Articles 71-80

Influences of rabbit breed on relative size of the intestinal tract and the composition of its content

Petra Wolf, Birgit Zumbrock, R. Tabeling and J. Kamphues

Institute of Animal Nutrition, School of Veterinary Medicine Hannover, Bischofsholer Damm 15, D-30173 Hannover

While in laboratories and in meat production primarily large rabbit breeds are used, smaller breeds (e.g. dwarf rabbits) are predominantly kept as pets. At the same time, data on nutrition physiology and digestive capacity generally gathered for larger rabbit breeds are sometimes indiscriminately applied to smaller ones. But in feeding studies on digestibilities in different rabbits breeds (smaller and greater ones) dwarf rabbits showed a higher digestion capacity than New Zealand White or Belgian Giants (1). Aim of this study, therefore, was to illustrate physiological parameters in the intestinal tract (IT) and possible breed-related peculiarities to explain such differences and to take these into account in optimizing the nutrition of dwarfs.

5 adult female rabbits each of the breeds Belgian Giant (BG; Æ 7.27 ± 0.18 kg BW), New Zealand White (NZ; Æ 4.36 ± 0.60 kg BW) and Dwarf rabbit (DR; Æ 1.82 ± 0.30 kg BW) were available. The rabbits were fed a pelleted complete diet on the basis of green meal (offered restrictively: 3 g DM/100 g BW). After an adaptation of 10 days the rabbits fasted about 24 hours. On the next day they got 1 g diet per 100 g BW and were sacrificed 6 h ppr. to obtain the chyme. The individual compartments (stomach, duodenum, caecum, proximal/distal colon, rectum) were ligated, weighted and the content extracted. The chyme was analyzed using standard methods of analysis (nutrients, pH, NH3, FFA, lipopolysaccharides). Particle sizes in chyme and feces were determined via wet sieve analysis. The following table shows some of the

  • · weight of IT (excl. chyme)

  • - total (% of BW) 5.70 ± 0.76 5.93 ± 0.50 5.55 ± 0.58
    - stomach (% of BW) 1.29 ± 0.39 1.80 ± 0.34 1.34 ± 0.34
    - caecum (% of BW) 1.34 ± 0.15 1.34 ± 0.09 1.47 ± 0.18
  • · amounts of chyme

  • - total (g DM/100 g BW) 1.61 ± 0.21 1.52 ± 0.24 1.41 ± 0.24
    - proportion in stomach (%) 40.4 ± 10.9 47.0 ± 6.70 34.0 ± 6.12
    - proportion in caecum (%) 40.3 ± 11.0 37.5 ± 4.06 46.6 ± 4.25
  • · particle size (%)

  • - stomach (_ 1.0 / _ 0.25) 61.1±9.92 27.7±8.36 51.0±2.55 35.2±5.23 50.1±3.39 30.4±6.4
    - feces (_ 1.0 / _ 0.20) 69.7±15.8 10.1±6.01 60.4±2.11 22.7±2.84 55.7±5.14 24.0±6.9

    Microbiological investigation of caecum chyme showed – without breed differences - following results (data in Cfu/g): Cl. perfringens: 102–107; E. coli < 102; Lactobacillae < 102; Enterococcus: < 103 and gramneg. Bacteria 2.6-7.1 x 108. Data on pH, ammonia (slightly higher levels in dwarf rabbits) or FFA in the chyme did not indicate breed influences.

    Dwarf rabbits showed the lowest weight of ITT. The stomach was slightly lower and the chyme left them earlier than in other ones. Most of total chyme is located in the large ITT (especially caecum). Furthermore the chyme (stomach) of DR is characterized by a high level of well grounded particles (chewing intensity­?). It seems, that dwarfs follow up the strategy to channel quickly the chyme from stomach to caecum. The apparently higher transit time leads to a higher intensity of caecotrophy and therefore to a higher digestion capacity.

    (1) B. ZUMBROCK, P. WOLF and J. KAMPHUES (2001): Investigations on ingestion behaviour and digestibility of organic matter in rabbits of different breeds. Proc. 5th ESVCNConference, 13th –14th September 2001, Sursee, Switzerland

    Relationship of genotype, body composition and sexual maturity in females of different rabbit breeds

    Kinga Fodor, L. Zöldág, S. Fekete, A. Bersényi, Emese Andrásofszky, Margit Kulcsár and R.

