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An improved ileal cannula for adult cockerels
Research in Veterinary Science /986, 4/, 283-284
An improved ileal cannula for adult cockerels M. P. GURNSEY, Applied Biochemistry Division, Department of Scientific and Industrial Research, Private Bag, Palmerston North, New Zealand, D. C. JOHNS, Poultry Research Centre, Massey University, Palmerston, New Zealand
The design of a t-piece ileal cannula and collecting device suitable for long term implantation in adult cockerels, is described. An inner retaining plate sutured to the serosal surface of the ileum prevents expulsion of the cannula while an outer retaining plate prevents the cannula from moving into the abdominal cavity. The cannulae, which were machined from pvc rod, were implanted in 11 cockerels, 10 of which survived in good health for 12 months. Reasons for the failures with earlier designs of cannulae are discussed. ILEAL cannulation has been investigated by a number of workers (Raharjo and Farrell 1981, 1984, Crissey and Thomas 1983, Thomas and Crissey 1983) as a means of determining amino acid digestibility of feedstuffs. The technique has the advantage of avoiding any influences of microbial activity in the caecae upon the digesta. Unfortunately, little detailed information has been published concerning the surgical procedure, design of the cannula or, more importantly, the success rate of the technique. Simple t-piece cannulae made either of glass (Summers et al 1982, Raharjo and Farrell 1984), nylon or teflon (Summers et al 1982) have been investigated. D. J. Farrell (personal communication) indicated that the main problem with their glass cannulae was the ease with which they could pull out of the body wall. Crissey and .Thomas (1983) examined the use of glass, plexiglass, teflon and polypropylene cannulae. They favoured the use of polypropylene and again pointed out the high (50 per cent) rate of expulsion of simple t-piece cannulae. Gurnsey et al (1985) reported the use of modified I ml disposable syringes and described in detail the surgical implantation technique. This procedure had a long term (nine months) success rate of 66 per cent. The present communication describes a new cannula and modified surgical technique which improves the stability and hence retention of the cannula. Reasons for the failures with earlier techniques are discussed. The cannula and collection device are shown in Fig I. The cannula, cap and plug (i) and adaptor for the collection device (ii) were machined from solid pvc rod. Each cannula was 36 mm long with the threaded portion of the barrel being 16 mm in length. Internal and external diameters of the barrel were 5 and 8 mrn, respectively, while the long axis of the foot of the cannula was 18 mm. Important elements in the design are the internal (A) and external retaining plates (B). The internal retaining plate was 18 mm in diameter, I· 5 mm thick and had four I· 5 mm holes for suturing. The external retaining plate was 18 mm in diameter, 2 mm thick and its central' hole was threaded in such a way that it engaged the threaded portion of the barrel of the t-piece cannula.
283
Cannulae were implanted in II crossbred cockerels aged 25 weeks or older in a manner similar to that described by Gurnsey et al (1985). The surgical technique was modified slightly in two respects: the inner retaining plate (A) was sutured to the serosal surface of the ileum but not secured to the abdominal air sac; the air sac, peritoneum and muscle layers were closed separately and not secured to each other. Following skin closure, the outer retaining plate (B) was screwed into place thus obviating the need for a rubber elastrator ring as a retaining device. When samples of ileal digesta were required, the cannula cap and its attached plug were removed and replaced with the collection device (ii) (Fig I). This consisted of an adaptor (C), which screws on to the threaded barrel of the cannula, and a collection vessel (D). The adaptor was tapered slightly at one end to fit snugly into a 3· 5 ml polystyrene, conical, autoanalyser cup. Further, the adaptor has three longitudinal grooves round the outer edge to permit expulsion of air from the autoanalyser cup as digesta flows in. Following surgical implantation of ileal cannulae, 10 of the II cockerels survived in good health for 12 months while the II th bird died after six months. This bird had been in good health before its demise and as there were no signs of bowel blockage or infection at the surgical site, it was presumed that the death of the bird was not related to the surgical procedure. The main complication of ileal cannulation reported by
(i)
(ij)
FIG 1: Ileal cannula and collection device. (i) Cannula. cap and plug, (A) internal retaining plate, (8) external retaining plate, IC) adaptor, (D) autoanalyser cup
(i;) collection device.
