The Effectiveness of Ligating or Detaching Ceca as an Alternative to Cecectomy

(1)

Alternative to Cecectomy

TERESA F. POPPEMA1 and GARY E. DUKE

Department of Veterinary PathoBiology, University of Minnesota, St. Paul, Minnesota, 55108

ABSTRACT Cecectomy (the surgical removal of ceca) is a technique that has been used to explore the nutritional and osmoregulatory role of the ceca in domestic fowl and other birds. The operation imposes a high level of physiolog-ical stress on a bird. The current study describes the effectiveness of ligating or detaching the ceca in young turkeys as an alternative to complete removal of the organ.

Birds with ligated ceca showed less postsurgical depression and initiated feeding and other normal activities sooner than birds with detached ceca. Birds with detached ceca also had a significantly slower rate of weight gain 1 wk after surgery. Both surgically treated groups were more depressed than were sham-operated turkeys. Post-mortem examinations revealed that cecal detachment was more successful in actually separating the ceca from the rectum and in preventing flow of digesta in and out of the ceca. Evidence of growth of cecal stumps that remained attached to the rectum was found following both ligation and detachment.

Post-mortem examinations revealed that in four birds both ligated or detached ceca left in the abdominal cavity became enlarged and filled with a dark, pasty, odorous substance. This increase in cecal size and volume of contents with time apparently indicates that some microbial metabolic activity continued in the cecal lumen. If so, this might have negative implications for studies that assume that such ceca are no longer functional.

(Key words: cecectomy, ligations, detachment, cecal stumps, cecal enlargement)

1992 Poultry Science 71:1384-1390 INTRODUCTION

Interspecific variations in the shape, size, and presence of avian ceca suggest that these organs may have several func-tions and that their primary role within a species may be determined by food habits or needs for water conservation. In an effort to better understand cecal function, many investigators have surgically re-moved the ceca (cecectomy) in various species to examine the effect on food metabolism and energetics (Payne et al, 1971; Thompson and Boag, 1975; McBee, 1977; Sudo and Duke, 1980; Duke et al,

Received for publication January 24, 1992. Accepted for publication March 31, 1992.

To whom correspondence should be addressed.

1981, 1984), uric acid excretion (Kese and March, 1975), amino acid excretion (Kess-ler et al, 1981; Green, 1988), amino acid synthesis (Parsons, 1984), susceptibility to disease (Schlotthauer et al, 1933; Dziuk et

al, 1970), serum cholesterol levels

(Tor-tuero et al, 1975), and water absorption, uptake, and excretion (Duke et al, 1981; Chaplin, 1989; Hughes et al, 1991).

The complete surgical excision of the ceca, however, is difficult and physically stressful to the subjects. Large amounts of the ileocecal ligament must be severed in order to completely isolate the ceca at the ileo-cecal-colic junction (ICCJ). Great cau-tion must be exercised while excising the ceca at the ICCJ to avoid damage to, or excessive hemorrhage from, the large caudal mesenteric vein lying parallel to and nearly touching the ceca just dorsal to 1384

at Penn State University (Paterno Lib) on May 16, 2016

http://ps.oxfordjournals.org/

(2)

the ICCJ. This is true not only for domestic fowl, but for wild birds as well. Both Duke et al. (1981) and Chaplin (1989) indicated a decrease in surgical survival rates and an increase in recovery time following cecec-tomies on great horned owls, relative to other surgeries involving the gastrointesti-nal tract.

An alternative method has been em-ployed to avoid these complications. Dur-ant (1929) and Schlotthauer et al. (1933), Anderson and Braun (1984), and Hughes et al. (1991) tied ligatures around the ceca near the ICCJ of domestic turkeys (Meleagris gallopavo), Gambel's quail (Lophortyx gambelii), and Pekin ducks (Anas platyrhynchos), respectively. Al-though ceca were left in the abdominal cavity in these four studies, it was as-sumed that cecal functions were elimi-nated.

This assumption, however, raises sev-eral questions: Is cecal ligation successful in eliminating cecal participation in diges-tion and osmoreguladiges-tion? Is this surgical technique less stressful to the bird than cecectomy? Is there a disadvantage in leaving the ligated ceca in the abdominal cavity? Will the ceca become necrotic, or will metabolic activity continue inside the ceca even though the flow of digesta into the ceca does not? If so, will the actions of cecal microflora contribute to the energet-ics of the bird or be detrimental by absorbing nutrients from the blood for exclusive use of the cecal flora?

