Background We recently reported that supplementing glycine to soybean meal-based diets is necessary for the optimum growth of 5-to 40-g(Phase-I)and 110-to 240-g(Phase-II)hybrid striped bass(HSB),as well as their intes...Background We recently reported that supplementing glycine to soybean meal-based diets is necessary for the optimum growth of 5-to 40-g(Phase-I)and 110-to 240-g(Phase-II)hybrid striped bass(HSB),as well as their intestinal health.Although glycine serves as an essential substrate for syntheses of creatine and glutathione(GSH)in mammals(e.g.,pigs),little is known about these metabolic pathways or their nutritional regulation in fish.This study tested the hypothesis that glycine supplementation enhances the activities of creatine-and GSH-forming enzymes as well as creatine and GSH availabilities in tissues of hybrid striped bass(HSB;Morone saxatilis♀×Morone chrysops♂).Methods Phase-I and Phase-II HSB were fed a soybean meal-based diet supplemented with 0%,1%,or 2%glycine for 8 weeks.At the end of the 56-d feeding,tissues(liver,intestine,skeletal muscle,kidneys,and pancreas)were collected for biochemical analyses.Results In contrast to terrestrial mammals and birds,creatine synthesis occurred primarily in skeletal muscle from all HSB.The liver was most active in GSH synthesis among the HSB tissues studied.In Phase-I HSB,supplementation with 1%or 2%glycine increased(P<0.05)concentrations of intramuscular creatine(15%–19%)and hepatic GSH(8%–11%),while reducing(P<0.05)hepatic GSH sulfide(GSSG)/GSH ratios by 14%–15%,compared with the 0-glycine group;there were no differences(P>0.05)in these variables between the 1%and 2%glycine groups.In Phase-II HSB,supplementation with 1%and 2%glycine increased(P<0.05)concentrations of creatine and GSH in the muscle(15%–27%)and liver(11%–20%)in a dose-dependent manner,with reduced ratios of hepatic GSSG/GSH in the 1%or 2%glycine group.In all HSB,supplementation with 1%and 2%glycine dose-dependently increased(P<0.05)activities of intramuscular arginine:glycine amidinotransferase(22%–41%)and hepaticγ-glutamylcysteine synthetase(17%–37%),with elevated activities of intramuscular guanidinoacetate methyltransferase and hepatic GSH synthetase and GSH reductase in the 1%or 2%glycine group.Glycine supplementation also increased(P<0.05)concentrations of creatine and activities of its synthetic enzymes in tail kidneys and pancreas,and concentrations of GSH and activities of its synthetic enzymes in the proximal intestine.Conclusions Skeletal muscle and liver are the major organs for creatine and GSH syntheses in HSB,respectively.Dietary glycine intake regulates creatine and GSH syntheses by both Phase-I and Phase-II HSB in a tissue-specific manner.Based on the metabolic data,glycine is a conditionally essential amino acid for the growing fish.展开更多
Background:Most embryonic loss in pigs occurs before d 30 of gestation.Dietary supplementation with L-arginine(Arg) during early gestation can enhance the survival and development of conceptuses(embryo/fetus and its e...Background:Most embryonic loss in pigs occurs before d 30 of gestation.Dietary supplementation with L-arginine(Arg) during early gestation can enhance the survival and development of conceptuses(embryo/fetus and its extraembryonic membranes) in gilts.However,the underlying mechanisms remain largely unknown.Methods:Between d 14 and 30 of gestation,each gilt was fed daily 2 kg of a corn-and soybean-meal based diet(12% crude protein) supplemented with either 0.4% Arg(as Arg-HCl) or an isonitrogenous amount of L-alanine(Control).There were 10 gilts per treatment group.On d 30 of gestation,gilts were fed either Arg-HCl or L-alanine 30 min before they were hysterectomized,followed by the collection of placentae,embryos,fetal membranes,and fetal fluids.Amniotic and allantoic fluids were analyzed for nitrite and nitrate [NOx;stable oxidation products of nitric oxide(NO)],polyamines,and amino acids.Placentae were analyzed for syntheses of NO and polyamines,water and amino acid transport,concentrations of amino acid-related metabolites,and the expression of angiogenic factors and aquaporins(AQPs).Results:Compared to the control