瘤胃厌氧真菌对木质素含量不同底物附着及发酵特性研究

结合体外发酵和瘤胃尼龙袋法,研究了本地山羊瘤胃厌氧真菌对木质素含量不同底物(黑麦草叶、黑麦草茎、稻草秸、花生壳,木质素含量依次上升)的附着及发酵特性.结果表明,随体外发酵的进行,真菌数量逐渐增加,以黑麦草叶、黑麦草茎、稻草秸为底物时,瘤胃真菌数量均在48 h达到最大值,且真菌数量的最大值随底物木质素含量的上升呈下降趋势.显微观察显示,体外发酵前72 h附着于稻草秸表面孢子囊数量均显著高于黑麦草叶和黑麦草茎(P<0.05),而切缘孢子囊数量三者差异不显著.瘤胃内培养结果表明,稻草秸切缘和表面孢子囊数量均在48 h时最大,72 h后数量显著下降(P<0.05),而黑麦草茎切缘和表面上的孢子囊数量均在24 h 时最大,72 h后数量显著下降(P<0.05);稻草秸切缘和表面上孢子囊数量均要高于黑麦草茎上的数量.不同底物进行厌氧真菌体外发酵时其累计产气量、干物质消失率和纤维素消失率差异均不显著,但在瘤胃内培养时,各底物的干物质消失率则随底物木质素含量的上升而显著下降(P<0.05).

Effect of substrates with different lignin content on rumen fungal attachment and fermentation in the rumen of goats

Research was conducted to investigate the attachment on and fermentation profiles of substrates with different lignin contents by rumen anaerobic fungi in the rumen of goats. The substrates used in the study were: ryegrass leaf, ryegrass stem, rice straw and peanut hull. The research employed nylon bag implantation and in vitro fermentation techniques. With the procession of in vitro fermentation, anaerobic fungal population density in the cultures were shown to increase, with the largest fungal populations growing on ryegrass leaves, ryegrass stem and straw occurring after 48 h of incubation. Microscopic studies revealed that the number of sporangia attached to rice straw surfaces was significantly larger than those on ryegrass leaf and ryegrass stem during the initial 72 h of in vitro incubation (P<0.05), while the number of sporangia attached to cut edges of different substrates were similar. In the rumen, sporangia attached to rice straw surfaces and to cut edges reached their respective maximal population numbers after 48 h of incubation and declined significantly after 72 h incubation (P<0.05). However, sporangia attached to ryegrass stem surfaces and those attached to cut edges reached their maximal numbers at 24 h and declined sharply after 72 h of incubation (P<0.05). The number of sporangia attached to the rice straw surface and cut edges was greater than ryegrass stem during the whole incubation period (P<0.05). During the in vitro fermentation, the substrates showed no apparent differences in gas production, dry matter loss and cellulose loss. In the rumen, however, dry matter loss varied significantly between substrates, with values shown to be negatively correlated to the substrates lignin content (P<0.05).