Impacts of feeding peroxidized oils on growth and oxidative status in swine and poultry

It is common for vegetable oils to be supplemented to livestock diets to improve the energy density of the feed. Vegetable oils, however, have high concentrations of polyunsaturated fatty acids (PUFA). Due to this increased unsaturation, they are predisposed to lipid damage through lipid peroxidation. Lipid peroxidation is a dynamic free radical chain reaction that can be initiated by thermal processing in the presence of oxygen. This reaction progresses based on duration and intensity of thermal processing to produce a wide range of potentially oxidative and toxic compounds. Lipid peroxidation products of interest include peroxide value (PV) which measures hydroperoxides formed, and p-anisidine value (AnV) which is a measure of the molecular weight of aldehydes. Two key aldehydes are also formed including 2,4-decadienal (DDE) and 4-hydroxynonenal (HNE), are formed from the peroxidation of linoleic acid and are of interest because of their reactiveness with lipids, proteins, and DNA. Oils from ethanol, rendering or the restaurant industries may be an economical energy source compared to fresh oil, but at the expense of oil quality as they may be thermally peroxidized. Consumption of these peroxidized oils may induce increased oxidative stress and antagonize livestock performance. Oxidative stress occurs in the event that oxidative compounds such as free radicals and reactive oxygen species (ROS) overwhelm the antioxidant defense system. Enzymatic antioxidants including superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) function in detoxifying (reducing) oxidative compounds to protect the body from oxidative stress. Oxidative compounds can bind to lipids, proteins, and DNA to stabilize resulting in tissue or cellular damage. Commonly, thiobarbituric acid reactive substances (TBARS) and F2-isoprostanes (ISP) are measured as indicators of lipid damage, protein carbonyls (PC) are measured as an indicator of protein damage, and 8-hydroxy-2\u27-deoxyguanosine (8-OH-2dG) is measured as an indicator of DNA damage. However, there is a poor understanding of the effects of feeding peroxidized oils on growth performance, digestibility, and oxidative status in livestock. Therefore, the overall objectives of this thesis were to determine the impact of feeding peroxidized oils on growth and digestibility parameters, and whole body oxidative status in growing pigs and poultry. To accomplish these objectives, a series of experiments were conducted and are outlined in three chapters (Chapter 2, 3, and 4). In Chapter 2, an experiment was conducted feeding variable levels of peroxidized soybean oil (SO) on growth, digestibility, and intestinal integrity parameters in growing pigs. In Chapter 3 oxidative stress markers associated with lipid, protein, and DNA damage along with enzymatic antioxidants, were measured in pigs fed variable levels of dietary peroxidized soybean oil. The final chapter (Chapter 4) assessed the effects of feeding multiple fresh and peroxidized oil sources on growth performance and markers of oxidative stress in broilers. The data herein indicate that thermally processing oils at 90oC for 72 h yielded the most harmful lipid peroxidation products as exhibited by reduced overall growth performance and feed efficiency in swine and poultry. Pigs fed thermally peroxidized SO (heated at 90oC for 72 h, 90oC SO) had reduced ADG, energy and lipid digestibility, and whole body N retention (Chapter 2). Further, these pigs also had increases in liver weight as a percentage of BW and generally had increased oxidative stress as measured by serum PC and GPx, urine ISP, and liver 8-OH-2dG (Chapter 3). To build on Chapters 2 and 3, Chapter 4 evaluated the effects of feeding fresh and peroxidized palm, soybean, flaxseed, and fish oils on performance and oxidative status in poultry. An interaction between oil source and peroxidation status was noted for ADFI, ADG, G:F, and plasma GPx in broilers where peroxidation status reduced each of these variables in birds fed palm, soybean, and flaxseed oil, apart from birds fed fish oil. In general, oil unsaturation increased plasma TBARS, PC and 8-OH-2dG; furthermore, broilers fed peroxidized oils had increased plasma 8-OH-2dG. An interaction was noted in liver TBARS where broilers fed peroxidized palm oil had increased liver TBARS compared to fresh palm oil, while the opposite was true in broilers fed soybean oil, and no change was noted in broilers fed flaxseed oil and fish oil. An interaction was also noted for liver PC where broilers fed palm, flaxseed, and fish oil had similar liver PC regardless of peroxidation status while broilers fed peroxidized soybean oil had increased liver PC compared to the fresh soybean oil diet. Generally speaking, the unsaturation content of the dietary oil increased liver 8-OH-2dG and CAT activity and peroxidation status increased liver SOD activity. In summary, this thesis reported that formulating diets for pigs and poultry containing thermally processed oils (5-10% of total diet) were shown to have detrimental effects on performance particularly ADG. In pigs, thermally peroxidized SO also reduced digestibility of energy, ether extract, and nitrogen retention in comparison to pigs fed fresh SO. Additionally, growth performance was decreased in poultry fed peroxidized palm, soybean, and flaxseed oils. Oxidative stress was induced in swine and poultry fed peroxidized oils and different oil sources as measured in urine (pigs only), blood, and liver. Further, this data suggests that PV, DDE or AnV, PTAGS, and total tocopherols are important lipid peroxidation products that need to be measured as suggested by their consistent correlations with growth performance and oxidative status in swine and poultry. Additionally, these experiments and a review of literature indicate that markers of oxidative stress that should be measured include ISP and 8-OH-2dG in urine (pigs), and PC and GPx in blood (pigs and poultry). Overall, this thesis showed that oil quality should not be underestimated in livestock production. Feeding peroxidized oils can induce oxidative stress and antagonizes growth performance and digestibility in swine and poultry

