Digestive Tract Of Rabbits Research Articles

Sand accumulation in the digestive tract of rabbits (Oryctolagus cuniculus) and guinea pigs (Cavia porcellus): The role of the appendix.

We determined location and amount of accumulated sand in the gastrointestinal tract (GIT) of rabbits (Oryctolagus cuniculus) and guinea pigs (Cavia porcellus) fed diets containing external (silicate) abrasives. Computed tomographic abdominal images of rabbits (n = 44) and guinea pigs (n = 16) that each received varying numbers (4–7) of different diets for 14 days each (total n = 311 computed tomographs), and radiographs of dissected GIT and presence of silica in GIT content (n = 46 animals) were evaluated. In rabbits, the majority of accumulated sand was located in the caecal appendix, an elongated, intestinal structure in the left side of the abdomen. The ‘wash‐back’ colonic separation mechanism in rabbits may be partly responsible for a retrograde transport of sand back to the caecum, where dense, small particles accumulate in the appendix. The appendix likely acted as a reservoir of these particles, leading to significant effects not only of the momentary but also of the previous diet on recorded sand volumes in the rabbits. Guinea pigs have no caecal appendix and a colonic separation mechanism not based on a ‘wash‐back’. Less sand accumulation was found in their GIT without a specific location pattern, and there were less previous diet effects in this species. None of the rabbits or guinea pigs developed clinical signs of obstruction during the study, and the recorded sand volumes represented 1.0 ± 1.2% of the 14‐d sand intake in rabbits and 0.2 ± 0.2% in guinea pigs. Accumulation of sand in volumes up to 10 cm3 in the GIT of rabbits does not seem to cause clinical health impairment. Large inter‐individual differences in rabbits indicate inter‐individual variation in proneness to sand accumulation. The reason for the presence of a sand‐trapping caecal appendix in animals that are, due to their burrowing lifestyle and feeding close to the ground, predestined for accidental sand ingestion, remains to be unveiled.

Increasing food intake affects digesta retention, digestibility and gut fill but not chewing efficiency in domestic rabbits (Oryctolagus cuniculus).

In ruminants, the level of food intake affects net chewing efficiency and hence faecal particle size. For nonruminants, corresponding data are lacking. Here, we report the effect of an increased food intake of a mixed diet in four domestic rabbit does due to lactation, and assess changes in particle size (as determined by wet sieving analysis) along the rabbit digestive tract. During lactation, rabbits achieved a distinctively higher dry matter intake than at maintenance, with a concomitant reduction in mean retention times of solute and particle markers, an increase in dry matter gut fill, a reduction in apparent digestibility of dry matter, and an overall increase in digestible dry matter intake. By contrast, there was no change in faecal mean particle size (mean ± SD: 0.58 ± 0.02 vs. 0.56 ± 0.01 mm). A comparison of diet, stomach content and faecal mean particle size suggested that 98% of particle size reduction occurred due to ingestive mastication and 2% due to digestive processes. Very fine particles passing the finest sieve, putatively not only of dietary but mainly of microbial origin, were particularly concentrated in caecum contents, which corresponds to retention of microbes via a ‘wash‐back' colonic separation mechanism, to concentrate them in caecotrophs that are re‐ingested. This study gives rise to the hypothesis that chewing efficiency on a consistent diet is not impaired by intake level in nonruminant mammals.

Cyniclomyces guttulatus em amostras fecais de cães: infecção simples e multiparasitismo

Cyniclomyces guttulatus é um fungo comensal do trato digestório de coelhos e roedores, mas que vem sendo diagnosticado também em cães, sendo responsável por quadros de diarreia, podendo também estar presente em cães hígidos. O objetivo deste estudo foi detectar a presença deste agente em fezes de cães e também observar associação com outros parasitos. Para realização deste trabalho, foram coletadas 150 amostras fecais ambientais, presentes na orla das praias de Pelotas, RS. As técnicas utilizadas para processamento do material foram a de Faust (1938), Willis-Molay (1921) e Hoffman, Pons e Janer (1934). Dentre as amostras testadas, 15 foram positivas para C. guttulatus (10%), destas, 4 apresentaram contaminação apenas por este agente e em 11 foram observadas associação com outros parasitos, representando 26,7% e 73,3% respectivamente. A partir dos resultados encontrados, conclui-se que C. gutulattus é frequentemente encontrado em animais acometidos por outro gênero de parasito, evidenciando seu caráter oportunista, porém também pode ser encontrado em animais hígidos.

