Background In this study,the effects of L-leucine(Leu)on rumen fermentation parameters,rumen epithelium development,amino acid composition,rumen bacterial communities and rumen metabolites in beef cattle were investig...Background In this study,the effects of L-leucine(Leu)on rumen fermentation parameters,rumen epithelium development,amino acid composition,rumen bacterial communities and rumen metabolites in beef cattle were investigated.Twenty-four fattening Angus females of similar initial weight(575.5±22.1 kg)were randomly assigned to 2 treatments with 4 replicate pens(3 cattle per pen).They were fed either a basal diet or a basal diet supplemented with 6.0 g L-Leu/100 kg BW/d for 120 d.Results(1)Leu increased the ruminal concentrations of total volatile fatty acid(VFA)(P=0.017),propionate(P=0.023),isovalerate(P=0.001),and branched-chain volatile fatty acid(BCVFA)(P=0.01)at 4 h post-feeding.It also tended to increase acetate(P=0.083)and decrease the ammonia-N(NH_3-N)concentration(P=0.055),but it did not affect ruminal pH(P>0.1).Leu also increased microbial crude protein(MCP)(P=0.026)at 4 h post-feeding,but decreased MCP at 8 h post-feeding(P=0.010).(2)Supplementation with L-Leu increased the ruminal concentrations of phenylalanine(P=0.011),lysine(P=0.034),and tyrosine(P=0.033),while decreasing the cystine concentration(P=0.010).(3)Leu increased the thickness of the stratum spinosum and basal(P<0.05),while decreasing the thickness of the stratum granulosum(P<0.05).(4)Leu upregulated the relative mRNA abundance of genes involved in tight junction proteins(P<0.05)and VFA absorption and metabolism(P<0.01)in the rumen epithelium.This upregulation was positively correlated with the concentrations ruminal isovalerate and BCVFA(P<0.01).(5)L-Leu did not affect the diversity and richness of ruminal microbes(P>0.05),but differential bacterial biomarkers(LEfSe,LDA>2)were either positively or negatively correlated with ruminal MCP,NH_3-N,and BCVFA concentrations(P<0.001).Additionally,differential bacterial metabolites(OPLS-DA,VIP>1.5)were primarily enriched in the amino acid metabolism pathway and the cofactors and vitamins metabolism pathway(P<0.05).Conclusions Dietary supplementation with L-Leu altered rumen fermentation parameters and patterns,improved rumen epithelial morphology,and enhanced the expression of genes related to VFA absorption and metabolism in the rumen epithelium of beef cattle.展开更多
The 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR ) is an essential enzyme in cholesterol biosynthesis. To study the expression of HMGR in adipose and muscle tissues, and some performance indexes of four age stages, ...The 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR ) is an essential enzyme in cholesterol biosynthesis. To study the expression of HMGR in adipose and muscle tissues, and some performance indexes of four age stages, twelve Lilu cattle were selected. The results indicated that the Lilu beef cattle have good production and slaughter performance. HMGR mRNA expression level in adipose was higher than in muscle, but the trend in adipose was the same as in muscle. HMGR mRNA expression is difference in adipose and muscle tissues suggesting this gene is expressed in a tissue-dependent manner in cattle. Understanding the causes of variation in HMGR gene expression may provide crucial information about cholesterol biosynthesis in Lilu beef cattle.展开更多
