乳酸菌和烷基多糖苷对玉米秸秆黄贮品质及其体外发酵特性影响研究

Effects of lactic acid bacteria and alkyl polyglycoside on yellow corn stover silage quality and fermentation in vitro

研究玉米秸秆中添加乳酸菌和烷基多糖苷时对其黄贮品质与体外发酵特性的影响。采用3×3双因素试验设计,即乳酸菌设3个水平(0、1×10^(10)、2×10^(10) CFU·kg^(-1)),烷基多糖苷设3个水平(0、0.10、0.20 g·kg^(-1)),每个处理3个重复。玉米秸秆黄贮完成后,采用体外发酵技术评定其瘤胃发酵特性。结果表明:随乳酸菌添加水平的上升,黄贮玉米秸乳酸含量、比表面积、外观总评分、酸性洗涤纤维和干物质含量显著(P<0.05)提高,氨氮/总氮显著(P<0.05)降低,体外发酵潜在最大产气量显著(P<0.05)增加、总挥发性脂肪酸浓度极显著(P<0.01)增加、产气速率显著(P<0.05)降低;随烷基多糖苷添加水平的升高,黄贮玉米秸外观总评分、酸性洗涤纤维和干物质含量、以及体外发酵后Zeta电位、电子迁移率及干物质消失率显著(P<0.05)升高;黄贮玉米秸粗蛋白质、pH值、乙酸和异丁酸含量以及体外发酵后丁酸、异丁酸、戊酸和异戊酸的摩尔百分比受乳酸菌与烷基多糖苷交互作用(P<0.05)的影响。结果表明:乳酸菌添加量为2×10^(10) CFU·kg^(-1),烷基多糖苷添加量为0.2 g·kg^(-1)时,既能够保证玉米秸秆较好的黄贮品质,同时又能提高其降解特性。

The aim of this experiment was to study the effect of lactic acid bacteria and alkyl polyglycoside addition on the quality of yellow corn stover silage and its’ in vitro fermentation characteristics. A 3×3 factorial design, i.e. three lactic acid bacteria levels (0, 1×10^10 , 2×10^10 CFU·kg^-1 ) and three alkyl polyglycoside levels (0, 0.10, 0.20 g·kg^-1 ) with three replicates per treatment was employed in this study. After the yellow silage from corn stover had completed fermentation, its rumen degradation characteristics were evaluated by in vitro fermentation techniques. It was found that the levels of lactic acid, acid detergent fiber, and dry matter in silage, specific surface area and total score of sensory evaluation significantly (P<0.05) increased, while the ratio of ammonia to total nitrogen significantly (P<0.05) decreased with increased addition of lactic acid bacteria. The potential maximum gas production (P<0.05) and the total volatile fatty acids significantly (P<0.01) increased, while the rate of gas production was significantly (P<0.05) reduced with increased lactic acid bacteria supplementation. With increased rate of alkyl polyglycoside addition, the total score and the content of acid detergent fiber and dry matter of the silage, the Zeta potential and electron mobility of microorganism in fermentation liquor and the in vitro dry matter disappearance of the silage were significantly (P< 0.05 ) increased. The lactic acid bacteria interacted (P<0.05) with the alkyl polyglycosides with respect to crude protein content and pH value of the silage, and the proportion of acetate, isobutyrate, butyrate, valerate, and isovalerate in vitro fermentation. In conclusion, when the dosage of lactic acid bacteria was 2×10^10 CFU·kg^-1 and the amount of alkyl polyglycoside was 0.20 g·kg^-1 , the quality of yellow corn stover silage could be guaranteed and the degradation characteristics were be improved.