Affiliation:
1. Richard B. Russell Agricultural Research Center, U.S. Department of Agriculture, Athens, Georgia 30613.
Abstract
Bermudagrass (Cynodon dactylon) leaf blades and whole cordgrass (Spartina alterniflora) fiber were evaluated for degradation of cell walls by microbial groups in ruminal fluid. The groups were selected by the addition of antibiotics to the inoculum as follows: (i) whole ruminal fluid (WRF), no antibiotics; (ii) cycloheximide (C) to inhibit fungi, thus showing potential bacterial activity; (iii) streptomycin and penicillin (S,P) to inhibit fiber-degrading bacteria, showing potential fungal activity; (iv) streptomycin, penicillin, and chloramphenicol (S,P,CAM) to inhibit all bacteria including methanogens; (v) streptomycin, penicillin, and cycloheximide (S,P,C) to inhibit all microbial activity as a control; and (vi) autoclaved ruminal fluid (ARF) to inhibit all biological activity as a second control. Scanning electron microscopy of tissue degradation indicated that tissues not giving a positive histological reaction for lignin were more readily degraded. Cordgrass was more highly lignified, with more tissues resisting degradation than in bermudagrass. Patterns of degradation due to treatment resulted in three distinct groups of data based on the extent of fiber or component losses: WRF and C greater than S,P and S,P,CAM greater than S,P,C and ARF. Therefore, bacterial activity was responsible for most of the fiber loss. Fiber degradation by anaerobic fungi was significantly less (P = 0.05). Cupric oxide oxidation of undigested and digested bermudagrass fiber indicated that phenolic constituents differed in their order of resistance to removal or solubilization. Vanillyl and syringyl components of lignin were the most resistant to decomposition, whereas ferulic acid was readily solubilized from fiber in the absence of microbial activity.(ABSTRACT TRUNCATED AT 250 WORDS)
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Reference49 articles.
1. Akin D. E. 1982. Microbial breakdown of feed in the digestive tract p. 201-223. In J. B. Hacker (ed.) Nutritional limits to animal production from pastures. Commonwealth Agricultural Bureaux Farnham Royal United Kingdom.
2. Forage cell wall degradation and p-coumaric, ferulic, and sinapic acids;Akin D. E.;Agron. J.,1982
3. Interaction of ruminal bacteria and fungi with southern forages;Akin D. E.;J. Anim. Sci.,1986
4. Association of rumen fungi with various forage grasses;Akin D. E.;Anim. Feed. Sci. Technol.,1987
5. Rumen bacterial and fungal degradation of Digitaria pentzii grown with or without sulfur;Akin D. E.;Appl. Environ. Microbiol.,1983
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