The present trial was performed to reveal the regulatory effects of L-theanine on the levels of lipopolysaccharide(LPS)endotoxin within different biofluids,as well as relevant inflammatory responses of dairy cattle un...The present trial was performed to reveal the regulatory effects of L-theanine on the levels of lipopolysaccharide(LPS)endotoxin within different biofluids,as well as relevant inflammatory responses of dairy cattle under heat stress conditions.Thirty lactating Chinese Holstein dairy cattle(189±47 d in milk,and 2±1 parities)were allocated in a completely randomized design to each of 3 dietary treatments:the control(CON,0 g/d per cow L-theanine),the low L-theanine dosage treatment(LL,16 g/d per cow L-theanine),and the high L-theanine dosage treatment(HL,32 g/d per cow L-theanine).This trial consisted of 38 d(7 d for adaption and 31 d for data and sample collection),and sample collection for rumen liquid,blood plasma or serum,and milk were conducted on the d 27 and 38,respectively.Dairy cattle were constantly exposed to environmental heat stress during this experiment according to the recorded temperature-humidity index(THI).In the LL treatment,LPS concentration in rumen liquid was higher(P<0.05),whilst LPS densities in plasma and milk were lower(P<0.05)than those of the CON.Supplementing L-theanine at 2 dosages both significantly lowered(P<0.05)the level of interleukin(IL)-1βin the serum.Results of the present study suggested that L-theanine could be a promising additive in reducing the detrimental effects of heat stress on dairy cows,and L-theanine supplementation at 16 g/d per cow is preferred because it reduced the LPS translocation into the peripheral blood and LPS accumulation in the milk,as well as mitigated LPS-induced inflammatory reactions in dairy cows during heat stress.Further studies are necessitated to investigate the underlying mechanisms of L-theanine in LPS alteration and inflammation alleviation.展开更多
The purpose of this study was to investigate the effects of dietary L-theanine supplementation on apparent nutrient digestibility,milk yield,milk composition,and blood biochemical indices of dairy cows under heat stre...The purpose of this study was to investigate the effects of dietary L-theanine supplementation on apparent nutrient digestibility,milk yield,milk composition,and blood biochemical indices of dairy cows under heat stress.Thirty Chinese Holstein cows(19.84±2.42 kg milk/d,192.36±40.77 d in milk and2±0.93 parities)were divided into 3 groups of 10 animals each.The control group was fed a basal total mixed ration(TMR)diet,while treatment 1(LTA16)and treatment 2(LTA32)groups were fed a basal TMR diet supplemented with L-theanine at 16 and 32 g/cow per day,respectively.The results showed that feeding the dairy cows with LTA16 treatment decreased(P<0.05)their rectal temperature,whereas feeding with LTA32 treatment decreased(P<0.05)their rumen fluid ammonia nitrogen content.In comparison to the control group,the supplementation of L-theanine had no significant effect(P>0.05)on the dry matter intake,nutrient digestibility,total volatile fatty acid(TVFA)concentration and molar proportion of volatile fatty acid,milk yield,milk composition,feed efficiency and antioxidant capacity of the dairy cows.The triglyceride(TG)content of the LTA32 group was significantly greater(P=0.014)than that of the control group.With the increase in L-theanine dosage,the serum cholesterol(CHOL)content significantly increased(P=0.013).The serum albumin(ALB;P=0.067),low-density lipoprotein cholesterol(LDL-C;P=0.053),and high-density lipoprotein cholesterol(HDL-C;P=0.067)contents showed an upward trend as L-theanine dosage increased.Ultimately,the results of this study show that supplementing dairy cow diet with L-theanine could decrease dairy cow rectal temperature,affect lipid metabolism,and potentially relieve the heat stress of dairy cows to some extent.展开更多
This study was to evaluate how low phosphorus(P)diets affect growth performance and fecal P excretion in Xia-Nan cattle and to elucidate the underlying mechanisms.Thirty-two healthy Xia-Nan bulls with similar body wei...This study was to evaluate how low phosphorus(P)diets affect growth performance and fecal P excretion in Xia-Nan cattle and to elucidate the underlying mechanisms.Thirty-two healthy Xia-Nan bulls with similar body weights(BW;267.42±45.77 kg)were assigned to four groups with eight individual replicate pens per group in a completely randomized block design,stratified by initial BW and average dry matter intake(DMI).Cattle