group,Arg supplementation increased(P < 0.05) the number of viable fetuses by 1.9 per litter,the number and diameter of placental blood vessels(+ 25.9% and + 17.0% respectively),embryonic survival(+ 18.5%),total placental weight(+ 36.5%),the total weight of viable fetuses(+ 33.5%),fetal crown-to-rump length(+ 4.7%),and total allantoic and amniotic fluid volumes(+ 44.6% and + 75.5% respectively).Compared to control gilts,Arg supplementation increased(P < 0.05) placental activities of GTP cyclohydrolase-1(+ 33.1%) and ornithine decarboxylase(+ 29.3%);placental syntheses of NO(+ 26.2%) and polyamines(+ 28.9%);placental concentrations of NOx(+ 22.5%),tetrahydrobiopterin(+ 21.1%),polyamines(+ 20.4%),c AMP(+ 27.7%),and c GMP(+ 24.7%);total amounts of NOx(+ 61.7% to + 96.8%),polyamines(+ 60.7% to + 88.7%),amino acids(+ 39% to + 118%),glucose(+ 60.5% to + 62.6%),and fructose(+ 41.4% to + 57.0%) in fetal fluids;and the placental transport of water(+ 33.9%),Arg(+ 78.4%),glutamine(+ 89.9%),and glycine(+ 89.6%).Furthermore,Arg supplementation increased(P < 0.05) placental m RNA levels for angiogenic factors [VEGFA120(+ 117%),VEGFR1(+ 445%),VEGFR2(+ 373%),PGF(+ 197%),and GCH1(+ 126%)] and AQPs [AQP1(+ 280%),AQP3(+ 137%),AQP5(+ 172%),AQP8(+ 165%),and AQP9(+ 127%)].Conclusion:Supplementing 0.4% Arg to a conventional diet for gilts between d 14 and d 30 of gestation enhanced placental NO and polyamine syntheses,angiogenesis,and water and amino acid transport to improve conceptus development and survival.展开更多
This study was to evaluate the effects of glucose tolerance status,maternal starch supplementation and soybean substitution in diets on the performance of dams and their offspring.Eighty-eight pregnant sows(Landrace x...This study was to evaluate the effects of glucose tolerance status,maternal starch supplementation and soybean substitution in diets on the performance of dams and their offspring.Eighty-eight pregnant sows(Landrace x Large White)were selected from an initial total of 120 sows,based on blood glucose test values,and assigned to 4 experimental treatments in a 2×2 factorial design.The factors were glucose tolerance status(glucose intolerant[GIT]vs.normal glucose tolerant[NGT])or dietary treatments(corn starch diet[CS]vs.soybean substitution diet[SSI]).A higher area under the curve(AUC)for post-meal glucose was observed(P<0.05)in the GIT group than in the NGT group on d 109 of gestation.The CS group had a lower value of homeostasis model assessment-insulin resistance than the SS group(P<0.05)on d 109 of gestation.Corn starch supplementation for sows decreased the stillbirth rate(P<0.05),regardless of the sows’glucose tolerance status.The villus height of the jejunum and the villus height to crypt depth ratio of the ileum were greater in normal birth weight piglets from the CS group than from the SS group(P<0.01),and so was the activity of sucrase in the jejunum and ileum(P<0.01).Compared with the SS group,the CS group showed a reduction in pre-weaning mortality rate,an increase in the number of high-birth-weight piglets,and a decrease in the number of low-birth-weight piglets(P<0.05)under GIT status.In conclusion,sows fed CS decreased stillbirth rate and improved insulin resistance,as well as improving the intestinal morphology and digestive enzyme activities of their progeny,regardless of glucose tolerance status.Additionally,the CS group improved birth weight distribution and decreased pre-weaning mortality rate of piglets under GIT status.展开更多
Aims Biological and environmental factors determine geographic patterns of plant nutrient stoichiometry jointly.Unraveling the distribution pattern and the potential drivers of nutrient stoichiometry is therefore crit...Aims Biological and environmental factors determine geographic patterns of plant nutrient stoichiometry jointly.Unraveling the distribution pattern and the potential drivers of nutrient stoichiometry is therefore critical for understanding the adaptive strategies and biogeochem-istry cycling.Aimed to determine how leaf nitrogen(N):phosphorus(P)stoichiometry is linked to biological and environmental factors,we investigated the patterns of psammophyte leaf