Faculty of Veterinary Medicine, USAMV Cluj-Napoca, 3-6 Calea Mănăştur, Cluj-Napoca, România,

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1 Bulletin UASMV, Veterinry Medicine, 69(1-2)/2012 Print ISSN ; Electronic ISSN Comprtive study of the internl conformtion of the posdiphrgmtic digestive trct in the dog (Cnis lupus fmiliris) nd in the ct (Felis ctus) Aurel DAMIAN 1), Irin IRIMESCU 1), Alexndru GUDEA 1), Florin STAN 1), Cristin DEZDROBITU 1), Flviu TUNS 1), Melni CRIŞAN 1) 1) Fculty of Veterinry Medicine, USAMV Cluj-Npoc, 3-6 Cle Mănăştur, Cluj-Npoc, Români, Astrct. The present study offers detiled ntomicl description of the mcroscopicl chrcteristics of the internl conformtion of the postdiphrgmtic digestive trct in the min pet species - the dog nd the ct. After domestiction, the two species, while of common philogenetic origins, hve evolved with certin differences from the point of view of feeding hits in the modern er, to omnivore for dogs nd strict crnivore for cts. This fct reflects itself in the pthology of this segment nd in therpeutic necessities. This spect justifies the need for etter ntomicl knowledge of the differences etween the two species in the digestive segment. Hving discussed in previous rticle the differences etween these species in terms of externl shpe, fetures nd orgn topogrphy, we hve turned to the inner conformtion of the gstrointestinl trct. Our study focused on species chrcteristics description, without underlining rce prticulrities. The study ws crried out in the Comprtive Antomy Lortory of the Fculty of Veterinry Medicine of Cluj-Npoc, on five dog odies nd 5 ct odies lcking digestive pthologicl modifictions. The reserch used usul dissection techniques, followed y the isoltion, the section nd the exmintion of the gstro-intestinl segment in ll sujects. Common trits of crnivorous species displyed overll y the digestive trct side, the min internl conformtion differences etween dogs nd cts were minly registered in the stomch. In this segment, the ct displys uniform gstric mucos, while the linen vries in the dog. The duodenum of oth species hs similr mucos nd two duodenl ppille, ut the plcement nd presence of the ppille differ. The lrge intestine of dogs nd cts hs lesser differences, side from the disposition of the lining folds of the colon. Keywords: dog, ct, postdiphrgmtic digestive trct, internl conformtion INTRODUCTION Gstrointestinl pthology is one of the most frequent cuses of illness mong cts nd dogs, mking up circ 20% of the csuistic of smll nimls veterinry clinics (Simpson nd Else, 1991; Hll et l., 2005). This predominnce requires estlishing therpeutic protocols etter dpted to ech species needs. Turning from the ferl wy of cquiring food - pck hunting for dogs, solitry hunting for cts - to forging for oth species nd relying on food sources provided y humns hs progressed slowly throughout history (Ntionl Reserch Council, 2006). However, these two species hve seen in the lst decdes even more rdicl chnges in their lifestyle nd nutrition hits. They were switched from tle scrps nd home cooked mels to industrilly prepred food nd professionl diets. As dogs rely lmost entirely on their owner for food nd tend to e omnivorous, most cts still ct s semi-domesticted nimls, remining strict crnivores (Ntionl Reserch Council, 2006) nd supplement their diets y hunting if llowed, widening the dietry gp etween the two species. 75