Food habits of European rabbit and its role as seed dispersal of two Mosqueta roses: Facilitation among non-native species in a semiarid protected area of Argentina?

Herbivore and plant invasions can modify the structure and functioning of ecosystems through positive interactions that facilitate their mutual establishment. An important consequence of the feeding behaviour of rabbits is that they can play a key role in seed dispersal by endozoochory. We examined the diet and potential for dispersing Rosa rubiginosa and R. canina (Rosa spp.) of European rabbits introduced in a semiarid protected area of Argentina. We found entire seeds in 100% of the samples of Rosa spp. analysed (n = 11, 187 pellets). Our results indicate that the passage of Rosa spp. seeds through the digestive tract of rabbits (64%) did not diminish their viability in comparison to the seeds taken directly from fruits (66%) (χ2 = 0.09, p > 0.05). This study has identified new positive interactions between an invasive mammal and two invasive plants, a finding that suggests that these invader complexes could have a reciprocal effect on one another, which would potentially aid their invasive process in a semiarid protected area of Argentina.

Fate of transgenic deoxyribonucleic acid fragments in digesta and tissues of rabbits fed genetically modified soybean meal.

Numerous animal feeding studies have investigated the presence of DNA from transgenic plants in tissues from different animal species, but the data reported are sometimes controversial. The aim of this study was to investigate the presence of transgenic DNA (tDNA) in the digesta and tissues of a meat rabbit breed fed genetically modified (GM) soybean meal. Fifteen male New Zealand White rabbits were used for the experimental trial. Ten rabbits (treated group [TG]) were fed a mixed feed containing 10% GM soybean meal and 5 rabbits (control group [CG]) received a mixed feed containing conventional soybean meal, both from weaning (28 d of age) to slaughter (80 ± 3 d). Samples of blood, liver, kidney, heart, stomach, intestine (jejunum), lateral quadricep muscle, longissimus muscle, and perirenal adipose tissue were collected to assess the possible DNA transfer from GM feed to animal tissues. Samples of stomach contents and feces were also taken to study the degradability of ingested tDNA from feed in the digestive tract of rabbit. Moreover, samples of hair were collected to determine the possible environmental contamination from feed powders present on the farm. The DNA extraction was performed using specific genomic DNA kits. All samples were monitored, by using real-time PCR, for oligonucleotide primers and probes specific for the transgenic Roundup Ready soybean 40-3-2 and for the endogenous () gene. As an internal control of rabbit tissues, the presence of the () gene was used. In this study, no fragments of tDNA were detectable in tissue DNA samples of rabbits except in the extracted DNA from stomach digesta, feces, and hair of rabbits fed with GM soybean. Similar results were found for the reference gene, whereas the presence of the gene was detected in all rabbit tissues. The lack of tDNA of soybean in rabbit tissues represents an important result, which demonstrates that meat from rabbits fed a diet containing GM feed is as that derived from rabbits fed conventional crops. The recombinant DNA recovered in the stomach digesta and in feces indicates an incomplete digestion of the soybean DNA in the gastrointestinal tract of the rabbit, whereas the presence of trace soybean transgene in the hair of the TG rabbits is suggestive of an environmental contamination.

Live yeast (Saccharomyces cerevisiae var. boulardii) supplementation in fattening rabbit diet: Effect on productive performance and meat quality

The effects of dietary supplementation with Saccharomyces cerevisiae boulardii (CNCM I-1079 strain, LSB) at 0, 300 and 600mg/kg on apparent digestibility, growth performance, caecal fermentation, carcass characteristics and meat quality of broiler rabbits were studied from 37 to 84 days of age. One hundred and fifty New Zealand White rabbits were single housed and randomly allotted into three groups. Animals were fed isocaloric and isonitrogenous basal diets ad libitum, supplemented with different levels of concentrated live yeast LSB (0, 3×106 and 6×106 colony forming unit (CFU)/g diet, respectively). Protected LSB was resistant to the pelleting process and to passage through the rabbit digestive tract as far as the caecum, where it showed an 86% survival rate in the 600mg/kg supplementation level group. Significant differences were found only for the fibrous fractions digestibility that were lowest (P=0.001) in the animals fed 300mg/kg supplemented diet, while yeast and mould populations in the caecum increased (P=0.001) in the animals fed 300 and 600mg/kg supplemented diets (4.16 and 4.76logCFU/g, respectively). Mortality did not differ amongst dietary treatments being 10%, 8% and 6% for groups fed LSB at 0, 300 and 600mg/kg, respectively.

