Seasonal faecal excretion, gut fill, liquid and particle marker retention in mouflonOvis ammon musimon, and a comparison with roe deerCapreolus capreolus

Abstract

Seasonal faecal excretion, gut fill, liquid and particle marker retention in mouflon ovis ammon musimon, and a comparison with roe deer capreolus capreolus Seasonal faecal excretion, gut fill, liquid and particle marker retention in mouflon ovis ammon musimon, and a comparison with roe deer capreolus capreolus AbstractFive mouflon (average body mass [BM] 33 kg) and two roe deer (average BM 20 kg) with rumen cannulas were kept in large enclosures under semi-natural conditions and were used for seasonal studies on gastrointestinal tract (GIT) indigestible fill and digesta passage kinetics. As the mouflon were not fully mature, both species had similar digesta volumes in the reticulorumen (RR; mouflon 5.5 ± 1.8% of BM; roe deer 5.4 ± 1.5% of BM); however, the mouflon had lower RR liquid flow rates (15.1 ± 4.3 ml h-1 kg-0.75) than the roe deer (19.2 ± 0.2 ml h-1 kg-0.75), and particle retention in the RR accounted for 68 ± 3% of total GIT retention in the mouflon versus 55 ± 6% in the roe deer. Annual average total GIT retention times for liquids and particles were longer in the mouflon (23.4 ± 0.9 h and 37.9 ± 4.0 h) than in the roe deer (18.4 ± 1.7 h and 22.4 ± 1.9 h). Similarly, annual average RR retention times for liquids and particles were longer in the mouflon (11.9 ± 0.9 h and 25.8 ± 3.3 h) than in the roe deer (8.1 ± 1.7 h and 12.5 ± 2.3 h). The factor of selective particle retention in the RR (retention of particles/retention of liquid) was 2.10 ± 0.09 in the mouflon versus 1.54 ± 0.01 in the roe deer. These observations are in accord with differences in digesta passage characteristics postulated between browsing and grazing ruminants. Total GIT indigestible fill was lower in the mouflon than in the roe deer (10.7 ± 2.1 g kg-1 and 13.3 ± 1.0 g kg-1). As the mouflon were not fully mature, both species had similar digesta volumes in the reticulorumen (RR; mouflon 5.5 ± 1.8% of BM; roe deer 5.4 ± 1.5% of BM); however, the mouflon had lower RR liquid flow rates (15.1 ± 4.3 ml h -1 kg -0.75 ) than the roe deer (19.2 ± 0.2 ml h -1 kg -0.75 ), and particle retention in the RR accounted for 68 ± 3% of total GIT retention in the mouflon versus 55 ± 6% in the roe deer. Annual average total GIT retention times for liquids and particles were longer in the mouflon (23.4 ± 0.9 h and 37.9 ± 4.0 h) than in the roe deer (18.4 ± 1.7 h and 22.4 ± 1.9 h). Similarly, annual average RR retention times for liquids and particles were longer in the mouflon (11.9 ± 0.9 h and 25.8 ± 3.3 h) than in the roe deer (8.1 ± 1.7 h and 12.5 ± 2.3 h). The factor of selective particle retention in the RR (retention of particles/retention of liquid) was 2.10 ± 0.09 in the mouflon versus 1.54 ± 0.01 in the roe deer. These observations are in accord with differences in digesta passage characteristics postulated between browsing and grazing ruminants. Total GIT indigestible fill was lower in the mouflon than in the roe deer (10.7 ± 2.1 g kg -1 and 13.3 ± 1.0 g kg -1 ).

The Morphophysiological Adaptations of Browsing and Grazing Mammals

“…Optimal digestion theory (Sibly 1981) predicts that animals adapted to a forage that yields energy and nutrients quickly would have short retention times, and those that ingest a forage that yields energy and nutrients more slowly would have longer retention times. This has been postulated for ruminants (Hanley 1982;Kay 1987a;Hofmann 1989;Clauss and Lechner-Doll 2001;Behrend et al 2004;Hummel et al 2005); however, a comprehensive dataset based on comparable measurements is still lacking.…”

“…GR have a more diverse protozoal fauna, whereas BR protozoa are mostly Entodinium sp. ; as these are particularly fast-growing ciliates, it has been suggested that other protozoa cannot establish viable populations in the reticulorumen (RR) of BR (Prins et al 1984;Dehority 1995;Dehority et al 1999;Clauss and Lechner-Doll 2001;Dehority and Odenyo 2003;Behrend et al 2004). Other parameters indicative of shorter ingesta retention times (Clauss and Lechner-Doll 2001; Behrend et al 2004) are a lower degree of unsaturated fatty acid hydrogenation in the RR, a greater number of glucose transporters, and a higher amylase activity in the small intestine of BR, 3 as well as larger faecal particles in BR.…”

“…; as these are particularly fast-growing ciliates, it has been suggested that other protozoa cannot establish viable populations in the reticulorumen (RR) of BR (Prins et al 1984;Dehority 1995;Dehority et al 1999;Clauss and Lechner-Doll 2001;Dehority and Odenyo 2003;Behrend et al 2004). Other parameters indicative of shorter ingesta retention times (Clauss and Lechner-Doll 2001; Behrend et al 2004) are a lower degree of unsaturated fatty acid hydrogenation in the RR, a greater number of glucose transporters, and a higher amylase activity in the small intestine of BR, 3 as well as larger faecal particles in BR. In order to maintain intake levels whilst still having prolonged ingesta retention in the rumen, GR should have more capacious rumens (Prins and Geelen 1971;Giesecke and Van Gylswyk 1975;Drescher-Kaden 1976;Hoppe 1977;Kay et al 1980;Owen-Smith 1982;Bunnell and Gillingham 1985;Van Soest 1994).…”

“…In order to maintain intake levels whilst still having prolonged ingesta retention in the rumen, GR should have more capacious rumens (Prins and Geelen 1971;Giesecke and Van Gylswyk 1975;Drescher-Kaden 1976;Hoppe 1977;Kay et al 1980;Owen-Smith 1982;Bunnell and Gillingham 1985;Van Soest 1994). It has been suggested that BR have more capacious hindguts (Hofmann 1988), but this view has recently been modified (Clauss et al 2003a;Clauss et al 2004). …”

Is there an influence of body mass on digesta mean retention time in herbivores? A comparative study on ungulates

“…Faecal samples from zoo 151 animals were collected at particular intervals (see below for details), dried at 103 °C and 152 ground through a 1 mm sieve. Marker concentration was measured after wet ashing, 153 according to Behrend et al (2004) In other words, a slope of one and an intercept of zero were statistically not excluded in either 169 case, indicating no systematic difference between the two sampling schemes. Only data 170 calculated from all available sampling intervals are presented in the discussion.…”