外源添加丝兰植物粉末对泌乳期奶牛瘤胃体外发酵特征的影响

Effects of Exogenous Addition Yucca Plant Powder on in Vitro Rumen Fermentation Characteristics of Lactating Dairy Cows

本试验旨在研究丝兰植物粉末对泌乳期奶牛瘤胃体外发酵特征的影响。试验选用泌乳中期荷斯坦奶牛(瘘管牛)用于采集瘤胃液,以该阶段奶牛饲粮作为发酵底物进行体外发酵试验。试验共分为5组,各组分别添加0(对照)、2.5、5.0、7.5、10.0 g/kg(干物质基础)的丝兰植物粉末,每组6个平行。通过AGRS-Ⅲ微生物发酵微量产气自动记录仪在39℃条件下进行48 h体外发酵。结果表明:1)随着丝兰植物粉末添加量的升高,发酵液总挥发性脂肪酸、乙酸、丙酸和丁酸含量呈显著线性增加(P<0.05)。2)添加5.0 g/kg丝兰植物粉末组发酵液氨氮含量较对照组有降低趋势(P=0.10)。3)添加丝兰植物粉末对干物质降解率无显著影响(P=0.18)。4)添加5.0 g/kg丝兰植物粉末48 h体外发酵总产气量最低,但与对照组无显著差异(P=0.13)。添加2.5 g/kg丝兰植物粉末48 h体外发酵甲烷产量最低,但与对照组无显著差异(P=0.53)。综上所述,添加5.0 g/kg的丝兰植物粉末可降低体外发酵甲烷产量和氨氮含量,对饲粮瘤胃降解有抑制作用。

This study was aimed to investigate the effects of Yucca plant powder on rumen fermentation characteristics in vitro.In this study,rumen fluids were collected from lactating Holstein cows with fistula,and a lactating diet was used as the fermentation substrates.Five groups were classified based on different levels of Yucca plant powder as follows:0(control),2.5,5.0,7.5,and 10.0 g/kg(dry matter basis),and each treatment was performed in 6 replicates.The AGRS-Ⅲmicrobial fermentation microgas production auto-recorder was used to perform in vitro fermentation at 39℃for 48 h.Results showed as follows:1)the contents of total volatile fatty acids,acetic,propionic and butyrate of the fermentation broth increased linearly with the increased doses of Yucca plant powder(P<0.05).2)The addition of 5.0 g/kg Yucca plant powder had a certain inhibitory effect on the ammonia nitrogen content compared with the control group(P=0.10).3)The addition of Yucca plant powder had no significant effect on the dry matter degradation rate(P=0.18).4)Adding 5.0 g/kg Yucca plant powder for 48 h had the lowest gas production in vitro,but there was no significant difference compared with control group(P=0.13).Besides,adding 2.5 g/kg Yucca plant powder had the lowest methane production in vitro for 48 h,but did not reach a significant difference compared with the control group(P=0.53).Data suggest that adding Yucca plant powder at a level at 5.0 g/kg in diet can reduce methane emissions and the content of ammonia nitrogen in vitro fermentation,and has an inhibiting effect on rumen degradation of diets.