were fed total mixed rations(concentrate-to-forage ratio 40:60)with varying dietary P levels(DM basis):0.16%(XPA),0.19%(XPB),0.22%(XPC),and 0.25%(XPD;control)for 90 d.The first three groups were considered low-P treatments.Compared with the XPD group,XPA showed significantly lower average daily gain(ADG;P=0.018)and DMI(P=0.046),while XPB and XPC showed no differences(P>0.05).XPB group showed a significant lower feed conversion ratio(FCR)than XPA(P=0.049)and had the lowest FCR among all groups.Total-tract apparent digestibility of calcium(Ca;P=0.006)and P(P=0.006)decreased linearly with dietary P reduction.P intake(P<0.001)and fecal P content(P<0.001)were significantly lower in low-P groups than in the XPD group and decreased linearly with P reduction.Serum concentrations of parathormone hormone(PTH;P<0.001),1,25-dihydroxyvitamin D_(3)(1,25(OH)_(2)D_(3);P=0.005),Ca(P<0.001),and P(P<0.001)were positively correlated with decreasing dietary P levels,whereas calcitonin(CT;P=0.016)and alkaline phosphatase(ALP;P=0.006)were negatively correlated.XPB and XPD groups had higher molar proportions of propionate(P<0.001)and butyrate(P=0.006)but lower acetate molar proportion(P<0.001)and acetate-to-propionate ratio(P<0.001)than XPA.Fecal P excretion correlated positively with Ruminococcaceae_UCG-005,Saccharofermentans,and Butyrivibrio,and negatively with Rikenellaceae_RC9_gut_group and uncultured_bacteriumf_F082.These results suggest that reducing dietary P to 0.19%(XPB)maintained optimal growth performance while reducing environmental P pollution in XiaNan cattle.展开更多
基金supported by the National Key R&D Program(Grant No.2022YFD1301101-1)National Natural Science Foundation of China(Grant No.32172758)Key Research and Development Program of Ningxia(Grant No.2024BBF01008)。
文摘Background In this study,the effects of L-leucine(Leu)on rumen fermentation parameters,rumen epithelium development,amino acid composition,rumen bacterial communities and rumen metabolites in beef cattle were investigated.Twenty-four fattening Angus females of similar initial weight(575.5±22.1 kg)were randomly assigned to 2 treatments with 4 replicate pens(3 cattle per pen).They were fed either a basal diet or a basal diet supplemented with 6.0 g L-Leu/100 kg BW/d for 120 d.Results(1)Leu increased the ruminal concentrations of total volatile fatty acid(VFA)(P=0.017),propionate(P=0.023),isovalerate(P=0.001),and branched-chain volatile fatty acid(BCVFA)(P=0.01)at 4 h post-feeding.It also tended to increase acetate(P=0.083)and decrease the ammonia-N(NH_3-N)concentration(P=0.055),but it did not affect ruminal pH(P>0.1).Leu also increased microbial crude protein(MCP)(P=0.026)at 4 h post-feeding,but decreased MCP at 8 h post-feeding(P=0.010).(2)Supplementation with L-Leu increased the ruminal concentrations of phenylalanine(P=0.011),lysine(P=0.034),and tyrosine(P=0.033),while decreasing the cystine concentration(P=0.010).(3)Leu increased the thickness of the stratum spinosum and basal(P<0.05),while decreasing the thickness of the stratum granulosum(P<0.05).(4)Leu upregulated the relative mRNA abundance of genes involved in tight junction proteins(P<0.05)and VFA absorption and metabolism(P<0.01)in the rumen epithelium.This upregulation was positively correlated with the concentrations ruminal isovalerate and BCVFA(P<0.01).(5)L-Leu did not affect the diversity and richness of ruminal microbes(P>0.05),but differential bacterial biomarkers(LEfSe,LDA>2)were either positively or negatively correlated with ruminal MCP,NH_3-N,and BCVFA concentrations(P<0.001).Additionally,differential bacterial metabolites(OPLS-DA,VIP>1.5)were primarily enriched in the amino acid metabolism pathway and the cofactors and vitamins metabolism pathway(P<0.05).Conclusions Dietary supplementation with L-Leu altered rumen fermentation parameters and patterns,improved rumen epithelial morphology,and enhanced the expression of genes related to VFA absorption and metabolism in the rumen epithelium of beef cattle.
