The distribution of polysaccharide-degrading enzymes in the bovine rumen digesta ecosystem

Williams, Alan G.; Strachan, N. H.

doi:10.1007/bf01627258

Cited by 68 publications

(29 citation statements)

References 19 publications

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“…Filtering the ruminal content through two layers of cheesecloth allows a substantial amount of small feed particles carrying associated microorganisms to pass into the filtrate, which (following extraction) would release their PDE activities into the cell-free supernatant. Whereas cell-free rumen liquor contains insignificant amounts of fibrolytic activities, bacteria and protozoa associated with the liquid phase of rumen content have high xylanase and CMCase specific activities (Williams and Strachan 1984). Amylase activity is largely concentrated in the protozoal fraction (Williams and Strachan 1984).…”

Section: Discussionmentioning

confidence: 99%

“…Whereas cell-free rumen liquor contains insignificant amounts of fibrolytic activities, bacteria and protozoa associated with the liquid phase of rumen content have high xylanase and CMCase specific activities (Williams and Strachan 1984). Amylase activity is largely concentrated in the protozoal fraction (Williams and Strachan 1984). Huhtanen and Khalili (1992) also found considerable amounts of CMCase and xylanase activities in strained ruminal fluid (layers of cheesecloth were not specified), but activities in rumen particulate matter were 17 to 19 times higher.…”

Section: Discussionmentioning

confidence: 99%

“…As more enzymes were liberated into the extracellular environment due to blending (BERF vs. ERF), the reduction in enzyme activity as a result of freezing increased. If a large portion of rumen amylases are associated with protozoa and fluid-associated bacteria (Williams and Strachan 1984;Coleman 1986) and less is particle bound, sonication would release proportionally more amylase into the supernatant than CMCases or xylanases. It is also possible that rumen amylases are more resistant to freezing than CMCases or xylanases, which would explain the trend toward higher average amylase activity recovered from previously frozen samples than from fresh ones (P > 0.05, Table 4).…”

Section: Discussionmentioning

confidence: 99%

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Effect of diet, digesta processing, freezing and extraction procedure on some polysaccharide-degrading activities of ruminal contents

Hristov¹,

McAllister²,

Cheng³

1999

Can. J. Anim. Sci.

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. 1999. Effect of diet, digesta processing, freezing and extraction procedure on some polysaccharide-degrading activities of ruminal contents. Can. J. Anim. Sci. 79: 73-81. Three procedures for extracting polysaccharide-degrading enzymes (PDE) from ruminal contents were compared, and the effects of diet, inoculum preparation and freezing of samples on recovery of enzyme activities were evaluated. Four nonlactating cows and four heifers were fed either high-forage (83%, dry matter [DM] basis) or high-grain (91%, DM basis) diets. Three sample types, (1) enriched ruminal fluid; (2) blended enriched ruminal fluid; and (3) whole ruminal content, were analyzed fresh or after having been frozen (-40°C) for 48 h. Four cell-free preparations of each sample type were assayed: (1) control (no enzyme extraction); and enzymes extracted by (2) sonication; (3) lysozyme; and (4) lysozyme + EDTA. Animals fed a high-grain diet had lower carboxymethylcellulase and xylanase but higher amylase activities in the rumen. Blending ruminal solids with buffer and combining the filtrate with cheesecloth-filtered ruminal fluid produced higher polysaccharide-degrading activities per unit of DM compared with whole ruminal contents. In lysozyme treatments, freezing inactivated from 22 (amylase) to 52% (xylanase) of the enzyme activities measured in fresh ruminal fluid. Lysozyme treatment resulted in the highest enzyme recovery (from fresh ruminal fluid) of the extraction methods tested. With frozen samples, sonication and lysozyme gave similar results. If a large number of ruminal content samples are to be processed for PDE activities, freezing and subsequent sonication appear to be a practical alternative to extraction by lysozyme. Le passage au mixer des matières solides ruminales tamponnées et leur combinaison avec le filtrat ruminal donnaient lieu à des activités de dégradation des polysaccharides plus fortes par unité de m.s. que le contenu ruminal entier. Dans les traitements avec la lysozyme, la surgélation inactivait, de 22 % dans le cas de l'amylase, à 52 % dans celui de la xylanase, les activités enzymatiques dans le liquide ruminal frais. De toutes les méthodes d'extraction comparées, c'est le traitement avec la lysozyme qui produisait la récupération enzymatique la plus forte (à partir de liquide ruminal frais). Mais quand on utilisait des échantillons surgelés, la sonication et le traitement avec la lysozyme donnaient des résultats comparables. Si l'on doit préparer un grand nombre de prélèvements du contenu ruminal pour la mesure des activités EPD, la surgélation suivie de sonication apparaît comme une alternative pratique à l'extraction par la lysozyme.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Effect of diet, digesta processing, freezing and extraction procedure on some polysaccharide-degrading activities of ruminal contents