2 There is the necessity from the prctitioner s point of view to understnd how differently these dietry chnges hve shped the digestive systems of dogs nd cts, since they re interlinked from the metolic nd physiologicl levels generting nutritionl needs (Buddington,1996), to seprte fetures t mcroscopic level of ech segment of the gstrointestinl trct. Our study continues previous reserch, focused on the topogrphicl nd externl discrepncies etween the postdiphrgmtic digestive trct of dogs nd cts. This pper focuses on the internl fetures of the stomch nd intestinl mss of oth species, underlining existing differences. MATERIALS AND METHODS Reserch ws crried out on 5 dult dog odies, 3 mles, 2 femles, nd on 4 dult ct odies, 1 mle nd 3 femles. All specimens were common Europen mixed reed. The selection ws mde sed on cuse of deth nd medicl history, voiding ny digestive pthology. As the study did not involved reed-reltive fetures, ny pure-reed specimens were voided. The dissections nd exmintions were performed t the Comprtive Antomy Lortory of the Fculty of Veterinry Medicine of Cluj-Npoc, using stndrd tools nd methods. In the mjority of cses, the odies could not e dissected nd exmined within the first hours immeditely fter the occurrence of deth, in which cse they were preserved y freezing t low tempertures (-18 C), in order to void post mortem modifictions nd rtifcts. Common dissection techniques were used to expose the postdiphrgmtic digestive trct of ech specimen. These were isolted y cutting the oesophgus ove the crdic orifice, the surrounding tissues of the nl orifice, nd the peritonel folds nd ligments supporting the digestive trct. Ech ntomic segment of the postdiphrgmtic digestive trct ws identified, delimited nd incised long its longitudinl xis (the stomch ws opened long its greter/lesser curvture). The content ws removed nd the internl surfce wshed. The internl conformtion of ech smple ws then exmined, plpted nd photogrphed. RESULTS AND DISCUSSIONS Both cnine nd feline digestive trcts re known to hve the generl fetures of the crnivore type: single stomch with smll volume, short smll intestine nd lrge intestine with reduced length nd volume (Coţofn et l., 2007; Gheţie, 1967; Popovici et l., 2006). The stomch Due to wll elsticity, the internl volume of oth dog nd ct stomch specimens presents importnt vrition ccording to the size of the individuls, ut lso on the plenitude level of the orgn when deth occurred. This is expected nd hs lredy een signled throughout literture (NRC, 2006; Popovici et l., 2006; Stevens nd Hume, 1995). Corresponding to this sitution, the mucos covering the interior of the stomch forms multiple folds tht vry from eing flttened out to very prominent depending on the stomch s stte of plenitude. However, while exmining the interior of the empty or modertely distended stomch, we hve noticed tht there re specific ptterns tht re common to oth of the studied species: the folds of the mucos re regulr nd undulted, oriented long the longitudinl xis of the orgn (Fig.1 nd 1). At the level of the pyloric ntrum they ecome more prominent nd long the re of the smll curvture of the stomch, their pttern is less regulr. 76

3 Other chrcteristics of the mucos s color nd thickness re oservle on the clened specimen nd revel certin differences etween dogs nd cts. The first re of the stomch, the crdi sphincter, is lined with esophgel mucos, which hs is limited to this level only, forming smll nd there, nd then ending ruptly. This trit is displyed y oth species. The true gstric or fundic mucos lines most of the stomch s inner surfce. In cnine stomch smples, its spect is not uniform. In the fundus segment nd in the gret curvture region (elonging to the stomch s ody), it is thinner, hs light red color. Stevens nd Hume (1995) mention tht this re in dogs is rich in typicl fundic glnds. In the rest of the ody region of the stomch, the mucos hs lighter hue nd is thicker (Fig.1). Fig.1. Aspect of the stomch mucos in the dog () nd in the ct (). In feline stomch smples, the interior lining is of lmost exclusive gstric (fundic) nture. It covers the fundus segment nd more thn hlf of the ody segment, without reching the region of the smll curvture of the stomch. A prticulrity of the gstric mucos of cts is tht it hs uniform light pink hue spect (Fig. 1). This feture corresponds with wht hs een previously reported in literture (Mskell nd Johnson, 1993). In oth cnine nd feline stomch specimens, the pyloric mucos covers lmost the entire right surfce of the stomch (the entire pyloric segment) nd it clims long the lesser curvture reching towrds the crdi. In dogs, the mucos of the pyloric region hs yellow hue, esily differentited from the rest of red colored lining (Fig. 1), while in cts the trnsition is smoother, without ovious colortion chnges (Fig. 1). We hve noticed tht in ll the specimens elonging to oth species, the crdi nd the pyloric sphincters dilte esily, fct tht hs een previously signled in literture (Brone, 1976). In cts, however, the muscle lyer tht forms the crdi sphincter is thinner on plption tht tht of dogs, consistent with the frequency nd reltive ese of feline regurgittion. The smll intestine Both cts nd dog hve smller intestines tht re short compred to those of herivores, nd ruminnts in prticulr. However, they hve higher soring cpcity due to the intestinl vili of the mucos (Mskell nd Johnson, 1993). The first segment of the smller intestine, the duodenum is lined with deep pink mucos forming very shllow circulr folds perpendiculr to the longitudinl xe of the lumen (Fig.2 nd 2). This spect is common to oth dog nd ct 77

