The present study was conducted to determine effects of different forms of yeast （Saccharomyces cerevisiae, strain Y200007） on the growth performance, intestinal development, and systemic immunity in early-weaned pi...The present study was conducted to determine effects of different forms of yeast （Saccharomyces cerevisiae, strain Y200007） on the growth performance, intestinal development, and systemic immunity in early-weaned piglets. A total of 96 piglets （14-d old, initial average body weight of 4.5 kg） were assigned to 4 dietary treatments： （1） basa diet without yeast （Control）; （2） basal diet supplemented with 3.00 g/kg live yeast （LY）; （3） basal diet supplemented with 2.66 g/kg heat-killed whole yeast （HKY）; and （4） basal diet supplemented with 3.00 g/kg superfine yeast powders （SFY）. Diets and water were provided ad libitum to the piglets during 3-week experiment. Growth performance of piglets was measured weekly. Samples of blood and small intestine were collected at days 7 and 21 of experiment. Dietary supplementation with LY and SFY improved G：F of piglets at days ]-21 of the experiment （P 〈 0.05） compared to Control group. Serum concentrations of growth hormone （GH）, triiodothyronine （T3）, tetraiodothyronine （T4）, and insulin growth factor 1 （iGF-1） in piglets at day 21 of the experiment were higher when fed diets supplemented with LY and SFY than those in Control group （P 〈 0.05）. Compared to Control group, contents of serum urea nitrogen of piglets were reduced by the 3 yeast-supplemented diets （P 〈 0.05）. Diets supplemented with LY increased villus height and villus-to-crypt ratio in duodenum and jejunum of piglets （P 〈 0.05） compared to other two groups at day 7 of the experiment. Feeding diets supplemented with LY and SFY increased （P 〈 0.05） serum concentrations of IgA, IL-2, and IL-6 levels in piglets compared to Control. The CD4＋/CD8＋ ratio and proliferation of T-lymphocytes in piglets fed diets supplemented with LY were increased compared to that of Control group at day 7 of the experiment （P 〈 0.05）. In conclusion, dietary supplementation with both LY and SFY enhanced feed conversion, small intestinal development, and systemic immunity in early-weaned piglets, with better improvement in feed conversion by dietary supplementation with LY, while dietary supplementation with SFY was more effective in increasing systemic immune functions in early-weaned piglets.展开更多
Background： Although isoflavones are natural dietary antioxidants, they may have toxicological effects. This study aimed to evaluate the redox system in tissues of finishing pigs by supplementation with high dose of ...Background： Although isoflavones are natural dietary antioxidants, they may have toxicological effects. This study aimed to evaluate the redox system in tissues of finishing pigs by supplementation with high dose of daidzein（640 mg/kg）.Results： The supplementation of high dose of daidzein for 64 d increased the activity of superoxide dismutase and total antioxidant capacity in longissimus muscle but down-regulated the expression of reactive oxygen species（ROS）-producing enzyme NADPH oxidase-2 and cyclooxygenase-2. In contrast, high-level supplementation with daidzein exerted pro-oxidant changes in back fat, abdominal fat, liver, and plasma, as reflected by increased contents of malondialdehyde, a lipid peroxidation product, in these tissues. Furthermore, daidzein supplementation resulted in higher expression of ROS-producing enzymes, including NADPH oxidase-1 and cyclooxygenase-1in liver, 5-lipoxygenase（5-LOX） in backfat and NADPH oxidase-2 both in abdominal fat and backfat. The supplementation of daidzein did not affect meat quality parameters in longissimus muscle, including marbling score,eye muscle areas, intramuscular fat, shear force, drip loss, p H and meat color.Conclusions： This experiment suggests that dietary supplementation of finishing pigs with daidzein at a high dose level improves redox status in muscle but exerts pro-oxidant effect in liver and fat tissues.展开更多
