ASC 684 Advanced Ruminant Nutrition FIGURE 40. CELL WALL CHEMISTRY 

 

 

 

Chemical structure of the predominant building blocks of plant cell walls. Left panel: monomers. Right panel: subunit of the respective polymers 

From Sarkar et al., 2009. J. Exp. Botany 60:3615.

ASC 684 Advanced Ruminant Nutrition FIGURE 41. CELL WALL STRUCTURE 

 

 

Simplified 2D representation of general cell wall composition in the different groups of Kingdom Plantae. All groups have cellulose microfibrils. Non-grass angiosperms (A) have high amount of hemicelluloses (fucoside xyloglucan (XG), xylans, some mannans) and structural proteins. The primary walls have high amounts of pectins (homogalacturonans (HG), rhamnogalacturonan (RG) I and II) while the secondary walls have high amounts of lignins with guaicyl (G) and syringyl (S) units. XGs, HGs and RGs are lower in amount in grasses (B), which have higher amount of mixed-linkage glucans instead. Gymnosperms (C) have wall composition similar to non-grass angiosperms except they have higher amount of glucomannans and their lignins are homogeneous consisting primarily of guaicyl units. Leptosporangiates (D) have low amounts of XGs, HGs and RGs, but have high amounts of xylans, mannans, uronic acids, 3-O-methyl rhamnose and lignins. In eusporangiates, bryophytes and charophytes (E, F), the cell walls are not clearly differentiated into primary and secondary walls. Eusporangiates and bryophytes (E), cell walls have compositions similar to leptosporangiate walls except they lack xylans and lignins. Phenolic compounds such as lignans are present instead of lignins. Only mannans, glucuronic acids, mannuronic acids and 3-O-methyl rhamnose have been detected from cell walls of Charophytes (F) until now. Note: Spatial distribution, orientation, size and proportion of polymers in this diagram are not per scale.  

From Sarkar et al., 2009. J. Exp. Botany 60:3615.

ASC 684 Advanced Ruminant Nutrition 

TABLE 31. EFFECT OF WHITE ROT FUNGI ON IVDMD AND DM DECOMPOSITION OF WHEAT STRAWa

DM of straw, %  P. ostreatus  P. ostreatus + E. carotovora   IVDMD, %  DM loss, %  IVDMD, %  DM loss, % Nonincubated control  32.7b  ‐  32.7b  ‐ 25  31.6c 41.4c 37.3d  46.7d

33  35.1c 45.8c 42.9e  53.2c

50  39.7c 43.4c 47.7f  53.1caFrom Streeter et al. 1982. J. Anim. Sci. 54:183. 

 

TABLE 32. EFFECT OF WHITE ROT FUNGI ON DECOMPOSITION OF DM AND CELL WALL CONTENTS IN WHEAT STRAWa

Constituent  Decomposition, % DM  52 Cellulose  55 Hemicellulose  83 Lignin  69  aFrom Streeter et al. 1982. J. Anim. Sci. 54:183. Ten grams of ground straw preheated at 25C and incubated at 25C and 50% DM for 56d.. 

 

TABLE 33. EFFECT OF DIFFERENT SOLID STATE REACTOR DESIGNS ON LIGNIN AND CELLULOSE DIGESTIONa

Reactor Design  5th day lignin degradation, %  5th day cellulose degradation, % Horizontal H‐G1  27  16 Vertical     

V‐G1a  51  26 V‐G1b  49  18 V‐G1c  23  16 V‐G2a  23  36 V‐G2b  29  29 V‐G3  21  28 

aKumar and Gomes. 2008. Anim. Feed Sci. Tech. 144:149‐166.