research article histological features of the gastrointestinal … · 2019. 7. 31. · research...

Research ArticleHistological Features of the Gastrointestinal Tract ofWild Indonesian Shortfin Eel Anguilla bicolor bicolor(McClelland 1844) Captured in Peninsular Malaysia

Nurrul Shaqinah Nasruddin1 Mohammad Noor Amal Azmai2 Ahmad Ismail2

Mohd Zamri Saad1 Hassan Mohd Daud1 and Syaizwan Zahmir Zulkifli2

1Department of Veterinary Laboratory Diagnostics Faculty of Veterinary Medicine Universiti Putra Malaysia (UPM)43400 Serdang Selangor Malaysia2Department of Biology Faculty of Science Universiti Putra Malaysia (UPM) 43400 Serdang Selangor Malaysia

Correspondence should be addressed to Mohammad Noor Amal Azmai mnamalupmedumy

Received 23 May 2014 Revised 5 December 2014 Accepted 7 December 2014 Published 23 December 2014

Academic Editor De-Li Shi

Copyright copy 2014 Nurrul Shaqinah Nasruddin et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

This study was conducted to record the histological features of the gastrointestinal tract of wild Indonesian shortfin eel Anguillabicolor bicolor (McClelland 1844) captured in Peninsular Malaysia The gastrointestinal tract was segmented into the oesophagusstomach and intestine Then the oesophagus was divided into five (first to fifth) the stomach into two (cardiac and pyloric)and the intestine into four segments (anterior intermediate posterior and rectum) for histological examinations The stomachhad significantly taller villi and thicker inner circular muscles compared to the intestine and oesophagus The lamina propriawas thickest in stomach significantly when compared with oesophagus but not with the intestine However the intestine showedsignificantly thicker outer longitudinal muscle while gastric glands were observed only in the stomach The histological featureswere closely associated with the functions of the different segments of the gastrointestinal tract In conclusion the histologicalfeatures of the gastrointestinal tract of A b bicolor are consistent with the feeding habit of a carnivorous fish

1 Introduction

The Indonesian shortfin eelAnguilla bicolor bicolor (McClel-land 1844) is native to Malaysia Nevertheless the presenceof A b bicolor has been reported in different geograph-ical locations throughout the world such as Greater SundaIslands (Java and Sumatra in western Indonesia) north-western Australia Africa Myanmar India Sri LankaBangladesh and Malaysia [1ndash3] In Malaysia A b bicolorare found in estuarine areas and they occasionally migratearound 60 km from the ocean into freshwater rivers [3] Thisis due to themigration behavior of the eels as well as a strategyto avoid competition for space and food [4 5]

TheEuropean eelsA anguilla have a broad diet and theirprimary food source is aquatic invertebrates but sometimesthey will eat any food they find including dead organisms[6] The feeding habits of A anguilla consisted of benthic

organisms primarily amphipod crustaceans polychaetesinsect larvae molluscs and small fishes [7] For A bicolor astudy showed that the fish change their feeding habits mark-edly as they grow They feed mainly on invertebrates whensmall and become more piscivorous as they grow while noseasonal variation in the feeding habits was observed [8]Their main feeding habits consisted of macrophytes algaecrustaceans mollusks insects annelids insect larvae andbony fishes [8ndash10]

Gastrointestinal tract of fish shows marked diversity inmorphology and function which is useful to determine thetaxonomy feeding habits and habitat [11 12] Indeed eachsegment of the digestive tract has amucosal specialization foran optimal efficiency of secretion absorption and digestivefunctions [13] Therefore the main function of fish intestineis to complete the digestive process which started in the sto-mach and to absorb the nutrients from food [14] The gross

Hindawi Publishing Corporatione Scientific World JournalVolume 2014 Article ID 312670 8 pageshttpdxdoiorg1011552014312670

2 The Scientific World Journal

andhistological features of gastrointestinal tract of fisheswerealso different based on taxonomy feeding habit and bodyshape [15] The morphological features of gastrointestinaltract of carnivorous fish were proved to diverge from herbiv-orous fishThe carnivorous fish tend to have shorter intestinethan the herbivorous fish due to lower percentage of plantmaterials in the diet [16 17] Histologically the oesophagusof a carnivorous fish has more mucous cells than herbivorousfish [18] For stomach of a carnivorous fish Schilbe mystusa study found that it can be divided into two compart-ments namely cardiofundic and pyloric although the organmorphologically consisted of three parts which are cardiacpyloric and fundic region [19] In addition the gastricmucosa of perch Perca fluviatilis was described to have threetypes of endocrine cells that produced hydrochloric acid[20] but it is absent in herbivorous fish such as sea garfishHyporhamphus melanochir [21] The mucosa of the intestineof S mystus consisted of simple columnar epithelium thatcontains Goblet cells similar to the histological structure inherbivorous fish Labeo niloticus [22]

There are limited studies on the histological features ofdigestive tract of Anguilla while most of the conductedstudies in this country focused more on the inventory surveyand migration behavior of the eels [2 3] Thus the presentstudy was conducted in order to describe the histological fea-tures of the gastrointestinal tract particularly the oesopha-gus stomach and intestine of wild A b bicolor captured inPeninsular Malaysia This may provide a comparative basisfor future studies of digestion absorption and feeding pat-tern In addition the ultrastructural analysis described fromthis study is important for the diagnosis of diseases related togastrointestinal tract of Anguilla