The present study compared the effec-tiveness of 1) ligating the ceca at the ICCJ; and 2) doubly ligating and removing a section of the ceca immediately distal to the ICCJ (i.e., detachment), as alternatives to cecectomy. As a test of the previously unvalidated assumption that ligated or detached ceca are no longer functional, post-mortem examinations were per-formed to determine the consequences of leaving ceca in the abdominal cavity.

2T-10 Turkey Starter, 25% protein, 6.4% fat, 2% fiber, 2,689.7 kcal/kg metabolizable energy.

3Squibb-Marsan, Cherry, NJ 08002.

4Sherwood Pharmaceutical Co., Mahwah, NJ 07430.

5Beecham Laboratories, Bristol, TN 37621.

MATERIALS AND METHODS Study Specimens

Thirty-two female Nicholas turkeys (Meleagris gallopavo) were housed in indi-vidual cages (46 x 46 x 61 cm) in environ-mentally controlled rooms in which the temperature was maintained from 21 to 23 C, relative humidity was kept between 40 and 50%, and the photoperiod was auto-matically timed to provide 12 h of light from 0800 to 2000 h. All birds had ad libitum access to water and a diet2 prepared by the Animal Science Department of the Univer-sity of Minnesota, and were allowed to acclimate to holding conditions for 1 wk prior to surgery.

Surgical Procedure

The birds were 5 wk old at the time of surgery and were fasted for 12 h prior to surgery. They were anesthetized with so-dium pentobarbital3 (40 mg/kg) via the basilic vein. Their abdominal feathers were removed and the skin was sterilized with Betadine scrub4 and alcohol. A 3- to 4-cm incision was made parallel and to the right of the linea alba starting just below the sternum. Skin and muscle layers were retracted to expose the duodenal loop. Cranial reflection of the duodenal loop exposed the distal ends of the ceca, which could then be traced orad to the ICCJ in the craniodorsal area of the abdominal cavity. After surgical manipulation, the ceca were returned to their original orientation in the abdominal cavity and the abdominal mus-cle layers and skin were closed. Each bird was given an antibiotic treatment of penicil-lin G benzathine and penicilpenicil-lin G procaine5 (.2 mL/kg intramuscularly) on the days before and after surgery.

Types of Surgery

Eight birds were assigned to each of four groups. In the "ligated" procedure, birds had 2-0 braided silk ligatures tied around each cecum 1.0 cm from its origin at the ICCJ. Care was taken so as to effectively close the lumen and at the same time not cut through the gut. In the "detached" group, ligatures were tied around each cecum at

(3)

1.0 and 2.0 cm from their origin at the ICCJ and the segment between the two ligatures was removed. Care was taken to avoid spillage of digesta. The sectioned surfaces were cauterized with AgNC>3 sticks. To control for the effects of surgery, sham-operated birds simply had the ceca exposed and manipulated at the ICCJ. A control group of birds from the same stock, which experienced no surgical manipulation, was also maintained.

Measurements

The subjects were carefully monitored postoperatively to assess their recovery. Visual observations such as piloerection, wing droop, eyelid droop, alertness, and time required for initiation of feeding following surgery were recorded. Excreta were observed daily for moisture content, bolus shape, color, and the presence of discrete cecal droppings. Body mass was recorded as follows after surgery: daily for 1 wk, every other day for the next 8 wk, and once a week after 9 wk. To determine whether there was a significant difference in initial weight gain among the ligated, detached, and sham-operated groups, the Student's t test6 (two-tailed) was used to determine whether the slope of the regres-sion lines were equal. This test is analogous to testing for differences between popula-tion means (Zar, 1974).

Two birds from each of the four treat-ment groups were euthanatized (T-61,7 i.v.) at 3, 6, 9, and 12 wk postsurgery to assess the effectiveness of ligations and detach-ments. Evidence of intact ligatures, separa-tion of the ceca from ICCJ, growth of the cecal stump that remained attached to the rectum, flow of digesta into the ceca, and the physical appearance of the ligated and detached ceca was sought. The develop-ment of adhesions as a consequence of the surgery was also recorded.