Morphological and functional events associated to weaning in rabbits

It is acknowledged that the most critical period of rabbit post natal development comprises the first 10-15days after weaning, when the animals are most susceptible to gastrointestinal infections and at greatest risk of a fatal outcome. Detailed information on rabbits' weaning is provided. The advantages and disadvantages of early weaning (under 23days of age) are summarised. Regardless of the numerous reports, the effects of early weaning on the growth and development of bunnies and the physiological status of rabbit does are contradictory. The morphological changes in rabbit digestive tract related to weaning - development of intestinal mucosa, height of villi, crypt depth and villus height to crypt depth ratio - are described in detail. The review also goes over several functional changes in rabbits' organism during weaning: blood cholesterol, triglycerides, α-amylase, lysozyme, complement, triiodothyronine and thyroxine concentrations, and the time course of epidermal growth factor in the milk of lactating does. Based on published research reports, both ours and of other authors, we suggest that from a physiological point of view, the early weaning of rabbits is not fully justified at present. Nevertheless, the increasing market demand for rabbit meat makes early weaning an attractive alternative for farmers and necessitates further studies on the optimisation of weaning in this species.

Live yeast stability in rabbit digestive tract: Consequences on the caecal ecosystem, digestion, growth and digestive health

Live yeast Saccharomyces cerevisiae NCYC Sc 47 was added to the diet of weaning rabbits (35d old) to analyse the effects on the caecal ecosystem (biotope and bacterial community), digestion and health status. Two levels of yeast (1 and 10g/kg feed, group C1 and C10 corresponding to 106 and 107CFU/g DM) were compared to a control group (C0) without live yeast addition. Three groups of 10 young rabbits were used in a first experiment to measure digestibility and caecal parameters and to calculate the yeast survival rate in the digestive tract. Growth performance and health status were studied on 3 further groups of 40 rabbits (Experiment 2). The live yeast concentration fell slightly after diet pelleting (0.1–0.5logCFU/gDM), at 70–80°C. The survival rate of yeast in digestive tract was high and increased from 90 to 97% (P<0.01) with increasing yeast supplementation. Live yeast addition did not modify the total tract digestibility of nutrients, or the growth performance. Mortality rate between 42 and 56d of age was lower at the highest yeast level (C10: 4 dead on 40; P<0.05) compared to C0 and C1 groups (average 13/40),. The structure of the caecal bacterial community was not modified after 11d of yeast presence in the caecum, while the bacterial diversity tended to be higher (5.0 vs 5.4, P=0.10, for C0 vs [C1+C10]). The redox potential of the caecal content increased with yeast addition (−227 vs −251mV, P<0.05 for C0 vs [C1+C10]), whereas the fermentation pattern and the caecal pH remain unaffected (meanly 5.88).

Enterococcus faecium CCM7420, bacteriocin PPB CCM7420 and their effect in the digestive tract of rabbits

The effect of &lt;I&gt;Enterococcus faecium&lt;/I&gt; CCM7420, bacteriocin-producing strain with probiotic properties and its partially purified bacteriocin PPB CCM7420 on growth performance, microflora, &lt;I&gt;Eimeria&lt;/I&gt; sp. oocysts, biochemical blood parameters and glutathione-peroxidase activity in rabbits was determined. An increase in the body weight of rabbits (&lt;I&gt;P&lt;/I&gt; &lt; 0.01) was achieved after &lt;I&gt;E. faecium&lt;/I&gt; CCM7420 application. A non-significant reduction of faecal &lt;I&gt;E. coli&lt;/I&gt; (including haemolytic &lt;I&gt;E. coli&lt;/I&gt;), coagulase-positive staphylococci (CPS) and &lt;I&gt;Staphylococcus aureus&lt;/I&gt; was found in rabbits administered the &lt;I&gt;E. faecium&lt;/I&gt; CCM7420 strain and lower (non-significant) counts of &lt;I&gt;S. aureus&lt;/I&gt; and &lt;I&gt;Clostridium&lt;/I&gt;-like sp. were detected in PPB CCM7420 group, compared to the control. In the caecum, a significant reduction of CPS was noted in both experimental groups (&lt;I&gt;P&lt;/I&gt; &lt; 0.001 and &lt;I&gt;P&lt;/I&gt; &lt; 0.05 for EG1 and EG2, respectively). Biochemical blood parameters increased in both experimental groups (&lt;I&gt;P&lt;/I&gt; &lt; 0.05 and &lt;I&gt;P&lt;/I&gt; &lt; 0.001 for EG2 and EG1, respectively). In the CCM7420 group, the lowest activity of glutathione-peroxidase was measured (&lt;I&gt;P&lt;/I&gt; &lt; 0.001). After the application of PPB CCM7420 (&lt;I&gt;P&lt;/I&gt; &lt; 0.05; day 21), a reduction of &lt;I&gt;Eimeria &lt;/I&gt;sp. oocysts was recorded.

