The calpain system is ubiquitous in cells, mainly comprising calpains and calpain inhibitors, and is a widespread calcium-dependent cysteine protease in organisms that is involved in many cellular processes such as mu...The calpain system is ubiquitous in cells, mainly comprising calpains and calpain inhibitors, and is a widespread calcium-dependent cysteine protease in organisms that is involved in many cellular processes such as muscle degradation in vivo and affects the tenderness of meat after animal slaughter. The study found 128 DEGs that probably regulated tenderness traits were selected from 16 significantly enriched GO terms by transcriptome sequencing analysis, and found that the developmental changes in the expression levels of the CAPN1 gene in the pectoral and leg muscles were significantly positively correlated ( P <0.05) with the cumulative growth values of live weight and comb weight. The developmental changes in the expression levels of the CAST gene in the pectoral and leg muscles were not significantly correlated with the cumulative growth values of live weight and comb weight. Our results helped demonstrate the potential molecular mechanisms of tenderness in chickens and provide valuable information for chicken breeding.展开更多
The relevance of genetic mechanism to the phenotype of hypoxic adaptation remains elusive.Tibetan chickens typically used to investigate the mechanism for the adaptation of hypoxia and the recognition of hypoxia-relat...The relevance of genetic mechanism to the phenotype of hypoxic adaptation remains elusive.Tibetan chickens typically used to investigate the mechanism for the adaptation of hypoxia and the recognition of hypoxia-related piRNA remains an open issue.The purpose of this study was to illustrate whether the piRNAs were related to hypoxic adaptation.First of all,the differentially expressed piRNAs(DEpiRNAs)were identified through RNA sequencing between the Tibetan chickens and Daheng broilers.Subsequently,the target genes of DEpiRNAs were predicted and annotated by software.The network was constructed by Cytoscape.In our study,a total of 277 DEpiRNAs(33 down-regulated,244 up-regulated)were identified in the Tibetan chickens compared with the Daheng broilers.All of the 277 DEpiRNAs predicted 36658 targeted genes.Gene Ontology(GO)analysis showed that the target genes were significantly enriched in the biological process correlated with proliferation and apoptosis of cells,including cell cycle,mitochondrial outer membrane permeabilization,and positive regulation of stress-activated mitogen-activated protein kinase cascade.Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis implicated that the DEpiRNAs were mainly involved in immune and metabolism,including natural killer cell-mediated cytotoxicity,toll-like receptor signaling pathway and fatty acid metabolism.Furthermore,a predicted network with four piRNAs acted on 11 pathways via interacting with 22 target genes,in which piR-gga-1368839 regulated metabolic pathways by acting on DHCR24.In conclusion,we determined the DEpiRNAs in the Tibetan chickens and found that these piRNAs were associated with metabolism,which may be favorable for researching the biological adaptation to hypoxic stress.展开更多
Solid-liquid suspension in stirred tank is a common operation in the chemical industry. The power consumption, flow pattern and flow field instability of three systems named as unbaffled stirred tank, traditional baff...Solid-liquid suspension in stirred tank is a common operation in the chemical industry. The power consumption, flow pattern and flow field instability of three systems named as unbaffled stirred tank, traditional baffled stirred tank and punched baffled stirred tank(Pun-BST) were studied by using the computational fluid dynamic analysis. Results showed that perforating holes in the baffles could reduce power consumption of mixing. Meanwhile, the punched baffle system could maintain the solids in suspension as traditional baffle system. The results also showed that the baffles could increase the “effective flow” of stirred tank even though the whole velocity of the vessel is lower than un-baffled vessel. In addition, both the solid-liquid suspension and “effective flow” were related to instability of the flow field.Perfect solid-liquid suspension results always along with obvious instability of the flow field. But, the strengthening effect of punched baffle on flow field instability mainly happened in the near-wall area.It's because the collision and aggregation among sub-streams induced by holes intensified the unstable fluid flow. On the whole, the Pun-BST system provided much better mixing characteristics and recommended to apply in the industrial process.展开更多