2 Materials and Methods

Anguilla bicolor bicolor samples were captured in Balik PulauPenangMalaysia fromFebruary 2013 to January 2014A totalof 28 wild eel samples were obtained either by angling or byusing traditional fish traps Following capture the wet bodymass and total length were measured and recorded

Samples were placed in a solution containing tricainemethanesulfonate (MS 222) at 50mgL to achieve stage threeof anesthesia before they were sacrificed by cervical dislo-cation according to method approved by the Animal Utiliza-tion Protocol Universiti Putra Malaysia The entire digestivetract was immediately extracted by a midventral incisionremoved and then divided into oesophagus stomach andintestine

Anatomical description was carried out before the oeso-phagus stomach and intestine were divided into five (firstto fifth) two (cardiac and pyloric) and four (anterior inter-mediate posterior and rectum) segments respectively [23]Organs were then sampled in triplicate labeled and fixed in10 buffered formalin for 12 hours before they were embed-ded in paraffin sectioned at 5 120583m thick and stained routinelywith Harris haematoxylin and eosin (HE) and periodic acid-Schiff (PAS) The height of villi thickness of lamina propriainner circular muscle outer longitudinal muscle and gastricgland were measured according to Firdaus-Nawi et al [24]

The photos were recorded through photomicroscope (NikonEclipse 50i Japan) and analyzed through The Nikon NIS-Element D 32 Image Analyser (Nikon Instruments IncUSA)

The data was checked for normality using Shapiro-Wilktest of normality (119875 gt 005) and its homogeneity of variancesusing Levenersquos test for equality of variances (119875 gt 005) (IBMSPSS Statistics Version 21) The mean plusmn standard error ofmean (SEM) of the histological measurements for each struc-ture was compared among all of the segments and organsusing the analysis of variance with Tukey LSD All-PairwiseComparison Test (Statistix 9 Analytical Software) [25] Thesignificance value was at 119875 lt 005 The determined mea-surements were the height for the mucosal projection andthe thickness for lamina propria inner circular muscle outerlongitudinal muscle and gastric gland

3 Results

The mean (plusmnstandard deviations) of wet body mass andtotal length of the 28 samples of A b bicolor were 37847(plusmn24678) g and 56053 (plusmn14093)mm respectively

Table 1 shows the measurements of villus height thick-ness of lamina propria inner circular muscle outer longitu-dinal muscle and gastric gland of the sampled A b bicolorThe stomach showed significantly higher villous and thickerinner circular muscle than the intestine and oesophagusThe lamina propria was the thickest in the stomach andsignificantly thicker than in oesophagus but not than in theintestine The intestine showed significantly thicker outerlongitudinal muscle than oesophagus and stomach Thegastric glands were observed only in the stomach

31 Histological Features of the Oesophagus For oesophagusthe tunica mucosa consisted of ciliated pseudostratifiedcolumnar epithelium with numerous Goblet cells especiallyat the first to the third segments (Figure 1(a)) The numbersof Goblet cells gradually decreased towards the posterior part(fourth and fifth segments) The cilia which were located atthe tip of the epithelium were found abundantly at the firstthree segments but became lesser in number and eventuallyabsent at the posterior part of the oesophagus (Figure 1(b))The villi at the first part of the oesophagus were tall andbroad-based with finger-like structure which appeared star-shaped in transverse section (Figure 1(c)) The villi at theposterior segment showed gradual decrease in height andsmaller base The mean height of the mucosal projectionshowed no significant difference between most of the fivesegments of the oesophagus

The lamina propria consisted of loose connective tissuesand was highly vascularized (Figure 1(d)) However therewas no significant difference in the thicknesses of laminapropria among the segments of the oesophagus

Tunica muscularis was arranged in two obvious lay-ers the inner circular muscle and the outer longitudinalmuscle bundles The thickness of both structures graduallydecreased toward the posterior end of the oesophagusobviously for the outer longitudinal muscle Both muscularlayers were significantly thicker in the first and second

The Scientific World Journal 3

Table 1 The measurement of different features in all segments and between oesophagus stomach and intestine of collected Anguilla bicolorbicolor

Organs Segments Features (120583m)MP LP ICM OLM GG

Oesophagus

1st 11308 plusmn 721abc 1131 plusmn 119d 2781 plusmn 83c 2297 plusmn 62b mdash2nd 6755 plusmn 401d 744 plusmn 49d 2625 plusmn 122c 2176 plusmn 129bc mdash3rd 7398 plusmn 255cd 1238 plusmn 80d 737 plusmn 69d 1284 plusmn 61de mdash4th 7955 plusmn 287bcd 719 plusmn 109d 716 plusmn 62d 878 plusmn 70ef mdash5th 8588 plusmn 598bcd 410 plusmn 24d 745 plusmn 45d 639 plusmn 39f mdash

Mean plusmn SEM 8401 plusmn 279C 849 plusmn 51B 1521 plusmn 118B 1455 plusmn 85B mdash

StomachCardiac 14382 plusmn 1344a 4240 plusmn 379ab 5555 plusmn 250a 1519 plusmn 59d 2228 plusmn 157a

Pyloric 11463 plusmn 1206ab 2667 plusmn 173c 2821 plusmn 88c 1735 plusmn 96cd 2415 plusmn 682a

