for confinement-induced subbands in the phase diagram of SrTiO$_3$ surface states, and establish gating as a means to control the relative energy of these states.Comment: 17 pages, 5 figure

Methaanreductie melkvee : een onderzoeksproject naar de inschatting van de methaanproductie vanuit de voeding en naar de reductiemogelijkheden via de voeding van melkkoeien

De doelen van het project zijn om inzicht te verschaffen in de mogelijkheid van de methaanproductie in te schatten vanuit de voeding en aan te sluiten met de voeroptimalisering in de praktijk, en inzicht te verschaffen welke voermaatregelen een bijdrage kunnen leveren aan de reductie van de methaanvorming door melkkoeien. Een mechanistisch rekenmodel werd ontwikkeld om de productie van methaan in de pens te berekenen vanuit de vluchtige vetzuren. Met dit model werd de methaanvorming uit individuele ruwvoeders en krachtvoergrondstoffen berekend

Linoleic and a-linolenic acid as precursor and inhibitor for the synthesis of long-chain polyunsaturated fatty acids in liver and brain of growing pigs.

Studies suggested that in human adults, linoleic acid (LA) inhibits the biosynthesis of n-3 long-chain polyunsaturated fatty acids (LC-PUFA), but their effects in growing subjects are largely unknown. We used growing pigs as a model to investigate whether high LA intake affects the conversion of n-3 LC-PUFA by determining fatty acid composition and mRNA levels of ¿5- and ¿6 desaturase and elongase 2 and -5 in liver and brain. In a 2 × 2 factorial arrangement, 32 gilts from eight litters were assigned to one of the four dietary treatments, varying in LA and a-linolenic acid (ALA) intakes. Low ALA and LA intakes were 0.15 and 1.31, and high ALA and LA intakes were 1.48 and 2.65 g/kg BW0.75 per day, respectively. LA intake increased arachidonic acid (ARA) in liver. ALA intake increased eicosapentaenoic acid (EPA) concentrations, but decreased docosahexaenoic acid (DHA) (all P 40%) at high ALA intakes. Concentration of EPA (>35%) and DHA (>20%) was decreased by high LA intake (all P <0.001). Liver mRNA levels of ¿5- and ¿6 desaturase were increased by LA, and that of elongase 2 by both ALA and LA intakes. In contrast, brain DHA was virtually unaffected by dietary LA and ALA. Generally, dietary LA inhibited the biosynthesis of n-3 LC-PUFA in liver. ALA strongly affects the conversion of both hepatic n-3 and n-6 LC-PUFA. DHA levels in brain were irresponsive to these diets. Apart from ¿6 desaturase, elongase 2 may be a rate-limiting enzyme in the formation of DH

Immune stimulation in fish and chicken through weak low frequency electromagnetic fields

A hypothesis is proposed how Low Frequency Electromagnetic Field (LF EMF) exposure can stimulate an immune response, based on recent insights in immunology. We hypothesize that the Immunent EMF treatment induces mild stress to cells, which then produce cytokines that function as alarms or so called danger signals for the immune system. In this way EMF treatment takes the place of multiplying pathogens, and the damage these cause, in the triggering of an immune response. In a first series of experiments in¿vitro common carp head kidney-derived phagocytes were used to determine ROS production as a measure for immune activation. Exposure to LF EMF signals (200¿5,000 Hz) at 5 ¿T or 1.5 mT led to 42 or 33% increase in immune activity, respectively, compared to negative control values. EMF could also additionally stimulate chemically pre-stimulated samples up to 18% (5 ¿T) or 22% (1.5 mT). Significance of increase in ROS production in the total series was: p <0.0001. In a second series of experiments in¿vitro commercial goldfish were used. Groups of fish were housed under equal conditions in at least four control tanks and 8¿16 EMF-exposed tanks. Exposure was done with a predominantly vertical field at field strengths (rms) between 0.15 and 50 ¿T. Without treatment mortality was about 50% after 18 days, while the treatment at 5 ¿T reduced it to 20% on average. At field strengths 0.15, 0.5, 1.5, 5, 15 and 50 ¿T an equally strong effect was found. Reducing the field strength to 0.05, 0.06, 0.01 and 0.003 ¿T showed a gradually decreasing effect, which only at 0.003 ¿T is no longer statistically significant. Finally, in¿vitro experiments were done with 560 commercial broiler chickens exposed to infection pressure from coccidiosis. EMF exposure at 6.5 ¿T reduced intestinal lesions by 40% and improved feed conversion by 8%

