In dairy and food industries lactic acid bacteria （LAB） have been used in form of starter culture that plays vital role in fermentation; as flavouring and texturizing or as preservative agents. There is increasing e...In dairy and food industries lactic acid bacteria （LAB） have been used in form of starter culture that plays vital role in fermentation; as flavouring and texturizing or as preservative agents. There is increasing evidence that lactobacilli which inhabit the gastrointestinal tract develop antimicrobial activities and participate in the host＇s defence system[1]. During fermentation, most of the LAB produces a number of different compounds like organic acids, hydrogen peroxide, diacetyl, acetaldehyde, carbon dioxide, polysaccharides, and proteinaceous compounds called bacteriocins or bacteriocinogenic peptides.展开更多
The objective of the present study was to examine the effect of different weaning methods on the ruminal methanogenic archaea composition and diversity in Holstein calves.Thirty-six newborn Holstein bull calves were a...The objective of the present study was to examine the effect of different weaning methods on the ruminal methanogenic archaea composition and diversity in Holstein calves.Thirty-six newborn Holstein bull calves were assigned to 1 of 3 treatments:(1)conventional weaning(d 56)and fed a high proportion of solid feed(CWS);(2)conventional weaning(d 56)and fed a high proportion of liquid feed(CWL);(3)early weaning(d 42)and fed with a high proportion of solid feed(EWS).High-throughput sequencing of the methyl coenzyme M reductase(mcr A)gene,which encodes theα-subunit of methyl coenzyme M reductase-the enzyme that catalyzes the final step in methanogenesis was used to determine the composition and diversity of rumen methanogens.No significant difference(P>0.05)was observed for operational taxonomic units(OTUs)or richness indices,but diversity indices increased(P<0.05)for calves fed high dietary solids.Predominant families across the three treatments were Methanobacteriaceae,Thermoplasmataceae and Methanomassiliicoccaceae.Calves in the EWS treatment had a higher(P<0.05)relative abundance of Methanobrevibacter sp.strain AbM4 and Methanosphaera stadtmanae,while calves in the CWL treatment had a higher(P<0.05)abundance of Methanosphaera sp.strain SM9.A positive(P<0.05)relationship was identified between butyrate and Methanobrevibacter sp.strain AbM4.In conclusion,the composition and diversity of methanogens in the rumen of Holstein calves varied under the different weaning methods.This study identified a positive relationship between butyrate and Methanobrevibacter sp.strain AbM4,potentially reflecting correlations between ruminal fermentation variables and methanogenesis function.These in-depth analyses provide further understanding of weaning methods for intensified production systems.展开更多
以活菌数、水分含量、感官品质、消化特性、贮藏稳定性、干燥能耗和得率为指标,探究发酵豆乳粉的最佳干燥方式。结果表明:真空冷冻干燥处理的发酵豆乳粉具有较高的乳酸菌活菌数、抗性淀粉含量和贮藏稳定性,并具有较好的色泽、外观和冲调...以活菌数、水分含量、感官品质、消化特性、贮藏稳定性、干燥能耗和得率为指标,探究发酵豆乳粉的最佳干燥方式。结果表明:真空冷冻干燥处理的发酵豆乳粉具有较高的乳酸菌活菌数、抗性淀粉含量和贮藏稳定性,并具有较好的色泽、外观和冲调性,但其能耗高,生产效率较低;喷雾干燥处理的发酵豆乳粉具有较好的色泽、外观和冲调性,且水分含量低,其乳酸菌活菌数和贮藏稳定性略低于真空冷冻干燥,贮藏6个月后的活菌数仍能保持在7.31 lg CFU/g,且其干燥速度快,能耗小,适于发酵豆乳粉的规模化生产;与其他两种方式相比,45℃热风干燥处理的发酵豆乳粉冲调性和贮藏稳定性最差。综上,考虑到生产效率、能耗优势和产品质量,建议在发酵豆乳粉生产中运用喷雾干燥技术。展开更多
文摘In dairy and food industries lactic acid bacteria （LAB） have been used in form of starter culture that plays vital role in fermentation; as flavouring and texturizing or as preservative agents. There is increasing evidence that lactobacilli which inhabit the gastrointestinal tract develop antimicrobial activities and participate in the host＇s defence system[1]. During fermentation, most of the LAB produces a number of different compounds like organic acids, hydrogen peroxide, diacetyl, acetaldehyde, carbon dioxide, polysaccharides, and proteinaceous compounds called bacteriocins or bacteriocinogenic peptides.
基金supported by the Key Program for International S&T Cooperation Projects of China(2016YFE0109000)the National Key R&D Program of China(2017YFF0211702)+1 种基金the National Natural Science Foundation of China(41475126 and 31802085)the Young Scientist Lifting Project,China(2017–2019)
文摘The objective of the present study was to examine the effect of different weaning methods on the ruminal methanogenic archaea composition and diversity in Holstein calves.Thirty-six newborn Holstein bull calves were assigned to 1 of 3 treatments:(1)conventional weaning(d 56)and fed a high proportion of solid feed(CWS);(2)conventional weaning(d 56)and fed a high proportion of liquid feed(CWL);(3)early weaning(d 42)and fed with a high proportion of solid feed(EWS).High-throughput sequencing of the methyl coenzyme M reductase(mcr A)gene,which encodes theα-subunit of methyl coenzyme M reductase-the enzyme that catalyzes the final step in methanogenesis was used to determine the composition and diversity of rumen methanogens.No significant difference(P>0.05)was observed for operational taxonomic units(OTUs)or richness indices,but diversity indices increased(P<0.05)for calves fed high dietary solids.Predominant families across the three treatments were Methanobacteriaceae,Thermoplasmataceae and Methanomassiliicoccaceae.Calves in the EWS treatment had a higher(P<0.05)relative abundance of Methanobrevibacter sp.strain AbM4 and Methanosphaera stadtmanae,while calves in the CWL treatment had a higher(P<0.05)abundance of Methanosphaera sp.strain SM9.A positive(P<0.05)relationship was identified between butyrate and Methanobrevibacter sp.strain AbM4.In conclusion,the composition and diversity of methanogens in the rumen of Holstein calves varied under the different weaning methods.This study identified a positive relationship between butyrate and Methanobrevibacter sp.strain AbM4,potentially reflecting correlations between ruminal fermentation variables and methanogenesis function.These in-depth analyses provide further understanding of weaning methods for intensified production systems.
文摘以活菌数、水分含量、感官品质、消化特性、贮藏稳定性、干燥能耗和得率为指标,探究发酵豆乳粉的最佳干燥方式。结果表明:真空冷冻干燥处理的发酵豆乳粉具有较高的乳酸菌活菌数、抗性淀粉含量和贮藏稳定性,并具有较好的色泽、外观和冲调性,但其能耗高,生产效率较低;喷雾干燥处理的发酵豆乳粉具有较好的色泽、外观和冲调性,且水分含量低,其乳酸菌活菌数和贮藏稳定性略低于真空冷冻干燥,贮藏6个月后的活菌数仍能保持在7.31 lg CFU/g,且其干燥速度快,能耗小,适于发酵豆乳粉的规模化生产;与其他两种方式相比,45℃热风干燥处理的发酵豆乳粉冲调性和贮藏稳定性最差。综上,考虑到生产效率、能耗优势和产品质量,建议在发酵豆乳粉生产中运用喷雾干燥技术。