Mean plusmn SEM 12922 plusmn 928A 3454 plusmn 251A 4189 plusmn 285A 1627 plusmn 59B 2321 plusmn 419

Intestine

Anterior 10223 plusmn 12259bcd 2579 plusmn 214c 2359 plusmn 42c 1201 plusmn 86de mdashIntermediate 11603 plusmn 928ab 4809 plusmn 328a 2379 plusmn 82c 1179 plusmn 82def mdashPosterior 9640 plusmn 1120bcd 3029 plusmn 227c 2878 plusmn 106c 2129 plusmn 139bc mdashRectum 8958 plusmn 689bcd 3335 plusmn 189bc 3799 plusmn 234b 4697 plusmn 297a mdash

Mean plusmn SEM 10106 plusmn 509B 3438 plusmn 162A 2854 plusmn 101B 2302 plusmn 205A mdashMP height of mucosal projection LP thickness of lamina propria ICM thickness of inner circular muscle OLM thickness of outer longitudinal muscle andGG thickness of gastric gland Data are presented in mean plusmn (standard error of mean) SEM from 28 collected samples For comparison features in differentorgans and segments the same superscript in uppercase letter within columns and lowercase letter within rows respectively are not significantly different

100120583m

(a)

50120583m

A

(b)

500120583m

(c)

100120583m

(d)

Figure 1 (a) Goblet cells at the mucosal surface of oesophagus HE 200x (b) Ciliated pseudostratified squamous epithelium of oesophagus(rarr) HE 400x (c) Tall finger-like shape of mucosal projection of oesophagus HE 40x (d) Vascularized lamina propria of oesophagus HE200x


500120583m

(a)

100120583m

(b)

lowast

100120583m

(c)

50120583m

(d)

Figure 2 (a) Goblet cells (rarr) at the mucosal surface of stomach with glycogen positive stain PAS 40x (b) Short sharp angle of mucosalprojection of stomach HE 200x (c) Inner circular (998835) and outer longitudinal muscle of the stomach (lowast) HE 40x (d) Chief cells (998835) andparietal cells (rarr) at the gastric glands of stomach HE 400x

segments of the oesophagus than in the third to fifth seg-ments

32 Histological Features of the Stomach The stomach of Ab bicolor consisted of the cardiac and pyloric segments Thetunica mucosa consisted of the epithelium the basementmembrane the gastric gland and the lamina propria Theepithelium demonstrated abrupt change from pseudostrati-fied columnar epithelium in the oesophagus to single colum-nar epitheliumwith PAS-positivemucous cells in the stomach(Figure 2(a)) The mucosal projections were short and broadwith angular edge (Figure 2(b)) However the mean heightof mucosal projection at the cardiac and pyloric stomachshowed no significant difference

The lamina propria was thick with loads of blood vesselsThe cardiac segment of the stomach showed significantlythicker lamina propria than the pyloric stomach Similarlytunicamuscularis of the stomachwas composed of two layersthe inner circular muscle layer and the outer longitudinalmuscle bundles (Figure 2(c)) The inner muscle at cardiacsegment was significantly thicker than the pyloric segmentHowever there was no significant difference in the thicknessof the outer muscle layer between both segments

Gastric glands were observed only in the stomach Thetubular-like structure was abundant and was made up ofmainly chief cells with occasional parietal cells (Figure 2(d))

There was no significant difference in the thickness of gastricgland between both segments

33 Histological Features of the Intestine The intestine con-sisted of four segments namely the anterior intermediateposterior and the rectum The anterior intestine compriseda simple layer of columnar epithelium with prominentmicrovilli and scattered PAS-positivemucous cellsThe inter-mediate and posterior intestinal mucosa showed high degreeof villous folding with abundant Goblet cells (Figure 3(a))The mucosa of the rectum was lined by a simple columnarepithelium with abundance of Goblet cells compared to therest of the intestinal segments There were clear histologicaldifferences that characterized the intestinal segments Theanterior segment consisted of columnar epithelium cellswith brush-like border while the intermediate and posteriorintestines and the rectum had no microvilli The villous fold-ing was thicker and the number of villi was lesser towards theend of the section but no significant difference was noted inthe height of mucosal projections among the four segmentsThe number of Goblet cells increased tremendously at thedistal part of the tract (Figure 3(b))

The lamina propria consisted of compact connectivetissues with numerous blood vessels especially at the tipof the villi (Figure 3(c)) The thickness of lamina propriavaried without any trend throughout the intestinal tract


100120583m

(a)

100120583m

(b)

100120583m

(c)

lowast 500120583m

(d)

Figure 3 (a) The anterior part of intestine HE 200x (b) Goblet cells at the mucosal lining of intestine HE 100x (c) Vascularized villi of theintestine HE 400x (d) Inner circular (998835) and outer longitudinal muscle (lowast) of intestine HE 40x

However the lamina propria in the intermediate segmentof the intestine was significantly thicker than in the otherintestinal segments

Tunica muscularis of the intestine included the internalcircular muscle layer and the external longitudinal musclebundles At the last quarter of the intestinal tract bothmuscles were found to be significantly thicker than the otherparts of the intestine (Figure 3(d))

