Activity of cellulolytic enzymes in the contents of reticulorumen and caecocolon of roe deer (Capreolus capreolus)

The Effect of Protozoa on the Bacterial Composition and Hydrolytic Activity of the Roe Deer Rumen

Simple Summary

Ruminants are herbivorous animals which obtain their energy and nutrients from plant material due to a symbiotic relationship with microorganisms. The main site of this interaction is the rumen, where the intensive digestion processing of plant material takes place. The bacteria, fungi and protozoa create a unique ecosystem—a complex consortium based on mutual interactions. Protozoa are an important component of the microbiome. They have a major impact on the rumen ecosystem as well as on the ruminant’s welfare. Most information on protozoal importance in the digestive processes was obtained from studies on domestic ruminants, with results from studies on wild ruminants being limited. Therefore, the purpose of our study was to compare any effects of the presence of protozoa in the rumen of roe deer (Capreolus capreolus) on the bacterial composition and the digestion rate on the main carbohydrates of their forage. The results obtained from these pilot studies are presented as a short report investigating the relationship between these factors. The analysis of the bacterial composition indicated that the presence of protozoa did not have an effect on bacterial diversity, and furthermore, the protozoa had no effect on the digestion rate of carbohydrates in the rumen.

Abstract

The purpose of this study was to compare the effect of the presence of protozoa in the rumen of wild roe deer (Capreolus capreolus) on the bacteria composition and digestion rate of the main carbohydrates of forage. The research material involved rumen content and rumen fluid, which were collected in the autumn-winter season, from eight adult males of roe deer with an average body mass of 22.6 kg. The microscopic analysis demonstrated that there were only protozoa in 50% of the animals sampled. Qualitative analysis revealed the presence of protozoa belonging to the genus Entodinium. The density of protozoal population varied from 6.5 to 38.7 × 10⁵/mL rumen fluid. The analysis of bacteria composition indicated that protozoa did not have an effect on bacterial diversity. Furthermore, the results of hydrolytic activity revealed that the fastest digestion of carbohydrates was for pectin, while the slowest was inulin. The pH and redox potential in the rumen varied from 5.9 to 6.1 and from −248.1 to −251.1 mV, respectively. In summary, the presence of protozoa in the rumen of wild roe deer does not have an effect on the bacterial population and has no effect on the digestion rate of carbohydrates in the rumen.

Response of roe deer (Capreolus capreolus) to seasonal and local changes in dietary energy content and quality

Context In terms of their nutritional physiology, roe deer have been called ‘concentrate selectors’. This implies that they select proteins in their diet and are not able to digest fibre. It is, thus, suggested that in an agricultural landscape, they are unable to digest the high fibre content of arable crops and, thus, suffer and need to be given supplementary feed. Aims Our aim was to determine the nutrient composition and energy content of the roe deer diet in an agricultural habitat compared with that in a natural forest habitat. Methods Rumen contents of 245 roe deer were collected to represent each month of the year for 3 years, weighed, and analysed by standard methods for nutrient and fibre content. Key results Roe deer in the agricultural habitat had rumen contents with significantly higher metabolisable energy (ME) concentrations, with a median of 6.2 MJ ME/kg DM, than did roe deer in the forest habitat, where the median was 5.4 MJ ME/kg DM. The mass of rumen contents in the forest habitat was, on average, 240 g higher than that in the agricultural habitat. Roe deer in the forest habitat compensate for the lower energy concentration in their natural diet by increasing their food intake. The concentration in the agricultural habitat is a result of the higher proportion of easily digestible carbohydrates in the diet. The concentration of crude protein in the rumen contents did not differ statistically between the two areas. In both habitats, the mean crude fibre concentration varied between 24% DM and 34% DM, and was significantly higher in the forest. The concentration of crude fibre selected by the roe deer is similar to the concentration of crude fibre known to be selected by red deer and fallow deer (intermediate feeders) and mouflon (a grazer) (Hofmann 1989). Conclusions The term ‘concentrate selector’ should be replaced by ‘selector’ to avoid misinterpretations. Energy shortfalls were not observed in either of the populations during the study period. Implications Supplemental feeding was not necessary to maintain the population.