This work aims to systematically study hydrodynamics and mixing characteristics of non-Newtonian fluid(carboxyl methyl cellulose,CMC)in dual shaft eccentric mixer.Fluid rheology was described by the power law rheologi...This work aims to systematically study hydrodynamics and mixing characteristics of non-Newtonian fluid(carboxyl methyl cellulose,CMC)in dual shaft eccentric mixer.Fluid rheology was described by the power law rheological model.Computational fluid dynamics was employed to simulate the velocity field and shear rate inside the stirred tank.The influence mechanism of the rotational modes,height difference between impellers,impeller eccentricities,and impeller types on the flow field have been well investigated.We studied the performance of different dual-shaft eccentric mixers at the constant power input with its fluid velocity profiles,average shear strain rate,mixing time and mixing energy.The counter-rotation mode shows better mixing performance than co-rotation mode,and greater eccentricity can shorten mixing time on the basis of same stirred condition.To intensify the hydrodynamic interaction between impellers and enhance the overall mixing performance of the dual shaft eccentric mixers,it is critical to have a reasonable combination of impellers and an appropriate spatial position of impellers.展开更多
Stochastic gradient descent(SGD),a widely used algorithm in deep-learning neural networks,has attracted continuing research interests for the theoretical principles behind its success.A recent work reported an anomaly...Stochastic gradient descent(SGD),a widely used algorithm in deep-learning neural networks,has attracted continuing research interests for the theoretical principles behind its success.A recent work reported an anomaly(inverse)relation between the variance of neural weights and the landscape flatness of the loss function driven under SGD[Feng Y and Tu Y Proc.Natl.Acad.Sci.USA 118 e2015617118(2021)].To investigate this seeming violation of statistical physics principle,the properties of SGD near fixed points are analyzed with a dynamic decomposition method.Our approach recovers the true“energy”function under which the universal Boltzmann distribution holds.It differs from the cost function in general and resolves the paradox raised by the the anomaly.The study bridges the gap between the classical statistical mechanics and the emerging discipline of artificial intelligence,with potential for better algorithms to the latter.展开更多
Background： The protein/energy ratio is important for the production performance and utilization of available feed resources by animals. Increased protein consumption by mammals leads to elevated feed costs and incre...Background： The protein/energy ratio is important for the production performance and utilization of available feed resources by animals. Increased protein consumption by mammals leads to elevated feed costs and increased nitrogen release into the environment. This study aimed to evaluate the effects of dietary protein/energy ratio on the growth performance, carcass traits, meat quality, and plasma metabolites of pigs of different genotypes. Methods： Bama mini-pigs and Landrace pigs were randomly assigned to two dietary treatment groups （Chinese conventional diet with low protein/energy ratio or National Research Council diet with high protein/energy ratio; n = 24 per treatment） in a 2 x 2 factorial arrangement. Blood and muscle samples were collected at the end of the nursery, growing, and finishing phases. Results： We observed significant interactions （P 〈 0.05） between breed and diet for total fat percentage, intramuscular fat （IMF） content, protein content in biceps femoris （BF） muscle, and plasma urea nitrogen （UN） concentration in the nursery phase; for average daily gain （ADG）, average daily feed intake （ADFI）, dry matter, IMF content in psoas major （PM） muscle, and plasma total protein and albumin concentrations in the growing phase; and for drip loss and plasma UN concentration in the finishing phase. Breed influenced （P 〈 0.05） growth performance, carcass traits, and meat quality, but not plasma metabolites. Throughout the trial, Landrace pigs showed significantly higher （P 〈 0.0_5） ADG, ADFI, dressing percentage, lean mass rate, and loin-eye area than did Bama mini-pigs, but significantly lower （P 〈 0.0.5） feed/gain ratio, fat percentage, backfat thickness, and IMF content. Dietary protein/energy ratio influenced the pH value, chemical composition of BF and PM muscles, and plasma activities of glutamic-pyruvic transaminase and gamma-glutamyl transpeptidase, and plasma concentration of UN. Conclusions： Compared with Landrace pigs, Bama mini-pigs showed slower growth and lower carcass performance, but had better meat quality. Moreover, unlike Landrace pigs, the dietary protein/energy ratio did not affect the growth performance of Bama mini-pigs. These results suggest that, in swine production, low dietary protein/energy ratio may be useful for reducing feed costs and minimizing the adverse effects of ammonia release into the environment.展开更多