4 Discussion

A comprehensive study of the histology of the digestive tractin A b bicolor had not been established yet although fewstudieswere conducted on thewild and rearedA anguilla butwith minimal descriptions [23 26] Therefore this study iscrucial to understand their feeding behavior and habitat thusproviding fundamental information for further anatomicaland physiological studies

The presence of taste buds at the tip of certain mucosalprojections of the anterior oesophagus of A anguilla hasbeen previously described [26 27] This however was notobserved for A b bicolor in this study Instead this studyrevealed numerous cilia covering the tip of the epithelium ofthe oesophagus which is believed to help in the movementof food particles and protects the oesophagus from injurieswhen the solid particles pass through the lumen [27] TheGoblet cells which were abundant at anterior oesophagus

produce mucoid substance that lubricates food bolos tobe easily swallowed [28] The findings were similar to theoesophagus ofMylio cuvieri which demonstrated numerousmucous cells which reacted positively to Alcian blue and PASstains [15] Furthermore the oesophageal mucus is importantin immunological mechanisms against bacterial infectionand osmoregulatory function [29]

The height and thickness of mucosal projections and thethickness of muscularis externa of the oesophagus dramati-cally decreased from the anterior to the posterior part Thismay be because the anterior oesophagus is the first segmentto receive food bolos from the mouth and needs morecontraction and movements to move the food bolos caudallyduring peristalsis [23] In addition the muscularis layer ofcarnivorous fish is proved to be thicker than herbivorous fishto prevent any damage or engorgement to the mucosa duringswallowing preys [30]

The stomach of A b bicolor is a sac that can be stretchedcaudally suggesting a feeding pattern of carnivorous fishTheorgan can act as a holding area for larger bolos such as smallfish that they eat Both parts of the stomach demonstratedsimilar histological patterns consisting of epithelial layer andlamina propria that contained gastric glands and muscularisexterna which is in agreement with previous study onA anguilla [26] In addition the histological features ofstomach layer of A b bicolor were also similar as observedin other carnivorous fishes such asMisgurnus mizolepis [31]


Engraulis anchoita [32] and Dentex dentex [33] Accordingto Moog and Wenger [34] cells that contain a mucoidsubstance which is present at the epithelium surface arevery important for gastric protection and gastric pH controlBesides that mucoid containing cells play an importantrole in complementing the digestion process [35] and wassimilarly observed in the stomach of D dentex [33] andSeriola dumerili [36] Most of the cells found in the tubulargastric glands are chief cells that secrete pepsinogen anenzyme important for protein digestion Few parietal cellswhich secrete hydrochloric acid can be found throughoutthe stomach The stomach of herbivorous fishes L niloticus[19] H melanochir [21] and Arrhamphus sclerolepis krefftii[37] demonstrated absence of or less hydrolysis acid whichsuggested that the fishes depend on their strong pharyngealaction and teeth to rupture and grind the plant cell wallThe inner longitudinal muscle of the cardiac region wassignificantly thicker than pyloric region due to its sphincterfunction which has some voluntary control of the foodpassage into the gastric sac [38] In addition the thickmuscle fibers which arranged in two layers demonstratedthe powerful trituration mechanism [19] Nevertheless inAfrican butter catfish S mystus the muscularis mucosa onlyfound in pyloric region but absent in cardiofundic part whichmay be due to the primary function of the pyloric portionof stomach is mixing and pushing the food bolus distally[39] As A anguilla mainly feeds on amphipod crustaceansinsect larvae and small fishes this microstructure reflects thecarnivorous feeding habits of the A b bicolor [40]

The intestine is a tubular organ where food from stomachpasses through to start an alkaline digestion before theabsorption of nutrients [41] In fish the length of the intestinevaries and depends on the diet but is basically between 04and 38 times longer than the body length The amount ofvegetal materials in diets is the main determination factorfor intestinal length Usually herbivorous fish have longerintestine compared to carnivorous fish [16 17 42] Althoughthe intestinal segments were well differentiated histologicallyno significant difference between the regionsmacroscopicallywas observed similar to previous study on carnivorousgilthead sea bream Sparus aurata [43]

The brush border epithelium of the anterior intestine ofA b bicolor was found to be similar to a previous study on Aanguilla [23] and Salvelinus alpinus [44] However this struc-ture was not found in other sections According to Infanteand Cahu [45] the brush border structure of marine teleostis linked to the presence of peptidase and disaccharidaseenzymes important tomaximize the digestion and absorptionprocesses Goblet cells were found throughout the intestinaltract but the number of cells increased towards the posteriorintestine a finding similar to A anguilla [23] In additionnumerous Goblet cells were found in carnivorous fishes suchas S dumerili [36] and Ambassis spp [46] These differencesare important in the process of expulsion of feces that needsmucus substances for lubrication to ease the excretion [12]Significantly the herbivorous fishes such as L niloticus [22]and L horie [47] demonstrated little number of Goblet cellsat the posterior part of the intestine

This study revealed that the thickness of intestinal villigradually decreased from the anterior to the posterior sec-tion The remnants of food particles that were not absorbedin the anterior intestine then migrate into the intermediateintestine where the absorption process continues Since theamounts of food particles that migrate toward the interme-diate and posterior intestine were lesser the number andlength of villi were significantly reduced The result wassimilar to the intestine of a typical predator and a predator-facultative benthophage which are pike Esox lucius andburbot Lota lota respectively [48] The fishes demonstratedhighest villi measurement when observed in the anterior partof the intestine compared to the posterior part Finally theremaining unabsorbed food particles and wastes migrate intothe rectum waiting to be removed from the body throughthe anus The villous folding and the microvilli functioned toincrease the intestinal surface areas which are important fornutrient absorption [49]

