研究旨在应用康奈尔绵羊净碳水化合物和蛋白质体系(Cornell sheep net carbohydrate and protein system,CNCPS-S)的预测模型预测日粮瘤胃pH值与微生物蛋白质(MCP)合成量,并通过实测验证模型预测值的准确性。选取3只安装瘤胃和十二指肠...研究旨在应用康奈尔绵羊净碳水化合物和蛋白质体系(Cornell sheep net carbohydrate and protein system,CNCPS-S)的预测模型预测日粮瘤胃pH值与微生物蛋白质(MCP)合成量,并通过实测验证模型预测值的准确性。选取3只安装瘤胃和十二指肠瘘管的哈萨克公羊为试验动物,配制3种精粗比为30:70、35:65、40:60的全混合日粮(TMR)。采用3×3拉丁方设计,共3期试验,每期18 d,其中10 d为预试期,8 d为样品采集,测定瘤胃液pH和MCP合成量。同时利用CNCPS-S模型预测3种日粮的MCP合成量,评价模型预测的准确性。结果表明:①3种TMR的瘤胃液pH的实测值分别在6.38~6.71、6.01~6.59、5.81~6.41之间,模型预测pH为固定值6.46;②随着精料水平增加,3种TMR均为瘤胃能氮负平衡型,瘤胃能氮平衡(RENB)值均呈下降趋势(P<0.05),3种TMR的MCP的模型预测值依次升高,分别为210.29、215.31、246.94 g/d(P>0.05),实测值也依次升高,分别为93.83、97.33、100.27 g/d(P<0.05);③经线性回归分析,3种日粮MCP的预测值与十二指肠MCP实测值之间的平均偏差比较大(平均偏差≥116 g/d),相关性低(R^2≤0.75),误差均方根(RMSE)都较高。以上结果说明,CNCPS-S对我国绵羊瘤胃pH值具有较好的预测能力,但对MCP合成量具有较低的预测能力。展开更多
In nature, there are two conformational types of amino acids: L- and D-isomers. The L-amino acids are the predominant form and are used mainly for protein synthesis, while the D-amino acids are few in quantity but mor...In nature, there are two conformational types of amino acids: L- and D-isomers. The L-amino acids are the predominant form and are used mainly for protein synthesis, while the D-amino acids are few in quantity but more diverse in terms of their biological functions. D-amino acids are produced by many marine microbes, which are important players in carbon and energy cycles in the ocean. As the major constituent of the marine organic carbon pool, D-amino acids can persist in the water column for a long time before being further transformed by chemical or biological processes or transported through physical processes(such as absorption and aggregation). This article reviews the microbial synthesis of D-amino acids, their physiological function and metabolism in microbes, and the contribution of D-amino acids as a carbon source to the oceanic carbon reservoir.展开更多
文摘研究旨在应用康奈尔绵羊净碳水化合物和蛋白质体系(Cornell sheep net carbohydrate and protein system,CNCPS-S)的预测模型预测日粮瘤胃pH值与微生物蛋白质(MCP)合成量,并通过实测验证模型预测值的准确性。选取3只安装瘤胃和十二指肠瘘管的哈萨克公羊为试验动物,配制3种精粗比为30:70、35:65、40:60的全混合日粮(TMR)。采用3×3拉丁方设计,共3期试验,每期18 d,其中10 d为预试期,8 d为样品采集,测定瘤胃液pH和MCP合成量。同时利用CNCPS-S模型预测3种日粮的MCP合成量,评价模型预测的准确性。结果表明:①3种TMR的瘤胃液pH的实测值分别在6.38~6.71、6.01~6.59、5.81~6.41之间,模型预测pH为固定值6.46;②随着精料水平增加,3种TMR均为瘤胃能氮负平衡型,瘤胃能氮平衡(RENB)值均呈下降趋势(P<0.05),3种TMR的MCP的模型预测值依次升高,分别为210.29、215.31、246.94 g/d(P>0.05),实测值也依次升高,分别为93.83、97.33、100.27 g/d(P<0.05);③经线性回归分析,3种日粮MCP的预测值与十二指肠MCP实测值之间的平均偏差比较大(平均偏差≥116 g/d),相关性低(R^2≤0.75),误差均方根(RMSE)都较高。以上结果说明,CNCPS-S对我国绵羊瘤胃pH值具有较好的预测能力,但对MCP合成量具有较低的预测能力。
基金the National Key Basic Research Program of China (Grant No. 2013CB955700)the State Oceanic Administration of China (SOA project) (Grant No. GASI-03-01-02-05)+1 种基金the National Natural Science Foundation of China (Grant No. 91428308)the project CNOOC-KJ 125 FZDXM 00 ZJ 001-2014
文摘In nature, there are two conformational types of amino acids: L- and D-isomers. The L-amino acids are the predominant form and are used mainly for protein synthesis, while the D-amino acids are few in quantity but more diverse in terms of their biological functions. D-amino acids are produced by many marine microbes, which are important players in carbon and energy cycles in the ocean. As the major constituent of the marine organic carbon pool, D-amino acids can persist in the water column for a long time before being further transformed by chemical or biological processes or transported through physical processes(such as absorption and aggregation). This article reviews the microbial synthesis of D-amino acids, their physiological function and metabolism in microbes, and the contribution of D-amino acids as a carbon source to the oceanic carbon reservoir.