N:P stoichiometry in sandy region,northern China,and the potential factors affecting leaf N:P stoichiometry were explored.Methods Based on 10 m×10 m quadrates survey,the leaves of 352 dominant psammophyte samples belonging to 167 species were collected cross a 3000 km east-west transect in sandy environments,north-ern China.The samples were further classified into the following groups on the basis of plant life forms and functional groups(pho-tosynthesis pathways and nitrogen fixation).The structural equation modeling was employed to clarify the importance of biological and environmental factors on leaf N:P stoichiometry.Important Findings Generally,the higher leaf N and P concentrations,but lower N:P ratio were found in psammophyte compared with other ecosystems.Mean annual temperature(MAT)influenced the leaf N,P concentra-tions negatively,while mean annual precipitation(MAP)did posi-tively.MAP played greater influence on leaf N,P concentrations than MAT did.MAP affected leaf N,P concentrations directly or indirectly through phylogeny,while MAT only shown direct effect on leaf N concentration.The psammophyte was more limited by N,rather P,in sandy region of northern China.These results suggest that phylogeny of psammophyte and climate jointly influence leaf N:P stoichiometry,and the results could be helpful in modeling bio-geochemical nutrients cycling in vulnerable ecosystems like sandy environment.展开更多
基金supported by Agriculture and Food Research Initiative Competitive Grants(2022-67015-36200)from the USDA National Institute of Food and Agriculture。
文摘Background We recently reported that supplementing glycine to soybean meal-based diets is necessary for the optimum growth of 5-to 40-g(Phase-I)and 110-to 240-g(Phase-II)hybrid striped bass(HSB),as well as their intestinal health.Although glycine serves as an essential substrate for syntheses of creatine and glutathione(GSH)in mammals(e.g.,pigs),little is known about these metabolic pathways or their nutritional regulation in fish.This study tested the hypothesis that glycine supplementation enhances the activities of creatine-and GSH-forming enzymes as well as creatine and GSH availabilities in tissues of hybrid striped bass(HSB;Morone saxatilis♀×Morone chrysops♂).Methods Phase-I and Phase-II HSB were fed a soybean meal-based diet supplemented with 0%,1%,or 2%glycine for 8 weeks.At the end of the 56-d feeding,tissues(liver,intestine,skeletal muscle,kidneys,and pancreas)were collected for biochemical analyses.Results In contrast to terrestrial mammals and birds,creatine synthesis occurred primarily in skeletal muscle from all HSB.The liver was most active in GSH synthesis among the HSB tissues studied.In Phase-I HSB,supplementation with 1%or 2%glycine increased(P<0.05)concentrations of intramuscular creatine(15%–19%)and hepatic GSH(8%–11%),while reducing(P<0.05)hepatic GSH sulfide(GSSG)/GSH ratios by 14%–15%,compared with the 0-glycine group;there were no differences(P>0.05)in these variables between the 1%and 2%glycine groups.In Phase-II HSB,supplementation with 1%and 2%glycine increased(P<0.05)concentrations of creatine and GSH in the muscle(15%–27%)and liver(11%–20%)in a dose-dependent manner,with reduced ratios of hepatic GSSG/GSH in the 1%or 2%glycine group.In all HSB,supplementation with 1%and 2%glycine dose-dependently increased(P<0.05)activities of intramuscular arginine:glycine amidinotransferase(22%–41%)and hepaticγ-glutamylcysteine synthetase(17%–37%),with elevated activities of intramuscular guanidinoacetate methyltransferase and hepatic GSH synthetase and GSH reductase in the 1%or 2%glycine group.Glycine supplementation also increased(P<0.05)concentrations of creatine and activities of its synthetic enzymes in tail kidneys and pancreas,and concentrations of GSH and activities of its synthetic enzymes in the proximal intestine.Conclusions Skeletal muscle and liver are the major organs for creatine and GSH syntheses in HSB,respectively.Dietary glycine intake regulates creatine and GSH syntheses by both Phase-I and Phase-II HSB in a tissue-specific manner.Based on the metabolic data,glycine is a conditionally essential amino acid for the growing fish.
