Based on annual pork yield of each province in 1996-2014,using Gini coefficient and spatial polarization index model,empirical analysis was carried out for spatial imbalance and polarization degree of swine production...Based on annual pork yield of each province in 1996-2014,using Gini coefficient and spatial polarization index model,empirical analysis was carried out for spatial imbalance and polarization degree of swine production distribution. Results indicate that there is high imbalance in spatial distribution of swine production. The imbalance takes on first rise then declines with fluctuation,largely because of inter-group gap. From the perspective of regions,the regions with balanced grain production have the highest imbalance in swine production,followed by main sales regions,and the main grain production regions have the lowest imbalance. The polarization index indicates that the overall polarization degree of the spatial distribution of swine production takes on a growing trend,and that of each functional region of grain production is also growing.展开更多
Tryptophan(Trp)is an essential amino acid that cannot be synthesized by animals.It has been characterized into two different isomers,levorotation-Trp(L-Trp)and dextrorotation-Trp(D-Trp),based on their distinct molecul...Tryptophan(Trp)is an essential amino acid that cannot be synthesized by animals.It has been characterized into two different isomers,levorotation-Trp(L-Trp)and dextrorotation-Trp(D-Trp),based on their distinct molecule orientation.Intestinal epithelial cells and gut microbiota are involved in metabolizing L-Trp in the gut via the activation of the kynurenine,serotonin,and indole pathways.However,knowledge regarding D-Trp metabolism in the gut remains unclear.In this review,we briefly update the current understanding of intestinal L/D-Trp metabolism and the function of their metabolites in modulating the gut physiology and diseases.Finally,we summarize the effects of Trp nutrition on swine production at different stages,including growth performance in weaned piglets and growing pigs,as well as the reproduction performance in sows.展开更多
Meeting the increasing demands for high-quality pork protein requires not only improved diets but also biotechnology-based breeding to generate swine with desired production traits.Biotechnology can be classified as t...Meeting the increasing demands for high-quality pork protein requires not only improved diets but also biotechnology-based breeding to generate swine with desired production traits.Biotechnology can be classified as the cloning of animals with identical genetic composition or genetic engineering(via recombinant DNA technology and gene editing)to produce genetically modified animals or microorganisms.Cloning helps to conserve species and breeds,particularly those with excellent biological and economical traits.Recombinant DNA technology combines genetic materials from multiple sources into single cells to generate proteins.Gene(genome)editing involves the deletion,insertion or silencing of genes to produce:(a)genetically modified pigs with important production traits;or(b)microorganisms without an ability to resist antimicrobial substances.Current gene-editing tools include the use of zinc finger nuclease(ZFN),transcription activator-like effector nuclease(TALEN),or clustered regularly interspaced short palindromic repeats-associated nuclease-9(CRISPR/Cas9)as editors.ZFN,TALEN,or CRISPR/Cas9 components are delivered into target cells through transfection(lipid-based agents,electroporation,nucleofection,or microinjection)or bacteriophages,depending on cell type and plasmid.Compared to the ZFN and TALEN,CRISPR/Cas9 offers greater ease of design and greater flexibility in genetic engineering,but has a higher frequency of off-target effects.To date,genetically modified pigs have been generated to express bovine growth hormone,bacterial phytase,fungal carbohydrases,plant and C.elagan fatty acid desaturases,and uncoupling protein-1;and to lack myostatin,α-1,3-galactosyltransferase,or CD163(a cellular receptor for the"blue ear disease"virus).Biotechnology holds promise in improving the efficiency of swine production and developing alternatives to antibiotics in the future.展开更多
Recent advances in swine protein nutrition are characterized by the development of functional a- mino acids （AA） in regulating fetal and postnatal survival, growth and development. These AA include arginine, glutami...Recent advances in swine protein nutrition are characterized by the development of functional a- mino acids （AA） in regulating fetal and postnatal survival, growth and development. These AA include arginine, glutamine, glutamate, proline, leucine, cyste- ine and tryptophan. Due to limited knowledge on AA nutrition, pork producers have traditionally paid little attention to supplementing the arginine family of AA to swine diets. Results of recent studies indicate that functional AA serve important regulatory functions in nutrient metabolism, protein turnover, and immune function, therefore enhancing efficiency of feed utili- zation by pigs. The underlying mechanisms include activation of nitric oxide, mammalian target of rapam- ycin, gaseous signaling, and AMP-activated protein ki- nase pathways, as well as anti-oxidative function. Di- etary supplementation