The antioxidant and protective properties of a synthetic soybean isoflavone (ISO) were investigated using sow mammary gland cell. Cells were cultured with 10, 20 and 30 uM ISO, respectively, under 80 uM FeSO4·7H2...The antioxidant and protective properties of a synthetic soybean isoflavone (ISO) were investigated using sow mammary gland cell. Cells were cultured with 10, 20 and 30 uM ISO, respectively, under 80 uM FeSO4·7H2O/H2O2 conditions. After 48 h of incubation, the cells in the presence of ISO were lost less compared with that of control under oxidative damage by H2O2/FeSO4;ISO decreased the cell number at G1 and G2 stages, increased the cell number at S stage (all P < 0.05), it also reduced apoptosis of the cells (P P P < 0.05). The addition of ISO significantly promoted cell proliferation (P rd to 6th days. Upon these, the activities of total superoxide dismutase (SOD), glutathione peroxidase (GPX), total antioxidant ability (T-AOC) also were increased and the activities of NADPH oxidase (NOX) decreased by ISO treatment (all P < 0.05). ISO decreased the concentration of ROS (P P < 0.05). 10 uM, 20 uM, 30 uM ISO increased the relative mRNA abundance of SOD1 (all P P P P < 0.05) and SOD3 (all P < 0.05);ISO significantly increased the relative mRNA abundance of GPX4 (all P P < 0.05), 20 uM ISO also increased the relative mRNA abundance of NOX2 (P < 0.05). It was concluded that supplementation of ISO enhanced the anti-oxidative function and prevented lipid peroxidation, possibly through the activation of the antioxidant enzymes and inhibition of cell apoptosis.展开更多
NBI fast ion losses in the presence of the toroidal field ripple on EAST have been investigated by using the orbit code GYCAVA and the NBI code TGCO.The ripple effect was included in the upgraded version of the GYCAVA...NBI fast ion losses in the presence of the toroidal field ripple on EAST have been investigated by using the orbit code GYCAVA and the NBI code TGCO.The ripple effect was included in the upgraded version of the GYCAVA code.It is found that loss regions of NBI fast ions are mainly on the low field side near the edge in the presence of ripple.For co-current NBIs,the synergy effect of ripple and Coulomb collision on fast ion losses is dominant,and fast trapped ions located on the low field side are easily lost.The ripple well loss and the ripple stochastic loss of fast ions have been identified from the heat loads of co-current NBI fast ions.The ripple stochastic loss and the collisioninduced loss are much larger than the ripple well loss.Heat loads of lost fast ions are mainly localized on the right side of the radio frequency wave antennas from the inside view toward the first wall.For counter-current NBIs,the first orbit loss due to the magnetic drift is the dominant loss channel.In addition,fast ion loss fraction with ripple and collision for each NBI linearly increases with the effective charge number,which is related to the pitch angle scattering effect.展开更多
It was found that there are multiplicity of low shear toroidicity-induced Alfv′en eigenmodes in a zero beta limit if the inverse aspect ratio is larger than the magnetic shear at the mode location(Candy 1996 Phys. Le...It was found that there are multiplicity of low shear toroidicity-induced Alfv′en eigenmodes in a zero beta limit if the inverse aspect ratio is larger than the magnetic shear at the mode location(Candy 1996 Phys. Lett. A 215 299). Because the reversed shear Alfv′en eigenmode(RSAE) and even the RSAE associated with the non-circular triangularity-induced Alfv′en eigenmode(NAE) gap(NAE–RSAE) usually reside near the shear-reversal point, the condition that the inverse aspect ratio is larger than the magnetic shear is naturally satisfied. For this reason, we numerically investigate the existence of multiplicity of core-localized NAE–RSAEs and mode characteristics in the present work. We firstly verify the existence of the multiplicity for zero beta plasma by using a D-shaped equilibrium. It is pointed out that, for a given toroidal mode number, the Alfv′en cascade spectrum accommodates down-sweeping and up-sweeping modes above and below the NAE range of frequencies. An analytical model for the existence of multiple RSAE modes is in good agreement with the simulation results. One notices that the triangularity has a greater effect on the odd-type modes than that on the even-type modes: the odd-type modes come into existence because of the plasma triangularity.展开更多