Molecular analysis of the bacterial community in digestive tract of rabbit

This work aimed to study the stability over time of the bacterial community in cæcum and fæces of the rabbit (diversity index and structure) without experimental disturbance and to evaluate its relationships with environmental parameters. Soft and hard fæces of 14 rabbits were sampled for 5 weeks while cæcal content was sampled on the 3rd week (by surgery) and the 5th week (at slaughter). Bacterial communities were assessed by studying CE-SSCP profiles of 16S rRNA genes fragments. Redox potential, pH, NH3-N concentration and volatile fatty acid concentrations were measured in the cæcum. Data showed that bacterial communities of soft and hard fæces barely differed from that of the cæcum (ANOSIM-R < 0.25; p < 0.05). Without disturbance, the bacterial communities of fæces were stable over time (ANOSIM-R < 0.25; p < 0.001). However, the bacterial communities of cæcum and fæces were affected by the surgery (ANOSIM-R = 0.22–0.33; p < 0.001). The cæcal content was an acidic (pH = 6.03 ± 0.33) and an anaerobic environment (redox potential = −160 ± 43 mV). Only the redox potential was correlated with the diversity index of the bacterial community of the cæcum ( R 2 = 0.35; p < 0.05) and no environmental parameters were correlated to its structure.

Comparison of some local melon genotypes selected from Lake Van Basin with some commercial melon cultivars for some yield and quality related traits observed in field and high tunnel conditions

This study deals with the ingestion of fermented milk with Bifidobacterium infantis, and its effect on intestinal disorders and on the intestinal lining during antibiotherapy with amoxicillin and contamination with enteropathogenic Escherichia coli EPEC O111.B4, the latter being responsible for 45% of infant diarrhoea in Algeria. Our results showed that the growth of B. infantis was not affected either by the presence of EPEC or by the administration of Amoxicillin. Inversely, an antagonistic effect of B. infantis on EPEC was observed with inhibition rates reaching 100% whether in presence of Amoxicillin or not, with survival rates of 100% versus zero in batches where B. infantis was not ingested. An inhibiting effect on Enterobacteria was observed. After dissection of all rabbits, macroscopic and microscopic observations of histological sections of the digestive tract (small intestine and colon), showed that rabbits that received amoxicillin associated or not with contamination with EPEC suffered from severe intestinal atrophy with degradation of intestinal tissues (lining and mucous membranes). However, a less significant impact was observed among rabbits that underwent antibiotherapy associated with contamination with EPEC but ingested fermented milk with B. infantis. Total regeneration of tissues was observed 15 days after the first dissection. On the other hand, no pathological anomaly was observed among rabbits that ingested fermented milk with B. infantis associated with contamination with EPEC or amoxicillin. These results showed that the number and the length of survival of B. infantis cells in the rabbit digestive tract during the ingestion of fermented milk with B. infantis and after ingestion ended were sufficient to enable it to exert probiotic effects.