R-Modes in Superfluid Neutron Stars

The analogs of r-modes in superfluid neutron stars are studied here. These modes, which are governed primarily by the Coriolis force, are identical to their ordinary-fluid counterparts at the lowest order in the small angular-velocity expansion used here. The equations that determine the next order terms are derived and solved numerically for fairly realistic superfluid neutron-star models. The damping of these modes by superfluid ``mutual friction'' (which vanishes at the lowest order in this expansion) is found to have a characteristic time-scale of about 10^4 s for the m=2 r-mode in a ``typical'' superfluid neutron-star model. This time-scale is far too long to allow mutual friction to suppress the recently discovered gravitational radiation driven instability in the r-modes. However, the strength of the mutual friction damping depends very sensitively on the details of the neutron-star core superfluid. A small fraction of the presently acceptable range of superfluid models have characteristic mutual friction damping times that are short enough (i.e. shorter than about 5 s) to suppress the gravitational radiation driven instability completely.Comment: 15 pages, 8 figure

Gravitational Radiation Instability in Hot Young Neutron Stars

We show that gravitational radiation drives an instability in hot young rapidly rotating neutron stars. This instability occurs primarily in the l=2 r-mode and will carry away most of the angular momentum of a rapidly rotating star by gravitational radiation. On the timescale needed to cool a young neutron star to about T=10^9 K (about one year) this instability can reduce the rotation rate of a rapidly rotating star to about 0.076\Omega_K, where \Omega_K is the Keplerian angular velocity where mass shedding occurs. In older colder neutron stars this instability is suppressed by viscous effects, allowing older stars to be spun up by accretion to larger angular velocities.Comment: 4 Pages, 2 Figure

Relativistic Stellar Pulsations With Near-Zone Boundary Conditions

A new method is presented here for evaluating approximately the pulsation modes of relativistic stellar models. This approximation relies on the fact that gravitational radiation influences these modes only on timescales that are much longer than the basic hydrodynamic timescale of the system. This makes it possible to impose the boundary conditions on the gravitational potentials at the surface of the star rather than in the asymptotic wave zone of the gravitational field. This approximation is tested here by predicting the frequencies of the outgoing non-radial hydrodynamic modes of non-rotating stars. The real parts of the frequencies are determined with an accuracy that is better than our knowledge of the exact frequencies (about 0.01%) except in the most relativistic models where it decreases to about 0.1%. The imaginary parts of the frequencies are determined with an accuracy of approximately M/R, where M is the mass and R is the radius of the star in question.Comment: 10 pages (REVTeX 3.1), 5 figs., 1 table, fixed minor typos, published in Phys. Rev. D 56, 2118 (1997

The metaphysics of Machian frame-dragging

The paper investigates the kind of dependence relation that best portrays Machian frame-dragging in general relativity. The question is tricky because frame-dragging relates local inertial frames to distant distributions of matter in a time-independent way, thus establishing some sort of non-local link between the two. For this reason, a plain causal interpretation of frame-dragging faces huge challenges. The paper will shed light on the issue by using a generalized structural equation model analysis in terms of manipulationist counterfactuals recently applied in the context of metaphysical enquiry by Schaffer (2016) and Wilson (2017). The verdict of the analysis will be that frame-dragging is best understood in terms of a novel type of dependence relation that is half-way between causation and grounding

