In Vitro Study and Comparison of Caecal Methanogenesis and Fermentation Pattern in the Brown Hare (Lepus europaeus) and Domestic Rabbit (Oryctolagus cuniculus)

Abstract

The brown hare and the domestic rabbit are mid-sized herbivorous mammals and hindgut fermenters, though their digestive physiologies differ in some traits. The objective of this study was to estimate and compare the caecal microbial activity in hares and rabbits via an analysis of the following end-products of in vitro caecal fermentation: methane, total gas production, short chain fatty acids and ammonia concentration. Hare caecal methanogenesis occurred at a much lower level (0.25 mmol/kg for samples incubated without substrate and 0.22 mmol/kg for samples incubated with substrate) than that of the rabbit (15.49 and 11.73 mmol/kg, respectively) (P<0.001). The impact of the substrate’s presence on caecal methanogenesis was not significant, though its presence increased the total gas production during fermentation (P<0.001). Hare caecal microflora produced a lower short chain fatty acids concentration than did rabbit microorganisms (P<0.05). In unincubated hare samples, the short chain fatty acids concentration was 28.4 mmol/kg, whereas in unincubated rabbit samples, the short chain fatty acids concentration was 51.8 mmol/kg. The caecal fermentation pattern of the hare was characterised by higher propionate and isobutyrate molar proportions compared with those observed in rabbit caecum (P<0.01). No significant changes in the ammonia concentration in either rabbit or hare caecum were found. The results obtained indicate some differences in the activity of the microbial populations colonising the hare and rabbit caecum, particularly in regards to methanogenic Archaea.

Effect of dietary fibre and condensed tannins concentration from various fibrous feedstuffs on <i>in vitro gas</i> production kinetics with rabbit faecal inoculum

“…Similar results were obtained by Miśta et al (2015) who found that the gas production of wheat bran in rabbit equalled 37.9 ml · 0.5 g -1 (90.96/1.2 g). Whereas Bovera et al (2006) estimated in rabbits the potential gas production at 86 ml · 0.5 g -1 and 155 ml · 0.5 g -1 for dehydrated lucerne meal and beet pulp, respectively.…”

Comparative in vitro study of caecal microbial activity in brown hares and domestic rabbits which were offered the same diet

“…The distinctive feature of the rabbit SCFA profile is that the molar proportion of butyrate exceeded that of propionate, what is opposite that in most herbivorous and omnivorous mammals, which produce more propionate than butyrate in their digestive tract (Bergman 1990). In our previous study (Miśta et al 2015), lower SCFA production was found in the hare caecum compared to in the rabbit caecum, and it was explained by the lower digestibility of hemicelluloses in the hare (Stott 2008). In the present study, the total SCFA concentration was still lower in the hares regardless of the supplementary substrate, which was either rich in hemicelluloses (wheat bran) or rich in non-structural carbohydrates with a higher fat level (oat bran).…”

“…These differences were mainly focused on total SCFA concentration, which was higher in rabbits compared to hares, as well as the propionate/butyrate ratio, which was higher in hares than in rabbits. In our previous experiments, the most surprising result was that methane production was very low in hare caecal samples compared to those of rabbits, and we established that caecal methanogenesis in the hare remained very low despite the addition of substrate into inoculums (Miśta et al 2015). However, the impact of diet, which differed between rabbits and hares, on the variations in the products of microbial activity between species was uncertain.…”

“…Our previous research, performed in vitro using caecal inocula obtained from brown hares (Lepus europaeus) from a natural environment and caged domestic rabbits, showed some differences in the SCFA profile of these animals, suggesting different activities of the bacteria inhabiting their caeca (Marounek et al 2013;Miśta et al 2015). These differences were mainly focused on total SCFA concentration, which was higher in rabbits compared to hares, as well as the propionate/butyrate ratio, which was higher in hares than in rabbits.…”

In vitro fermentation pattern in the large intestine of hybrids between wild boars and domestic pigs - a preliminary study

“…The total concentration of SCFAs measured in the large intestine of the species studied so far fitted within the range of 30-240 mM, but most commonly averaged 70-120 mM (Bergman 1990;Mista et al 2015;Pecka-Kielb et al 2016). There are no published data concerning fermentation processes in WBPHs, so we compared our results to the values obtained for pigs, as the closest relatives of these animals.…”