Bacteriocin-producing strain of Enterococcus faecium EK 13 with probiotic character and its application in the digestive tract of rabbits

Enterococcus faecium EK 13 is a bacteriocin-enterocin A producing strain with probiotic properties. In this study its colonization, stability and effect on microflora in rabbits was studied as well as its influence on zootechnical parameters. Fifty rabbits of both sexes (HYPLUS, 30-day old; after weaning) were divided into control (CG) and experimental (EG) groups. They were fed a standard diet. Moreover, 25 rabbits in EG were fed daily (for 4 weeks) 15 g (separate doses ∼1.6 g) of lyophilized EK13 strain (rifampicin resistant variant — rifR; 109 cfu/g) dissolved in drinking water. After cessation of EK13 (rifR) strain application, the rabbits in both groups were fed a standard diet for the next 2 weeks. Sampling was performed in double on day 0 (at the beginning of experiment), weekly during EK13 (rifR) strain application as well as on week 1 and 2 after cessation of EK13 (rifR) strain application. The counts of EK13 (rifR) strain reached 7.1 ± 2.6 log10 cfu/g after 4 weeks and even on week 2 after its cessation the counts 5.6 ± 2.3 log10 cfu/g were determined. The total counts of enterococci in the rabbits were already increased in EG comparing with CG (p < 0.05); even 2 weeks after EK13 (rifR) strain cessation, their counts in EG were 7.2 ± 2.6 log10 cfu/g (p < 0.001). Enterococci in CG reached at the same time the value 3.7 ± 2.6 log10 cfu/g. The counts of E. coli were significantly reduced in EG during 4 weeks (p < 0.05, p < 0.001). Even 2 weeks after EK13 (rifR) strain cessation significant difference in E. coli counts between CG and EG was detected (p < 0.001). Enterobacteria in EG were significantly reduced (p < 0.001). Average daily gain in EG was 41.0 ± 3.83 in comparison to CG (40.6 ± 3.72); it means almost the same; although rabbits in EG showed higher feed intake per kg of gain than rabbits in CG. Preliminary results demonstrated that EK13 is a perspective probiotic candidate for rabbits.

Influence of Supplemental Enzymes, Yeast Culture and Effective Micro-organism Culture on Gut Micro-flora and Nutrient Digestion at Different Parts of the Rabbit Digestive Tract

An experiment of 10 weeks duration was carried out to study the influence of supplemental effective microorganism (EM) culture, yeast culture and enzymes on nutrient digestibility and gut microflora in rabbit gastrointestinal (GI) tract. Twenty four eight to nine weeks old, New Zealand White rabbits were allotted to four dietary treatments; a basal (control) feed, basal feed supplemented with either EM (1%), yeast culture or enzymes (400 ppm). Nutrient flow in digesta and their digestibility at ileum, caecum, colon and in the total tract as well as gut microflora distribution were studied. Feed dry matter was diluted from 92% to about 14% up to the ileum and about 95% of this water was reabsorbed by the colonic rectal segment followed by caecum (25%). EM and yeast improved protein digestibility at a lower rate than enzymes. Ileal, caecal, colonic and total tract digestibility of crude protein with enzymes were higher by 10.8, 9.4, 11.3 and 10.7%, respectively, as compared to the control. Yeast and enzymes increased crude fiber digestibility at ileum, caecum, colon and in the total tract by 8.5, 9.6, 9.0 and 8.3%, respectively, while EM improved them at a lower rate. Irrespective of treatments, total tract digestibility of crude protein (0.698-0.773) and fiber (0.169-0.183) were greater (p<0.05) than the ileal digestibility. Even though a post-caecal protein digestibility was observed, fiber digestion seemed to be completed in the caecum especially with yeast and enzymes. High precaecal digestibility of crude fiber (97%) and protein (95%) were observed even without additives probably due to caecotrophy. EM and yeast culture promoted the growth of lactic acid bacteria especially in the caecum but they did not influence gut yeast and mould. Present findings reveal that even though rabbits digest nutrients efficiently through hind gut fermentation, they can be further enhanced by EM, yeast and enzymes. Of the three additives tested, enzymes found to be the best. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 6 : 830-835)