The rotational modes of relativistic stars: Numerical results

We study the inertial modes of slowly rotating, fully relativistic compact stars. The equations that govern perturbations of both barotropic and non-barotropic models are discussed, but we present numerical results only for the barotropic case. For barotropic stars all inertial modes are a hybrid mixture of axial and polar perturbations. We use a spectral method to solve for such modes of various polytropic models. Our main attention is on modes that can be driven unstable by the emission of gravitational waves. Hence, we calculate the gravitational-wave growth timescale for these unstable modes and compare the results to previous estimates obtained in Newtonian gravity (i.e. using post-Newtonian radiation formulas). We find that the inertial modes are slightly stabilized by relativistic effects, but that previous conclusions concerning eg. the unstable r-modes remain essentially unaltered when the problem is studied in full general relativity.Comment: RevTeX, 29 pages, 31 eps figure

Data analysis of continuous gravitational wave: Fourier transform-II

In this paper we obtain the Fourier Transform of a continuous gravitational wave. We have analysed the data set for (i) one year observation time and (ii) arbitrary observation time, for arbitrary location of detector and source taking into account the effects arising due to rotational as well as orbital motion of the earth. As an application of the transform we considered spin down and N-component signal analysis.Comment: Accepted in MNRAS, 14 pages, 4 figure

The r-modes in accreting neutron stars with magneto-viscous boundary layers

We explore the dynamics of the r-modes in accreting neutron stars in two ways. First, we explore how dissipation in the magneto-viscous boundary layer (MVBL) at the crust-core interface governs the damping of r-mode perturbations in the fluid interior. Two models are considered: one assuming an ordinary-fluid interior, the other taking the core to consist of superfluid neutrons, type II superconducting protons, and normal electrons. We show, within our approximations, that no solution to the magnetohydrodynamic equations exists in the superfluid model when both the neutron and proton vortices are pinned. However, if just one species of vortex is pinned, we can find solutions. When the neutron vortices are pinned and the proton vortices are unpinned there is much more dissipation than in the ordinary-fluid model, unless the pinning is weak. When the proton vortices are pinned and the neutron vortices are unpinned the dissipation is comparable or slightly less than that for the ordinary-fluid model, even when the pinning is strong. We also find in the superfluid model that relatively weak radial magnetic fields ~ 10^9 G (10^8 K / T)^2 greatly affect the MVBL, though the effects of mutual friction tend to counteract the magnetic effects. Second, we evolve our two models in time, accounting for accretion, and explore how the magnetic field strength, the r-mode saturation amplitude, and the accretion rate affect the cyclic evolution of these stars. If the r-modes control the spin cycles of accreting neutron stars we find that magnetic fields can affect the clustering of the spin frequencies of low mass x-ray binaries (LMXBs) and the fraction of these that are currently emitting gravitational waves.Comment: 19 pages, 8 eps figures, RevTeX; corrected minor typos and added a referenc

Reducing orbital eccentricity in binary black hole simulations

Binary black hole simulations starting from quasi-circular (i.e., zero radial velocity) initial data have orbits with small but non-zero orbital eccentricities. In this paper the quasi-equilibrium initial-data method is extended to allow non-zero radial velocities to be specified in binary black hole initial data. New low-eccentricity initial data are obtained by adjusting the orbital frequency and radial velocities to minimize the orbital eccentricity, and the resulting ($\sim 5$ orbit) evolutions are compared with those of quasi-circular initial data. Evolutions of the quasi-circular data clearly show eccentric orbits, with eccentricity that decays over time. The precise decay rate depends on the definition of eccentricity; if defined in terms of variations in the orbital frequency, the decay rate agrees well with the prediction of Peters (1964). The gravitational waveforms, which contain $\sim 8$ cycles in the dominant l=m=2 mode, are largely unaffected by the eccentricity of the quasi-circular initial data. The overlap between the dominant mode in the quasi-circular evolution and the same mode in the low-eccentricity evolution is about 0.99.Comment: 27 pages, 9 figures; various minor clarifications; accepted to the "New Frontiers" special issue of CQ

Stable radiation-controlling boundary conditions for the generalized harmonic Einstein equations

This paper is concerned with the initial-boundary value problem for the Einstein equations in a first-order generalized harmonic formulation. We impose boundary conditions that preserve the constraints and control the incoming gravitational radiation by prescribing data for the incoming fields of the Weyl tensor. High-frequency perturbations about any given spacetime (including a shift vector with subluminal normal component) are analyzed using the Fourier-Laplace technique. We show that the system is boundary-stable. In addition, we develop a criterion that can be used to detect weak instabilities with polynomial time dependence, and we show that our system does not suffer from such instabilities. A numerical robust stability test supports our claim that the initial-boundary value problem is most likely to be well-posed even if nonzero initial and source data are included.Comment: 27 pages, 4 figures; more numerical results and references added, several minor amendments; version accepted for publication in Class. Quantum Gra