4 smples. Another prticulr feture which is found in thing digestive segment of oth species is the presence of secondry duodenl ppill. Fig.2. Aspect of the dduodenum mucos in the dog () nd in the ct (). The mjor ppill in dog specimens is plced t 4 to 12 cm from the pyloroduodenl opening, ner the crnil curve of the duodenum. It houses oth the opening of the mjor pncretic duct (Wirsung) nd tht of the ile duct. The minor duodenl ppill is found t n verge of cm down the lumen further from the mjor one nd receives the opening of the secondry pncretic duct. One of the cnine duodenum specimens presented mjor ppill without the mjor pncretic duct. In the ct specimens the mjor duodenl ppill is situted t n verge of 2 to 3 cm from the pyloroduodenl opening, t the eginning of the descending segment. One of the four ct specimens we exmined presented minor duodenl ppill 1.7 cm further down long the lumen, with the opening of secondry pncretic cnl. This finding is concurrent with previous descriptions y other uthors like Brone (1976) or Popovici (2006). Fig.3. Aspect of the jejuno-ileum mucos in the dog () nd in the ct (). In oth species, the smll intestine mucos presents severl lymphoid plques tht re ovoid, with slightly rised profile, nd re covered with vili like the rest of the lining. Most lymphoid plques re situted in the duodenum (Fig.2 nd 2), nd the rest re found in the first hlf of the jejunum in dogs, nd up to the ileum in cts. The jejunum nd the ileum re the min sorptive segments of the intestine for oth species. Mskell nd Johnson (1993) stte tht 50% of intestinl sorption in dogs tkes plce in 78

5 the jejunum nd 40% in the ileum. The mucos of these two segments is esily distinguishle from the duodenum lining, ecuse it hs more yellow hue, thicker velvet spect cused y the vili nd it forms trnsversl folds. Both species specimens presented these chrcteristics, with more pronounced folds in the ct (Fig.3 nd 3). The dimeter of the lumen in the jejunum nd ileum segments is constnt their length in the cnine smples, ut in the feline ones, the dimeter of the lumen visily increses in the second hlf. The lrge intestine The generl fetures of the lrge intestine in dog nd cts re short length, especilly of the cecum, non-osselted colon nd reduced volume in ll segments, s descried y the consensus of ntomy literture (Brone, 1976; Coţofn et l., 2007; Gheţie, 1967; Popovici et l., 2006). Mskell nd Johnson (1993) reinforce this, y stting tht only 10% of intestinl soption in dogs tkes plce in the the lrge intestine, correlting function with morphology. The cecum of oth species is very reduced, especilly in cts where it tends to ecome simpler curved diverticulum. The ileo-cecl opening represents the first difference in terms of internl fetures etween the two species. In dogs, the ilel ppill ctully opens directly into the colon. It is reduced, ut presents well developed sphincter. The ceco-colic opening is situted lterlly form this ppill, hs lrge lumen, ut lso presents its own sphincter. Fig.4. Aspect of the ceccl mucos in the dog () nd in the ct (). In cts, the ileo-cecl pssge lso leds directly into the colon, ut the ppill through which it opens is eeter developed nd rised. The ceco-colic opening is lrge, similr to dogs, ut it hs no plple sphincter. The mucos of the cecum in dogs hs yellow hue, cretes prominent irregulr folds (Fig. 4). It contins mny solitry lymph nodes, ut they re not grouped in lrger structures. In cts, however, the mucos is redder, smoother (Fig. 4) nd the lymph nodes re gthered in smll group t the tip of the orgn. The oth cnine nd feline colons re short ut hve ll the three min segments: scendnt, trnsverse nd descendent. The lumen is smll in dogs (n verge of 3 cm), nd in cts s well, ut in the ltter it is lrger thn tht of the smll intestine. 79