Simulations of first-orbit losses of neutral beam injection(NBI)fast ions in the EAST tokamak have been studied in detail by using the orbit-following code GYCAVA and the NBI code TGCO.Beam ion losses with the wall bo...Simulations of first-orbit losses of neutral beam injection(NBI)fast ions in the EAST tokamak have been studied in detail by using the orbit-following code GYCAVA and the NBI code TGCO.Beam ion losses with the wall boundary are smaller than those with the last closed flux surface boundary.In contrast to heat loads on the wall without radio frequency wave(RFW)antennas,heat loads on the wall with RFW antennas are distributed more locally near the RFW antennas.The direction of the toroidal magnetic field dramatically affects the final positions of lost fast ions,which is related to the magnetic drift.The numerical results on heat loads of beam ions corresponding to different toroidal magnetic fields are qualitatively consistent with the experimental results.Beam ion losses increase with the beam energy for the co-current NBIs and the counter-perpendicular NBI.We have studied the behavior of fast ions produced by a small section neutral beam(beamlet)by using the numerical tool NBIT.The distributions of the loss fraction of beamlet fast ions peaked near the edge of the beam section for the counter-current NBIs,and they are related to the injection angle.This indicates that the first-orbit losses can be reduced by changing the shape of beam cross section.展开更多
Suppression and mitigation of a high-frequency Alfvén-like mode(HFAM)between type-I edge localized modes(ELMs)during ELM mitigation by resonant magnetic perturbation(RMP)is observed for the first time in the EAST...Suppression and mitigation of a high-frequency Alfvén-like mode(HFAM)between type-I edge localized modes(ELMs)during ELM mitigation by resonant magnetic perturbation(RMP)is observed for the first time in the EAST tokamak.This mode is located near the edge pedestal region.The modeling result of the Alfvén continuum shows that the HFAM is located near the elipical Alfvén eigenmode(EAE)gap.During the application of n=1 RMP for ELM mitigation,the HFAM can be fully suppressed when the RMP amplitude exceeds a threshold,below which the HFAM is mitigated.The suppression is caused by a reduction of pedestal height induced by RMP.In the case using n=3 RMP,the mode is localized toroidally at specific phase depending on the phase of applied RMP,i.e.locked in the three-dimensional equilibrium formed by RMP.The dominant toroidal mode number of HFAM is around n=-6 and it reduces to-3 during the application of n=3 RMP,which indicates the existence of possible nonlinear coupling between the HFAM and RMP.Here the negative mode number denotes that the mode rotates in electron diamagnetic drift direction.The observation reported here improves the understanding of pedestal dynamics and its stability in RMP ELM control.展开更多
The excitation condition of reversed shear Alfven eigenmodes(RSAEs)has been investigated during sawtoothlike oscillation in the EAST tokamak.The sawtooth-like phenomena can be reproduced in the configuration of revers...The excitation condition of reversed shear Alfven eigenmodes(RSAEs)has been investigated during sawtoothlike oscillation in the EAST tokamak.The sawtooth-like phenomena can be reproduced in the configuration of reversed magnetic shear,and the threshold gradient of electron temperature is formed accordingly,together with the increasing of the confinement of thermal particles.The distribution function of energetic ions density is altered dramatically when the neutral beam is switched from NBI1 L(tangent)to NBI1 R(perpendicular),which can be captured by the measurement of radial neutron camera.The RSAEs are excited easily in the vicinity of q_(min)(1.99 m≤R≤2.06 m)for the injection of neutral beam with perpendicular direction,which should be excited by the steep gradient of energetic ions density.Furthermore,the excitation of RSAEs and the formation of threshold gradient of electron temperature can take place concurrently,which means that the neutral beam with perpendicular injection is beneficial for the establishment of internal transport barrier.展开更多
The classical prompt loss of fast ions produced by minority ion cyclotron resonance heating(ICRH)is studied by a guiding center orbit following code in the Experimental Advanced Superconducting Tokamak(EAST).It is fou...The classical prompt loss of fast ions produced by minority ion cyclotron resonance heating(ICRH)is studied by a guiding center orbit following code in the Experimental Advanced Superconducting Tokamak(EAST).It is found that the loss of fast ions produced by ICRH mainly appears in both ends of the resonance layer,while the loss of fast ions in the middle resonance layer is very small.The dominant fast loss comes from trapped ions,rather than from passing ions.Controlling the location of resonance layer at the plasma core may be more beneficial to the EAST tokamak ICRH.In addition,the loss distribution of fast ions is studied.The results show that the fast ions are mainly lost near the midplane in the poloidal direction,but almost uniformly in the toroidal direction.Moreover,we investigate the dependence of fast ion loss on the ICRH power.The simulation results show that the loss fraction of fast ions in both ends of the resonance region increases with the ion cyclotron range of frequencies(ICRF)power,but barely affects the loss of fast ions in the middle region.展开更多
