COMPARATIVE STUDY ON CAECAL FERMENTATION PATTERN IN ADULT DOMESTIC RABBITS AND WILD HARES
M. Marounek1, 3, D. Mista2, Z. Volek1, O.G. Savka3, L.G. Kalachnyuk4, G.I. Kalachnyuk4
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This email address is being protected from spambots. You need JavaScript enabled to view it.1Institute of Animal Science, 104 00 Prague, Czech Republic
2Wroclaw University of Environmental and Life Sciences, Faculty of Veterinary Medicine, 50375 Wroclaw, Poland
3Institute of Animal Physiology and Genetics, Academy of Science of the Czech Republic, 142 20 Prague, Czech Republic
4National University of Life and Environmental Sciences of Ukraine, Heroiv Oborony str.,15; Kyiv, 03041, Ukraine
Due to the activity of microorganisms in the caecum of rabbits, acetate is formed in the result of processes of glycolysis and synthesis of CO2 and H2. In rabbits,there is peculiarity of fermentation of caecal microorganisms in greater butyrate production compared with propionate. The butyrate overproduction is characteristic only for rabbits in contrast to all herbivorous animals (including ruminants, in which, in the rumen, it’s produced more propionate than butyrate). The research presented in this paper was aimed to increase knowledge about digestion in leporids. Therefore, it was defined the concentration of metabolites in fermentation processes in the caecum of rabbits and hares, and production of metabolites in cultures caecum content. It’s important to note that the use of the same diet was not feasible in the present experiment because of sporadic rabbit breedings.
Eight hares (3.3–4.5 kg of weight) lived in their natural environment.In November, before noon,animals were trapped with a soft net(length, 400 m) and slaughtered in the afternoon. Eight rabbits were housed individually in cages and slaughtered at 9:00 a.m. at the age of 11 weeks. Samples of caecum contentof rabbits and hares were analyzed, including measurement of concentrations of volatile fatty acids (VFA) and ammonium, and used for the cultivation of microorganisms with subsequent determination production of VFA and methane.
Rabbits and hares, despite their morphological resemblance and similar type of digestion, differ in profile of caecal fermentation end-products. Caecal concentration of total volatile fatty acids were higher and ammonia concentrations was lower in rabbits than in hares (98.9 ± 18.1 and 20.7 ± 8.0 mmol/l vs 46.8±14.0 and 33.4 ± 12.5 mmol/l, respectively). Caecal microorganisms of rabbits produced more acetate (66.4 ± 3.3 mmol/l) and butyrate (19.5 ± 3.1 mmol/l) than propionate (10.1 ± 2.9 mmol/l). Corresponding acetate, butyrate and propionate concentrations in hares were 28.4 ± 1.8, 5.5 ± 1.9 and 8.7 ± 1.0 mmol/l, respectively. This finding was confirmed in in vitro experiment. In rabbit caecal cultures fermentation was accompanied with a significant methane release (15.3 ± 2.2 mmol/l). In hares only traces of methane were produced (0.1 mmol/l). Calculations of metabolic hydrogen recovery suggest that reductive acetogenesis (an alternative electron sink) exists in caeca of both animal species. Thus, in rabbits caecal fermentation in vitro is accompanied by significant release of methane, while in hares it is produced in very small quantities.
Key words: RABBIT, HARE, CAECUM, FERMENTATION, AMMONIUM, METHANE.