The intestinal muscularis of A b bicolor was dividedinto two layers inner circular layer and outer longitudinallayer which was in agreement with Leporinus friderici andL taeniofasciatus [28] but was opposed to S dumerili whichwas described to have three layers of unstriated musclefibers [36] It is postulated that the carnivorous fish consumevarious kinds of protein sources and need powerful musclecontraction at the rectal area to defecate The propulsivecontractions are caused by the muscularis externa Becauseof that the thickness of the muscle is more remarkable at theposterior part of the intestine In contrast the herbivorousfish which consume high fibrous contents encourage theintestinal peristalsis and less rectal muscle contraction wasneeded The findings were in agreement with what has beenobserved in amberjack S dumerili [36] but contradictedmuscularis layer of Tilapia spp which demonstrated similarthickness throughout the intestine [50]

5 Conclusions

The present study suggested that the histological featuresof the gastrointestinal tract of A b bicolor were consistentwith the feeding habit of a carnivorous fish However morestudies should be carried out for deeper understanding of thedigestion process and nutrient absorption of those fish

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgment

This research was financially supported by the Research Uni-versity Grant no 01-02-12-2171RU Universiti PutraMalaysia

References

[1] V Ege ldquoA revision of the genus Anguilla Shawrdquo Dana-Reportvol 16 pp 8ndash256 1939


[2] T Arai and N Chino ldquoTiming of maturation of a tropical eelAnguilla bicolor bicolor in Malaysiardquo Journal of Applied Ichthy-ology vol 29 no 1 pp 271ndash273 2013

[3] T Arai N Chino S Z Zulkifli and A Ismail ldquoNotes on theoccurrence of the tropical eel Anguilla bicolor bicolor in Pen-insular Malaysia Malaysiardquo Journal of Fish Biology vol 80 no3 pp 692ndash697 2012

[4] J C Shiao Y Iizuka CWChang andWN Tzeng ldquoDisparitiesin habitat use and migratory behavior between tropical eelAnguilla marmorata and temperate eel A japonica in fourTaiwanese riversrdquo Marine Ecology Progress vol 261 pp 233ndash242 2003

[5] N J Leander W-N Tzeng N-T Yeh K-N Shen and Y-SHan ldquoEffects of metamorphosis timing and the larval growthrate on the latitudinal distribution of sympatric freshwater eelsAnguilla japonica and A marmorata in the western NorthPacificrdquo Zoological Studies vol 52 article 30 2013

[6] V R P Sinha and J W Jones The European Freshwater EelLiverpool University Press Liverpool UK 1975

[7] J-L Bouchereau C Marques P Pereira O Guelorget S-MLourie and Y Vergne ldquoFeeding behaviour of Anguilla anguillaand trophic resources in the Ingril Lagoon (MediterraneanFrance)rdquo Cahiers de Biologie Marine vol 50 no 4 pp 319ndash3322009

[8] H Rupasinghe and M V E Attygalle ldquoFood and feeding ofbrown-stage eels of Anguilla bicolor in the Bolgoda EstuaryrdquoVidyodaya Journal of Science vol 13 pp 1ndash8 2006

[9] R Lecomte-Finiger ldquoDiet of elvers and small eels (Anguillaanguilla) in three brackish lagoons from Roussillon ProvincerdquoBulletin drsquoecologie vol 14 no 4 pp 297ndash306 1983

[10] E M Waldt R Abbett J H Johnson D E Dittman and J EMcKenna ldquoFall diel diet composition of American eel (Anguillarostrata) in a tributary of the Hudson River New York USArdquoJournal of Freshwater Ecology vol 28 no 1 pp 91ndash98 2013

[11] H Hellberg and I Bjerkas ldquoThe anatomy of the oesophagusstomach and intestine of the common wolffish (Anarhichaslupus L) a basis for diagnostic work and researchrdquo ActaVeterinaria Scandinavica vol 41 no 3 pp 283ndash297 2000

[12] HMMurray GMWright andG P Goff ldquoA comparative his-tological and histochemical study of the post-gastric alimentarycanal from three species of pleuronectid the Atlantic halibutthe yellowtail flounder and the winter flounderrdquoThe Journal ofFish Biology vol 48 no 2 pp 187ndash206 1996

[13] D N Ezeasor and W M Stokoe ldquoLight and electron micro-scopic studies on the absorptive cells of the intestine caecaand rectum of the adult rainbow trout Salmo gairdneri RichrdquoJournal of Fish Biology vol 18 no 5 pp 527ndash544 1981

[14] J M Wilson and L F C Castro ldquoMorphological diversity ofthe gastrointestinal tract in fishesrdquo in The Multifunctional Gutof Fish M Grosell A P Farrell and C J Brauner Eds pp 2ndash44 Academic Press Boston Mass USA 2011

[15] H A Al Abdulhadi ldquoSome comparative histological studies onalimentary tract of tilapia fish (Tilapia spilurus) and sea bream(Mylio cuvieri)rdquo Egyptian Journal of Aquatic Research vol 31no 1 pp 387ndash397 2005

