Enzyme activities of rumen solid‐adherent microorganisms in chronically underfed ewes

Abstract

Four ruminally cannulated ewes were used in a series of two crossover designs to investigate the effects of underfeeding and of supplementation with slowly degradable protein on polysaccharide and glycoside-degrading enzyme activities in rumen solid-adherent microorganisms. The ewes were fed twice daily on a hay based diet to satisfy either 1.2 or 0.5 maintenance energy requirements, with or without 125 and 65 g fish meal supplement for the high and the low intakes, respectively. Enzyme preparations were isolated from rumen solid contents 2, 6, and 12 h after feeding. Protein supplementation had no significant effect on the activity of any of the enzymes measured. The effects of feeding level on carboxymethycellulase and xylanase activities were small, the specific activity (expressed per mg microbial protein) being slightly increased at low intake (P < 0.10). However, B-D-galactosidase, B-D-glucosidase, B-D-xylosidase, and B-D-cellobiosidase activities were considerably increased with low feeding level ( + 5 6 to +70% for specific activities; +31 to +50% when expressed per g dry matter). The activities of all enzymes tested increased significantly with time after feeding. The extent of specific activity response to variation of feeding level was greater for late sampling times than 2 h post-feeding. Ruminal degradation of the dietary hay was not affected by fish meal supplementation, but increased with reduction of feeding level ( + 59.7 g kg-' for neutral detergent fibre during the first 12 h of rumen incubation; P < 0.001). The higher microbial efficiency associated with greater retention time of feed particles in the rumen may account for the increase in cell wall degradation usually observed when feeding level declines.

Differences in microbial fermentation of barley straw induced by its treatment with anhydrous ammonia

“…In this sense, Xase activity was numerically higher in residues from straws incubated in sheep given US, except at 12 h, and CMCase was higher with US diet from 8 h onwards. Kabre et al (1994) found a high specific activity of polysaccharide-degrading enzymes in underfed animals, associated with a greater expression of the degradative potential of the solid adherent bacteria. Kabre et al (1994) found a high specific activity of polysaccharide-degrading enzymes in underfed animals, associated with a greater expression of the degradative potential of the solid adherent bacteria.…”

Effects of level of intake and nitrogen supplementation on digestion by cows in a tropical environment

“…In contrast, Kabré et al [25] evidenced that reducing amounts of forage supplied to ewes results in an increase in NDF and ADF digestibility and in an increase in NDF degradability; this latter increases due to a higher enzymatic activity of cellulolytic bacteria [24]. In our experiment, the lack of variation in the theoretical degradability compared with the decrease in apparent digestibility could be due to a lack of sensitivity of the in situ method to appreciate differences in fibrolytic activity, when fibre degradation is impaired: the time spent by the particles in the rumen, the lack of mastication and the confinement of the feed in the bags may be responsible for the differences in the fibrolytic activity between the microbes present in the rumen content and in the bags [33].…”

Utilization of nutrients as influenced by different restriction levels of feed intake under sub-tropical conditions in crossbred calves

“…Conversely, with forage based diets in situ DM degradability either did not vary (Aitchison et al, 1986) or increase (Kabre et al, 1995) when intake decreased and digestibility increased. Kabre et al (1994) found that such an increase was due to a higher enzymatic activity of cellulolytic bacteria.…”