添加外源纤维水解酶对羊草体外瘤胃发酵酶活性及特性的影响

试验通过分别添加纤维素酶与木聚糖酶0,10.0与50.0 mg水平,0与24 h两个预处理时间,每个处理3个重复,体外法评价纤维素酶与木聚糖酶复合处理羊草后与瘤胃液共培养对木聚糖酶与葡聚糖酶活性及发酵特性的影响。结果表明,添加纤维水解酶能提高0与8 h培养液中木聚糖酶和内切葡聚糖酶活性以及0 h培养液中外切葡聚糖酶活性,且具有添加剂量效应。当培养至24及48 h,添加外源酶制剂并不能提高培养液中相关酶活性。外源酶制剂显著增加培养24与48 h发酵液中乙酸含量,8,24与48 h 总挥发性脂肪酸产量 (P<0.05)以及48 h累积产气量(P<0.05),但对培养期内戊酸与异戊酸含量没有影响(P＞0.05)。结果提示添加外源酶制剂能提高早期培养液中木聚糖酶和葡聚糖酶活性、增加VFA产量和改善体外瘤胃发酵特性。

Effects of exogenous fibrolytic enzymes on the enzyme activities and fermentation characteristic of Chinese wildrye by mixed ruminal microorganisms in vitro

Three levels of mixture of cellulase and xylanase supplementations (0, 10.0 and 50.0 mg, respectively) and two pretreatment time (0 and 24 h) in triplicate were used to determine the effects of the mixture enzyme on the enzyme activities and fermentation characteristic of Chinese wildrye by mixed ruminal microorganisms in vitro. Fibrolytic enzymes increased (P<0.05) activities of xylanase and endoglucanase at 0 and 8 h and exoglucanase activity at 0 h postincubation in fermentation fluid. In addition, the enzyme activities increased with exogenous enzyme preparation level. However, the exogenous enzyme preparation did not affect the enzyme activities at 24 and 48 h of incubation. The content of acetic acid at 24 and 48 h, the total volatile fatty acids content at 8, 24, 48 h incubation and the cumulative gas production at end of incubation were increased (P<0.05) by the enzyme treatment. Exogenous enzyme had no effects the concentrations of valeric acid and isovaleric acid during incubation (P>0.05). The results suggested that the exogenous fibrolytic enzymes enhanced the activities of xylanase, endoglucanase and exoglucanase in the fermentation fluid in early incubation, finally increased total volatile fatty acids output and improved rumainal fermentation characteristic in vitro.