    SZIU Faculty of Veterinary Science Budapest, Institute of Animal Breeding, Nutrition and Laboratory Animal Science, H-1400 Budapest, POB 2., *Masterfoods Magyarország BT, H-1141 Budapest, Szugló utca 83-85. Hungary

    Trial using young female twenty-six, 6-week-old New Zealand White and a twenty-two 7- week-old Hungarian Giant rabbit was carried out to establish the total body composition and sexual maturity in function of feeding intensity. Animals in each breed were divided into two groups: the control (nNZW=13; nHG=11), which was fed ad libitum (AL) while their sisters’ (nNZW=13; nHG=11) feeding was restricted exactly the 70% of ad libitum intake (RS). The energy concentration of pelleted feed mixture was 11.5 MJ/kg DE and that of crude protein 15.9%. The trial lasted between the age of 6 to 18 weeks of the NZW and 7-24 ones of HG animals. To establish the basic values at the beginning of experimental feeding, another analogue 5-5 rabbits were analysed for major chemical components in both breeds. At the end of the trial the total body’s major chemical composition has been measured in all rabbits. In order to follow ovarian and pituitary actives, hCG and GnRH hormonal treatments were used for four times in each animal during the trial. Clinical observation (colour and swelling of the external genitalia) has been made on days 2 and 5 following the hormone treatments.
    Blood plasma progesterone levels (P4) were determined from samples, collected 8 days after hormone treatment. At the end of the experiment, the average body weight was significantly lower in RS-Group (NZW: 84.4%; HG: 89.7%) when compared to AL-Group. During the trial the average body weight gain were in the AL-Groups 80.9% in NZW and 87.5% in HG of RS-Groups. As a result of restricted feeding in both breed groups the ash and protein content expressed both in total body and dry matter were increased, while the fat concentration decreased. In Hungarian Giant Females till 11 weeks, and in New Zealand Whites till 13 weeks of age the pituitary and ovarian response to exogenous HCG and GnRH administration failed. In the late maturing Hungarian Giant the intensity of feeding exercised effect from 10-11 weeks of age during the growing period, while in the early maturing New Zealand breed this response could be observed only from 12-14 weeks of age on.
    Amongst the individuals of both breeds, those animals became pregnant the earliest, which had the highest body fat content. HCG promoted sexual maturity in both breeds in case of ad libitum feeding, while in case of restricted feeding no such effect was observed. In case of GnRH administration there was no difference between breeds and feeding levels regarding sexual maturity. It was concluded that restriction of feeding intensity of growing breeding rabbits is a delicate procedure and a 30% rationing exerted unfavourable effect on the body composition, and consequently, slowed down the reproductive maturation of future does.

    Influence of body size on fermentative activity and faecal consistency in dogs

    David Hernot1, Mickael Weber1, Lucile Martin1, Henri Dumon1, Brigitte Siliart1, Vincent
    Biourge2 and Patrick Nguyen1

    1 National Veterinary School of Nantes, France
    2 Royal Canin Research Centre, Aimargues, France

    Observations on food tolerance in dogs have shown that large breeds have a higher faecal water content and a greater frequency of soft stools. This could be explained by significant differences in colonic functions i.e. a limited water absorption and/or an important fermentative activity. The aim of this study was to investigate the fermentative aspect of this theory by comparing gut microflora activity in dogs differing in body size.

    Materials and methods:
    Adult dogs of four breeds, with body weights varying from 4 to 55 kg, were included in the study: six miniature poodles (MP), six medium size schnauzers (MS), six giant size schnauzers (GS) and six great Danes (GD). The faecal moisture content and faecal consistency were scored daily for two weeks. Fermentative activity was evaluated through the intensity and appearance kinetics of the sulfapyridine (SP) in blood during 30 h, after oral administration of sulfasalazine (SLZ). The maximum concentration of SP and the area under the curve were considered representative for the fermentative intensity in each animal. Lactic acid and volatile fatty acid (VFA) faecal concentrations were also evaluated as well as the total fibre (TDF) digestibility.