6Statistix®, NH Analytical Software, St. Paul, MN 55108.

7Hoechst-Roussel AgriVet Co., Somerville, NJ 08876.

RESULTS

Visual Observations

Birds with detached ceca were the slowest to recover from surgery and showed more severe depression, but their feeding and normal activity resumed within 24 h, at which time wing and eyelid droop also ceased. Sham-operated birds began eating as soon as they recovered from anesthesia. Birds with ligated ceca began eating 8 h postsurgery and showed little depression.

Excreta

The excreta of birds with detached or ligated ceca were extremely moist through-out the entire experiment, and discrete fecal boli were usually not present. Boli usually were present in both sham-operated and control birds. No cecal droppings were observed from birds with detached ceca but their excreta were darker in color than excreta from the sham-operated and control birds. Excreta from birds with ligated ceca were generally very similar in color to those of the birds with detached ceca except for the consistent presence of "cecal" drop-pings first observed at 8,13,18, and 21 days after surgery, respectively, from four birds. These apparent cecal droppings appeared to be evacuated separately from rectal droppings, but they were not as dark in color nor as homogeneous in texture as the true cecal droppings of sham-operated and control birds. Their occurrence was the first indication that either the ligation technique was ineffective, or a rapid adaptation had occurred in which cecal-like excreta were produced by some other part of the gut (e.g., rectum). Rectal excreta from these four birds were well-formed, drier, and more similar to the excreta of sham-operated and control birds.

Weight Gain

The rate of weight gain the 1st wk after surgery was significantly lower in birds with detached ceca than in either birds with ligated ceca (t.o5[i2] = 5.6) or sham-operated birds (£.05[12] = 7.2) (Figure 1). Birds with detached ceca also weighed less at 3, 6, and

(4)

1.300

'00

Days

FIGURE 1. The rate of weight gain during the 1st

wk postsurgery by birds with ligated (• = 6), detached (• = 8), and sham-operated (A = 8) ceca. Points are means and bars are standard deviations. Day "0" is the day of surgery.

9 wk postsurgery, but by the 12th wk, their weights were nearly the same as the other operated birds.

Post-Mortem Examinations

The 3rd- and 6th-wk post-mortem ex-aminations of birds with ligated ceca showed successful blockage of digesta m o v e m e n t i n t o t h e ceca, w h e r e a s 9th- and 12th-wk examinations showed that the ligatures were less successful. In one case, fibrous tissue had formed around the ligature and the ligated cecal tissue had been reabsorbed, thus creating a lumen of approximately 1.0 mm in diameter, which would presumably have allowed some digesta to move in and out of the cecum. A similar lumen, although very small, was found inside the ligatures of two other ceca. In all post-mortem examinations involving detached ceca, however, the operation was successful in preventing digesta flow into the ceca. Complete separation of the prox-imal end of the ceca from the ICCJ was apparent in all subjects.

Sectioned surfaces of the detached ceca and of the remaining 1.0-cm cecal stumps healed normally, but there were some cases of regrowth of cecal stumps. One stump of a bird killed at 9 wk postsurgery was 2.5 cm long, and the two stumps of a bird killed after 12 wk had grown to 3.5 and 5.5 cm in length, respectively. These stumps did not appear to contain any fermentative residue,

FIGURE 2. Left. Intact distal ileum, rectum, cloaca, and ceca from a sham-operated bird euthanatized 12 wk postsurgery (length = 34.0 cm; diameter = 1.0 cm). Right. A detached cecum from one of the experimental birds euthanatized 12 wk postsurgery (length = 55.0 cm; diameter = 4.0 cm). Bar length = 5.0 cm. I = ileum; R = rectum; C = cecum; and dC = distal end of cecum.

but small amounts of green liquid, possibly bile, were present. Cecal stump growth also occurred in birds with ligated ceca. One b i r d e x a m i n e d after 6 w k h a d a 2.0-cm stump, another after 9 wk had a 4.8-cm stump, and the stumps of one bird examined after 12 wk had increased to 3.0 and 5.2 cm in length, respectively.