6 Fig.5. Aspect of the colic mucos in the dog () nd in the ct (). An importnt difference hs een noted when compring the mucos of the colons. In the dog specimens, the mucos is folded in regulr prllel longitudinl lines nd hs drk pink color (Fig. 5), while in the ct specimens, the folds of the colon pper quite irregulr in shpe, with vgue overll trnsversl orienttion with regrds to the longitudinl xis of the trct (Fig. 5). Their color hs yellow hue. The lst segment of the lrge intestine, the rectum is proportionlly short in oth species, nd it displys smll groupings of lymph nodes disseminted in the mucos. CONCLUSION The min internl conformtion differences of the gstrointestinl trct etween dogs nd cts oserved in this study hve een situted in the stomch nd, in smller mesure, in the duodenum nd other intestinl segments. The gstric mucos lining the dog stomch is thin nd hs light red color in the fundus region, while in the ody segment of the stomch it ecomes pler nd thicker. In the ct, this mucos hs constnt thickness nd the sme reddish color on the entire covered surfce (the fundus nd the ody regions). In the dog, the pyloric mucos is clerly delimited form the gstric one through its yellow hue, while the trnsition etween the two types is much more sutle in the ct. The crdi pssge is esy to dilte in oth species, ut in the ct, the musculr lir tht forms its sphincter is much weker on plption, which explins the ese with which this species regurgittes. In the duodenum, oth species cn e endowed with two duodenl ppille: mjor one, where the pncretic nd the ile ducts open, nd minor one, housing the opening of secondry pncretic duct. In the dog, the opening nd the primry pncretic duct cn e missing, while in cts there is very low frequency of the presence of the minor duodenl ppill.the folds of the mucos of the jejunum nd the ileum re etter outlined nd the dimeter of the intestinl lumen increses visily in its second hlf in the ct, s compred to the dog. The ilel ppill is smll in dogs, while it is prominent nd well developed in cts. The ceco-colic opening hs strong sphincter in dogs, while in cts it is wide. The mucos of the cecum hrors solitry lymph nodes in the dog, while in the ct these nodes re grouped t the tip of the orgn. The folds of the colon lining hve n irregulr, overll trnsverse orienttion in the ct, while in the dog they re longitudinlly plced long the xis of the lumen, in regulr pttern. 80

7 REFERENCES 1. Brone, R. (1976). Antomie comprée des mmiferes domestique, tome III, Spnchnologie: Appreil digestif - Appreil respirtoire. Ecole Ntionle Veterinire de Lyon, pg.: Buddington, R.K. nd P.T. Sngild (2011). Compnion nimls symposium: development of the mmmlin gstrointestinl trct, the resident microiot, nd the role of diet in erly life. Journl of niml science. 89(5): Coţofn, V., R. Plicic, Crmen Gnţă, V. Hriţcu, V. Enciu (2007). Antomi nimlelor domestice. Vol. II, Editur Orizonturi universitre, Timişor, pg.: Gheţie, V. (1967). Antomi nimlelor domestic. Ed. Didctică şi Pedgogică, Bucureşti, pg.: Hll, E.J., J.W. Simpson nd D.A. Willims (2005). BSAVA Mnul of Cnine nd Feline Gstroenterology. Second Edition. pg 6. Mskell, I.E. nd Johnson J.V. (1993). Digestion nd sorption. In: The Wlthm Book of Compnion Animl Nutrition. L.H. Burger (Eds), Oxford, Pergmon Press Ntionl Reserch Council (U.S.) Ad Hoc Committee on Dog nd Ct Nutrition (2006). Nutrient Requirements of Dogs nd Cts. Wshington, DC: The Ntionl Acdemies Press, pg Popovici, I., A. Dmin, N. Popovici, Ion Chirilen (2006). Trtt de ntomie comprtă: Splnchnologie. Editi dou, Ed. Acdemic Pres, Cluj-Npoc, pg Simpson, J.W. nd R.W. Else (1991). Digestive Disese in the Dog nd Ct (Lirry of Veterinry Prctice). Wiley-Blckwell Pulishing. pg 10. Stevens, C.E. nd I.D. Hume (1995). Second Edition. Cmridge University Press. Pg