Peste des petits ruminants(PPR) is a highly contagious transboundary animal disease with a severe socio-economic impact on the livestock industry, particularly in poor countries where it is endemic. Full understanding...Peste des petits ruminants(PPR) is a highly contagious transboundary animal disease with a severe socio-economic impact on the livestock industry, particularly in poor countries where it is endemic. Full understanding of PPR virus(PPRV)pathobiology and molecular biology is critical for effective control and eradication of the disease. To achieve these goals,establishment of stable reverse genetics systems for PPRV would play a key role. Unfortunately, this powerful technology remains less accessible and poorly documented for PPRV. In this review, we discussed the current status of PPRV reverse genetics as well as the recent innovations and advances in the reverse genetics of other non-segmented negative-sense RNA viruses that could be applicable to PPRV. These strategies may contribute to the improvement of existing techniques and/or the development of new reverse genetics systems for PPRV.展开更多
Background Bovine milk is an important source of nutrition for human consumption,and its quality is closely associated with the microbiota and metabolites in it.But there is limited knowledge about the milk microbiome...Background Bovine milk is an important source of nutrition for human consumption,and its quality is closely associated with the microbiota and metabolites in it.But there is limited knowledge about the milk microbiome and metabolome in cows with subacute ruminal acidosis.Methods Eight ruminally cannulated Holstein cows in mid lactation were selected for a 3-week experiment.The cows were randomly allocated into 2 groups,fed either a conventional diet(CON;40%concentrate;dry matter basis)or a high-concentrate diet(HC;60%concentrate;dry matter basis).Results The results showed that there was a decreased milk fat percentage in the HC group compared to the CON group.The amplicon sequencing results indicated that the alpha diversity indices were not affected by the HC feeding.At the phylum level,the milk bacteria were dominated by Proteobacteria,Actinobacteria,Bacteroidetes,and Firmicutes both in the CON and HC groups.At the genus level,the HC cows displayed an improved proportion of Labrys(P=0.015)compared with the CON cows.Results of both the principal components analysis and partial least squares of discriminant analysis of milk metabolome revealed that samples of the CON and HC groups clustered separately.A total of 31 differential metabolites were identified between the two groups.Of these,the levels of 11 metabolites decreased(α-linolenic acid,prostaglandin E2,L-lactic acid,L-malic acid,3-hydroxysebacic acid,succinyladenosine,guanosine,pyridoxal,L-glutamic acid,hippuric acid,and trigonelline),whereas the levels of the other 20 metabolites increased in the HC group with respect to the CON group(P<0.05).Conclusion These results suggested that subacute ruminal acidosis less impacted the diversity and composition of milk microbiota,but altered the milk metabolic profiles,which led to the decline of the milk quality.展开更多
Subacute ruminal acidosis(SARA)represents one of the most important digestive disorders in intensive dairy farms,and dairy cows are individually different in the severity of SARA risk.The objectives of the current stu...Subacute ruminal acidosis(SARA)represents one of the most important digestive disorders in intensive dairy farms,and dairy cows are individually different in the severity of SARA risk.The objectives of the current study were to investigate differences in the ruminal bacterial community and metabolome in dairy cattle with different susceptibility to SARA.In the present study,12 cows were initially enrolled in the experiment.Based on average ruminal pH,4 cows with the lowest ruminal pH were assigned to the susceptible group(SUS,pH=5.76,n=4)and 4 cows with the highest ruminal pH assigned to the tolerant group(TOL,pH=6.10,n=4).Rumen contents from susceptible(SUS,n=4)and tolerant(TOL,n=4)dairy cows were collected through rumen fistula to systematically reveal the rumen microbial and metabolic alterations of dairy cows with different susceptibility to SARA using multi-omics approaches(16S and 18S rRNA gene sequencing and metabolome).The results showed that despite being fed the same diet,SUS cows had lower ruminal pH and higher concentrations of total volatile fatty acids(VFA)and propionate than TOL cows(P<0.05).No significant differences were observed in dry matter intake,milk yield,and other milk compositions between the SUS and TOL groups(P>0.05).The principal coordinates analysis based on the analysis of molecular variance indicated a significant difference in bacterial composition between the two groups(P=0.01).More specifically,the relative abundance of starch-degrading bacteria(Prevotella spp.)was greater(P<0.05),while the proportion of fiber-degrading bacteria(unclassified Ruminococcaceae spp.,Ruminococcus spp.,Papillibacter,and unclassified Family_-XIII)was lower in the rumen of SUS cows compared with TOL cows(P<0.05).Community analysis of protozoa showed that there were no significant differences in the diversity,richness,and community structure(P>0.05).Metabolomics analysis revealed that the concentrations of organic acids(such as lactic acid),biogenic amines(such as histamine),and bacterial degradation products(such as hypoxanthine)were significantly higher in the SUS group compared to the TOL group(P<0.05).These findings revealed that the higher proportion of starch-degrading bacteria/lower fiber-degrading bacteria in the rumen of SUS cows resulted in higher VFA-producing capacity,in particular propionate.This caused a disruption in metabolic homeostasis in the rumen which might be the reason for the higher susceptibility to SARA.Overall,these findings enhanced our understanding of the ruminal microbiome and metabolic changes in cows susceptible to SARA.展开更多
