Kinetics of in situ degradation of Leymus chinensis stems in the dairy cow rumen and changes in cellulolytic bacteria in digesta

doi:10.11686/cyxb2015298

Abstract

Abstract: In this study, we investigated the degradation characteristics of Leymus chinensis stems in the dairy cow rumen and evaluated the changes in cellulolytic bacteria during the degradation process. L. chinensis stems were cut and packed into six nylon bags, which were incubated for 6, 12, 24, 48, and 72 h in the rumen of a dairy cow. Changes in the ultra-structure of L. chinensis stems during digestion in the rumen were evaluated by scanning electron microscopy. L. chinensis stems incubated for 0.5, 2, 6, 12, 24, 48, and 72 h in the rumen were evaluated to determine their neutral detergent fiber (NDF) digestibility. The cellulolytic bacteria in these digesta samples were also analyzed. The results showed that the non-lignified parenchymal tissue and phloem were quickly degraded and the vascular bundle was released from the plant tissues after degradation of the parenchymal tissue. The main bacterial species attached to the stem tissues were Fibrobacter succinogenes>Ruminococcus albus>Ruminococcus flavefaciens. The numbers of these bacteria peaked at 24 h (10⁹/g dry matter for F. succinogenes and 10⁵/g for R. flavefaciens) or 12 h (10⁸/g DM for R. albus) of digestion in the rumen. The numbers of cellulolytic bacteria in digesta remained constant after 24 h, while the disappearance of NDF from the L. chinensis stems showed a linear increase up to 72 h of digestion. These results suggest that the disappearance of NDF from the L. chinensis stem is not synchronized with changes in the populations of cellulolytic bacteria in digesta, and may instead be related to a delayed increase in the activities of fibrolytic enzymes.

XU Jun, HOU Yu-Jie, ZHAO Guo-Qi, LUO Lin-Guang. Kinetics of in situ degradation of Leymus chinensis stems in the dairy cow rumen and changes in cellulolytic bacteria in digesta[J]. Acta Prataculturae Sinica, 2016, 25(4): 166-171.

References

[1] Hristov A, Callaway T, Lee C, et al . Rumen bacterial, archaeal, and fungal diversity of dairy cows in response to ingestion of lauric or myristic acid. Journal of Animal Science, 2012, 90(12): 4449-4457.
[2] Thoetkiattikul H, Mhuantong W, Laothanachareon T, et al . Comparative analysis of microbial profiles in cow rumen fed with different dietary fiber by tagged 16S rRNA gene pyrosequencing. Current Microbiology, 2013, 67(2): 130-137.
[3] Koike S, Kobayashi Y. Development and use of competitive PCR assays for the rumen cellulolytic bacteria: Fibrobacter succinogenes , Ruminococcus albus and Ruminococcus flavefaciens . FEMS Microbiology Letters, 2001, 204(2): 361-366.
[4] Krause D O, Denman S E, Mackie R I, et al . Opportunities to improve fiber degradation in the rumen: microbiology, ecology, and genomics. FEMS Microbiology Reviews, 2006, 27(5): 663-693.
[5] Mosoni P, Fonty G, Gouet P. Competition between ruminal cellulolytic bacteria for adhesion to cellulose. Current Microbiology, 1997, 35(1): 44-47.
[6] Bhat S, Wallace R, Ørskov E. Adhesion of cellulolytic ruminal bacteria to barley straw. Applied and Environmental Microbiology, 1990, 56(9): 2698-2703.
[7] Xu J, Hou Y J, Zhao G Q, et al . Effcets of rumen microorganisms on degradation characteristics and ultrastructure of alfalfa stem. Chinese Journal of Animal Nutrition, 2014, 26(3): 776-782.
[8] Yang J L, Hou X Z, Gao A W. Quantity of microorganisms associated with solid and liquid phases of rumen contents using RT-PCR. Chinese Academy of Agricultural Sciences, 2009, 42(6): 2126-2132.
[9] Xu J, Hou Y J, Yang H B, et al . In situ degradation of oat grass stem and ultrastructure changes by rumen microorganism. Chinese Journal of Animal Science, 2014, 50(7): 35-39.
[10] Gomes D I, Detmann E, Valadares Filho S D C, et al . Evaluation of lignin contents in tropical forages using different analytical methods and their correlations with degradation of insoluble fiber. Animal Feed Science and Technology, 2011, 168(3): 206-222.
[11] Chen Y, Wang Z S, Zhang X M, et al . Analysis of the nutritional components and feeding values of commonly used roughages. Acta Prataculturae Sinica, 2015, 24(5): 117-125.
[12] McAllister T, Bae H, Jones G, et al . Microbial attachment and feed digestion in the rumen. Journal of Animal Science, 1994, 72(11): 3004-3018.
[13] Edwards J E, Huws S A, Kim E J, et al . Characterization of the dynamics of initial bacterial colonization of nonconserved forage in the bovine rumen. FEMS Microbiology Ecology, 2007, 62(3): 323-335.
[14] Koike S, Pan J, Kobayashi Y, et al . Kinetics of in sacco fiber-attachment of representative ruminal cellulolytic bacteria monitored by competitive PCR. Journal of Dairy Science, 2003, 86(4): 1429-1435.
[15] Michalet-Doreau B, Fernandez I, Fonty G. A comparison of enzymatic and molecular approaches to characterize the cellulolytic microbial ecosystems of the rumen and the cecum. Journal of Animal Science, 2002, 80(3): 790-796.
[16] Michalet-Doreau B, Fernandez I, Peyron C, et al . Fibrolytic activities and cellulolytic bacterial community structure in the solid and liquid phases of rumen contents. Reproduction Nutrition Development, 2001, 41(2): 187.
[17] Metzler-Zebeli B U, Schmitz-Esser S, Klevenhusen F, et al . Grain-rich diets differently alter ruminal and colonic abundance of microbial populations and lipopolysaccharide in goats. Anaerobe, 2013, 20: 65-73.
[18] Weimer P, Waghorn G, Odt C, et al . Effect of diet on populations of three species of ruminal cellulolytic bacteria in lactating dairy cows. Journal of Dairy Science, 1999, 82(1): 122-134.
[7] 徐俊, 侯玉洁, 赵国琦, 等. 瘤胃微生物对苜蓿茎降解特性及超微结构的影响. 动物营养学报, 2014, 26(3): 776-782.
[8] 杨金丽, 侯先志, 高爱武, 等. 蒙古绵羊瘤胃固, 液相附着微生物的 RT-PCR 检测. 中国农业科学, 2009, 42(6): 2126-2132.
[9] 徐俊, 侯玉洁, 杨宏波, 等. 尼龙袋法研究燕麦草茎杆在瘤胃中降解超微结构的动态变化. 中国畜牧杂志, 2014, 50(7): 35-39.
[11] 陈艳, 王之盛, 张晓明, 等. 常用粗饲料营养成分和饲用价值分析. 草业学报, 2015, 24(5): 117-125.