[16] N E R El-Bakary andH L El-Gammal ldquoComparative histolo-gical histochemical and ultrastructural studies on the proximalintestinal of flathead greymullet (Mugil cephalus) and sea bream(Sparus aurata)rdquoWorld Applied Science Journal vol 8 no 4 pp477ndash485 2010

[17] R K Buddington and S I Doroshov ldquoStructural and functionalrelations of white sturgeon alimentary canal (Acipenser trans-montanus)rdquo Journal of Morphology vol 190 no 2 pp 201ndash2131986

[18] OA Abuzinadah Studies on Red Sea fish [PhD thesis] Depart-ment of Zoology School of Biological Science University Col-lege of Swansea 1990

[19] S A A Naguib H A El-Shabaka and F Ashour ldquoComparativehistological and ultrastructural studies on the stomach ofSchilbe mystus and the intestinal swelling of Labeo niloticusrdquoJournal of American Science vol 7 no 8 pp 251ndash263 2011

[20] J Noaillac-Depeyre and N Gas ldquoStructure and function of theintestinal epithelial cells in the perch (Perca fluviatilis L)rdquo TheAnatomical Record vol 195 no 4 pp 621ndash639 1979

[21] D W Klumpp and P D Nichols ldquoNutrition of the southern seagarfish Hyporhamphus melanochir gut passage rate and dailyconsumption of two food types and assimilation of seagrasscomponentsrdquo Marine Ecology Progress Series vol 12 pp 207ndash216 1983

[22] F I Amer S A A Naguib and F A A El Ghafar ldquoComparativestudy on the intestine of Schilbe mystus and Labeo niloticusin correlation with their feeding habitsrdquo Journal of AmericanScience vol 7 no 8 pp 465ndash484 2011

[23] S Kuzir E Gjurcevic S Nejedli B Bazdaric and Z KozaricldquoMorphological and histochemical study of intestine in wildand reared European eel (Anguilla anguilla L)rdquo Fish Physiologyand Biochemistry vol 38 no 3 pp 625ndash633 2012

[24] M Firdaus-Nawi M Zamri-Saad N Y Nik-Haiha M A BZuki and A W M Effendy ldquoHistological assessments of intes-tinal immuno-morphology of tiger grouper juvenile Epinephe-lus fuscoguttatusrdquo SpringerPlus vol 2 article 611 2013

[25] G P Quinn and M J Keough Experimental Design and DataAnalysis for Biologists Cambridge University Press CambridgeUK 2002

[26] M V O Garrido C G Oller and M A A Equisoain ldquoEffectof diet on gastric mucosa cells in the European eel (Anguillaanguilla L) Histochemical and ultrastructural studyrdquo Micronvol 27 no 1 pp 25ndash34 1996

[27] M A Abaurrea-Equisoain and M V Ostos-Garrido ldquoCelltypes in the esophageal epithelium of Anguilla anguilla (PiscesTeleostei) Cytochemical and ultrastructural characteristicsrdquoMicron vol 27 no 6 pp 419ndash429 1996

[28] M P Albrecht M F N Ferreira and E P Caramaschi ldquoAna-tomical features and histology of the digestive tract of tworelated neotropical omnivorous fishes (Characiformes Anosto-midae)rdquo Journal of Fish Biology vol 58 no 2 pp 419ndash430 2001

[29] W Humbert R Kirsch and M F Meister ldquoScanning electronmicroscopic study of the oesophageal mucous layer in the eelAnguilla anguilla Lrdquo Journal of Fish Biology vol 25 no 1 pp117ndash122 1984

[30] C Domeneghini S R Ponnelli and A Veggetti ldquoGut glyocon-jugates in spasm owratal (Pisces Teleostei ) Comparative histo-chemical study in larval and adult agesrdquo Histology and Histo-patholology vol 13 no 2 pp 359ndash372 1998

[31] J Y Park and I S Kim ldquoHistology and mucin histochemistryof the gastrointestinal tract of the mud loach in relation to res-pirationrdquo Journal of Fish Biology vol 58 no 3 pp 861ndash872 2001

[32] A O Dıaz A M Garcıa C V Devincenti and A L Goldem-berg ldquoMorphological and histochemical characterization of themucosa of the digestive tract in Engraulis anchoita (Hubbs andMarini 1935)rdquo Anatomia Histologia Embryologia vol 32 no6 pp 341ndash346 2003


[33] M Carrasson A Grau L R Dopazo and S Crespo ldquoA histo-logical histochemical and ultrastructural study of the diges-tive tract of Dentex dentex (Pisces Sparidae)rdquo Histology andHistopathology vol 21 no 6 pp 579ndash593 2006

[34] F Moog and E L Wenger ldquoThe occurrence of a neutralmucopolysaccharide at sites of high alkaline phosphatase activ-ityrdquo The American Journal of Anatomy vol 90 no 3 pp 339ndash377 1952

[35] A H Al-Hussaini and A A Kholy ldquoOn the functional mor-phology of the alimentary tract of some omnivorous fishrdquoProceedings of the Egyptian Academy of Sciences vol 4 pp 17ndash39 1953

[36] A Grau S Crespo M C Sarasquete and M L G de CanalesldquoThe digestive tract of the amberjack Seriola dumerili Risso a light and scanning electron microscope studyrdquo Journal of FishBiology vol 41 no 2 pp 287ndash303 1992