Influenza A virus(IAV) has a wide host range,including wild birds,poultry,various mammals,and even humans(Xu et al.2024).Currently,two subtypes of canine influenza virus(CIV),H3N8 and H3N2,are primarily circulating in...Influenza A virus(IAV) has a wide host range,including wild birds,poultry,various mammals,and even humans(Xu et al.2024).Currently,two subtypes of canine influenza virus(CIV),H3N8 and H3N2,are primarily circulating in dogs.The H3N8 CIV was introduced from horses into dogs in 2004(Crawford et al.2005),while the H3N2 CIV originated from chickens in Asia in 2007(Song et al.2008).In China,H3N2 is the predominant CIV subtype,with a prevalence rate of up to 5.63% in the canine population,as reported by Chen et al.(2023).CIV infection typically manifests with symptoms such as coughing,sneezing,runny nose,and fever but is rarely fatal.However,co-infection with other pathogens(e.g.,Streptococcus,Mycoplasma or canine parainfluenza virus) can exacerbate symptoms and lead to lethal outcomes(Yondo et al.2023).展开更多
This review aims to give an overview of the efficacy of yeast supplementation on growth performance,rumen pH,rumen microbiota,and their relationship to meat and milk quality in ruminants.The practice of feeding high g...This review aims to give an overview of the efficacy of yeast supplementation on growth performance,rumen pH,rumen microbiota,and their relationship to meat and milk quality in ruminants.The practice of feeding high grain diets to ruminants in an effort to increase growth rate and weight gain usually results in excess deposition of saturated fatty acids in animal products and increased incidence of rumen acidosis.The supplementation of yeast at the right dose and viability level could counteract the acidotic effects of these high grain diets in the rumen and positively modify the fatty acid composition of animal products.Yeast exerts its actions by competing with lactate-producing(Streptococcus bovis and Lacto-bacillus)bacteria for available sugar and encouraging the growth of lactate-utilising bacteria(Mega-sphaera elsdenii).M.elsdenii is known to convert lactate into butyrate and propionate leading to a decrease in the accumulation of lactate thereby resulting in higher rumen pH.Interestingly,this creates a conducive environment for the proliferation of vaccenic acid-producing bacteria(Butyrivibrio fibrisolvens)and ciliate protozoa,both of which have been reported to increase the ruminal concentration of trans-11 and cis-9,trans-11-conjugated linoleic acid(CLA)at a pH range between 5.6 and 6.3.The addition of yeast into the diet of ruminants has also been reported to positively modify rumen biohydrogenation pathway to synthesise more of the beneficial biohydrogenation intermediates(trans-11 and cis-9,trans-11).This implies that more dietary sources of linoleic acid,linolenic acid,and oleic acid along with beneficial biohydrogenation intermediates(cis-9,trans-11-CLA,and trans-11)would escape complete bio-hydrogenation in the rumen to be absorbed into milk and meat.However,further studies are required to substantiate our claim.Therefore,techniques like transcriptomics should be employed to identify the mRNA transcript expression levels of genes like stearoyl-CoA desaturase,fatty acid synthase,and elon-gase of very long chain fatty acids 6 in the muscle.Different strains of yeast need to be tested at different doses and viability levels on the fatty acid profile of animal products as well as its vaccenic acid and rumenic acid composition.展开更多
基金supported by the National Key Research and Development Program of China (2016YFD0500108 and 2016YFE0204100)the International Cooperation Project of CAAS Innovation Program (CAAS-GJHZ201700X)
文摘Peste des petits ruminants(PPR) is a highly contagious transboundary animal disease with a severe socio-economic impact on the livestock industry, particularly in poor countries where it is endemic. Full understanding of PPR virus(PPRV)pathobiology and molecular biology is critical for effective control and eradication of the disease. To achieve these goals,establishment of stable reverse genetics systems for PPRV would play a key role. Unfortunately, this powerful technology remains less accessible and poorly documented for PPRV. In this review, we discussed the current status of PPRV reverse genetics as well as the recent innovations and advances in the reverse genetics of other non-segmented negative-sense RNA viruses that could be applicable to PPRV. These strategies may contribute to the improvement of existing techniques and/or the development of new reverse genetics systems for PPRV.
