Short note

Liver biopsy in sheep

M Hidiroglou M Ivan

Centre for Food and Animal Research, Agriculture Canada, Ottawa, Ontario, Canada K1A OC6

(Received 12 June 1992; accepted 15 September 1992)

Summary ― Liver biopsies were performed in the same group of 16 sheep on 8 consecutive wkusing an apparatus with a fibre optic continuous light source and a telescope. The sheep wereplaced in a sternal position on a special table constructed of metal pipes (3.8 cm diameter) and 4.5cm spacing. Approximately 300 mg of fresh liver sample was removed from each sheep to be anal-yzed for copper or vitamin E.

liver biopsy I sheep I fibre optics I telescope

Résumé ― Biopsie du foie chez le mouton. Les biopsies du foie ont été réalisées chez 16 mou-tons pendant 8 sem consécutives en utilisant un appareil possédant une fibre optique avec unesource lumineuse continue et un téléscope. Les moutons ont été placés en décubitus ventral surune table spéciale faite de tuyaux métalliques (3,8 cm de diamètre) espacés de 4,5 cm. Des échan-tillons de foie d’environ 300 mg ont été prélevés sur chaque mouton, pour faire le dosage du cuivreet de la vitamine E.

biopsie / foie mouton / fibre optique / téléscope

INTRODUCTION

The ovine liver plays a central role in cop-per (Cu) metabolism and is the main stor-age organ, accumulating 70―90% of ab-sorbed Cu. Consequently, the hepatic Cuconcentration in dead or living animals isoften used as an index of Cu status. Re-

cently, Hidiroglou and Charmley (1990) re-ported that hepatic a-tocopherol is a goodindicator of dietary vitamin E intake, while

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Correspondence and reprints

plasma a-tocopherol is an unreliable indi-cator of vitamin E status in sheep. Liver bi-opsy is widely used for obtaining liver

samples from living animals. It is often

preferred to killing experimental animals,because repeated observations can be

made on the same animal. However, theusefulness of the liver biopsy depends onthe purity and the size of the sample ob-tained, and on the severity of the stressimposed on the animal.

Several biopsy techniques for sheephave been described (Dick, 1944, 1952;Phillippo, 1973; Rodriguez et al, 1981;Donald et al, 1984; Duncan, 1984). Morerecently, however, an excellent liver biopsytechnique employing a fibre optic continu-ous light source to view the site to be biop-sied has been developed for cattle (White-hair et al, 1988). We have modified thistechnique for use in sheep and the modi-fied technique is reported here.

MATERIALS AND METHODS

The biopsy instrument (fig 1) (Carl Storz Co, LosAngeles, CA, USA) consisted of a miniature coldlight fountain (Model 481C), a fibre optic lightcable (Model 495 NL), a Hopkins telescope(Model 26031 A), trochar and cannula (7 mm)(Model 26031 G), a pump, a biopsy forceps(Model 26175 DB), a trochar and cannula (5.5mm) (Model 26/72 C) and 2 stylets. It was used

to obtain liver samples (= 300 mg) from thesame 16 sheep on 8 consecutive wk.

The sheep were fasted for 12 h before sur-gery. Each sheep was given approximately 1 hbefore surgery, a tranquilliser (Acepromazine;Austin, Montreal, Quebec, Canada) by im injec-tion (50-60 mg) and placed in a sternal positionon a table with a grid-like top made from metalpipes (diameter 3.8 cm) with 4.5 cm spacing(fig 2). The legs of the sheep extended throughthe grid while the body of the sheep was rotatedcounter-clockwise to elevate the surgical location.The right abdomen was soaked and lathered withan antiseptic shampoo, and then shaved andwashed. A topical antiseptic was applied and asterile surgical technique was performed follow-ing a subcutaneous injection of 4 ml of 2% lido-caine (Langford Inc, Guelph, Ontario, Canada),middle distance from the superior angle of the tu-ber coxae bone and ventral line, 3 cm behind thelast rib, and securing a sterile drape.