Post-mortem examinations at 9 and 12 wk revealed that two of the four birds with detached ceca and two of the four birds with ligated ceca were enlarged. In one subject with ligated ceca examined at 12 wk, the cecum was completely separated from the ligature and sealed off from the ICCJ. This cecum was exceptional in that it had increased in size to approximately 55.0 cm long and 4.0 cm in diameter (Figure 2), 62% longer and 400% wider than ceca in control birds (which averaged 34.0 cm length, 1.0

(5)

cm diameter). This cecum had vascular connections to the ileum throughout the ileal-cecal ligament, and was embedded in adipose tissue. This bird did not show any signs of depressed appetite or activity relative to the other turkeys. The enlarged cecum was not distended by abnormal amounts of gas, but was completely filled with a dark green, pasty, odorous matter, of similar consistency to normal cecal contents b u t of much greater volume.

To determine whether detaching the ceca interfered with normal hindgut motility, normal rectal antiperistaltic movement was positively identified radiographically in one subject given a barium enema. Fre-quently, uric acid was found in the upper colon during post-mortem inspections, again verifying the occurrence of rectal antiperistalsis.

The greatest development of visceral adhesions was found in the birds with detached ceca. At both the 3rd- and 6th-wk post-mortem examinations, large clumps of connective tissue surrounded the distal ileum and ICCJ, nearly blocking the flow of digesta from the ileum to the rectum. Although birds with ligated ceca had fewer adhesions than the birds with detached ceca, they had more than the sham-operated birds. Overall, the amount of adhesive tissue was less at each post-mortem inspection and was nearly nonexis-tent after 12 wk.

DISCUSSION

The Effectiveness of Ligating and Detaching Ceca as Alternatives to Cecectomy

Even though cecal ligations were less stressful physically then cecal detachment, and the onset of recovery and weight gain was more rapid after ligations, ligations were less likely to completely eliminate digesta entrance into the ceca. Growth of cecal stumps was observed in three of the eight birds with ligated ceca and two of the eight birds with detached ceca. The inci-dence and size of cecal stumps varied considerably regardless of treatments, but w a s best developed at the 9th- and 12-wk examinations. Cecal stump growth

has also been reported in cecectomized chickens (Kese, 1976). Because cecal stump growth occurred after detachment as well as after ligation, it is hypothesized that the phenomenon is not an artifact of poor surgical technique (e.g., ligature slippage), but that it may result from the presence of some humoral growth factor (e.g., epider-mal growth factor) released into the circula-tion or into the lumen of the cecal stub.

The evacuation of apparent "cecal" drop-pings (i.e., fermentative products) distin-guishable from rectal droppings by birds with ligated ceca suggests that either a bacterial population was functional in ei-ther the cecal stump or the rectum or that the lumen between one or both of the ligated ceca was still patent. The volume of the enlarged cecal stumps was in all cases much less than the original cecal volume, but the volume of the "cecal" droppings was visibly greater than the capacity of the cecal stumps. If fermentation was occurring in the cecal stumps, it would probably be less complete due to reduction of time for microbial activity and thus the fermenta-tion products would look less like typical cecal droppings. This may explain why the "cecal" droppings were less homogeneous and slightly lighter in color than cecal droppings from sham-operated and control birds. It is unlikely, however, that the cecal stumps were source of all of these fermenta-tive products because the stumps were also observed with detached ceca, but none of these birds evacuated "cecal" droppings. Thus, some of the "cecal" droppings may have been derived from microbial activity occurring in the rectum.

The watery excreta that were observed in the birds with effectively ligated and detached ceca may indicate the loss of cecal water absorption capacity when refluxed urine can no longer gain entrance into the ceca (Lai and Duke, 1978; Anderson and Braun, 1984; Chaplin, 1989). In birds with incompletely ligated ceca, excreta did not appear to be as fluid as in birds with detached ceca and those with effective ligations. The high moisture content of the excreta may also partly be a result of an osmotic gradient created by an increase in solute concentration in the rectum, because solutes could not be further digested and absorbed in the ceca.

(6)

The Disadvantages of Leaving the Detached or Ligated Ceca in the Abdominal Cavity

In an intact turkey, rectal retrograde flow moves liquids and fine particles in suspen-sion from the rectum into the ceca. Typi-cally, cecal fermentation yields energy-rich volatile fatty acids (VFA) and some amino acids, which can be absorbed by the host or used by the cecal microflora (McBee and West, 1969; Gasaway, 1976; Karasawa, 1989). Although the flow of digesta in and out of the ceca can be prevented by detachment, and somewhat less success-fully (as shown) by ligatures, it has not been confirmed that these techniques render the ceca or cecal microflora completely non-functional. Because the blood supply to the ceca was not interrupted, they did not become necrotic.