With the widespread ban on the use of antibiotics in swine feed, alternative measures need to be sought to maintain swine health and performance, Antimicrobial peptides （AMPs） are part of the nonspecific defense sys...With the widespread ban on the use of antibiotics in swine feed, alternative measures need to be sought to maintain swine health and performance, Antimicrobial peptides （AMPs） are part of the nonspecific defense system and are natural antibiotics produced by plants, insects, mammalians, and micro-organisms as well as by chemical synthesis. Due to their broad microbicidal activity against various fungi, bacteria and enveloped viruses AMPs are a potential alternative to conventional antibiotics for use in swine production. This review focuses on the structure and mechanism of action of AMPs, as well as their effects on performance, immune function and intestinal health in pigs. The aim is to provide support for the application of AMPs as feed additives replacing antibiotics in swine nutrition.展开更多
Background: There is growing evidence to support the beneficial effects of supplementing direct-fed microbials(DFM) on performance, health status, and immune responses of weaned pigs. Therefore, the objective of this ...Background: There is growing evidence to support the beneficial effects of supplementing direct-fed microbials(DFM) on performance, health status, and immune responses of weaned pigs. Therefore, the objective of this study was to investigate dietary supplementation of Bacillus subtilis(DSM 25841) on growth performance, diarrhea, gut permeability and immunity of weaned pigs experimentally infected with a pathogenic F-18 Escherichia coli(E. coli).Results: The F18 E. coli infection reduced(P < 0.05) growth performance and intestinal villi height, whereas increased(P < 0.05) diarrhea and transcellular and paracellular permeability in the jejunum compared with non-challenged control. Supplementation of Bacillus subtilis linearly enhanced average daily gain of E. coli infected pigs from d 0 to 5 post-inoculation(PI)(P < 0.05) and d 0 to 11 PI(P = 0.058). Supplementation of high dose of Bacillus subtilis reduced(P < 0.05) both transcellular and paracellular permeability on d 5 and d11 PI compared with the E. coli infected pigs fed with control diet. E. coli infection up-regulated(P < 0.05)the m RNA expression of SLC5 A10(soluble carrier family 5 member 10) and MUC2(mucin 2) on d 5 PI, but down-regulated(P < 0.05) expression of SLC5 A10, MUC2, and CLDN1 on d 11 PI in jejunal mucosa when pigs were fed with the control diet. Supplementation of Bacillus subtilis linearly up-regulated(P < 0.05) the m RNA expression of CFTR and ZO1 on d 5 PI and SLC5 A10 and MUC2 on d 11 PI in jejunal mucosa of E. coli infected pigs. In addition, E. coli infection increased(P < 0.05) the m RNA expression of several immune genes(IL1 A, IL1 B, and IL7 on d 5 PI, and IL1 B, IL6, IL7, and TNF on d 11 PI) in the ileal mucosa of weaned pigs. Inclusion of Bacillus subtilis to control diet linearly down-regulated gene expression of IL1 A on d 5 PI(P = 0.07) and IL6 on d 11 PI(P < 0.05) in ileal mucosa of E. coli infected pigs.Conclusions: Supplementation of Bacillus subtilis(DSM 25841) enhanced growth rate and improved gut barrier function of weaned pigs experimentally infected with a pathogenic E. coli.展开更多