基金supported by Agriculture and Food Research Initiative Competitive Grant no.2014–05142 from the USDA National Institute of Food and Agriculture.
文摘Background:Most embryonic loss in pigs occurs before d 30 of gestation.Dietary supplementation with L-arginine(Arg) during early gestation can enhance the survival and development of conceptuses(embryo/fetus and its extraembryonic membranes) in gilts.However,the underlying mechanisms remain largely unknown.Methods:Between d 14 and 30 of gestation,each gilt was fed daily 2 kg of a corn-and soybean-meal based diet(12% crude protein) supplemented with either 0.4% Arg(as Arg-HCl) or an isonitrogenous amount of L-alanine(Control).There were 10 gilts per treatment group.On d 30 of gestation,gilts were fed either Arg-HCl or L-alanine 30 min before they were hysterectomized,followed by the collection of placentae,embryos,fetal membranes,and fetal fluids.Amniotic and allantoic fluids were analyzed for nitrite and nitrate [NOx;stable oxidation products of nitric oxide(NO)],polyamines,and amino acids.Placentae were analyzed for syntheses of NO and polyamines,water and amino acid transport,concentrations of amino acid-related metabolites,and the expression of angiogenic factors and aquaporins(AQPs).Results:Compared to the control group,Arg supplementation increased(P < 0.05) the number of viable fetuses by 1.9 per litter,the number and diameter of placental blood vessels(+ 25.9% and + 17.0% respectively),embryonic survival(+ 18.5%),total placental weight(+ 36.5%),the total weight of viable fetuses(+ 33.5%),fetal crown-to-rump length(+ 4.7%),and total allantoic and amniotic fluid volumes(+ 44.6% and + 75.5% respectively).Compared to control gilts,Arg supplementation increased(P < 0.05) placental activities of GTP cyclohydrolase-1(+ 33.1%) and ornithine decarboxylase(+ 29.3%);placental syntheses of NO(+ 26.2%) and polyamines(+ 28.9%);placental concentrations of NOx(+ 22.5%),tetrahydrobiopterin(+ 21.1%),polyamines(+ 20.4%),c AMP(+ 27.7%),and c GMP(+ 24.7%);total amounts of NOx(+ 61.7% to + 96.8%),polyamines(+ 60.7% to + 88.7%),amino acids(+ 39% to + 118%),glucose(+ 60.5% to + 62.6%),and fructose(+ 41.4% to + 57.0%) in fetal fluids;and the placental transport of water(+ 33.9%),Arg(+ 78.4%),glutamine(+ 89.9%),and glycine(+ 89.6%).Furthermore,Arg supplementation increased(P < 0.05) placental m RNA levels for angiogenic factors [VEGFA120(+ 117%),VEGFR1(+ 445%),VEGFR2(+ 373%),PGF(+ 197%),and GCH1(+ 126%)] and AQPs [AQP1(+ 280%),AQP3(+ 137%),AQP5(+ 172%),AQP8(+ 165%),and AQP9(+ 127%)].Conclusion:Supplementing 0.4% Arg to a conventional diet for gilts between d 14 and d 30 of gestation enhanced placental NO and polyamine syntheses,angiogenesis,and water and amino acid transport to improve conceptus development and survival.