The larger trochar and cannula (7 mm) wereinserted into the abdominal cavity at the site oflocal anaesthesia (subcutaneous injection of lid-ocaine). The trochar was removed and the tele-scope was inserted in its place. The omental fat,

diaphragm and liver were identified (fig 3). Theabdominal cavity was inflated by the introductionof 6 I COz gas (2 I/min) via a Verres needle

(fig 4). The second (smaller) trochar and cannu-la were inserted through the abdomen wall 3 cmbelow the telescope. The trochar was removedand the biopsy forceps inserted in its place anddirected towards the point of the telescope. Apoint on the liver periphery was identified

through the telescope and was grasped firmlywith the forceps (fig 5). An = 300-mg sample ofthe liver, encapsulated in the head of the biopsyforceps, was removed (fig 6) and stored forchemical analysis. All instruments were then re-moved from the abdominal wall and the skin per-forations were sprayed with healing compounds.The instruments were swabbed and disinfectedbefore an additional sheep was biopsied.

RESULTS AND DISCUSSION

A total of 16 sheep were each repeatedlybiopsied on 8 consecutive wk. None of the

sheep developed any complication follow-ing the biopsy and were in good generalhealth. However, our previous experienceshowed that sheep fasted for 24 h maydevelop polioencephalomalacia. The sheepbecome dull or blind, circle or become castwith a twisted neck and a bruised eyebrow.Such sheep respond dramatically to dosingof thiamine, 150 mg iv and 150 mg im.

The maximum time required to obtain aliver sample was 15 min. This is similar tothe time reported by Phillippo (1973). In

some sheep fatty omentum covered the tipof the scope. In such a case the telescopewas withdrawn and again directed be-

tween the abdominal wall and the omen-

tum. Understanding of the anatomy andpatience are very important for the suc-cess of the technique. The liver samplesthat were obtained by the present tech-nique were used for analysis of Cu and vi-tamin E.

Our previous work indicated that vitaminE is distributed evenly within the liver; vita-min E analysis of samples from variousparts of the liver in 5 sheep on a silage dietwithout a vitamin E supplement showedmean concentrations (in pg/g fresh tissue)of 6.02 ± 0.3 for the right lobe, 6.01 ± 0.2for the caudal lobe and 6.03 ± 0.2 at the

fringe of the liver. Therefore, sampling bybiopsy can be successfully used for meas-urement of vitamin E concentration in theliver. The advantage of the present para-costal method for liver biopsy was that itwas less traumatic for the animal than the

existing methods.

ACKNOWLEDGMENTS

The authors thank K Hartin and the staff of

Building 701, Greenbelt Farm, for technical as-sistance.

REFERENCES

Dick AT (1944) Aspiration biopsy of the liver ofsheep. Aust Vet J 20, 298-303

Dick AT (1952) Improved apparatus for aspira-tion biopsy of the liver in sheep. Aust Vet J28, 234-235

Donald GE, Paull DR, Langlands JP (1984) Liv-er biopsy as a technique for assessing cop-per status of sheep. Aust J Vet 61, 121-122

Duncan IF (1984) Liver biopsy and black dis-ease in a sheep. Aust Vet J 61, 272-273

Hidiroglou M, Charmley E (1990) Response ofplasma and tissue o-a-tocopheroi in sheep tograded dietary levels of DL-a-tocopheryl ace-tate. Res Vet Sci 49, 122-124

Phillippo M (1973) A technique for liver biopsy insheep. J Agric Sci 80, 313-314 4

Rodriguez A, Gonzalez JL, Pérez P, Fuentes 0(1981) La endoscopia en el control de la pun-cion hepatica en ovinos. Rev Salud Anim 3,3-8

Whitehair CK, Da Silva RB, Ames NK (1988) Liv-er biopsy in cattle. Bovine Pract23, 144-147