    A poorer faecal quality (higher moisture and looser consistency) was recorded in large breed of dogs. Larger SP concentration and area under the curve were shown in GS and GD than in MS and MP. The measurement of fermentation products in stools revealed significant higher lactic acid and VFA concentrations in GD (23 and 299 mmol/kg faeces as is, respectively) than in MP (7 and 159 mmol/kg faeces as is, respectively) (p<0.0001). In the same way, TDF digestibility was dramatically higher in large dogs (52.5% vs 38.7% in GD and MP respectively) (p<0.0001).

    This study confirms the predisposition of large breed dogs to have soft stools. Greater concentrations of SP and faecal fermentation products in GS and GD suggest a higher fermentative activity in large and giant dogs. This inference is confirmed by a higher TDF digestibility in GS and GD than in MS and MP. These results suggest that a high fermentative activity is a possible cause of poor faecal quality in large breed of dogs.

    Age-related changes in digestibility and gastric emptying in growing dogs

    Mickael Weber1, Fouzia Stambouli1, David Hernot1, Lucile Martin1, Henri Dumon1, Vincent
    Biourge2 and Patrick Nguyen1

    1 National Veterinary School of Nantes, France
    2 Royal Canin Research Centre, Aimargues, France

    Many changes occur in morphology as well as in function of the gastrointestinal tract during growth. It could be thus hypothesized that age could affect the transit time (overall or sequential, gastric, intestinal or colonic). These changes could also modify the digestive process and efficiency and lead to significant nutritional consequences. The aim of this study was therefore to assess eventual changes in both the digestibility of a dry diet and its gastric emptying time using radiopaque markers in growing dogs.

    Materials and methods:
    Twenty four dogs from very small to giant breeds, 6 miniature poodles (MP), 6 medium schnauzers (MS), 6 giant schnauzers (GS) and 6 great Danes (GD) were studied at 12, 22, 36 and 60 weeks of age. The same diet was used for the overall period. Digestibility coefficients were determined over a 7-day period in each dog at each age. One week after each digestibility trial, dogs received 30 radiopaque markers (BIPSâ, 1.5 mm diameter, Chemstock Animal Health Ltd, New Zealand) mixed with the diet. Abdominal radiographs were made hourly for 12 h and the time (T50) at which 50% of the markers had left the stomach was then determined for each dog.

    The mean apparent digestibility coefficient of organic matter, crude protein, fat and gross energy significantly increased between 12 and 60 weeks of age in the four breeds. The gastric emptying time significantly increased with age in all dogs so that T50 was significantly longer in adult dogs (3.4 ± 0.4 vs 6.4 ± 0.5 h in MP, 4.4 ± 0.3 vs 6.5 ± 1.2 h in MS, 5.2 ± 0.9 vs 7.8 ± 0.7 h in GS and 4.3 ± 0.6 vs 6.4 ± 1.1 h in GD at 12 and 60 weeks of age respectively). These results show (1) a higher nutrient utilization in adult dogs and (2) a slowing down of gastric emptying time during growth. That suggests that the faster gastric emptying of puppies could take part in their lower digestive efficiency.