284
M. P. Gurnsey, D. C. Johns
other workers (Crissey and Thomas 1983, D. J. Farrell, personal communication) is the high rate of expulsion of cannulae from the ileum. This high failure rate is probably the result of relying on a simple purse string suture to retain the foot of the cannula within the ileum. To overcome this problem Gurnsey et al (1985) used a retaining plate which was passed over the barrel of the cannula and sutured in two places to the serosal surface of the ileum. This simple precaution has been most successful in preventing the foot of the cannula from pulling out of the ileum. A total of 27 cockerels have now been cannulated and only one case of expulsion of the cannula has been recorded (Gurnsey et al 1985), the result of failure of sutures securing the retaining plate. The major problem reported by Gurnsey et al (1985) was blockage of the bowel leading to the deaths of several birds. This occurred in one third of the operated birds about three weeks after surgery. This complication has not occurred since the newly designed cannulae, which incorporate an outer retaining plate, have been used. It therefore seems likely that the rubber elastrator ring previously employed, allowed sufficient movement of the cannula into the ileum to cause partial and, in some birds, complete blockage of the ileum. The presence of the outer securing plate, which in the current cannula design is screwed into place, does not allow movement of the cannula into the abdominal cavity. Another problem of the earlier cannula design was the durability of cannulae made from disposable plastic syringes. After a few months the rubber plungers deteriorated and were often lost into the gut lumen of the bird when removing the plunger before sampling. This necessitated a constant supply of replacement parts. After many months it was found that the plastic syringe barrels were prone to splitting. It became clear that disposable plastic syringes, while they were suitable for short term implantation, were unsuitable for long term (up to 12 months) use. For this reason it was decided that cannulae for
long term implantation should be specially designed for the purpose and machined from durable materials. pvc has been found most suitable for this use: it is easily machined, it is strong without being brittle and it does not cause undue tissue reaction. The sample collection device, which was part of the overall design concept, has worked well. It is easily used and makes sample collection a simple matter. It has been noted, however, that in some birds flow of digesta through the cannula was rather slow. Consideration might, therefore, be given to slight modifications of the present design, eg, shortening the cannula and, or, slight increase in internal diameter. Acknowledgements The authors wish to thank Mr P. C. Van Dingenen for his assistance in manufacturing the cannulae and Mr R. G. Mildon for the technical drawing of the cannula and collection device. References CRISSEY, S. D. & THOMAS, O. P. (1983) Poultry Science 62, 1406 GURNSEY, M. P., JAMES, K. A. C. & JOHNS, D. C. (1985) Research in Veterinary Science 39,390-391 RAHARJO, Y. & FARRELL, D. J. (1981) Recent Advances in Animal Nutrition in Australia 1981. Ed D. J. Farrell. Armidale, University of New England Publishing Unit. pp 197-218 RAHARJO, Y. & FARRELL, D. J. (1984) Animal Feed Science and Technology 12, 29-45 SUMMERS, D. J, BERZINS, R. & ROBBLEE, A. R. (1982) Poultry Science 6t, 1551-1552 THOMAS, O. P. & CRISSEY, S. D. (1983) Proceedings of the 4th European Symposium on Poultry Nutrition 1983. Ed M. Larbier. pp 82-85
Received for publication May 28, 1986 Accepted June II, 1986
An improved ileal cannula for adult cockerels M. P. GURNSEY, Applied Biochemistry Division, Department of Scientific and Industrial Research, Private Bag, Palmerston North, New Zealand, D. C. JOHNS, Poultry Research Centre, Massey University, Palmerston, New Zealand
The design of a t-piece ileal cannula and collecting device suitable for long term implantation in adult cockerels, is described. An inner retaining plate sutured to the serosal surface of the ileum prevents expulsion of the cannula while an outer retaining plate prevents the cannula from moving into the abdominal cavity. The cannulae, which were machined from pvc rod, were implanted in 11 cockerels, 10 of which survived in good health for 12 months. Reasons for the failures with earlier designs of cannulae are discussed. ILEAL cannulation has been investigated by a number of workers (Raharjo and Farrell 1981, 1984, Crissey and Thomas 1983, Thomas and Crissey 1983) as a means of determining amino acid digestibility of feedstuffs. The technique has the advantage of avoiding any influences of microbial activity in the caecae upon the digesta. Unfortunately, little detailed information has been published concerning the surgical procedure, design of the cannula or, more importantly, the success rate of the technique. Simple t-piece cannulae made either of glass (Summers et al 1982, Raharjo and Farrell 1984), nylon or teflon (Summers et al 1982) have been investigated. D. J. Farrell (personal communication) indicated that the main problem with their glass cannulae was the ease with which they could pull out of the body wall. Crissey and .Thomas (1983) examined the use of glass, plexiglass, teflon and polypropylene cannulae. They favoured the use of polypropylene and again pointed out the high (50 per cent) rate of expulsion of simple t-piece cannulae. Gurnsey et al (1985) reported the use of modified I ml disposable syringes and described in detail the surgical implantation technique. This procedure had a long term (nine months) success rate of 66 per cent. The present communication describes a new cannula and modified surgical technique which improves the stability and hence retention of the cannula. Reasons for the failures with earlier techniques are discussed. The cannula and collection device are shown in Fig I. The cannula, cap and plug (i) and adaptor for the collection device (ii) were machined from solid pvc rod. Each cannula was 36 mm long with the threaded portion of the barrel being 16 mm in length. Internal and external diameters of the barrel were 5 and 8 mrn, respectively, while the long axis of the foot of the cannula was 18 mm. Important elements in the design are the internal (A) and external retaining plates (B). The internal retaining plate was 18 mm in diameter, I· 5 mm thick and had four I· 5 mm holes for suturing. The external retaining plate was 18 mm in diameter, 2 mm thick and its central' hole was threaded in such a way that it engaged the threaded portion of the barrel of the t-piece cannula.