基金financially supported by grants from China Agriculture Research System(CARS-36)the Special Fund for Agro-scientific Research in the Public Interest(No.201403047)+1 种基金National Basic Research Program of China(2013CB127301 and 2013CB127304)Presidential Foundation of Guangdong Academy of Agricultural Sciences(201312)
文摘The present study was conducted to determine effects of different forms of yeast （Saccharomyces cerevisiae, strain Y200007） on the growth performance, intestinal development, and systemic immunity in early-weaned piglets. A total of 96 piglets （14-d old, initial average body weight of 4.5 kg） were assigned to 4 dietary treatments： （1） basa diet without yeast （Control）; （2） basal diet supplemented with 3.00 g/kg live yeast （LY）; （3） basal diet supplemented with 2.66 g/kg heat-killed whole yeast （HKY）; and （4） basal diet supplemented with 3.00 g/kg superfine yeast powders （SFY）. Diets and water were provided ad libitum to the piglets during 3-week experiment. Growth performance of piglets was measured weekly. Samples of blood and small intestine were collected at days 7 and 21 of experiment. Dietary supplementation with LY and SFY improved G：F of piglets at days ]-21 of the experiment （P 〈 0.05） compared to Control group. Serum concentrations of growth hormone （GH）, triiodothyronine （T3）, tetraiodothyronine （T4）, and insulin growth factor 1 （iGF-1） in piglets at day 21 of the experiment were higher when fed diets supplemented with LY and SFY than those in Control group （P 〈 0.05）. Compared to Control group, contents of serum urea nitrogen of piglets were reduced by the 3 yeast-supplemented diets （P 〈 0.05）. Diets supplemented with LY increased villus height and villus-to-crypt ratio in duodenum and jejunum of piglets （P 〈 0.05） compared to other two groups at day 7 of the experiment. Feeding diets supplemented with LY and SFY increased （P 〈 0.05） serum concentrations of IgA, IL-2, and IL-6 levels in piglets compared to Control. The CD4＋/CD8＋ ratio and proliferation of T-lymphocytes in piglets fed diets supplemented with LY were increased compared to that of Control group at day 7 of the experiment （P 〈 0.05）. In conclusion, dietary supplementation with both LY and SFY enhanced feed conversion, small intestinal development, and systemic immunity in early-weaned piglets, with better improvement in feed conversion by dietary supplementation with LY, while dietary supplementation with SFY was more effective in increasing systemic immune functions in early-weaned piglets.
基金supported by the“National Natural Science Foundation of China”(Grant No.31072041)“National Basic Research Program of China(973 Program)”(Grant No.2012CB124706-4,2012CB124706-5)+1 种基金Science and Technology Planning Project of Guangdong Province(Grant No.2013A061401020)Science and Technology Program of Guangzhou(Grant NO.2014Y2-00121)
文摘Background： Although isoflavones are natural dietary antioxidants, they may have toxicological effects. This study aimed to evaluate the redox system in tissues of finishing pigs by supplementation with high dose of daidzein（640 mg/kg）.Results： The supplementation of high dose of daidzein for 64 d increased the activity of superoxide dismutase and total antioxidant capacity in longissimus muscle but down-regulated the expression of reactive oxygen species（ROS）-producing enzyme NADPH oxidase-2 and cyclooxygenase-2. In contrast, high-level supplementation with daidzein exerted pro-oxidant changes in back fat, abdominal fat, liver, and plasma, as reflected by increased contents of malondialdehyde, a lipid peroxidation product, in these tissues. Furthermore, daidzein supplementation resulted in higher expression of ROS-producing enzymes, including NADPH oxidase-1 and cyclooxygenase-1in liver, 5-lipoxygenase（5-LOX） in backfat and NADPH oxidase-2 both in abdominal fat and backfat. The supplementation of daidzein did not affect meat quality parameters in longissimus muscle, including marbling score,eye muscle areas, intramuscular fat, shear force, drip loss, p H and meat color.Conclusions： This experiment suggests that dietary supplementation of finishing pigs with daidzein at a high dose level improves redox status in muscle but exerts pro-oxidant effect in liver and fat tissues.