基金jointly supported by the Project of National Natural Science Foundation China(No.31790411 and 31902165)Natural Science Foundation of Guangdong Province(2021A1515012116 and 2019A1515011443)。
文摘This study was to evaluate the effects of glucose tolerance status,maternal starch supplementation and soybean substitution in diets on the performance of dams and their offspring.Eighty-eight pregnant sows(Landrace x Large White)were selected from an initial total of 120 sows,based on blood glucose test values,and assigned to 4 experimental treatments in a 2×2 factorial design.The factors were glucose tolerance status(glucose intolerant[GIT]vs.normal glucose tolerant[NGT])or dietary treatments(corn starch diet[CS]vs.soybean substitution diet[SSI]).A higher area under the curve(AUC)for post-meal glucose was observed(P<0.05)in the GIT group than in the NGT group on d 109 of gestation.The CS group had a lower value of homeostasis model assessment-insulin resistance than the SS group(P<0.05)on d 109 of gestation.Corn starch supplementation for sows decreased the stillbirth rate(P<0.05),regardless of the sows’glucose tolerance status.The villus height of the jejunum and the villus height to crypt depth ratio of the ileum were greater in normal birth weight piglets from the CS group than from the SS group(P<0.01),and so was the activity of sucrase in the jejunum and ileum(P<0.01).Compared with the SS group,the CS group showed a reduction in pre-weaning mortality rate,an increase in the number of high-birth-weight piglets,and a decrease in the number of low-birth-weight piglets(P<0.05)under GIT status.In conclusion,sows fed CS decreased stillbirth rate and improved insulin resistance,as well as improving the intestinal morphology and digestive enzyme activities of their progeny,regardless of glucose tolerance status.Additionally,the CS group improved birth weight distribution and decreased pre-weaning mortality rate of piglets under GIT status.
基金State Key Basic Research and Development Plan(2013CB429904)grants from National Natural Science Foundation of China(31170371,31570393).
文摘Aims Biological and environmental factors determine geographic patterns of plant nutrient stoichiometry jointly.Unraveling the distribution pattern and the potential drivers of nutrient stoichiometry is therefore critical for understanding the adaptive strategies and biogeochem-istry cycling.Aimed to determine how leaf nitrogen(N):phosphorus(P)stoichiometry is linked to biological and environmental factors,we investigated the patterns of psammophyte leaf N:P stoichiometry in sandy region,northern China,and the potential factors affecting leaf N:P stoichiometry were explored.Methods Based on 10 m×10 m quadrates survey,the leaves of 352 dominant psammophyte samples belonging to 167 species were collected cross a 3000 km east-west transect in sandy environments,north-ern China.The samples were further classified into the following groups on the basis of plant life forms and functional groups(pho-tosynthesis pathways and nitrogen fixation).The structural equation modeling was employed to clarify the importance of biological and environmental factors on leaf N:P stoichiometry.Important Findings Generally,the higher leaf N and P concentrations,but lower N:P ratio were found in psammophyte compared with other ecosystems.Mean annual temperature(MAT)influenced the leaf N,P concentra-tions negatively,while mean annual precipitation(MAP)did posi-tively.MAP played greater influence on leaf N,P concentrations than MAT did.MAP affected leaf N,P concentrations directly or indirectly through phylogeny,while MAT only shown direct effect on leaf N concentration.The psammophyte was more limited by N,rather P,in sandy region of northern China.These results suggest that phylogeny of psammophyte and climate jointly influence leaf N:P stoichiometry,and the results could be helpful in modeling bio-geochemical nutrients cycling in vulnerable ecosystems like sandy environment.
