
TY  - JOUR
A1  - Urdaneta, A. Barrios 
A1  - Fondevila, M. 
A1  - Balcells, J. 
A1  - Dapoza, C. 
A1  - Castrillo, C. 
T1  - <emph type="2">In vitro</emph> microbial digestion of straw cell wall polysaccharides in response to supplementation with different sources of carbohydrates
JF  - Australian Journal of Agricultural Research
JO  - Aust. J.  Agric. Res.
Y1  - 2000
VL  - 51
IS  - 3
SP  - 393
EP  - 400
KW  - rumen bacteria, carbohydrate supplements, adhesion, enzymatic activity.
UR  - https://doi.org/10.1071/AR99079 
N2  - The effect of carbohydrate supplementation on microbial fibre digestion was studied in vitro, by measuring the disappearance of cell wall monosaccharides, bacterial adhesion (mmol purine bases per g residue), and total (per g residue) and bacterial (per mmol purine bases) polysaccharidase activity. Straw cell walls (CW, 0.5% w/v) were cultured in medium supplemented with (0.275% w/v) or without starch, a sugar mixture, or pectin. Supplementation with these constituents did not cause a drop in pH below 6.1, and increased all parameters investigated with the exception of bacterial polysaccharidase activity, which was higher for CW cultures, suggesting a higher proportion of fibrolytic bacteria in the adherent population. By comparison with starch and sugar, pectin supplementation resulted in a lower proportion of residual sugars remaining from cell walls after 60 and 72 h (P &#60; 0.05), which resulted in greater bacterial adhesion after 8 and 12 h (P &#60; 0.05) and higher total cellulase activity after 8 h (P &#60; 0.01). This was perhaps because pectin may cover particle surfaces, protecting the digestive area from external factors, or may act as a substrate for cellulolytic bacteria. The lack of differences in bacterial enzymatic activities suggests the absence of qualitative or quantitative differences in the adherent fibrolytic population. 
ER  -

