纤维素酶来源对粗饲料体外发酵特性及甲烷产量的影响

采用体外发酵技术研究了瘤胃真菌、长柄木霉和李氏木霉三种来源纤维素酶在4种活性水平(0 IU/kg DM、1200 IU/kg DM、3700 IU/kg DM、6700 IU/kg DM)下对粗饲料体外发酵特性及甲烷产量的影响。结果表明:粗饲料添加来源于李氏木霉的纤维素酶时,48h、72h产气量及最大产气量显著低于来源于瘤胃真菌和长柄木霉组及对照组。粗饲料添加来源于瘤胃真菌,李氏木霉和长柄木霉来源的纤维酶时各时间点干物质平均消失率比对照组分别高15%(P<0.001),20%(P<0.001)和6.8%(P<0.05)以上。干物质消失率随纤维素酶添加水平的增加呈三次曲线(P<0.01)增加,酶的添加量为1200 IU/kg DM时48h及72h干物质平均消失率达到最高。添加瘤胃真菌及李氏木霉来源纤维素酶时,粗饲料甲烷产量显著(P<0.001)低于对照组和长柄木霉组。各时间点粗饲料甲烷产量随酶添加水平的增加呈三次曲线降低(P<0.001)。结论认为:添加纤维素酶虽然对产气量的影响不明显,但可提高粗饲料干物质消失率及降低甲烷产量,纤维素酶的来源可影响粗饲料的发酵特性。

Effects of Cellulase Origination on in vitro Fermentation Characteristics and Methane Production of Forage

In vitro fermentation technique was used to investigate the effects of cellulase which was extracted from rumen fungi, Trichoderma longibrachiatum and Lee trichoderma, respectively, on in vitro fermentation characteristics and methane production of forage at four activity levels (0 IU/kg DM, 1200 IU/kg DM, 3700 IU/kg DM, 6700 IU/kg DM). The results showed that the gas production and the maximum gas production at 48h and 72h, for forage supplemented with cellulase extracted from Lee trichoderma was significantly lower (P<0.001) than that from rumen fungi and Trichoderma longibrachiatum, and control treatment. On average, more than 15.0%, 20.0 % and 6.8% dry matter was degraded as forage supplemented with cellulase extracted from rumen fungi (P<0.001), Lee trichoderma (P<0.001) and Trichoderma longibrachiatum (P<0.05) compared with control treatment. Dry matter disappearance cubically increased (P<0.01) with the increasing of cellulase supplementation, and reached the highest value at the level of 1200 IU/kg DM for 48 and 72h incubation time. Methane production was significantly lower (P<0.001) for forage supplemented with cellulase extracted from rumen fungi and Lee trichoderma compared with control and Trichoderma longibrachiatum treatment. Also, methane production cubically decreased (P<0.001) with the increasing of cellulase supplementation at three incubation times. It was concluded that cellulase supplementation could improve dry matter disappearance and decrease methane production though its effects on in vitro gas production characteristics was weak. The origination of cellulase could affect in vitro fermentation characteristics of forage.