Comparing nuclear power trajectories in Germany and the UK: from ‘regimes' to ‘democracies’ in sociotechnical transitions and Discontinuities

This paper focuses on arguably the single most striking contrast in contemporary major energy politics in Europe (and even the developed world as a whole): the starkly differing civil nuclear policies of Germany and the UK. Germany is seeking entirely to phase out nuclear power by 2022. Yet the UK advocates a ‘nuclear renaissance’, promoting the most ambitious new nuclear construction programme in Western Europe.Here,this paper poses a simple yet quite fundamental question: what are the particular divergent conditions most strongly implicated in the contrasting developments in these two countries. With nuclear playing such an iconic role in historical discussions over technological continuity and transformation, answering this may assist in wider understandings of sociotechnical incumbency and discontinuity in the burgeoning field of‘sustainability transitions’. To this end, an ‘abductive’ approach is taken: deploying nine potentially relevant criteria for understanding the different directions pursued in Germany and the UK. Together constituted by 30 parameters spanning literatures related to socio-technical regimes in general as well as nuclear technology in particular, the criteria are divided into those that are ‘internal’ and ‘external’ to the ‘focal regime configuration’ of nuclear power and associated ‘challenger technologies’ like renewables. It is ‘internal’ criteria that are emphasised in conventional sociotechnical regime theory, with ‘external’ criteria relatively less well explored. Asking under each criterion whether attempted discontinuation of nuclear power would be more likely in Germany or the UK, a clear picture emerges. ‘Internal’ criteria suggest attempted nuclear discontinuation should be more likely in the UK than in Germany– the reverse of what is occurring. ‘External’ criteria are more aligned with observed dynamics –especially those relating to military nuclear commitments and broader ‘qualities of democracy’. Despite many differences of framing concerning exactly what constitutes ‘democracy’, a rich political science literature on this point is unanimous in characterising Germany more positively than the UK. Although based only on a single case,a potentially important question is nonetheless raised as to whether sociotechnical regime theory might usefully give greater attention to the general importance of various aspects of democracy in constituting conditions for significant technological discontinuities and transformations. If so, the policy implications are significant. A number of important areas are identified for future research, including the roles of diverse understandings and specific aspects of democracy and the particular relevance of military nuclear commitments– whose under-discussion in civil nuclear policy literatures raises its own questions of democratic accountability

Rapamycin and the transcription factor C/EBPβ as a switch in osteoclast differentiation: implications for lytic bone diseases

Lytic bone diseases and in particular osteoporosis are common age-related diseases characterized by enhanced bone fragility due to loss of bone density. Increasingly, osteoporosis poses a major global health-care problem due to the growth of the elderly population. Recently, it was found that the gene regulatory transcription factor CCAAT/enhancer binding protein beta (C/EBPβ) is involved in bone metabolism. C/EBPβ occurs as different protein isoforms of variable amino terminal length, and regulation of the C/EBPβ isoform ratio balance was found to represent an important factor in osteoclast differentiation and bone homeostasis. Interestingly, adjustment of the C/EBPβ isoform ratio by the process of translational control is downstream of the mammalian target of rapamycin kinase (mTOR), a sensor of the nutritional status and a target of immunosuppressive and anticancer drugs. The findings imply that modulating the process of translational control of C/EBPβ isoform expression could represent a novel therapeutic approach in osteolytic bone diseases, including cancer and infection-induced bone loss