湿贮玉米体外发酵pH值、总产气量及菌体蛋白变化的研究

Study on changes of pH value, total gas production and mycoprotein by in vitro fermentation of wet-stored maize

试验旨在为湿贮玉米在牧场的科学精准利用提供参考,利用体外发酵培养法对同一地区6个不同牧场的高水分湿贮玉米测定了体外发酵pH值、总产气量(GP)和菌体蛋白(BCP)等代谢参数指标。结果显示:经过12h的体外发酵,各组样品平均pH值由高到低排序是5号>2号>3号>6号>4号>1号,均在4.70~5.51之间;其中1号牧场湿贮玉米的pH值显著低于4号与5号(P<0.05)。不同牧场湿贮玉米体外发酵BCP含量由高到低排序为:3号=4号>6号>5号>2号>1号,数值范围在4.20~9.22g/L之间;3号、4号、5号、6号样品体外发酵BCP含量极显著高于1号(P<0.01);3号、4号样品体外发酵BCP含量显著高于2号(P<0.05)。发酵2~4h时,2号样品GP极显著高于其他样品(P<0.01);6h时,3号样品极显著高于其他样品(P<0.01);8h时,1号样品极显著高于2号、4号、5号样品(P<0.01),显著高于6号(P<0.05);10~12h,1号样品极显著高于其他样品(P<0.05)。在进行体外发酵的前4h内,各样品产气缓慢,平均速率在5.77mL/h;4~8h速率迅速增加,达到11.38mL/h;8h后各样品湿贮产气速率变慢,仅有5.40mL/h。研究表明,不同牧场的高水分湿贮玉米体外发酵GP、产气速率和BCP等代谢参数差异极显著,pH值差异不显著。

The experiment aims to provide reference for scientific and accurate utilization of wet stored corn in pasture.Metabolic parameters such as pH value of in vitro fermentation, GP and BCP were measured for high moisture wet stored corn in six different pastures in the same area by using in vitro fermentation culture method.The results showed that after 12 h of in vitro fermentation,the average pH values of the samples in each group were ranked from high to low as No.5>No.2>No.3>No.6>No.4>No.1, all between 4.70~5.51. The pH value of wet stored corn in No.1 pasture was significantly lower than that of No. 4 and No. 5(P<0.05). The BCP content in vitro fermentation of samples in different pastures was ranked from high to low as: No.3=No.4>No.6>No.5>No.2>No.1, and the value range was 4.20~9.22 g/L. The content of BCP in vitro fermentation of samples in No.3, No.4, No.5 and No.6 pastures was extremely higher than that of No.1(P<0.01). The content of BCP in vitro fermentation of samples in No.3 and No.4pastures was significantly higher than that in No. 2 pastures(P<0.05). During fermentation for 2~4 h, GP of No. 2 was extremely higher than that of other samples(P<0.01). At 6 h, No.3 was extremely higher than other samples(P<0.01). At 8h, No.1 was extremely higher than No.2, No.4 and No.5(P<0.01), and significantly higher than No.6(P<0.05). 10~12 h,No.1 was significantly higher than other samples(P<0.05). During 0~4 h of in vitro fermentation, the gas production of each sample was slow, with an average rate of 5.77 mL/h. The rate increased rapidly from 4~8 h, reaching 11.38 mL/h. The gas production rate of each sample in wet storage slowed down after 8 h, only 5.40 mL/h. The study indicates that the metabolic parameters such as GP, gas production rate and BCP of high moisture wet storage corn in different pastures aresignificantly different, but the p H value is not significantly different.