The current observations of the increase in size of the ceca and in volume of their contents in many of the ligated or detached ceca with time indicate that some microbial activity must have continued. It is unlikely that mere was very much fermentable substrate in the ceca, as the turkeys were fasted for 12 h prior to surgery and no more substrate could have entered the ceca after surgery. With the normal circulation still serving the ceca, it is possible that nutrients could have entered the cecal lumen from the blood. Moreover, the cecal bacteria may be able to get their food sources, protein in particular, from secretions from the mucosal epithelium of the ceca, the defolia-tion of the villi of the mucosal surface, and the population turnover of the bacteria themselves. The current study did not analyze the contents of the enlarged ceca at the time of the necropsy, but in an intact cecum, the dark, green pasty contents contains free monosaccharides, VFA, and uric acid (Savory and Knox, 1991).

The current findings give rise to several questions. Do detached ceca still receive nutrients via the bloodstream? Are any of the cecal contents fermentable? If so, could the products be transported back into the blood stream, e.g., passive diffusion of VFA (Sudo and Duke, 1980) or active transport of nutrients (Ferrer et al, 1986; Vinardell et al, 1986), just as they are in intact ceca?

To the authors' knowledge, comparable cecal enlargement has been observed in

turkeys only by Durant (1929) during a post-mortem examination 6 mo after the ceca were ligated. Durant (1929) suggested that a combination of cecal contents and exfoliation of the mucosal surface of the ceca produced an engorgement due to gas that stimulated growth and enlargement of the ceca. In contrast, the present authors observed ceca completely filled with a thick, pasty material and with no evidence of distension by gas. The walls of distended ceca, however, appeared thinner than those of normal ceca, suggesting that the former were enlarged more by distension than by growth. In time, the cecal walls might have ruptured, releasing cecal contents into the peritoneal cavity. The distension may result from impaired absorptive capacity in detached and ligated ceca: because the proximal region of the ceca is known to be the most effective absorptive surface of the organ (Ferrer et al, 1986; Vinardell et al, 1986) and it is the area that is damaged by cecal ligation or detachment.

There remains the question of why cecal enlargement and cecal stump growth didn't occur following all the ligations and detach-ments in the current study, and why the phenomenon has not been reported more often by other authors. Is the frequency of occurrence rare? Are post-mortem investi-gations seldom performed? Or, are post-mortem results simply not reported? Of 20 reports involving cecectomies, only 1 indi-cated that regrowth of the cecal stumps had occurred (Kese, 1976). Although three of the four studies using the ligation technique indicated that post-mortem exams were done, only Durant (1929) reported that cecal enlargement had occurred. No other results of post-mortem exams were reported. The present authors believe that post-mortem inspections are necessary 1) to determine the effectiveness of cecal ligations or detachments; 2) to determine whether ceca left in the abdominal cavity were enlarged; and 3) to assess the presence of regenerating cecal stumps following total cecectomy. The present study calls into question the conclu-sions of cecectomy studies in which post-mortem examinations were not performed.

ACKNOWLEDGMENTS

The authors thank Matt Peterson of Olsen Farms, Wilmar, MN 56201, for

(7)

providing Nicholas turkeys. This research was partially supported by Minnesota Agricultural Experiment Station Project Number 1543-392-3210.

REFERENCES

Anderson, G. L., and E. L. Braun, 1984. Ceca of desert quail: importance in modifying the urine. Comp. Biochem. Physiol. 78A:91-94.

Chaplin, S., 1989. Effect of cecectomy on water and nutrient absorption of birds. J. Exp. Zool. Suppl. 3:81-86.

Duke, G. E., J. E. Bird, K. A. Daniels, and R. W. Bertroy, 1981. Food metabolizability and water balance in intact and cecectomized Great-horned Owls. Compl. Biochem. Physiol. 68A: 237-240.