    Seasonal changes in digestive tract function in marmots

    Ian D. Hume

    School of Biological Sciences, University of Sydney, NSW 2006, Australia

    Marmots are the largest members of the rodent family Sciuridae (squirrels). They are primarily herbivorous, while nearly all other sciurids are granivores. The dietary strategy of herbivory is made possible for marmots by their large body size and therefore large capacity of the digestive tract. The digestive tract of all sciurids is relatively simple, so that at the small body sizes typical of chipmunks (Eutamias spp.), digestive efficiency is limited by short mean retention times of food in the gut (Hume, Morgan and Kenagy 1993).
    This restricts them to easily digested foods such as seeds. The larger digestive tract of marmots overcomes some of the limitations of a simple tract morphology by increasing digesta mean retention times, enabling them to expand their dietary niche to include the structural parts of grasses and forbs. However, the dietary strategy of herbivory precludes the caching of food such as seeds and nuts to sustain the animal uring the annual winter hibernation as do most sciurids, and instead marmots store energy as body fat. Entry into hibernation appears to be triggered by the attainment of a certain level of body fat, in addition to an optimal level of polyunsaturated fatty acids in the stored fat. Marmots appear not to feed during their periodic arousal periods throughout the winter hibernation which, for alpine marmots (Marmota marmota), lasts for 6 months or more. The digestive tract is expensive to maintain, so if it is not being used during this long period it can be hypothesised that it should be reduced in size and/or activity.
    This hypothesis was tested during a marmot control program in Switzerland. The gastrointestinal tracts of 76 alpine marmots shot during this program were analysed for patterns of change in morphology and function over the active season (April to September) of 1999 and 2000 (Hume et al. 2002). Dramatic increases in fresh tissue mass (by 105% in the stomach to 259% in the small intestine) and in the pool size of short-chain fatty acids in the caecum (12-fold) between emergence from hibernation in April to mid-summer (July) were followed by decreases between July and September in anticipation of re-entry into hibernation. It appears that a low level of activity of the marmot gastrointestinal tract is maintained during winter, the main substrates in both the small and large intestine being of endogenous origin. The main signal to increased levels of activity in the spring seems to be ingested food rather than some endogenous signal. The earlier increase in tissue mass in the hindgut than the small intestine reflects the importance of microbial fermentation in the marmot digestive strategy. The delayed up-regulation of the small intestine in spring, together with its earlier down-regulation in autumn before re-entry into hibernation, are consistent with the high costs of maintaining this section of the gastrointestinal tract.

    Hume, I.D., Beiglböck, C., Ruf, T., Frey-Roos, F., Bruns, U. and Arnold, W. (2002). Seasonal changes in morphology and function of the gastrointestinal tract of free-living alpine marmots (Marmota marmota).
    J. Comp. Physiol. B172: 197-207. Hume, I.D., Morgan, K.R. and Kenagy, G.J. (1993). Digesta retention and digestive performance in sciurid and microtine rodents: effects of hindgut morphology and body size. Physiol. Zool. 66: 396-411.

    Effect of different fibre types on the digestibility of nutrients in cat

    S. Fekete, I. Hullár und Emese Andrásofszky, F. Kelemen*

    SZIU Faculty of Veterinary Science Budapest, Institute of Animal Breeding, Nutrition and Laboratory Animal Science, H-1400 Budapest, POB 2., *Masterfoods Magyarország BT, H-1141 Budapest, Szugló utca 83-85. Hungary

    In the last few years research about the role of dietary fibre in cats’ diet have been actively pursued. Until now, fibre was primarily added to commercial cat diets for two reasons: to alter stool consistency and to provide indigestible components helping slimming diets. In the present study the effect of different fibre types was investigated on the digestibility of nutrients in cat.

    Dried sugar beet pulp (source of hemicellulose and pectin), alfalfa meal (source of cellulose) and peanut hull (source of lignin) were mixed to a poultry meat based control diet at a level of 10% on dry matter (DM) basis. The digestibility of the major nutrients of the following four feed mixtures were determined. Diet (control): poultry meat based diet; Diet 2: Diet 1 (control) supplemented by 10% of dried sugar beet pulp; Diet 3: Diet 1 supplemented by 10% of alfalfa meal and Diet 4: Diet 1 supplemented by 10% of peanut hull. Digestibility trials were conducted by the same 10 castrated, adult cats (self-control study). Cats were housed individually, cages allowed the exact registration of the feed intake, and the quantitative collection of the faeces. Cats had free access to tap water. Animals were fed individually by providing 200 g original matter, resulting 80 g DM intake per day. The length of the test (collection) period lasted 6 days per treatments.

    Fibre supplementation did not influence the daily dry matter intake of cats. Perhaps it is due to the high palatability of the diets. Related to the Diet 1 (control) the digestibility of the dry matter content was lower in the Diet 2 and in the Diet 4 (76.74; 73.82, and 74.04, respectively). Surprisingly, by feeding Diet 3, the digestion coefficient (76.36%) practically did not differ (p<0.05) from the control. According to this results, Diet 3 containing cellulose, known to be poorly fermentable fibre, proved not to be of decreasing the dry matter digestibility of the feed mixture.