文摘The antioxidant and protective properties of a synthetic soybean isoflavone (ISO) were investigated using sow mammary gland cell. Cells were cultured with 10, 20 and 30 uM ISO, respectively, under 80 uM FeSO4·7H2O/H2O2 conditions. After 48 h of incubation, the cells in the presence of ISO were lost less compared with that of control under oxidative damage by H2O2/FeSO4;ISO decreased the cell number at G1 and G2 stages, increased the cell number at S stage (all P < 0.05), it also reduced apoptosis of the cells (P P P < 0.05). The addition of ISO significantly promoted cell proliferation (P rd to 6th days. Upon these, the activities of total superoxide dismutase (SOD), glutathione peroxidase (GPX), total antioxidant ability (T-AOC) also were increased and the activities of NADPH oxidase (NOX) decreased by ISO treatment (all P < 0.05). ISO decreased the concentration of ROS (P P < 0.05). 10 uM, 20 uM, 30 uM ISO increased the relative mRNA abundance of SOD1 (all P P P P < 0.05) and SOD3 (all P < 0.05);ISO significantly increased the relative mRNA abundance of GPX4 (all P P < 0.05), 20 uM ISO also increased the relative mRNA abundance of NOX2 (P < 0.05). It was concluded that supplementation of ISO enhanced the anti-oxidative function and prevented lipid peroxidation, possibly through the activation of the antioxidant enzymes and inhibition of cell apoptosis.
基金supported by National Natural Science Foundation of China(No.11775265)。
文摘NBI fast ion losses in the presence of the toroidal field ripple on EAST have been investigated by using the orbit code GYCAVA and the NBI code TGCO.The ripple effect was included in the upgraded version of the GYCAVA code.It is found that loss regions of NBI fast ions are mainly on the low field side near the edge in the presence of ripple.For co-current NBIs,the synergy effect of ripple and Coulomb collision on fast ion losses is dominant,and fast trapped ions located on the low field side are easily lost.The ripple well loss and the ripple stochastic loss of fast ions have been identified from the heat loads of co-current NBI fast ions.The ripple stochastic loss and the collisioninduced loss are much larger than the ripple well loss.Heat loads of lost fast ions are mainly localized on the right side of the radio frequency wave antennas from the inside view toward the first wall.For counter-current NBIs,the first orbit loss due to the magnetic drift is the dominant loss channel.In addition,fast ion loss fraction with ripple and collision for each NBI linearly increases with the effective charge number,which is related to the pitch angle scattering effect.
基金Project supported by the National Natural Science Foundation of China(Grant No.11675222)
文摘It was found that there are multiplicity of low shear toroidicity-induced Alfv′en eigenmodes in a zero beta limit if the inverse aspect ratio is larger than the magnetic shear at the mode location(Candy 1996 Phys. Lett. A 215 299). Because the reversed shear Alfv′en eigenmode(RSAE) and even the RSAE associated with the non-circular triangularity-induced Alfv′en eigenmode(NAE) gap(NAE–RSAE) usually reside near the shear-reversal point, the condition that the inverse aspect ratio is larger than the magnetic shear is naturally satisfied. For this reason, we numerically investigate the existence of multiplicity of core-localized NAE–RSAEs and mode characteristics in the present work. We firstly verify the existence of the multiplicity for zero beta plasma by using a D-shaped equilibrium. It is pointed out that, for a given toroidal mode number, the Alfv′en cascade spectrum accommodates down-sweeping and up-sweeping modes above and below the NAE range of frequencies. An analytical model for the existence of multiple RSAE modes is in good agreement with the simulation results. One notices that the triangularity has a greater effect on the odd-type modes than that on the even-type modes: the odd-type modes come into existence because of the plasma triangularity.
