半胱胺对山羊瘤胃微生物体外发酵的影响

利用来自4头装有永久性瘤胃瘘管本地成年山羊的瘤胃液，以0．7g草粉和0．3g精料（由70％玉米＋30％豆粕组成）为底物，在体外厌氧条件下，研究了不同浓度的半胱胺（10mg/L、50mg/L、100mg/L、200mg/L和500mg/L)对瘤胃微生物体外发酵的影响。结果表明：当培养液中半胱胺浓度为50mg/L时，培养液中氨氮浓度比对照组降低5．7％（P＜0．05），而微生物蛋白浓度、总挥发性脂肪酸浓度、丙酸比例和体外发酵总产气量分别比对照组提高66％（P＜0．05）、56％（P＜0．05）、6％（P＜0．05）和11．4％（P＜0．05），发酵总产气量和总挥发性脂肪酸浓度开始高于对照组，微生物蛋白在发酵5h后开始高于对照组。结果显示，半胱胺可促进山羊瘤胃微生物发酵。

Effects of Cysteamine on in vitro Fermentation by Rumen Microbes from Goats

The rumen fluid from four local male goats with permanent rumen fistulae was incubated in anaerobic media for 24 h with straw powder (0.7 g) and concentrates (0.3 g) as the substrate. The cysteamine stock solution was added to the incubation bottles with final concentrations at 10 mg/L,50 mg/L,100 mg/L,200 mg/L and 500 mg/L,respectively. Results showed that as compared with the control, at 50 mg/L cysteamine NH 3 -N concentration decreased by 5.7% ( P <0.05), while microbial protein concentration (MCP), TVFA, the percentage of propionate (P%) and total gas production increased by 66% ( P <0.05), 56% ( P <0.05), 6% ( P <0.05) and 11.4%( P <0.05),respectively. The time-course experiment indicated that the NH 3 -N concentration for the samples treated with cysteamine at 50 mg/L was significantly lower than that for the control samples after 3 h fermentation, while gas production and VFA concentration were higher. The MCP content was higher in the treatment samples than that in the control after 5 h fermentation. This suggested that cysteamine stimulated the in vitro fermentation of rumen microbes from goat.