Hydrolysis of phytic acid and its availability in rabbits

Twenty weaned rabbits were fed ad libitum two granulated feeds containing lucerne meal, barley, oats, wheat bran, oilseed meals and sugarbeet pulp in different proportions. Phytate P in these feeds represented 28.6 and 29.3 % of the total P. Digestibility trials were carried out in rabbits 7 and 10 weeks old. Digestibility of phytate P was 82.1 %, on average. Apparent digestibility of total P was 48.1 and 35.5 % in rabbits aged 7 and 10 weeks, respectively. Concentration of P in the faecal DM of these rabbits averaged 11.9 and 14.7 mg/g. Most of the faecal P was phosphates P (68.1 %). Proportion of phytate P in total faecal P was 9.0 %. Age effect on total P digestibility and faecal P concentration was significant (P<0.05). In five in vitro experiments twenty-four rabbits were killed at the age of 11 weeks, digesta samples diluted with physiological saline containing phytic acid and incubated anaerobically. Calculations of phytase activity in segments of the digestive tract were based on the estimation of phytic acid hydrolysed during the first 2 h of incubation. The caecum contained 58.6 % of the phytase activity of the digestive tract. Corresponding relative values for the phytase activity in the stomach, small intestine and colon were 22.3, 7.7 and 11.4 %, respectively. In incubations of the caecal contents, phytic acid was hydrolysed more rapidly at pH 5-6 than in the neutral pH region. The hydrolysis was inhibited by Ca cations, and to a small extent also by phosphate anions. Commercial fungal phytase (Natupho) was highly active in incubations of the contents of the stomach at pH 1.9. It can be concluded that phytic acid is hydrolysed quite efficiently in the digestive tract of rabbits. This hydrolysis occurred mainly in the caecum. Absorption of soluble inorganic phosphates in the gut is incomplete.

Survie des ferments du yaourt dans le tube digestif du lapin

Survival of starters of yogurt in the digestive tract of rabbits . Yogurt presents a probiotic interest for the consumer. Most of its properties are linked to the ingestion of living lactic acid bacteria (starters), some of which can survive during the crossing of the digestive tract. Our study is based on this perspective. The results obtained show that Streptococcus thermophilus(Sc. t.) and Lactobacillus delbrueckiissp. bulgaricus (Lb. b.) were relatively resistant to gastric acid, bile salts and intestinal flora. These starters were found at significant concentrations and at different levels of the digestive tract as the rabbits fed with a standard diet supplemented with yogurt (YB3). After stop- ping addition of the Sc. t. and Lb. b. yogurt to the diet of the rabbits, the number of Sc. t. and Lb. b. re- mained at an acceptable level for 24 h; the numbers were about 10 5 ,1 0 7 cells.mL -1 and 10 7 cells.g -1 wet faeces for the stomach, the duodenum and the large intestine, respectively. Sc. thermophilus / Lb. delbrueckii ssp. bulgaricus / gastric acid / bile salt / intestinal flora

Lactobacillus cells in the rabbit digestive tract and the factors affecting their distribution

Lactobacillus fermentum was present in small numbers in the caecum and colon of only one of 16 rabbits. Studies aimed at elucidating the factors affecting the colonization of lactobacilli in rabbit gut were thus performed. These studies included investigation of the effect of gastric juice and bile salts on the viability of lactobacilli, assay of the survival rates of lactobacilli in the gastrointestinal tracts of the rabbits with or without ileum cannulation and measurement of the adhesive capability of lactobacilli to the rabbit intestinal epithelial cells. Results showed that, although some lactobacilli were resistant to the rather low pH levels of rabbit gastric juice, lack of adhesive capability may prevent them from colonizing in the intestinal tract. Therefore, if lactobacilli are to be used as probiotics for rabbit, factors that affect their viability and ability to colonize should be considered.

Establishment, counts, and identification of the fibrolytic microflora in the digestive tract of rabbit. Influence of feed cellulose content

In the young rabbit, the celluloytic population appeared in the cecum and colon microflora between 12 and 16 days after birth. It increased rapidly with age to stabilize at a level of about 107 bacteria a few days after weaning. In the adult animal the xylanolytic and pectinolytic populations established at levels between 109 and 1010 bacteria g−1. The colic and cecal populations were comparable in size. When the feed cellulose content rose from 11 to 17% (P/V), the cellulolytic population increased about tenfold, and the range of individual variations decreased. All the fibrolytic strains isolated were strictly anaerobic;Eubacterium cellulosolvens was the most frequently isolated cellulolytic species. The eight xylanolytic strains and the twelve pectinolytic strains identified were assigned to the speciesBacteroides ruminicola.

Endogenous urea as a nitrogen source for microorganisms of the rabbit digestive tract.

The total urea release, measured in the different secretions of the digestive tract of the rabbit, is estimated to be 22 mmol/day, which represents half of the urea produced by the nitrogen catabolism of the animal. This quantity represents a significant source of nitrogen for symbiotic bacteria and, due to coprophagy , could be recycled in the bacterial proteins digested by the rabbit.