基金the support of the EAST teamsupported by National Natural Science Foundation of China (No. 11775265)
文摘Simulations of first-orbit losses of neutral beam injection(NBI)fast ions in the EAST tokamak have been studied in detail by using the orbit-following code GYCAVA and the NBI code TGCO.Beam ion losses with the wall boundary are smaller than those with the last closed flux surface boundary.In contrast to heat loads on the wall without radio frequency wave(RFW)antennas,heat loads on the wall with RFW antennas are distributed more locally near the RFW antennas.The direction of the toroidal magnetic field dramatically affects the final positions of lost fast ions,which is related to the magnetic drift.The numerical results on heat loads of beam ions corresponding to different toroidal magnetic fields are qualitatively consistent with the experimental results.Beam ion losses increase with the beam energy for the co-current NBIs and the counter-perpendicular NBI.We have studied the behavior of fast ions produced by a small section neutral beam(beamlet)by using the numerical tool NBIT.The distributions of the loss fraction of beamlet fast ions peaked near the edge of the beam section for the counter-current NBIs,and they are related to the injection angle.This indicates that the first-orbit losses can be reduced by changing the shape of beam cross section.
基金supported by the National Key R&D Program of China(No.2017YFE0301100)National Natural Science Foundation of China(No.11875292)。
文摘Suppression and mitigation of a high-frequency Alfvén-like mode(HFAM)between type-I edge localized modes(ELMs)during ELM mitigation by resonant magnetic perturbation(RMP)is observed for the first time in the EAST tokamak.This mode is located near the edge pedestal region.The modeling result of the Alfvén continuum shows that the HFAM is located near the elipical Alfvén eigenmode(EAE)gap.During the application of n=1 RMP for ELM mitigation,the HFAM can be fully suppressed when the RMP amplitude exceeds a threshold,below which the HFAM is mitigated.The suppression is caused by a reduction of pedestal height induced by RMP.In the case using n=3 RMP,the mode is localized toroidally at specific phase depending on the phase of applied RMP,i.e.locked in the three-dimensional equilibrium formed by RMP.The dominant toroidal mode number of HFAM is around n=-6 and it reduces to-3 during the application of n=3 RMP,which indicates the existence of possible nonlinear coupling between the HFAM and RMP.Here the negative mode number denotes that the mode rotates in electron diamagnetic drift direction.The observation reported here improves the understanding of pedestal dynamics and its stability in RMP ELM control.
基金the National MCF Energy R&D Program of China(Grant Nos.2019YFE03020000 and 2018YFE0304100)the National Nature Science Foundation of China(Grant Nos.11975267 and 11975273)。
文摘The excitation condition of reversed shear Alfven eigenmodes(RSAEs)has been investigated during sawtoothlike oscillation in the EAST tokamak.The sawtooth-like phenomena can be reproduced in the configuration of reversed magnetic shear,and the threshold gradient of electron temperature is formed accordingly,together with the increasing of the confinement of thermal particles.The distribution function of energetic ions density is altered dramatically when the neutral beam is switched from NBI1 L(tangent)to NBI1 R(perpendicular),which can be captured by the measurement of radial neutron camera.The RSAEs are excited easily in the vicinity of q_(min)(1.99 m≤R≤2.06 m)for the injection of neutral beam with perpendicular direction,which should be excited by the steep gradient of energetic ions density.Furthermore,the excitation of RSAEs and the formation of threshold gradient of electron temperature can take place concurrently,which means that the neutral beam with perpendicular injection is beneficial for the establishment of internal transport barrier.
基金supported by National Natural Science Foundation of China (No. 11805239)the Natural Science Foundation of Hunan Province (No. 2019JJ50011)
文摘The classical prompt loss of fast ions produced by minority ion cyclotron resonance heating(ICRH)is studied by a guiding center orbit following code in the Experimental Advanced Superconducting Tokamak(EAST).It is found that the loss of fast ions produced by ICRH mainly appears in both ends of the resonance layer,while the loss of fast ions in the middle resonance layer is very small.The dominant fast loss comes from trapped ions,rather than from passing ions.Controlling the location of resonance layer at the plasma core may be more beneficial to the EAST tokamak ICRH.In addition,the loss distribution of fast ions is studied.The results show that the fast ions are mainly lost near the midplane in the poloidal direction,but almost uniformly in the toroidal direction.Moreover,we investigate the dependence of fast ion loss on the ICRH power.The simulation results show that the loss fraction of fast ions in both ends of the resonance region increases with the ion cyclotron range of frequencies(ICRF)power,but barely affects the loss of fast ions in the middle region.