基金the National Key R&D Program of China(2022YFD1301001)Jiangsu Province Special Project for Carbon Peak&Carbon Neutral Science and Technology Innovation(BE2022309).
文摘Background Bovine milk is an important source of nutrition for human consumption,and its quality is closely associated with the microbiota and metabolites in it.But there is limited knowledge about the milk microbiome and metabolome in cows with subacute ruminal acidosis.Methods Eight ruminally cannulated Holstein cows in mid lactation were selected for a 3-week experiment.The cows were randomly allocated into 2 groups,fed either a conventional diet(CON;40%concentrate;dry matter basis)or a high-concentrate diet(HC;60%concentrate;dry matter basis).Results The results showed that there was a decreased milk fat percentage in the HC group compared to the CON group.The amplicon sequencing results indicated that the alpha diversity indices were not affected by the HC feeding.At the phylum level,the milk bacteria were dominated by Proteobacteria,Actinobacteria,Bacteroidetes,and Firmicutes both in the CON and HC groups.At the genus level,the HC cows displayed an improved proportion of Labrys(P=0.015)compared with the CON cows.Results of both the principal components analysis and partial least squares of discriminant analysis of milk metabolome revealed that samples of the CON and HC groups clustered separately.A total of 31 differential metabolites were identified between the two groups.Of these,the levels of 11 metabolites decreased(α-linolenic acid,prostaglandin E2,L-lactic acid,L-malic acid,3-hydroxysebacic acid,succinyladenosine,guanosine,pyridoxal,L-glutamic acid,hippuric acid,and trigonelline),whereas the levels of the other 20 metabolites increased in the HC group with respect to the CON group(P<0.05).Conclusion These results suggested that subacute ruminal acidosis less impacted the diversity and composition of milk microbiota,but altered the milk metabolic profiles,which led to the decline of the milk quality.
基金This research was funded by Natural Science Foundation of China(32072755)and the Fundamental Research Funds for the Central Universities(JCQY201905).
文摘Subacute ruminal acidosis(SARA)represents one of the most important digestive disorders in intensive dairy farms,and dairy cows are individually different in the severity of SARA risk.The objectives of the current study were to investigate differences in the ruminal bacterial community and metabolome in dairy cattle with different susceptibility to SARA.In the present study,12 cows were initially enrolled in the experiment.Based on average ruminal pH,4 cows with the lowest ruminal pH were assigned to the susceptible group(SUS,pH=5.76,n=4)and 4 cows with the highest ruminal pH assigned to the tolerant group(TOL,pH=6.10,n=4).Rumen contents from susceptible(SUS,n=4)and tolerant(TOL,n=4)dairy cows were collected through rumen fistula to systematically reveal the rumen microbial and metabolic alterations of dairy cows with different susceptibility to SARA using multi-omics approaches(16S and 18S rRNA gene sequencing and metabolome).The results showed that despite being fed the same diet,SUS cows had lower ruminal pH and higher concentrations of total volatile fatty acids(VFA)and propionate than TOL cows(P<0.05).No significant differences were observed in dry matter intake,milk yield,and other milk compositions between the SUS and TOL groups(P>0.05).The principal coordinates analysis based on the analysis of molecular variance indicated a significant difference in bacterial composition between the two groups(P=0.01).More specifically,the relative abundance of starch-degrading bacteria(Prevotella spp.)was greater(P<0.05),while the proportion of fiber-degrading bacteria(unclassified Ruminococcaceae spp.,Ruminococcus spp.,Papillibacter,and unclassified Family_-XIII)was lower in the rumen of SUS cows compared with TOL cows(P<0.05).Community analysis of protozoa showed that there were no significant differences in the diversity,richness,and community structure(P>0.05).Metabolomics analysis revealed that the concentrations of organic acids(such as lactic acid),biogenic amines(such as histamine),and bacterial degradation products(such as hypoxanthine)were significantly higher in the SUS group compared to the TOL group(P<0.05).These findings revealed that the higher proportion of starch-degrading bacteria/lower fiber-degrading bacteria in the rumen of SUS cows resulted in higher VFA-producing capacity,in particular propionate.This caused a disruption in metabolic homeostasis in the rumen which might be the reason for the higher susceptibility to SARA.Overall,these findings enhanced our understanding of the ruminal microbiome and metabolic changes in cows susceptible to SARA.