283
Cannulae were implanted in II crossbred cockerels aged 25 weeks or older in a manner similar to that described by Gurnsey et al (1985). The surgical technique was modified slightly in two respects: the inner retaining plate (A) was sutured to the serosal surface of the ileum but not secured to the abdominal air sac; the air sac, peritoneum and muscle layers were closed separately and not secured to each other. Following skin closure, the outer retaining plate (B) was screwed into place thus obviating the need for a rubber elastrator ring as a retaining device. When samples of ileal digesta were required, the cannula cap and its attached plug were removed and replaced with the collection device (ii) (Fig I). This consisted of an adaptor (C), which screws on to the threaded barrel of the cannula, and a collection vessel (D). The adaptor was tapered slightly at one end to fit snugly into a 3· 5 ml polystyrene, conical, autoanalyser cup. Further, the adaptor has three longitudinal grooves round the outer edge to permit expulsion of air from the autoanalyser cup as digesta flows in. Following surgical implantation of ileal cannulae, 10 of the II cockerels survived in good health for 12 months while the II th bird died after six months. This bird had been in good health before its demise and as there were no signs of bowel blockage or infection at the surgical site, it was presumed that the death of the bird was not related to the surgical procedure. The main complication of ileal cannulation reported by
(i)
(ij)
FIG 1: Ileal cannula and collection device. (i) Cannula. cap and plug, (A) internal retaining plate, (8) external retaining plate, IC) adaptor, (D) autoanalyser cup
(i;) collection device.
284
M. P. Gurnsey, D. C. Johns
other workers (Crissey and Thomas 1983, D. J. Farrell, personal communication) is the high rate of expulsion of cannulae from the ileum. This high failure rate is probably the result of relying on a simple purse string suture to retain the foot of the cannula within the ileum. To overcome this problem Gurnsey et al (1985) used a retaining plate which was passed over the barrel of the cannula and sutured in two places to the serosal surface of the ileum. This simple precaution has been most successful in preventing the foot of the cannula from pulling out of the ileum. A total of 27 cockerels have now been cannulated and only one case of expulsion of the cannula has been recorded (Gurnsey et al 1985), the result of failure of sutures securing the retaining plate. The major problem reported by Gurnsey et al (1985) was blockage of the bowel leading to the deaths of several birds. This occurred in one third of the operated birds about three weeks after surgery. This complication has not occurred since the newly designed cannulae, which incorporate an outer retaining plate, have been used. It therefore seems likely that the rubber elastrator ring previously employed, allowed sufficient movement of the cannula into the ileum to cause partial and, in some birds, complete blockage of the ileum. The presence of the outer securing plate, which in the current cannula design is screwed into place, does not allow movement of the cannula into the abdominal cavity. Another problem of the earlier cannula design was the durability of cannulae made from disposable plastic syringes. After a few months the rubber plungers deteriorated and were often lost into the gut lumen of the bird when removing the plunger before sampling. This necessitated a constant supply of replacement parts. After many months it was found that the plastic syringe barrels were prone to splitting. It became clear that disposable plastic syringes, while they were suitable for short term implantation, were unsuitable for long term (up to 12 months) use. For this reason it was decided that cannulae for
long term implantation should be specially designed for the purpose and machined from durable materials. pvc has been found most suitable for this use: it is easily machined, it is strong without being brittle and it does not cause undue tissue reaction. The sample collection device, which was part of the overall design concept, has worked well. It is easily used and makes sample collection a simple matter. It has been noted, however, that in some birds flow of digesta through the cannula was rather slow. Consideration might, therefore, be given to slight modifications of the present design, eg, shortening the cannula and, or, slight increase in internal diameter. Acknowledgements The authors wish to thank Mr P. C. Van Dingenen for his assistance in manufacturing the cannulae and Mr R. G. Mildon for the technical drawing of the cannula and collection device. References CRISSEY, S. D. & THOMAS, O. P. (1983) Poultry Science 62, 1406 GURNSEY, M. P., JAMES, K. A. C. & JOHNS, D. C. (1985) Research in Veterinary Science 39,390-391 RAHARJO, Y. & FARRELL, D. J. (1981) Recent Advances in Animal Nutrition in Australia 1981. Ed D. J. Farrell. Armidale, University of New England Publishing Unit. pp 197-218 RAHARJO, Y. & FARRELL, D. J. (1984) Animal Feed Science and Technology 12, 29-45 SUMMERS, D. J, BERZINS, R. & ROBBLEE, A. R. (1982) Poultry Science 6t, 1551-1552 THOMAS, O. P. & CRISSEY, S. D. (1983) Proceedings of the 4th European Symposium on Poultry Nutrition 1983. Ed M. Larbier. pp 82-85
Received for publication May 28, 1986 Accepted June II, 1986