体外法研究生石膏对瘤胃发酵、甲烷生成及微生态的影响

Effect of Gypsum Fibrosuum on ruminal microbial fermentation,methanogenesis and microbialflora in vitro

通过体外产气法研究了生石膏对瘤胃发酵、甲烷生成及微生态的影响。按单因子试验设计,在底物中分别按其干物质的0(对照组)、1.25%(低水平组)、2.5%(高水平组)添加生石膏,每个组设4个重复,进行24h体外发酵培养。结果显示,随生石膏添加水平升高,乙酸与总挥发性脂肪酸浓度、乙酸与丙酸的浓度比、12和24h产气量、氢的生成量及甲烷菌数量显著(P<0.05)或极显著(P<0.01)降低,而丙酸占总挥发性脂肪酸的比例与原虫数量极显著(P<0.01)升高;生石膏添加会显著(P<0.05)或显著(P<0.01)降低12和24h甲烷产量,而高水平添加会显著(P<0.05)降低丙酸浓度与乙酸占总挥发性脂肪酸的比例。结果表明,生石膏可通过减少氢的供应量和抑制甲烷菌生长而降低体外甲烷产量,同时会促进原虫增殖,致使2种添加水平的相对甲烷抑制潜势没有显著(P>0.05)差异。

This study was carried out to evaluate the effects of Gypsum Fibrosuum on rumen fermentation,methane emission and populations of ruminal microbes using an in vitro gas production technique.According to single factor random arrangement,Gypsum Fibrosuum was added at level of 0(control group),12.5g(low level group),25g(high level group)per kg of substrate dry matter,respectively.Every group was in quadruplicate.The duration of fermentation incubation was 24 h.The results showed that with increased addition level of Gypsum Fibrosuum,acetate and total volatile fatty acids(VFA)concentrations,acetate to propionate ratio,gas production at 12 h and 24 h,hydrogen production and methanogens population were significantly(P<0.05 or P<0.01)decreased,but ratio of propionate to total VFA and protozoa population were significantly(P<0.01)increased;the addition of Gypsum Fibrosuum significantly(P<0.05 or P<0.01)decreased methane production at 12 hand 24h,and the addition with high level significantly(P<0.05)decreased propionate concentrations and ratio of acetate to total VFA.The results suggested that the addition of Gypsum Fibrosuum could abate methane emission in vitro via the reduction of hydrogen supply and the inhibition of methanogens,and might promote the proliferation of protozoa,resulting in no significant(P>0.05)difference of relative methane reduction potential between the control group and the Gypsum Fibrosuum added groups.