Background: Ruminal microbes are vital to the conversion of lignocellulose-rich plant materials into nutrients for ruminants.Although protozoa play a key role in linking ruminal microbial networks,the contribution of ...Background: Ruminal microbes are vital to the conversion of lignocellulose-rich plant materials into nutrients for ruminants.Although protozoa play a key role in linking ruminal microbial networks,the contribution of protozoa to rumen fermentation remains controversial; therefore,this meta-analysis was conducted to quantitatively summarize the temporal dynamics of methanogenesis,ruminal volatile fatty acid(VFA) profiles and dietary fiber digestibility in ruminants following the elimination of protozoa(also termed defaunation).A total of 49 studies from 22 publications were evaluated.Results: The results revealed that defaunation reduced methane production and shifted ruminal VFA profiles to consist of more propionate and less acetate and butyrate,but with a reduced total VFA concentration and decreased dietary fiber digestibility.However,these effects were diminished linearly,at different rates,with time during the first few weeks after defaunation,and eventually reached relative stability.The acetate to propionate ratio and methane production were increased at 7 and 11 wk after defaunation,respectively.Conclusions: Elimination of protozoa initially shifted the rumen fermentation toward the production of more propionate and less methane,but eventually toward the production of less propionate and more methane over time.展开更多
Two experiments were conducted to determine the effects of fiber level from alfalfa meal and sampling time on the apparent ileal digestibility（AID） and standardized ileal digestibility（SID） of amino acids（AA） in...Two experiments were conducted to determine the effects of fiber level from alfalfa meal and sampling time on the apparent ileal digestibility（AID） and standardized ileal digestibility（SID） of amino acids（AA） in growing pigs. A total of 24 ileal-cannulated pigs（Duroc×（Large White×Landrace） with body weight（21.4±1.5） kg） were randomly allotted to 4 treatments. The pigs were provided a corn-soybean meal diet or a diet containing 5, 10 or 20% of alfalfa meal during two 10-d experimental periods. The AID of AA was measured. Six ileal-cannulated pigs were fed a protein-free diet in order to estimate the endogenous protein losses and SID of AA. Ileal AA digestibility was not affected by inclusion of 5 or 10% alfalfa meal in the diet（P〉0.05）. The AID of His, Lys, Met, Phe, Thr, Val, Ala, Asp, Cys, Gly, Pro, Ser and Tyr reduced by 2.0–6.8% with the addition level of alfalfa meal（linear, P〈0.05）. The SID of His, Lys, Ser, Thr and Tyr decreased by 2.2–4.3% as the level of alfalfa meal in the diet increased（linear, P〈0.05）. The AID and SID of AA were not affected by the sampling time（P〉0.05）. A multiple linear regression analysis, taking into account both the soluble and insoluble fiber content in the diets, explained more than 36% of variation in SID of Ser and Thr（P〈0.05）. In conclusion, the corn-soybean meal diet containing 10% of alfalfa meal did not affect ileal AA digestion. The AID and SID of AA were similar between two sampling times. Increasing the concentration of total dietary fiber from 12.3 to 21.4% by adding graded levels of alfalfa meal（0–20%） to a corn-soybean meal control diet induced a linear reduction in AID and SID of most AA. Soluble and insoluble fibers from alfalfa meal have differential roles in the AA digestion, which may help explain the variation observed in the SID of partial AA. These findings would provide important information for dietary fiber level and composition related to AA digestion.展开更多
本研究旨在通过检索文献构建数据库,建立肉羊饲粮营养物质表观消化率预测模型并解析其影响因素。通过检索Web of Science、PubMed、中国知网等文献数据库,搜集包含肉羊饲粮营养物质表观消化率的文献,提取相关数据构建数据库,采用多元回...本研究旨在通过检索文献构建数据库,建立肉羊饲粮营养物质表观消化率预测模型并解析其影响因素。通过检索Web of Science、PubMed、中国知网等文献数据库,搜集包含肉羊饲粮营养物质表观消化率的文献,提取相关数据构建数据库,采用多元回归法分别构建干物质表观消化率(DMD)、总能表观消化率(GED)、粗蛋白质表观消化率(CPD)、中性洗涤纤维表观消化率(NDFD)和酸性洗涤纤维表观消化率(ADFD)预测模型并进行模型准确性评估,使用方差分解法对肉羊饲粮营养物质表观消化率的影响因素进行解析。结果显示:本研究纳入文献99篇,数据4179条,成功构建包含肉羊DMD、GED、CPD、NDFD和ADFD及其潜在影响因素的数据库;DMD、GED、CPD、NDFD和ADFD分别为(66.13±8.63)%、(63.81±10.23)%、(64.18±9.31)%、(52.57±12.13)%和(46.11±12.14)%;相关性分析表明肉羊代谢体重(MBW)、相对体成熟度(RM)、平均日增重(ADG)和干物质采食量(DMI)以及饲粮干物质(DM)、代谢能(ME)、粗蛋白质(CP)、中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)含量均可影响其营养物质表观消化率;本研究构建的肉羊饲粮DMD、GED、CPD、NDFD和ADFD预测模型可分别解释65.0%、95.0%、67.0%、51.0%和47.0%的变异,平均偏差(MB)分别为0.332、6.346、-0.469、-0.073和0.098个百分点,预测均方根误差(RMSPE)分别为7.1%、23.1%、8.3%、17.5%和20.2%;方差分解结果显示,DMD最主要的影响因素是MBW和DMI;GED最主要的影响因素是RM和饲粮DM含量;CPD最主要的影响因素是DMI、ADG和MBW;NDFD和ADFD最主要的影响因素是饲粮DM、CP含量及MBW和RM。本研究获得了肉羊饲粮营养物质表观消化率的预测模型,并解析了其主要影响因素,可为我国肉羊营养需要量研究和精准化饲养提供参数。展开更多
基金supported by the National Key Research and Development Program of China(grant number:2017YFD0500500)
文摘Background: Ruminal microbes are vital to the conversion of lignocellulose-rich plant materials into nutrients for ruminants.Although protozoa play a key role in linking ruminal microbial networks,the contribution of protozoa to rumen fermentation remains controversial; therefore,this meta-analysis was conducted to quantitatively summarize the temporal dynamics of methanogenesis,ruminal volatile fatty acid(VFA) profiles and dietary fiber digestibility in ruminants following the elimination of protozoa(also termed defaunation).A total of 49 studies from 22 publications were evaluated.Results: The results revealed that defaunation reduced methane production and shifted ruminal VFA profiles to consist of more propionate and less acetate and butyrate,but with a reduced total VFA concentration and decreased dietary fiber digestibility.However,these effects were diminished linearly,at different rates,with time during the first few weeks after defaunation,and eventually reached relative stability.The acetate to propionate ratio and methane production were increased at 7 and 11 wk after defaunation,respectively.Conclusions: Elimination of protozoa initially shifted the rumen fermentation toward the production of more propionate and less methane,but eventually toward the production of less propionate and more methane over time.