Background： The intestinal epithelium is an important barrier that depends on a complex mixture of proteins and these proteins comprise different intercellular junctions. The purpose of this study was to investigate ...Background： The intestinal epithelium is an important barrier that depends on a complex mixture of proteins and these proteins comprise different intercellular junctions. The purpose of this study was to investigate the postnatal and developmental changes in morphology, intercellular junctions and voltage-gated potassium（Kv） channels in the intestine of piglets during the suckling and post-weaning periods.Results： Samples of the small intestine were obtained from 1-, 7-, 14-, and 21-d-old suckling piglets and piglets on d 1, 3, 5, and 7 after weaning at 14 d of age. The results showed that the percentage of proliferating cell nuclear antigen（PCNA）-positive cells and alkaline phosphatase（AKP） activity, as well as the abundances of E-cadherin,occludin, and Kv1.5 m RNA and claudin-1, claudin-3, and occludin protein in the jejunum were increased from d 1to d 21 during the suckling period（P 〈 0.05）. Weaning induced decreases in the percentage of PCNA-positive cells,AKP activity and the abundances of E-cadherin, occludin and zonula occludens（ZO）-1 m RNA or protein in the jejunum on d 1, 3 and 5 post-weaning（P 〈 0.05）. There were lower abundances of E-cadherin, occludin and ZO-1m RNA as well as claudin-1, claudin-3 and ZO-1 protein in the jejunum of weanling piglets than in 21-d-old suckling piglets（P 〈 0.05）. The abundances of E-cadherin, occludin, ZO-1 and integrin m RNA were positively related to the percentage of PCNA-positive cells.Conclusion： Weaning at 14 d of age induced damage to the intestinal morphology and barrier. While there was an adaptive restoration on d 7 post-weaning, the measured values did not return to the pre-weaning levels, which reflected the impairment of intercellular junctions and Kv channels.展开更多
基金Supported by Science and Technology Support Planning Project of Sichuan Province(2021YFYZ0031SASA2024CZYX002)National Modern Agricultural Technology System Construction of China(CARS-41-G07)。
文摘The calpain system is ubiquitous in cells, mainly comprising calpains and calpain inhibitors, and is a widespread calcium-dependent cysteine protease in organisms that is involved in many cellular processes such as muscle degradation in vivo and affects the tenderness of meat after animal slaughter. The study found 128 DEGs that probably regulated tenderness traits were selected from 16 significantly enriched GO terms by transcriptome sequencing analysis, and found that the developmental changes in the expression levels of the CAPN1 gene in the pectoral and leg muscles were significantly positively correlated ( P <0.05) with the cumulative growth values of live weight and comb weight. The developmental changes in the expression levels of the CAST gene in the pectoral and leg muscles were not significantly correlated with the cumulative growth values of live weight and comb weight. Our results helped demonstrate the potential molecular mechanisms of tenderness in chickens and provide valuable information for chicken breeding.
基金Supported by Science and Technology Support Planning Project of Sichuan Province(2021YFYZ00312020YFN0146+1 种基金SASA2022CZYX002)National Modern Agricultural Technology System Construction of China(CARS-41-G04)。
文摘The relevance of genetic mechanism to the phenotype of hypoxic adaptation remains elusive.Tibetan chickens typically used to investigate the mechanism for the adaptation of hypoxia and the recognition of hypoxia-related piRNA remains an open issue.The purpose of this study was to illustrate whether the piRNAs were related to hypoxic adaptation.First of all,the differentially expressed piRNAs(DEpiRNAs)were identified through RNA sequencing between the Tibetan chickens and Daheng broilers.Subsequently,the target genes of DEpiRNAs were predicted and annotated by software.The network was constructed by Cytoscape.In our study,a total of 277 DEpiRNAs(33 down-regulated,244 up-regulated)were identified in the Tibetan chickens compared with the Daheng broilers.All of the 277 DEpiRNAs predicted 36658 targeted genes.Gene Ontology(GO)analysis showed that the target genes were significantly enriched in the biological process correlated with proliferation and apoptosis of cells,including cell cycle,mitochondrial outer membrane permeabilization,and positive regulation of stress-activated mitogen-activated protein kinase cascade.Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis implicated that the DEpiRNAs were mainly involved in immune and metabolism,including natural killer cell-mediated cytotoxicity,toll-like receptor signaling pathway and fatty acid metabolism.Furthermore,a predicted network with four piRNAs acted on 11 pathways via interacting with 22 target genes,in which piR-gga-1368839 regulated metabolic pathways by acting on DHCR24.In conclusion,we determined the DEpiRNAs in the Tibetan chickens and found that these piRNAs were associated with metabolism,which may be favorable for researching the biological adaptation to hypoxic stress.