[37] I R Tibbetts ldquoThe distribution and function of mucous cellsand their secretions in the alimentary tract of Arrhamphussclerolepis krefftiirdquo Journal of Fish Biology vol 50 no 4 pp 809ndash820 1997

[38] T Caceci H A El-Habback S A Smith and B J Smith ldquoThestomach of Oreochromis niloticus has three regionsrdquo Journal ofFish Biology vol 50 no 5 pp 939ndash952 1997

[39] C W Reifel and A A Travill ldquoStructure and carbohydrate his-tochemistry of the stomach in eight species of teleostsrdquo Journalof Morphology vol 158 no 2 pp 155ndash167 1978

[40] W Yunming and W Wen ldquoMicroscopic and ultramicroscopicstudies on gastric gland cells of several freshwater fishesrdquo ActaHydrobiologica Sinica vol 13 no 4 pp 334ndash339 1989

[41] B CananW S do Nascimento N B da Silva and S ChellappaldquoMorphohistology of the digestive tract of the damsel fishStegastes fuscus (Osteichthyes Pomacentridae)rdquo The ScientificWorld Journal vol 2012 Article ID 787316 9 pages 2012

[42] K D Clements and D Raubenheimer ldquoFeeding and nutritionrdquoinThePhysiology of Fishes D H Evans and J B Claiborne EdsTaylor amp Francis Boca Raton Fla USA 2006

[43] M T Elbal and B Agulleiro ldquoA histochemical and ultrastruc-tural study of the gut of Sparus auratus (Teleostei)rdquo Journal ofSubmicroscopic Cytology vol 18 no 2 pp 335ndash347 1986

[44] R E Olsen R Myklebust T Kaino and E Ringoslash ldquoLipid diges-tibility and ultrastructural changes in the enterocytes of Arcticchar (Salvelinus alpinus L) fed linseed oil and soybean lecithinrdquoFish Physiology and Biochemistry vol 21 no 1 pp 35ndash44 1999

[45] J L Z Infante and C L Cahu ldquoOntogeny of the gastrointestinaltract of marine fish larvaerdquo Comparative Biochemistry andPhysiology Part C Toxicology amp Pharmacology vol 130 no 4pp 477ndash487 2001

[46] T J Martin and S J M Blaber ldquoMorphology and histology ofthe alimentary tracts of Ambassidae (Cuvier) (Teleostei) in rela-tion to feedingrdquo Journal of Morphology vol 182 no 3 pp 295ndash305 1984

[47] S Girgis ldquoOn the anatomy and histology of the alimentary tractof an herbivorous bottom-feeding Cyprinoid fish Labeo horie(Cuvier)rdquo Journal of Morphology vol 90 no 2 pp 317ndash3621952

[48] B I Kuperman and V V Kuzrsquomina ldquoThe ultrastructure of theintestinal epithelium in fishes with different types of feedingrdquoJournal of Fish Biology vol 44 no 2 pp 181ndash193 1994

[49] X Dai M Shu and W Fang ldquoHistological and ultrastructuralstudy of the digestive tract of rice field eel Monopterus albusrdquoJournal of Applied Ichthyology vol 23 no 2 pp 177ndash183 2007

[50] A M Gargiulo P Ceccarelli C DallrsquoAglio and V Pedini ldquoHis-tology and ultrastructure of the gut of the Tilapia (Tilapia spp)a hybrid teleostrdquoAnatomia Histologia Embryologia vol 27 no2 pp 89ndash94 1998

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of


Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology


Molecular Biology International

GenomicsInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


BioinformaticsAdvances in

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Signal TransductionJournal of


BioMed Research International

Evolutionary BiologyInternational Journal of



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ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Genetics Research International


Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational



Enzyme Research



Microbiology


andhistological features of gastrointestinal tract of fisheswerealso different based on taxonomy feeding habit and bodyshape [15] The morphological features of gastrointestinaltract of carnivorous fish were proved to diverge from herbiv-orous fishThe carnivorous fish tend to have shorter intestinethan the herbivorous fish due to lower percentage of plantmaterials in the diet [16 17] Histologically the oesophagusof a carnivorous fish has more mucous cells than herbivorousfish [18] For stomach of a carnivorous fish Schilbe mystusa study found that it can be divided into two compart-ments namely cardiofundic and pyloric although the organmorphologically consisted of three parts which are cardiacpyloric and fundic region [19] In addition the gastricmucosa of perch Perca fluviatilis was described to have threetypes of endocrine cells that produced hydrochloric acid[20] but it is absent in herbivorous fish such as sea garfishHyporhamphus melanochir [21] The mucosa of the intestineof S mystus consisted of simple columnar epithelium thatcontains Goblet cells similar to the histological structure inherbivorous fish Labeo niloticus [22]

There are limited studies on the histological features ofdigestive tract of Anguilla while most of the conductedstudies in this country focused more on the inventory surveyand migration behavior of the eels [2 3] Thus the presentstudy was conducted in order to describe the histological fea-tures of the gastrointestinal tract particularly the oesopha-gus stomach and intestine of wild A b bicolor captured inPeninsular Malaysia This may provide a comparative basisfor future studies of digestion absorption and feeding pat-tern In addition the ultrastructural analysis described fromthis study is important for the diagnosis of diseases related togastrointestinal tract of Anguilla