基金supported by the National Key Research and Development Program of China (2021YFD1800200)the National Natural Science Foundation of China (32170539)。
文摘Influenza A virus(IAV) has a wide host range,including wild birds,poultry,various mammals,and even humans(Xu et al.2024).Currently,two subtypes of canine influenza virus(CIV),H3N8 and H3N2,are primarily circulating in dogs.The H3N8 CIV was introduced from horses into dogs in 2004(Crawford et al.2005),while the H3N2 CIV originated from chickens in Asia in 2007(Song et al.2008).In China,H3N2 is the predominant CIV subtype,with a prevalence rate of up to 5.63% in the canine population,as reported by Chen et al.(2023).CIV infection typically manifests with symptoms such as coughing,sneezing,runny nose,and fever but is rarely fatal.However,co-infection with other pathogens(e.g.,Streptococcus,Mycoplasma or canine parainfluenza virus) can exacerbate symptoms and lead to lethal outcomes(Yondo et al.2023).
基金the Jiangsu Agricultural Science and Technology Innovation Fund(CX(19)1006).
文摘This review aims to give an overview of the efficacy of yeast supplementation on growth performance,rumen pH,rumen microbiota,and their relationship to meat and milk quality in ruminants.The practice of feeding high grain diets to ruminants in an effort to increase growth rate and weight gain usually results in excess deposition of saturated fatty acids in animal products and increased incidence of rumen acidosis.The supplementation of yeast at the right dose and viability level could counteract the acidotic effects of these high grain diets in the rumen and positively modify the fatty acid composition of animal products.Yeast exerts its actions by competing with lactate-producing(Streptococcus bovis and Lacto-bacillus)bacteria for available sugar and encouraging the growth of lactate-utilising bacteria(Mega-sphaera elsdenii).M.elsdenii is known to convert lactate into butyrate and propionate leading to a decrease in the accumulation of lactate thereby resulting in higher rumen pH.Interestingly,this creates a conducive environment for the proliferation of vaccenic acid-producing bacteria(Butyrivibrio fibrisolvens)and ciliate protozoa,both of which have been reported to increase the ruminal concentration of trans-11 and cis-9,trans-11-conjugated linoleic acid(CLA)at a pH range between 5.6 and 6.3.The addition of yeast into the diet of ruminants has also been reported to positively modify rumen biohydrogenation pathway to synthesise more of the beneficial biohydrogenation intermediates(trans-11 and cis-9,trans-11).This implies that more dietary sources of linoleic acid,linolenic acid,and oleic acid along with beneficial biohydrogenation intermediates(cis-9,trans-11-CLA,and trans-11)would escape complete bio-hydrogenation in the rumen to be absorbed into milk and meat.However,further studies are required to substantiate our claim.Therefore,techniques like transcriptomics should be employed to identify the mRNA transcript expression levels of genes like stearoyl-CoA desaturase,fatty acid synthase,and elon-gase of very long chain fatty acids 6 in the muscle.Different strains of yeast need to be tested at different doses and viability levels on the fatty acid profile of animal products as well as its vaccenic acid and rumenic acid composition.