with arginine, glutamine, pro- line or leucine to weanling piglets enhances theirgrowth performance. Arginine or glutamine is also ef- fective in increasing milk production by lactating sows. Furthermore, supplementing arginine to the diet of pregnant gilts between days 30 and 114 of gestation increases the number of live-born piglets and litter birth-weight. Availability of feed-grade functional AA holds great promise for improving animal health and nutrient utilization in pig production worldwide. Addi- tionally, feedstuffs of animal origin [ e. g. , blood meal （ ring dried ）, feather meal （ hydrolyzed ）, meat and bone meal, porcine protein meal, and poultry by-prod- uct meal （both feed- and petfood-grades） ] are excel- lent and cost-effective sources of both essential and functional AA for formulating balanced swine diets. New knowledge on AA nutrition provides a much needed scientific basis for revising the next edition of swine nutrient requirements.展开更多
Animal production depends on nutrient utilization and if done there is an accelerated momentum towards growth with a low cost to feed ratio Public concern over the consumption of pork with antibiotic residues of the a...Animal production depends on nutrient utilization and if done there is an accelerated momentum towards growth with a low cost to feed ratio Public concern over the consumption of pork with antibiotic residues of the animals fed with antibiotic growth promoters （AGP） has paved the way to use other additives like herbs and their products, probiotics, prebiotics etc. Numerous feed additives are in vogue for achieving this target and one such classical example is the usage of organic acids and their salts. Usage of organic acids was in progress for over four decades. Early weaned piglets are （3-4 weeks age） exposed to stress with a reduced feed intake, little or no weight gain. This post weaning lag period is due to a limited digestive and absorptive capacity due to insufficient production of hydrochloric acid, pancreatic enzymes and sudden changes in feed consistency and intake. Lowering dietary pH by weak organic acids was found to overcome these problems. The main activity of organic acids is associated with a reduction in gastric pH converting the inactive pepsinogen to active pepsin for effective protein hydrolysis. Organic acids are both bacteriostatic and bactericidal. Lactic acid has been reported to reduce gastric pH and delay the multiplication of an enterotoxigenic E. coil These acids are the intermediary products in Kreb＇s cycle and thus act as an energy source preventing the tissue breakdown resulting from gluconeogenesis and lipolysis. Excretion of supplemental minerals and nitrogen are minimized with organic acids as these form complexes with minerals and aids for their bio-availability. Short chain fatty cids like acetic, propionic and n-butyric acid produced by microbial fermentation of dietary fibre in the large intestines may increase the proliferation of epithelial cells and have stimulatory effects on both endocrine and exocrine pancreatic secretions in pigs. Organic acids also enhances apparent total tract digestibility and improves growth performance. It is concluded that organic acids and their salts increase the protein utilization especially in weaner pigs and improves production indices.展开更多
基金Supported by Key Project of National Social Science Foundation(12&ZD048)
文摘Based on annual pork yield of each province in 1996-2014,using Gini coefficient and spatial polarization index model,empirical analysis was carried out for spatial imbalance and polarization degree of swine production distribution. Results indicate that there is high imbalance in spatial distribution of swine production. The imbalance takes on first rise then declines with fluctuation,largely because of inter-group gap. From the perspective of regions,the regions with balanced grain production have the highest imbalance in swine production,followed by main sales regions,and the main grain production regions have the lowest imbalance. The polarization index indicates that the overall polarization degree of the spatial distribution of swine production takes on a growing trend,and that of each functional region of grain production is also growing.
基金supported by the Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project(TSBICIP-CXRC-038)the National Natural Science Foundation of China(U20A2054)the Earmarked Fund for China Agriculture Research System(CARS-35).
文摘Tryptophan(Trp)is an essential amino acid that cannot be synthesized by animals.It has been characterized into two different isomers,levorotation-Trp(L-Trp)and dextrorotation-Trp(D-Trp),based on their distinct molecule orientation.Intestinal epithelial cells and gut microbiota are involved in metabolizing L-Trp in the gut via the activation of the kynurenine,serotonin,and indole pathways.However,knowledge regarding D-Trp metabolism in the gut remains unclear.In this review,we briefly update the current understanding of intestinal L/D-Trp metabolism and the function of their metabolites in modulating the gut physiology and diseases.Finally,we summarize the effects of Trp nutrition on swine production at different stages,including growth performance in weaned piglets and growing pigs,as well as the reproduction performance in sows.