Hristov¹,

McAllister²,

Cheng³

1999

Can. J. Anim. Sci.

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“…According to Coleman (1985), 62% of the total carboxymethylcellulase (EC 3.2.1.4; CMCase) activity in the rumen is associated with Atype protozoa. Williams & strachan (1984) also observed that the specific activities of CMC-and avicel (high -crystalline cellulose)-degrading enzymes were higher in protozoa than in bacteria isolated from the rumen of a cow fed on hay. But no in vivo digestion trials have been conducted to confirm the importance of protozoa in fibre digestion.…”

mentioning

confidence: 89%

Effect of defaunation on protein and fibre digestion in sheep fed on ammonia-treated straw-based diets with or without maize

et al. 1990

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Using a defaunating method which preserved bacteria and fungi in the rumen, the effect of protozoa on protein and fibre digestion was studied in six adult wethers in relation to the nature of the diet. Sheep were given daily, 42 g dry matter (DM)/kg metabolic body-weight (WO"), one of two isonitrogenous diets: one contained ammonia-treated wheat straw as the only energy source (diet S) and the other was supplemented with maize grain pellets (diet SM). Mean daily intakes (g/d) of nitrogen, neutral-detergent fibre and acid-detergent fibre were respectively 22, 573 and 373 for diet S and 23,450 and 334 for diet SM. Elimination of protozoa increased duodenal non-ammonia-nitrogen flow. This result was mainly due to an increase in microbial protein flow and, to a lesser extent, to a higher dietary protein Row.Defaunation markedly increased the efficiency of microbial protein synthesis. Maize-grain supplementation had a net positive effect on this variable in defaunated sheep, but not in faunated sheep. Cell-wall carbohydrates were less well digested in the defaunated rumen, and the negative effect of defaunation was greatest with the diet SM. Intestinal fibre digestion increased in the defaunated sheep especially in those fed on diet SM, but not enough to compensate for the decrease in rumen digestion.

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“…This measurement requires the extraction of these enzymes from microbes adhering to rumen content. Extractions by sonication (Williams and Strachan, 1984;Martin et al, 1993) or lysozyme and carbon tetrachloride (CC' 4 ) treatment (Silva ef al, 1987;Huhtanen and Khalili, 1992;Bowman and Firkins, 1993) (Williams et al, 1989) and dietary composition (Huhtanen and Khalili, 1992).…”

mentioning

confidence: 99%

Effect of extraction method on activities of polysaccharide-depolymerase enzymes in the microbial population from the solid phase in the rumen

Nozière¹,

Michalet-Doreau²

1994

Reprod. Nutr. Dev.

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The distribution of polysaccharide-degrading enzymes in the bovine rumen digesta ecosystem

Cited by 68 publications

References 19 publications

Effect of diet, digesta processing, freezing and extraction procedure on some polysaccharide-degrading activities of ruminal contents

Effect of diet, digesta processing, freezing and extraction procedure on some polysaccharide-degrading activities of ruminal contents

Effect of defaunation on protein and fibre digestion in sheep fed on ammonia-treated straw-based diets with or without maize

Effect of extraction method on activities of polysaccharide-depolymerase enzymes in the microbial population from the solid phase in the rumen

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