    According to this trial not only the absolute fibre content of the diet but also the type of the fibre, has to be taken into consideration, when evaluating the possible role of fibre fractions, as components of weight loss products.

    Digesta kinetics in feral pigeons (Columba livia)

    J.-M. Hatt

    Division of Zoo Animals and Exotic Pets, University of Zurich, Switzerland

    The experiment was conducted to determine the digesta kinetics of liquid phase and particles in feral pigeons (Columba livia). All animals were individually caged. Mean retention times (MRT) were estimated in seven adult pigeons (Bodyweight 275 – 320 g) fed a pulse dose of Co-EDTA (Co 8 mg/animal), Cr-mordanted fibre (Cr 1 mg/animal, particle size <2 mm) and the n-alkane hexatriacontane (C36 3 mg/animal, as labelled food pellets). For details concerning the marker analysis and the calculation refer to Hatt et al. ( 2001) and Hatt et al. ( in press). Individual samples were collected every 1 ½ h for 12 hours and one more sample was collected 24 h after marker application. Average MRT for the liquid phase marker Co was 5.3 h (± 3.18). For the particle phase markers Cr and C36, MRT was 6.8 h (± 2.87) and 8.4 h (± 3.25), respectively. Transit-time (TT) was in all birds < 1 h. This was shorter than the 2 ½ h published by Vogel ( 1980) The retention times of all three markers differed significantly. This is surprising since it as expected that the particle markers would not differ in their kinetic behaviour. As a possible explanation may be selective retention. The pellets which contained the n-alkane C36 could have dissolved into particles that were much smaller and easier to digest than the Crmordanted fibre. For a bird such as the pigeon, which flies long distances it may be of importance to eliminate less digestible food faster, to reduce weight. Further studies will have to test this assumption using particles of different size and digestibility.

    Hatt J.-M., et al., 2001. Anim Feed Sci Technol 94: 65-76.
    Hatt J.-M., et al., in press. Herpetol J
    Vogel K., 1980. Die Taube - Biologie, Haltung, Fütterung. Berlin: VEB Deutscher Landwirtschaftsverlag

    Dietary management of dental disease in the dog and cat

    DM Morgan, AJ Lepine, ER Cox

    The Iams Company, 47 Route de Saint Georges, 1213 Petit-Lancy, Geneva

    Periodontal disease is one of the most common problems affecting companion animals. It is the most common oral disease and a major reason for them to be presented at clinics. Periodontal disease includes both gingivitis (plaque induced inflammation) and periodontitis. Tooth brushing is effective in reducing plaque build-up but owner compliance towards this is very low. Plaque that is not removed can eventually be converted to dental calculus. Calculus can only be adequately removed by professional dental prophylaxis but its build-up can be reduced by specific dental diets. Dietary formulations that maximize oral-health care through reducing plaque and calculus build-up, increased owner compliance, and addressing the masticatory habits of companion animals, are available.
    One strategy involves using a mechanical scraping action while the pet chews the food. Some studies have shown a 19% reduction in plaque, and 32% reduction in calculus using such a diet in dogs. Mechanical abrasion from these specialized diets occurs where the food actually contacts the tooth surface. Relatively new technology to companion animal foods allows for mineral sources of phosphorus, in the form of polyphosphates, to enhance the properties of the dry kibble (pellet). The polyphosphates coat the outer surface of the dry food. Their benefit in dogs in reducing calculus build-up has already been demonstrated using both dry food and mouthrinses.
    More recent studies have shown an average of 55% reduction in calculus build-up in dogs and an average of 45% reduction of calculus build-up in cats. These enamel-safe minerals are used successfully in human dentifrices in helping reduce calculus build up. There are two phases to the effect of food coated with polyphosphate crystals:- (1) during chewing the hard food can help scrub away plaque (2) after chewing the polyphosphates embed into the plaque and help prevent calculus build-up through sequestering or complexing calcium within plaque forming soluble calcium complexes that diffuse into saliva. The benefit of the barrier approach is that polyphosphates can provide whole mouth benefits as they are released from the diet during mastication and are then carried throughout the oral cavity. The polyphosphates also provide benefits to non-chewing surfaces. The nutritional safety of polyphosphates is due to their conversion into orthophosphates which are utilized by the host. There is no detrimental effect on the nutritional value of the food as they make up part of the normal phosphorus dietary content. Polyphosphates offer an alternative strategy in helping reduce calculus build-up in companion animals when applied to the surface of complete and balanced diets.