基金supported by Agriculture and Food Research Initiative Competitive Grants(2014–67015-21770,2015–67015-23276,2016–67015-24958,and 2018–505706-95720)from the USDA National Institute of Food and Agriculture,and Texas A&M Agri Life Research(H-8200)
文摘Meeting the increasing demands for high-quality pork protein requires not only improved diets but also biotechnology-based breeding to generate swine with desired production traits.Biotechnology can be classified as the cloning of animals with identical genetic composition or genetic engineering(via recombinant DNA technology and gene editing)to produce genetically modified animals or microorganisms.Cloning helps to conserve species and breeds,particularly those with excellent biological and economical traits.Recombinant DNA technology combines genetic materials from multiple sources into single cells to generate proteins.Gene(genome)editing involves the deletion,insertion or silencing of genes to produce:(a)genetically modified pigs with important production traits;or(b)microorganisms without an ability to resist antimicrobial substances.Current gene-editing tools include the use of zinc finger nuclease(ZFN),transcription activator-like effector nuclease(TALEN),or clustered regularly interspaced short palindromic repeats-associated nuclease-9(CRISPR/Cas9)as editors.ZFN,TALEN,or CRISPR/Cas9 components are delivered into target cells through transfection(lipid-based agents,electroporation,nucleofection,or microinjection)or bacteriophages,depending on cell type and plasmid.Compared to the ZFN and TALEN,CRISPR/Cas9 offers greater ease of design and greater flexibility in genetic engineering,but has a higher frequency of off-target effects.To date,genetically modified pigs have been generated to express bovine growth hormone,bacterial phytase,fungal carbohydrases,plant and C.elagan fatty acid desaturases,and uncoupling protein-1;and to lack myostatin,α-1,3-galactosyltransferase,or CD163(a cellular receptor for the"blue ear disease"virus).Biotechnology holds promise in improving the efficiency of swine production and developing alternatives to antibiotics in the future.
基金supported by funds from National Research Initiative Competitive Grants(2008-35206-18764 and 2008-35203-19120)from the USDA Cooperative State Research,Education,Texas AgriLife Research Hatch project(H-8200)+1 种基金the Changjiang Scholar Lecturing Professorship Program of the Department of Education of Chinathe Thousand-People-Talent program at China Agricultural University
文摘Recent advances in swine protein nutrition are characterized by the development of functional a- mino acids （AA） in regulating fetal and postnatal survival, growth and development. These AA include arginine, glutamine, glutamate, proline, leucine, cyste- ine and tryptophan. Due to limited knowledge on AA nutrition, pork producers have traditionally paid little attention to supplementing the arginine family of AA to swine diets. Results of recent studies indicate that functional AA serve important regulatory functions in nutrient metabolism, protein turnover, and immune function, therefore enhancing efficiency of feed utili- zation by pigs. The underlying mechanisms include activation of nitric oxide, mammalian target of rapam- ycin, gaseous signaling, and AMP-activated protein ki- nase pathways, as well as anti-oxidative function. Di- etary supplementation with arginine, glutamine, pro- line or leucine to weanling piglets enhances theirgrowth performance. Arginine or glutamine is also ef- fective in increasing milk production by lactating sows. Furthermore, supplementing arginine to the diet of pregnant gilts between days 30 and 114 of gestation increases the number of live-born piglets and litter birth-weight. Availability of feed-grade functional AA holds great promise for improving animal health and nutrient utilization in pig production worldwide. Addi- tionally, feedstuffs of animal origin [ e. g. , blood meal （ ring dried ）, feather meal （ hydrolyzed ）, meat and bone meal, porcine protein meal, and poultry by-prod- uct meal （both feed- and petfood-grades） ] are excel- lent and cost-effective sources of both essential and functional AA for formulating balanced swine diets. New knowledge on AA nutrition provides a much needed scientific basis for revising the next edition of swine nutrient requirements.
文摘Animal production depends on nutrient utilization and if done there is an accelerated momentum towards growth with a low cost to feed ratio Public concern over the consumption of pork with antibiotic residues of the animals fed with antibiotic growth promoters （AGP） has paved the way to use other additives like herbs and their products, probiotics, prebiotics etc. Numerous feed additives are in vogue for achieving this target and one such classical example is the usage of organic acids and their salts. Usage of organic acids was in progress for over four decades. Early weaned piglets are （3-4 weeks age） exposed to stress with a reduced feed intake, little or no weight gain. This post weaning lag period is due to a limited digestive and absorptive capacity due to insufficient production of hydrochloric acid, pancreatic enzymes and sudden changes in feed consistency and intake. Lowering dietary pH by weak organic acids was found to overcome these problems. The main activity of organic acids is associated with a reduction in gastric pH converting the inactive pepsinogen to active pepsin for effective protein hydrolysis. Organic acids are both bacteriostatic and bactericidal. Lactic acid has been reported to reduce gastric pH and delay the multiplication of an enterotoxigenic E. coil These acids are the intermediary products in Kreb＇s cycle and thus act as an energy source preventing the tissue breakdown resulting from gluconeogenesis and lipolysis. Excretion of supplemental minerals and nitrogen are minimized with organic acids as these form complexes with minerals and aids for their bio-availability. Short chain fatty cids like acetic, propionic and n-butyric acid produced by microbial fermentation of dietary fibre in the large intestines may increase the proliferation of epithelial cells and have stimulatory effects on both endocrine and exocrine pancreatic secretions in pigs. Organic acids also enhances apparent total tract digestibility and improves growth performance. It is concluded that organic acids and their salts increase the protein utilization especially in weaner pigs and improves production indices.
