The effect of season on in vitro degradability and fermentability of feeds in red deers’ (Cervus elaphus L.) rumen fluid | Vpliv sezone na in vitro razgradljivost in fermentabilnost krmil v vampovem soku navadnega jelena (Cervus elaphus L.)

anglais. Transition from summer to winter changes red deer digestive tract physiology and digestive processes. The objective of the trial was to determine the effects of season on in vitro apparent (ivADMD) and true dry matter (ivTDMD) digestibility, in vitro gas production parameters and short-chain fatty acid synthesis (SCFA) in red deer hinds of eleven substrates naturally occurring in Slovenia (chestnut fruits, acorns of common and sessile oak, two fresh grasses) and those frequently used in supplemental red deer feeding (two grass hays and two grass silages, apple pomace and sugar beet roots). There were no differences in ivADMD, ivTDMD, determined by incubation of feeds in buffered rumen fluid, as there were no differences in majority of gas production parameters between autumn and winter season. Only the parameter “C” (specific gas production rate) was frequently higher (p < 0.05) in winter season than in autumn season. The amounts of SCFA were similar between two seasons. However, the proportion of acetic acid tended to be higher in winter, while the proportions of propionic and butyric acid tended to be higher in autumn than in winter especially in high fibre feeds. On contrary, in high starch feeds such as oak acorns and chestnut fruits, the proportion of propionic acid was higher (p < 0.05) in winter, while of butyric acid in autumn (p < 0.05). Despite the fact that the number of used substrates (n = 11) and animal rumen fluid donors (n = 6) were small, these results indicate a shift in rumen microbial metabolism between autumn and winter season.

slovène. Prehod iz poletja v zimo povzroči spremembe v fiziologiji prebavnega trakta navadnega jelena in v tam prisotnih prebavnih procesih. Zato je bil namen raziskave ugotoviti, kako sezona vpliva na in vitro navidezno (ivNRSS) in pravo razgradljivost suhe snovi (ivPRSS), na kazalnike in vitro tvorbe plina in na sproščanje hlapnih maščobnih kislin (HMK) iz enajstih krmil, ki jih zauživajo ali dokrmljujemo košutam navadnega jelena v Sloveniji (plodovi kostanja in gradna ter želod in dva vzorca sveže trave, dva vzorca mrve in travne silaže, jabolčne tropine in koreni sladkorne pese). IvNRSS in ivPRSS, določeni z inkubacijo krmil v puferiranem vampovem soku, se med sezonama nista razlikovali, prav tako tudi nismo ugotovili velikih razlik pri večini kazalnikov produkcije plina. Le kazalnik »C« (specifična hitrost tvorbe plina) je bil večji (p < 0,05) v zimski sezoni. Tudi količine HMK so bile med sezonama zelo podobne. Vendar pa je bil delež ocetne kisline pogosto nekoliko večji pozimi kot jeseni (0,05 < p < 0,10), medtem ko sta bila deleža propionske in maslene kisline pri krmilih, ki so vsebovala več vlaknine, večja (0,05 < p < 0,10) jeseni kot pozimi. Nasprotno pa smo ob inkubaciji krmil, ki vsebujejo veliko škroba (želod in kostanj), določili večji (p < 0,05) delež propionske kisline pozimi, medtem ko je bil pri teh krmilih delež maslene kisline večji (p < 0,05) jeseni. Čeprav sta bila tako število uporabljenih substratov (n = 11) kot število živali (n = 6), darovalk vampovega soka, majhna, pa ti rezultati kažejo na spremembo presnove vampovih mikroorganizmov med jesenjo in zimo.