基金supported by the National Natural Science Foundation of China (22078030, Z20200804)National Key Research and Development Program of China (2019YFC1905802)+1 种基金Key Project of Independent Research Project of State Key Laboratory of Coal Mine Disaster Dynamics and Control (2011DA105287zd201902)Hubei Three Gorges Laboratory Open/Innovation Fund (SK211009, SK215001)。
文摘Solid-liquid suspension in stirred tank is a common operation in the chemical industry. The power consumption, flow pattern and flow field instability of three systems named as unbaffled stirred tank, traditional baffled stirred tank and punched baffled stirred tank(Pun-BST) were studied by using the computational fluid dynamic analysis. Results showed that perforating holes in the baffles could reduce power consumption of mixing. Meanwhile, the punched baffle system could maintain the solids in suspension as traditional baffle system. The results also showed that the baffles could increase the “effective flow” of stirred tank even though the whole velocity of the vessel is lower than un-baffled vessel. In addition, both the solid-liquid suspension and “effective flow” were related to instability of the flow field.Perfect solid-liquid suspension results always along with obvious instability of the flow field. But, the strengthening effect of punched baffle on flow field instability mainly happened in the near-wall area.It's because the collision and aggregation among sub-streams induced by holes intensified the unstable fluid flow. On the whole, the Pun-BST system provided much better mixing characteristics and recommended to apply in the industrial process.
基金supported by the National Natural Science Foundation of China(22078030,52021004)National Natural Science Foundation of Chongqing(2022NSCQ-LZX0271)+2 种基金Fundamental Research Funds for the Central Universities(2022CDJQY-005)National Key Research and Development Project(2019YFC1905802,2022YFC3901204)Key Project of Independent Research Project of State Key Laboratory of coal mine disaster dynamics and control(2011DA105287-zd201902).
文摘This work aims to systematically study hydrodynamics and mixing characteristics of non-Newtonian fluid(carboxyl methyl cellulose,CMC)in dual shaft eccentric mixer.Fluid rheology was described by the power law rheological model.Computational fluid dynamics was employed to simulate the velocity field and shear rate inside the stirred tank.The influence mechanism of the rotational modes,height difference between impellers,impeller eccentricities,and impeller types on the flow field have been well investigated.We studied the performance of different dual-shaft eccentric mixers at the constant power input with its fluid velocity profiles,average shear strain rate,mixing time and mixing energy.The counter-rotation mode shows better mixing performance than co-rotation mode,and greater eccentricity can shorten mixing time on the basis of same stirred condition.To intensify the hydrodynamic interaction between impellers and enhance the overall mixing performance of the dual shaft eccentric mixers,it is critical to have a reasonable combination of impellers and an appropriate spatial position of impellers.
基金supported in part by the National Natural Science Foundation of China(Grant No.16Z103060007(PA))Shanghai Nanobubble Technology Co.,Ltd.for supporting this work。
文摘Stochastic gradient descent(SGD),a widely used algorithm in deep-learning neural networks,has attracted continuing research interests for the theoretical principles behind its success.A recent work reported an anomaly(inverse)relation between the variance of neural weights and the landscape flatness of the loss function driven under SGD[Feng Y and Tu Y Proc.Natl.Acad.Sci.USA 118 e2015617118(2021)].To investigate this seeming violation of statistical physics principle,the properties of SGD near fixed points are analyzed with a dynamic decomposition method.Our approach recovers the true“energy”function under which the universal Boltzmann distribution holds.It differs from the cost function in general and resolves the paradox raised by the the anomaly.The study bridges the gap between the classical statistical mechanics and the emerging discipline of artificial intelligence,with potential for better algorithms to the latter.