文摘The 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR ) is an essential enzyme in cholesterol biosynthesis. To study the expression of HMGR in adipose and muscle tissues, and some performance indexes of four age stages, twelve Lilu cattle were selected. The results indicated that the Lilu beef cattle have good production and slaughter performance. HMGR mRNA expression level in adipose was higher than in muscle, but the trend in adipose was the same as in muscle. HMGR mRNA expression is difference in adipose and muscle tissues suggesting this gene is expressed in a tissue-dependent manner in cattle. Understanding the causes of variation in HMGR gene expression may provide crucial information about cholesterol biosynthesis in Lilu beef cattle.
基金the funding through the Hunan Provincial Natural Science Foundation(Grant No.2019JJ50279,2019RS3021)Hunan Provincial Education Department(Grant No.19B257)+2 种基金Hunan Provincial Science and Technology Department(Grant No.2017NK1020)Ministry of Science and Technology of China(Grant No.2018YFD0501604)National Natural Science Foundation of China(Grant No.31772633)。
文摘The present trial was performed to reveal the regulatory effects of L-theanine on the levels of lipopolysaccharide(LPS)endotoxin within different biofluids,as well as relevant inflammatory responses of dairy cattle under heat stress conditions.Thirty lactating Chinese Holstein dairy cattle(189±47 d in milk,and 2±1 parities)were allocated in a completely randomized design to each of 3 dietary treatments:the control(CON,0 g/d per cow L-theanine),the low L-theanine dosage treatment(LL,16 g/d per cow L-theanine),and the high L-theanine dosage treatment(HL,32 g/d per cow L-theanine).This trial consisted of 38 d(7 d for adaption and 31 d for data and sample collection),and sample collection for rumen liquid,blood plasma or serum,and milk were conducted on the d 27 and 38,respectively.Dairy cattle were constantly exposed to environmental heat stress during this experiment according to the recorded temperature-humidity index(THI).In the LL treatment,LPS concentration in rumen liquid was higher(P<0.05),whilst LPS densities in plasma and milk were lower(P<0.05)than those of the CON.Supplementing L-theanine at 2 dosages both significantly lowered(P<0.05)the level of interleukin(IL)-1βin the serum.Results of the present study suggested that L-theanine could be a promising additive in reducing the detrimental effects of heat stress on dairy cows,and L-theanine supplementation at 16 g/d per cow is preferred because it reduced the LPS translocation into the peripheral blood and LPS accumulation in the milk,as well as mitigated LPS-induced inflammatory reactions in dairy cows during heat stress.Further studies are necessitated to investigate the underlying mechanisms of L-theanine in LPS alteration and inflammation alleviation.
