添加不同水平糖蜜对全株“张杂谷”青贮体外瘤胃发酵特性和营养物质降解率的影响

本试验旨在研究添加不同水平糖蜜对全株"张杂谷"青贮发酵特性及其营养物质降解率的影响。选用3头安装有永久性瘤胃瘘管且体况相近的荷斯坦奶牛作为瘤胃液供体,在全株"张杂谷"青贮中分别添加0（对照组）、2%、4%和6%糖蜜,室温条件下贮存60 d,评定添加糖蜜对全株"张杂谷"青贮品质的影响。结果显示,①4%糖蜜组干物质（DM）含量显著高于2%、6%糖蜜组（P<0.05）,但与对照组间差异不显著（P>0.05）;各组间粗蛋白质（CP）含量无显著差异（P>0.05）;4%糖蜜组中性洗涤纤维（NDF）含量显著低于对照组及2%糖蜜组（P<0.05）,酸性洗涤纤维（ADF）含量显著低于其他组（P<0.05）。②添加4%糖蜜后干物质消失率（DMD）显著高于对照组及2%糖蜜组（P<0.05）;4%糖蜜组粗蛋白质消失率（CPD）、中性洗涤纤维消失率（NDFD）显著高于对照组及6%糖蜜组（P<0.05）,酸性洗涤纤维降解率（ADFD）含量显著高于对照组（P<0.05）。③与对照组相比,添加糖蜜组代谢能（ME）、泌乳净能（NE_L）和72 h总产气量（GP_{72 h}）升高（P>0.05）;添加4%糖蜜组产气量达到理论最大产气量的1/2时的时间（C）显著低于对照组（P<0.05）。④添加糖蜜组发酵液pH、氨态氮（NH₃-N）、微生物蛋白（MCP）、总挥发性脂肪酸（TVFA）、非生糖类挥发酸与生糖类挥发酸比例（NGR）、乙酸、丙酸、丁酸、戊酸及支链脂肪酸与对照组均无显著差异（P>0.05）,其中4%糖蜜组各项发酵指标均较好。综上所述,本研究条件下,糖蜜最适添加水平为4%。

Effects of Different Molasses Levels on in vitro Ruminal Fermentation Characteristics and Nutrient Degradation of Whole “Zhang Hybrid Millet” Silage

The study was aimed to explore the effects of different molasses levels on in vitro ruminal fermentation characteristics and nutrient degradation of whole "Zhang Hybrid Millet" silage.Three Holstein dairy cows with permanent rumen fistula and similar body condition were chosen and the rumen fluid was collected.0(control group),2%,4% and 6% molasses were added to whole "Zhang Hybrid Millet" silage for 60 d fermentation at indoors temperature.After that the quality of whole "Zhang Hybrid Millet" silage were valued.The results showed that:① The DM of 4% molasses group was significantly higher than that of 2% and 6% molasses groups (P < 0.05),which was not significantly different with control group (P > 0.05).There was no significant difference of CP content among the groups (P > 0.05);The content of NDF of 4% molasses group was significantly lower than that of control group and 2% molasses group (P < 0.05),while the ADF was significantly lower than other group (P < 0.05).② After adding 4% molasses,DMD was significantly higher than that in control group and 2% molasses group (P < 0.05).The CPD and NDFD of 4% molasses group was significantly higher than that of control group and 6% molasses group (P < 0.05),while the ADFD was significantly higher than that in control group (P < 0.05).③Compared with the control group,ME,NE_L and GP_{72 h} of molasses adding groups were increased (P > 0.05).And the C value of 4% molasses group was significantly lower than that of control group (P < 0.05) when the gas production volume reached the theoretical maximum yield of 1/2.④There was no significant difference of pH,NH₃-N,MCP,TVFA,NGR,acetic acid,propionic acid,butyric acid,valeric acid and branched-chain fatty acid between molasses adding groups and control group (P > 0.05),while the fermentation parameters of 4% molasses group were better.Under the condition of this study, the optimum level of molasses was 4%.