Duke, G. E., E. Eccleston, S. Kirkwood, C. Louis, and H. Bedbury, 1984. Cellulose digestion by domes-tic turkeys fed low or high fiber diets. J. Nutr. 114:95-102.

Durant, A. J., 1929. The control of blackhead in turkeys by cecal abligation. No. Am. Vet. 2: 52-55.

Dziuk, H. E., A. R. Scheiber, and G. E. Duke, 1970. Cecectomized turkeys—physiological character-istics and susceptibility to bluecomb. Poultry Sci. 49:244-247.

Ferrer, R., J. M. Planas, and M. Moreto, 1986. Age related changes in ct-methyl-D-glucoside ac-cumulation by cecal and jejunal chicken entero-cytes. Int. Res. Commun. Syst. Med. Sci. 14: 78-79.

Gasaway, W. C, 1976. Volatile fatty acid and metabolizable energy derived from cecal fer-mentation in the willow Ptarmigan. Comp. Biochem. Physiol. 53A:115-121.

Green, S., 1988. Effect of dietary fiber and caecectomy on the excretion of endogenous amino acids from adult cockerels. Br. Poult. Sci. 29:419-429. Hughes, M. R., T. Zentneo-Savih, and D. Kojwarg,

1991. Effects of saline acclimation and cecal ligation on body water and water flux in male and female Pekin ducks. Can. J. Zool. 69: 771-775.

Karasawa, Y., 1989. Ammonia production from uric acid, urea, and amino acids and its absorption from the ceca of the cockerel. J. Exp. Zool. Suppl. 3:75-80.

Kese, A. G., 1976. Some observations of studies

involving avian cecectomy. Poultry Sci. 55(Suppl. l):49.(Abstr.)

Kese, A. G., and B. L. March, 1975. The role of avian ceca in energy and protein metabolism. Poultry Sci. 54:1781.(Abstr.)

Kessler, J. W., T. H. Nguyen, and O. P. Thunas, 1981. The amino acid excretion values and intact and cecectomized negative control roosters used for determining metabolic plus endogenous urinary loss. Poultry Sci. 60:1576-1577.

Lai, H. C, and G. E. Duke, 1978. Colonic motility in domestic turkeys. Am. J. Dig. Dis. 23(8):673-681. McBee, R. H., 1977. Fermentation in the hindgut. Pages 185-250 in: Microbial Ecology of the Gut. R.T.J. Clark and T. Bauchap, ed. Academic Press, New York, NY.

McBee, R. H., and C. G. West, 1969. Cecal fermenta-tion in the Willow Ptarmigan. Condor 71:54-58. Parsons, C. M., 1984. Influence of caecectomy and source of dietary fiber or starch on excretion of endogenous amino acids by laying hens. Br. J. Nutr. 51:541-548.

Payne, W. L., R. R. Kifer, D. G. Snyder, and G. F. Combs, 1971. Studies on protein digestion in the chicken. 1. Investigation of apparent amino acid digestibility of fish meal protein using cecec-tomized, adult male chickens. Poultry Sci. 50: 143-150.

Savory, C, and A. Knox, 1991. Chemical composition of caecal contents in the fowl in relation to dietary fibre and time of day. Comp. Biochem. Physiol. 100A(3):739-743.

Schlotthauer, C. F., H. E. Essex, and F. C. Mann, 1933. Cecal occlusion in the prevention of blackhead (Enterohepatitis) in turkeys. J. Am. Vet. Med. Assoc. 36(2):218-228.

Sudo, S., and G. Duke, 1980. Kinetics of absorption of VFAs from the ceca of domestic turkeys. Comp. Biochem. Physiol. 67A:231-237.

Thompson, D. C, and D. A. Boag, 1975. Role of the caeca in Japanese quail energetics. Can. J. Zool. 53:166-170.

Tortuero, F., A. Brenes, and J. Rioperez, 1975. The influence of intestinal (ceca) flora on serum and egg yolk levels in laying hens. Poultry Sci. 54: 1935-1938.

Vinardell, C. C, M. T. Lopera, and M. Moreto, 1986. Absorption of 3-oxymethyl-D-glucose by chicken cecum and jejunum in vivo. Comp. Biochem. Physiol. -85A(1):171-173.

Zar, J. H., 1974. Biostatistical Analysis. Prentice Hall, Englewood Cliffs, NJ.