基金supported by the National Basic Research Program of China(No.2012CB124704 and 2013CB127305)KC.Wong Education Foundation,Hong Kong
文摘Background： The protein/energy ratio is important for the production performance and utilization of available feed resources by animals. Increased protein consumption by mammals leads to elevated feed costs and increased nitrogen release into the environment. This study aimed to evaluate the effects of dietary protein/energy ratio on the growth performance, carcass traits, meat quality, and plasma metabolites of pigs of different genotypes. Methods： Bama mini-pigs and Landrace pigs were randomly assigned to two dietary treatment groups （Chinese conventional diet with low protein/energy ratio or National Research Council diet with high protein/energy ratio; n = 24 per treatment） in a 2 x 2 factorial arrangement. Blood and muscle samples were collected at the end of the nursery, growing, and finishing phases. Results： We observed significant interactions （P 〈 0.05） between breed and diet for total fat percentage, intramuscular fat （IMF） content, protein content in biceps femoris （BF） muscle, and plasma urea nitrogen （UN） concentration in the nursery phase; for average daily gain （ADG）, average daily feed intake （ADFI）, dry matter, IMF content in psoas major （PM） muscle, and plasma total protein and albumin concentrations in the growing phase; and for drip loss and plasma UN concentration in the finishing phase. Breed influenced （P 〈 0.05） growth performance, carcass traits, and meat quality, but not plasma metabolites. Throughout the trial, Landrace pigs showed significantly higher （P 〈 0.0_5） ADG, ADFI, dressing percentage, lean mass rate, and loin-eye area than did Bama mini-pigs, but significantly lower （P 〈 0.0.5） feed/gain ratio, fat percentage, backfat thickness, and IMF content. Dietary protein/energy ratio influenced the pH value, chemical composition of BF and PM muscles, and plasma activities of glutamic-pyruvic transaminase and gamma-glutamyl transpeptidase, and plasma concentration of UN. Conclusions： Compared with Landrace pigs, Bama mini-pigs showed slower growth and lower carcass performance, but had better meat quality. Moreover, unlike Landrace pigs, the dietary protein/energy ratio did not affect the growth performance of Bama mini-pigs. These results suggest that, in swine production, low dietary protein/energy ratio may be useful for reducing feed costs and minimizing the adverse effects of ammonia release into the environment.
基金supported by the National Natural Science Foundation of China(No.3133007531372326)
文摘With the widespread ban on the use of antibiotics in swine feed, alternative measures need to be sought to maintain swine health and performance, Antimicrobial peptides （AMPs） are part of the nonspecific defense system and are natural antibiotics produced by plants, insects, mammalians, and micro-organisms as well as by chemical synthesis. Due to their broad microbicidal activity against various fungi, bacteria and enveloped viruses AMPs are a potential alternative to conventional antibiotics for use in swine production. This review focuses on the structure and mechanism of action of AMPs, as well as their effects on performance, immune function and intestinal health in pigs. The aim is to provide support for the application of AMPs as feed additives replacing antibiotics in swine nutrition.