2 Materials and Methods

Anguilla bicolor bicolor samples were captured in Balik PulauPenangMalaysia fromFebruary 2013 to January 2014A totalof 28 wild eel samples were obtained either by angling or byusing traditional fish traps Following capture the wet bodymass and total length were measured and recorded

Samples were placed in a solution containing tricainemethanesulfonate (MS 222) at 50mgL to achieve stage threeof anesthesia before they were sacrificed by cervical dislo-cation according to method approved by the Animal Utiliza-tion Protocol Universiti Putra Malaysia The entire digestivetract was immediately extracted by a midventral incisionremoved and then divided into oesophagus stomach andintestine

Anatomical description was carried out before the oeso-phagus stomach and intestine were divided into five (firstto fifth) two (cardiac and pyloric) and four (anterior inter-mediate posterior and rectum) segments respectively [23]Organs were then sampled in triplicate labeled and fixed in10 buffered formalin for 12 hours before they were embed-ded in paraffin sectioned at 5 120583m thick and stained routinelywith Harris haematoxylin and eosin (HE) and periodic acid-Schiff (PAS) The height of villi thickness of lamina propriainner circular muscle outer longitudinal muscle and gastricgland were measured according to Firdaus-Nawi et al [24]

The photos were recorded through photomicroscope (NikonEclipse 50i Japan) and analyzed through The Nikon NIS-Element D 32 Image Analyser (Nikon Instruments IncUSA)

The data was checked for normality using Shapiro-Wilktest of normality (119875 gt 005) and its homogeneity of variancesusing Levenersquos test for equality of variances (119875 gt 005) (IBMSPSS Statistics Version 21) The mean plusmn standard error ofmean (SEM) of the histological measurements for each struc-ture was compared among all of the segments and organsusing the analysis of variance with Tukey LSD All-PairwiseComparison Test (Statistix 9 Analytical Software) [25] Thesignificance value was at 119875 lt 005 The determined mea-surements were the height for the mucosal projection andthe thickness for lamina propria inner circular muscle outerlongitudinal muscle and gastric gland

3 Results

The mean (plusmnstandard deviations) of wet body mass andtotal length of the 28 samples of A b bicolor were 37847(plusmn24678) g and 56053 (plusmn14093)mm respectively

Table 1 shows the measurements of villus height thick-ness of lamina propria inner circular muscle outer longitu-dinal muscle and gastric gland of the sampled A b bicolorThe stomach showed significantly higher villous and thickerinner circular muscle than the intestine and oesophagusThe lamina propria was the thickest in the stomach andsignificantly thicker than in oesophagus but not than in theintestine The intestine showed significantly thicker outerlongitudinal muscle than oesophagus and stomach Thegastric glands were observed only in the stomach

31 Histological Features of the Oesophagus For oesophagusthe tunica mucosa consisted of ciliated pseudostratifiedcolumnar epithelium with numerous Goblet cells especiallyat the first to the third segments (Figure 1(a)) The numbersof Goblet cells gradually decreased towards the posterior part(fourth and fifth segments) The cilia which were located atthe tip of the epithelium were found abundantly at the firstthree segments but became lesser in number and eventuallyabsent at the posterior part of the oesophagus (Figure 1(b))The villi at the first part of the oesophagus were tall andbroad-based with finger-like structure which appeared star-shaped in transverse section (Figure 1(c)) The villi at theposterior segment showed gradual decrease in height andsmaller base The mean height of the mucosal projectionshowed no significant difference between most of the fivesegments of the oesophagus

The lamina propria consisted of loose connective tissuesand was highly vascularized (Figure 1(d)) However therewas no significant difference in the thicknesses of laminapropria among the segments of the oesophagus

Tunica muscularis was arranged in two obvious lay-ers the inner circular muscle and the outer longitudinalmuscle bundles The thickness of both structures graduallydecreased toward the posterior end of the oesophagusobviously for the outer longitudinal muscle Both muscularlayers were significantly thicker in the first and second




Oesophagus






Intestine



100120583m

(a)

50120583m

A

(b)

500120583m

(c)

100120583m

(d)



500120583m

(a)

100120583m

(b)

lowast

100120583m

(c)

50120583m

(d)










100120583m

(a)

100120583m

(b)

100120583m

(c)

lowast 500120583m

(d)




4 Discussion












5 Conclusions




Acknowledgment


References




























































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology




Oesophagus






Intestine



100120583m

(a)

50120583m

A

(b)

500120583m

(c)

100120583m

(d)



500120583m

(a)

100120583m

(b)

lowast

100120583m

(c)

50120583m

(d)










100120583m

(a)

100120583m

(b)

100120583m

(c)

lowast 500120583m

(d)




4 Discussion












5 Conclusions




Acknowledgment


References




























































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology


500120583m

(a)

100120583m

(b)

lowast

100120583m

(c)

50120583m

(d)










100120583m

(a)

100120583m

(b)

100120583m

(c)

lowast 500120583m

(d)




4 Discussion












5 Conclusions




Acknowledgment


References




























































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology


100120583m

(a)

100120583m

(b)

100120583m

(c)

lowast 500120583m

(d)




4 Discussion












5 Conclusions




Acknowledgment


References




























































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology







5 Conclusions




Acknowledgment


References




























































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology



























































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology

research article histological features of the gastrointestinal … · 2019. 7. 31. · research...

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