基金financially supported by the Project of State Key Laboratory of Animal Nutrition,Ministry of Science and Technology,China(2004DA125184G1104)the Agricultural Science and Technology Innovation Program,Chinese Academy of Agricultural Sciences,China(ASTIP-IAS07)
文摘Two experiments were conducted to determine the effects of fiber level from alfalfa meal and sampling time on the apparent ileal digestibility（AID） and standardized ileal digestibility（SID） of amino acids（AA） in growing pigs. A total of 24 ileal-cannulated pigs（Duroc×（Large White×Landrace） with body weight（21.4±1.5） kg） were randomly allotted to 4 treatments. The pigs were provided a corn-soybean meal diet or a diet containing 5, 10 or 20% of alfalfa meal during two 10-d experimental periods. The AID of AA was measured. Six ileal-cannulated pigs were fed a protein-free diet in order to estimate the endogenous protein losses and SID of AA. Ileal AA digestibility was not affected by inclusion of 5 or 10% alfalfa meal in the diet（P〉0.05）. The AID of His, Lys, Met, Phe, Thr, Val, Ala, Asp, Cys, Gly, Pro, Ser and Tyr reduced by 2.0–6.8% with the addition level of alfalfa meal（linear, P〈0.05）. The SID of His, Lys, Ser, Thr and Tyr decreased by 2.2–4.3% as the level of alfalfa meal in the diet increased（linear, P〈0.05）. The AID and SID of AA were not affected by the sampling time（P〉0.05）. A multiple linear regression analysis, taking into account both the soluble and insoluble fiber content in the diets, explained more than 36% of variation in SID of Ser and Thr（P〈0.05）. In conclusion, the corn-soybean meal diet containing 10% of alfalfa meal did not affect ileal AA digestion. The AID and SID of AA were similar between two sampling times. Increasing the concentration of total dietary fiber from 12.3 to 21.4% by adding graded levels of alfalfa meal（0–20%） to a corn-soybean meal control diet induced a linear reduction in AID and SID of most AA. Soluble and insoluble fibers from alfalfa meal have differential roles in the AA digestion, which may help explain the variation observed in the SID of partial AA. These findings would provide important information for dietary fiber level and composition related to AA digestion.
文摘本研究旨在通过检索文献构建数据库,建立肉羊饲粮营养物质表观消化率预测模型并解析其影响因素。通过检索Web of Science、PubMed、中国知网等文献数据库,搜集包含肉羊饲粮营养物质表观消化率的文献,提取相关数据构建数据库,采用多元回归法分别构建干物质表观消化率(DMD)、总能表观消化率(GED)、粗蛋白质表观消化率(CPD)、中性洗涤纤维表观消化率(NDFD)和酸性洗涤纤维表观消化率(ADFD)预测模型并进行模型准确性评估,使用方差分解法对肉羊饲粮营养物质表观消化率的影响因素进行解析。结果显示:本研究纳入文献99篇,数据4179条,成功构建包含肉羊DMD、GED、CPD、NDFD和ADFD及其潜在影响因素的数据库;DMD、GED、CPD、NDFD和ADFD分别为(66.13±8.63)%、(63.81±10.23)%、(64.18±9.31)%、(52.57±12.13)%和(46.11±12.14)%;相关性分析表明肉羊代谢体重(MBW)、相对体成熟度(RM)、平均日增重(ADG)和干物质采食量(DMI)以及饲粮干物质(DM)、代谢能(ME)、粗蛋白质(CP)、中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)含量均可影响其营养物质表观消化率;本研究构建的肉羊饲粮DMD、GED、CPD、NDFD和ADFD预测模型可分别解释65.0%、95.0%、67.0%、51.0%和47.0%的变异,平均偏差(MB)分别为0.332、6.346、-0.469、-0.073和0.098个百分点,预测均方根误差(RMSPE)分别为7.1%、23.1%、8.3%、17.5%和20.2%;方差分解结果显示,DMD最主要的影响因素是MBW和DMI;GED最主要的影响因素是RM和饲粮DM含量;CPD最主要的影响因素是DMI、ADG和MBW;NDFD和ADFD最主要的影响因素是饲粮DM、CP含量及MBW和RM。本研究获得了肉羊饲粮营养物质表观消化率的预测模型,并解析了其主要影响因素,可为我国肉羊营养需要量研究和精准化饲养提供参数。