基金supported by Chr.Hansen A/S,Hoersholm,Denmark and the United States Department of Agriculture(USDA)National Institute of Food and Agriculture,multistate project W3002
文摘Background: There is growing evidence to support the beneficial effects of supplementing direct-fed microbials(DFM) on performance, health status, and immune responses of weaned pigs. Therefore, the objective of this study was to investigate dietary supplementation of Bacillus subtilis(DSM 25841) on growth performance, diarrhea, gut permeability and immunity of weaned pigs experimentally infected with a pathogenic F-18 Escherichia coli(E. coli).Results: The F18 E. coli infection reduced(P < 0.05) growth performance and intestinal villi height, whereas increased(P < 0.05) diarrhea and transcellular and paracellular permeability in the jejunum compared with non-challenged control. Supplementation of Bacillus subtilis linearly enhanced average daily gain of E. coli infected pigs from d 0 to 5 post-inoculation(PI)(P < 0.05) and d 0 to 11 PI(P = 0.058). Supplementation of high dose of Bacillus subtilis reduced(P < 0.05) both transcellular and paracellular permeability on d 5 and d11 PI compared with the E. coli infected pigs fed with control diet. E. coli infection up-regulated(P < 0.05)the m RNA expression of SLC5 A10(soluble carrier family 5 member 10) and MUC2(mucin 2) on d 5 PI, but down-regulated(P < 0.05) expression of SLC5 A10, MUC2, and CLDN1 on d 11 PI in jejunal mucosa when pigs were fed with the control diet. Supplementation of Bacillus subtilis linearly up-regulated(P < 0.05) the m RNA expression of CFTR and ZO1 on d 5 PI and SLC5 A10 and MUC2 on d 11 PI in jejunal mucosa of E. coli infected pigs. In addition, E. coli infection increased(P < 0.05) the m RNA expression of several immune genes(IL1 A, IL1 B, and IL7 on d 5 PI, and IL1 B, IL6, IL7, and TNF on d 11 PI) in the ileal mucosa of weaned pigs. Inclusion of Bacillus subtilis to control diet linearly down-regulated gene expression of IL1 A on d 5 PI(P = 0.07) and IL6 on d 11 PI(P < 0.05) in ileal mucosa of E. coli infected pigs.Conclusions: Supplementation of Bacillus subtilis(DSM 25841) enhanced growth rate and improved gut barrier function of weaned pigs experimentally infected with a pathogenic E. coli.
基金funded by the National Key Basic Research Program of China(2013CB127302)National Natural Science Foundation of China(31330075,31372326,31301988,31301989)+4 种基金the State Key Laboratory of Animal Nutrition(2004DA125184F1401)the Spark Program of Jiangxi Province(20142BBF061051)Changsha Lvye Biotechnology Limited Company Academician Expert WorkstationGuangdong Wangda Group Academician Workstation for Clean Feed Technology Research and Development in SwineGuangdong Hinapharm Group Academician Workstation for Biological Feed and Feed Additives and Animal Intestinal Health
文摘Background： The intestinal epithelium is an important barrier that depends on a complex mixture of proteins and these proteins comprise different intercellular junctions. The purpose of this study was to investigate the postnatal and developmental changes in morphology, intercellular junctions and voltage-gated potassium（Kv） channels in the intestine of piglets during the suckling and post-weaning periods.Results： Samples of the small intestine were obtained from 1-, 7-, 14-, and 21-d-old suckling piglets and piglets on d 1, 3, 5, and 7 after weaning at 14 d of age. The results showed that the percentage of proliferating cell nuclear antigen（PCNA）-positive cells and alkaline phosphatase（AKP） activity, as well as the abundances of E-cadherin,occludin, and Kv1.5 m RNA and claudin-1, claudin-3, and occludin protein in the jejunum were increased from d 1to d 21 during the suckling period（P 〈 0.05）. Weaning induced decreases in the percentage of PCNA-positive cells,AKP activity and the abundances of E-cadherin, occludin and zonula occludens（ZO）-1 m RNA or protein in the jejunum on d 1, 3 and 5 post-weaning（P 〈 0.05）. There were lower abundances of E-cadherin, occludin and ZO-1m RNA as well as claudin-1, claudin-3 and ZO-1 protein in the jejunum of weanling piglets than in 21-d-old suckling piglets（P 〈 0.05）. The abundances of E-cadherin, occludin, ZO-1 and integrin m RNA were positively related to the percentage of PCNA-positive cells.Conclusion： Weaning at 14 d of age induced damage to the intestinal morphology and barrier. While there was an adaptive restoration on d 7 post-weaning, the measured values did not return to the pre-weaning levels, which reflected the impairment of intercellular junctions and Kv channels.