    Fluid and particle passage rate in captive black rhinoceros (Diceros bicornis)

    M. Clauss1, T. Froeschle2, M. Lechner-Doll3, E.S. Dierenfeld4, J.-M. Hatt5

    1Institute of Animal Physiology, Physiol. Chemistry and Animal Nutrition, Munich, Germany
    2Birkenweg 12, Pforzheim, Germany
    3Institute of Zoo Biology and Wildlife Research (IZW) Berlin, Germany
    4Nutrition Department, Wildlife Conservation Society, New York, USA
    5Division of Zoo Animals and Exotic Pets, Zurich, Switzerland

    In contrast to ruminants, hindgut fermenters are considered more flexible in their digestive response to different amounts of available forage. As they are not intake-limited due to the selective particle retention of a forestomach system, they can adapt their passage to the available food for intake to a distinctively higher degree. Recently, the feeding of captive rhinoceros has received considerable attention. As part of several different feeding trials, therefore, we measured the passage rate in captive black rhinoceros. Seven animals from different zoological institutions were given a pulse-dose of a combination of cobalt-EDTA as a fluid and chromium-mordanted fibre (particle size _ 2mm) as a particle marker. Faeces were collected continuously for 15 hours before to 80 hours after marker application. Food intake was measured simultaneously. Marker concentration of faecal subsamples was determined by atomic absorption spectometry. Mean retention times (MRT) were calculated according to the method of Thielemans et al. (1).
    The average fluid and particle MRT were 35.0 (± 8.1, range 27.4-48.0) and 42.5 (± 13.8, range 31.0-67.1) hours, respectivley. The particle marker was retained 1.1-1.4 times longer than the fluid marker. Animals that had a higher dry matter intake had faster passage rates. These results were considerably faster than the values obtained by Foose (2) of 51-60 hours. The difference is most probably due to the increased sampling interval of our investigation and indicates that black rhino MRT are closer to the time of 35 hours Demment and Van Soest (3) calculate for a reasonable exploitation of fast-fermenting plant material.

    (1) Thielemans et al. (1978) Ann Biol Anim Biochim Biophys 18: 237-247
    (2) Foose T (1982) PhD Thesis, University of Chicago
    (3) Demment DM, Van Soest PJ (1985) Am Nat 125: 641-672

    Morphological correlates of accelerated passage rates in very large herbivores

    B. Kiefer, W. Loehlein, M. Clauss

    Institute of Animal Physiology, Physiological Chemistry and Animal Nutrition, Veterinaerstr. 13, 80539 Munich, Germany

    The largest extant mammalian herbivore, the elephant, is characterised by comparatively short ingesta passage rates and low digestibility coefficients. We intended to search for morphological correlates of this obvious deviation from the general concept that an increase in body mass should enhance longer passage rates and hence more thorough digestion. There is a surprising paucity of anatomical data on the gastrointestinal tract (GIT) of large mammalian hindgut fermenters. We collated data on tapirs, equids, rhinoceroses and elephants. The few available data suggest the following trends: larger hindugt fermenters do not show an according increase in GIT length; the diameters of GIT sections tend to increase in larger species; the relative capacity of the caecum tends to be reduced in larger species. Although evidently more data is needed to substantiate these preliminary observations, they are in accord with the comparatively fast passage rates of the largest extant herbivores, and could be indicative of the trend the even larger extinct mammalian herbivores – all of which are thought to have been hindgut fermenters – would have had to follow. The reason for this adaptation probably lies in the fact that the fermentation of plant material cannot be optimized endlessly; there is a time when plant fibre is totally fermented, and another when energy losses due to methanogenic bacteria become punitive. Therefore, very large herbivores would need to evolve adaptations for a comparative acceleration of ingesta passage. To our knowledge, this phenomenon has not been emphasized in the literature to date.