基金financially supported by National Key Research and Development Program(Grant No.2018YFD0501604)Hunan Provincial Science and Technology Major Project(Grant No.2017NK1020)+3 种基金Hunan Provincial Natural Science Foundation(Grant No.2019JJ50279)The Construction of Innovative in Hunan Province(Grant No.2019RS3021)Hunan Agricultural University(Grant No.17QN09)Effect of secondary metabolites of rapeseed meal on methane emission from goats(Grant No.2019ZDSYS01)。
文摘The purpose of this study was to investigate the effects of dietary L-theanine supplementation on apparent nutrient digestibility,milk yield,milk composition,and blood biochemical indices of dairy cows under heat stress.Thirty Chinese Holstein cows(19.84±2.42 kg milk/d,192.36±40.77 d in milk and2±0.93 parities)were divided into 3 groups of 10 animals each.The control group was fed a basal total mixed ration(TMR)diet,while treatment 1(LTA16)and treatment 2(LTA32)groups were fed a basal TMR diet supplemented with L-theanine at 16 and 32 g/cow per day,respectively.The results showed that feeding the dairy cows with LTA16 treatment decreased(P<0.05)their rectal temperature,whereas feeding with LTA32 treatment decreased(P<0.05)their rumen fluid ammonia nitrogen content.In comparison to the control group,the supplementation of L-theanine had no significant effect(P>0.05)on the dry matter intake,nutrient digestibility,total volatile fatty acid(TVFA)concentration and molar proportion of volatile fatty acid,milk yield,milk composition,feed efficiency and antioxidant capacity of the dairy cows.The triglyceride(TG)content of the LTA32 group was significantly greater(P=0.014)than that of the control group.With the increase in L-theanine dosage,the serum cholesterol(CHOL)content significantly increased(P=0.013).The serum albumin(ALB;P=0.067),low-density lipoprotein cholesterol(LDL-C;P=0.053),and high-density lipoprotein cholesterol(HDL-C;P=0.067)contents showed an upward trend as L-theanine dosage increased.Ultimately,the results of this study show that supplementing dairy cow diet with L-theanine could decrease dairy cow rectal temperature,affect lipid metabolism,and potentially relieve the heat stress of dairy cows to some extent.
基金supported by the Research and demonstration of key Technologies for low-cost,healthy and Efficient Beef Cattle breeding(Grant No.2024BBF01008)National Natural Science Foundation of China(Grant No.32302764)Hunan Provincial Natural Science Foundation(Grant No.2024JJ5179).
文摘This study was to evaluate how low phosphorus(P)diets affect growth performance and fecal P excretion in Xia-Nan cattle and to elucidate the underlying mechanisms.Thirty-two healthy Xia-Nan bulls with similar body weights(BW;267.42±45.77 kg)were assigned to four groups with eight individual replicate pens per group in a completely randomized block design,stratified by initial BW and average dry matter intake(DMI).Cattle were fed total mixed rations(concentrate-to-forage ratio 40:60)with varying dietary P levels(DM basis):0.16%(XPA),0.19%(XPB),0.22%(XPC),and 0.25%(XPD;control)for 90 d.The first three groups were considered low-P treatments.Compared with the XPD group,XPA showed significantly lower average daily gain(ADG;P=0.018)and DMI(P=0.046),while XPB and XPC showed no differences(P>0.05).XPB group showed a significant lower feed conversion ratio(FCR)than XPA(P=0.049)and had the lowest FCR among all groups.Total-tract apparent digestibility of calcium(Ca;P=0.006)and P(P=0.006)decreased linearly with dietary P reduction.P intake(P<0.001)and fecal P content(P<0.001)were significantly lower in low-P groups than in the XPD group and decreased linearly with P reduction.Serum concentrations of parathormone hormone(PTH;P<0.001),1,25-dihydroxyvitamin D_(3)(1,25(OH)_(2)D_(3);P=0.005),Ca(P<0.001),and P(P<0.001)were positively correlated with decreasing dietary P levels,whereas calcitonin(CT;P=0.016)and alkaline phosphatase(ALP;P=0.006)were negatively correlated.XPB and XPD groups had higher molar proportions of propionate(P<0.001)and butyrate(P=0.006)but lower acetate molar proportion(P<0.001)and acetate-to-propionate ratio(P<0.001)than XPA.Fecal P excretion correlated positively with Ruminococcaceae_UCG-005,Saccharofermentans,and Butyrivibrio,and negatively with Rikenellaceae_RC9_gut_group and uncultured_bacteriumf_F082.These results suggest that reducing dietary P to 0.19%(XPB)maintained optimal growth performance while reducing environmental P pollution in XiaNan cattle.
