2-甲基丁酸对西门塔尔牛增重、日粮养分消化和甲烷排放的影响

摘要

试验旨在研究2‐甲基丁酸对西门塔尔牛日粮养分消化率、增重性能及甲烷排放的影响。选择12月龄左右、发育正常及体重相近的西门塔尔公牛36头，随机分为4组，即对照组及试验1～3组，每组9头牛，分别饲喂添加0、1.0、2.0及3.0 g／kg体重2‐甲基丁酸的玉米秸秆日粮，测定日粮养分消化率、西门塔尔牛增重性能及甲烷的排放情况。试验期70 d。结果表明，试验2、3组西门塔尔牛有机物质（OM ）消化率较对照组显著提高（P＜0.05）；3个试验组粗蛋白质（CP）消化率均较对照组显著提高（P＜0.05），但无氮浸出物（NFE）消化率在各组间差异不显著（P＞0.05）；试验2组西门塔尔牛中性洗涤纤维（NDF）消化率显著高于对照组和试验1组（P＜0.05），而其酸性洗涤纤维（ADF）消化率则显著高于其他各组（P＜0.05）；试验2、3组西门塔尔牛试验期间平均日增重显著高于对照组（P＜0.05），但其在试验1组与对照组间差异不显著（P＞0.05）；与对照组相比，试验2组的干物质采食量显著降低（P＜0.05），试验2、3组料重比也显著降低（P＜0.05）；在日粮中添加2‐甲基丁酸后，西门塔尔牛的甲烷排放呈降低趋势，试验2、3组排放的甲烷能显著低于对照组（ P＜0.05）。由以上结果推断，在日粮中添加2‐甲基丁酸可促进西门塔尔牛的生长及对营养物质消化，同时可有效降低甲烷排放，2‐甲基丁酸的适宜添加水平为2.0 g／kg体重。%The objective of this study was to evaluate the effects of 2‐methylbutyrate on daily gain ,dietary nutrient digestion and methane emissions in Simmental cattle .Thirty‐six Simmental cattle (12‐month‐old) consuming a corn straw diet were divided randomly into four groups (con‐trol group ,experimental groups 1 ,2 and 3) and supplemented with four levels of 2‐methylbutyrate as 0 ,1 .0 ,2 .0 and 3 .0 g/(kg · BW ) ,respectively .Dietary nutrient digestibilities ,average daily gain and methane emissions were determined .The results showed that OM digestibilities of the cattles in experimental group 2 and 3 ,CP digestibilities of the cattles in experimental groups 2 were significantly higher than that in control group (P<0 .05) .NFE digestibilities were not af‐fected by adding 2‐methylbutyrate (P>0.05) .NDF digestibilities of the cattles in experimental group 2 were significantly higher than that in control group and experimental group 1 (P<0 .05) , while their ADF digestibility were significantly higher than that in control and other experimental groups (P<0 .05) .Compared with control group ,the average daily gains of cattles increased sig‐nificantly in experimental groups 2 and 3 (P<0 .05) ,the dry matter intakes of cattles decreased significantly in experimental group 2 (P<0 .05) ,and the feed gain ratio decreased significantly in experimental groups 2 and 3 (P<0 .05) .In addition ,the methane emissions were decreased signif‐icantly in experimental groups 2 and 3 (P<0 .05) .The results indicated that the average daily gain ,nutrient digestion could be improved ,and methane emissions could be restrained by supple‐menting 2‐methylbutyrate in Simmental beef cattle ,the optimal dose of 2‐methylbutyrate supple‐mentation was 2 .0 g/(kg · BW).