本试验旨在研究稀释率对新型固液气分流式瘤胃模拟系统发酵效果的影响。采用单因子完全随机试验设计,共设4个处理,各处理稀释率分别为6%/h、8%/h、10%/h、12%/h,每个处理3个重复,每个重复1个发酵罐。试验期10 d。结果表明:随着稀释率的提高,发酵液pH极显著提高(P<0.01),而氨态氮(NH3-N)浓度则极显著降低(P<0.01)。稀释率由6%/h上升到10%/h,总挥发性脂肪酸(TVFA)及戊酸浓度极显著下降(P<0.01)。稀释率从6%/h提高到8%/h时,原虫数量极显著提高了6.91%(P<0.01),但当稀释率从8%/h提高到12%/h时,原虫数量却极显著下降了5.18%(P<0.01)。随着稀释率从6%/h增加到10%/h,木聚糖酶活性(P<0.01)及微生物蛋白质(MCP)产量(P<0.05)显著或极显著降低,粗蛋白质体外消失率极显著升高(P<0.01)。稀释率为10%/h和12%/h的2个处理,中性洗涤纤维体外消失率显著高于另外2个处理(P<0.05)。结果提示,稀释率能够影响新型固液气分流式瘤胃模拟系统的发酵情况,稀释率为8%/h时,原虫数量以及纤维素类酶活性、各瘤胃发酵参数更加有利于发酵,因此可推荐作为本系统最优运行条件。
The aim of this study was to evaluate the effects of dilution rate on fermentation in a new type of liquid-solid-vapor diffluent rumen simulation system. A single factor completely random design was introduced to this experiment, four treatments were set, and dilution rates were 6%/h, 8%/h, 10%/h and 12%/h, respectively. The results showed that with the increase of dilution rate, fermentation liquid pH was significantly increased (P<0.01), but ammonia nitrogen concentration was significantly decreased (P<0.01). The concentrations of total volatile fatty acid and valeric acid were significantly decreased with the increase of dilution rate from 6%/h to 10%/h (P<0.01). Protozoa number was increased by 6.91% in 6%/h dilution rate treatment than that in 8%/h dilution rate treatment (P<0.01), but there was a significant descent (5.18%) for protozoa number when dilution rate was increased from 8%/h to 12%/h (P<0.01). With dilution rate increased from 6%/h to 10%/h, xylanase activity (P< 0.01) and microprotein production (P< 0.05) were significantly decreased, whereas crude protein in vitro disappearance rate was significantly increased (P<0.01). Neutral detergent fiber in vitro disappearance rate in treatments of 10%/h and 12%/h dilution rates was significantly higher than that in the other two treatments (P<0.05). In conclusion, dilution rate has impacts on fermentation in the new type of liquid-solid-vapor diffluent rumen simulation system, when the dilution rate is 8%/h, protozoa number, cellulase activities, and ruminal fermentation parameters are more beneficial for fermentation. Therefor, 8%/h dilution rate can be used as the optimal dilution rate for the system.
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