Free Standard AU & NZ Shipping For All Book Orders Over $80!
Register      Login
Wildlife Research Wildlife Research Society
Ecology, management and conservation in natural and modified habitats
Shopping Cart: ( empty )
You are here: Home > Journals > WR > WR07072 > Fulltext
RESEARCH ARTICLE
Contents Vol 35(7)

Additional toxins for feral pig (Sus scrofa) control: identifying and testing Achilles’ heels

Brendan D. Cowled A B , Peter Elsworth C and Steven J. Lapidge A D
+ Author Affiliations
- Author Affiliations

A Invasive Animals Cooperative Research Centre, University of Canberra, ACT 2601, Australia.

B The University of Sydney, School of Veterinary Science, Sydney, NSW 2001, Australia.

C Biosecurity Queensland, Robert Wicks Pest Animal Research Centre, Inglewood, Qld 4387, Australia.

D Corresponding author. Email: steven.lapidge@invasiveanimals.com

Wildlife Research 35(7) 651-662 https://doi.org/10.1071/WR07072
Submitted: 22 June 2007  Accepted: 28 April 2008   Published: 17 November 2008

Abstract

A literature review was conducted in order to identify unique weaknesses in the physiology or metabolism of pigs that could be targeted with specific chemicals (i.e. an ‘Achilles’ heel’ search). A promising weakness identified was the species’ susceptibility to methaemoglobin-forming compounds, most likely related to their uniquely low levels of methaemoglobin reductase. Further examination revealed that sodium nitrite is a cost-effective, readily available methaemoglobin-forming compound that is highly toxic to domestic pigs, which has caused numerous accidental poisonings. Pen trials on pigs showed that sodium nitrite delivered by gavage (>90 mg kg−1) and freely consumed in bait (>400 mg kg−1) caused rapid and lethal rises in methaemoglobin. Sodium nitrite appeared to be more humane than currently used toxins, with deaths following bait consumption being considerably quicker and with fewer symptoms (within 80 min of clinical signs beginning; clinical signs including infrequent vomiting, lethargy, ataxia and dyspnoea). The review also identified a second deficiency in the metabolism of pigs, namely high sensitivity to selective inhibition of cytochrome P450 liver enzymes. This leads to potentially lethal interactions between various drugs, such as two antibiotics, monensin and tiamulin. A pen trial confirmed that the antibiotic combination in a single gavage dose was reliably and rapidly lethal to pigs. However, its utility as a pig toxin is low, because it was unpalatable to pigs when delivered in bait and appeared to cause pain and suffering (leading to the early termination of pen trials). The findings presented here demonstrate the potential of sodium nitrite as an additional feral pig toxin.


Acknowledgements

We thank Matt Gentle and Lee Allen for assistance with the pen studies, David Dall and Ricky Spencer for assistance with methaemoglobin analysis, and IDEXX laboratories for histopathology and biochemical analysis. The trials discussed were approved by the Queensland Natural Resources and Water (now Biosecurity Queensland) Pest Animal Ethics Committee (PAEC 050701 and 060301). The trials were financially supported by the Invasive Animals Cooperative Research Centre, with further support from Meat and Livestock Australia Ltd in the form of a postgraduate stipend for the senior author. We thank Tony Peacock and Tony English for reviewing this manuscript, as well as Pete Savarie and two anonymous referees for their considerable input. An international patent directed to baits comprising sodium nitrite and the use of sodium nitrite in a bait delivered to feral omnivores has been published (PCT/AU2008/000260; Feral Omnivore Bait and uses thereof).


References

Agar, N. S. , and Harley, D. (1972). Erythrocytic methaemoglobin reductases of various animal species. Experientia 28, 1248–1249.
| Crossref | GoogleScholarGoogle Scholar | CAS | PubMed | Bartik M. , and Piskac A. (1981). ‘Veterinary Toxicology.’ (Elsevier: New York.)

Beutler, E. , and Mikus, B. J. (1961). The effect of sodium nitrite and para-aminopropriophenone abministration on blood methemoglobin levels and red blood cell survival. Blood 18, 455–467.
|  CAS | PubMed | Buddle R. J. (2000). Differential diagnosis of diseases of pigs. The University of Sydney Post Graduate Foundation in Veterinary Science, University of Sydney, Sydney.

Calabrese, E. J. , Gareffl, J. A. , and Stanek, E. J. (1992). The effects of joint exposures to environmental oxidants on methaemoglobin formation: Copper/nitrite and copper/chlorite. Journal of Environmental Science and Health. Part A, Environmental Science and Engineering & Toxic and Hazardous Substance Control 27, 629–642.
Choquenot D. , McIlroy J. , and Korn T. (1996). ‘Managing Vertebrate Pests: Feral Pigs.’ (Ed. M. Bomford.) (Bureau of Resource Sciences & Australian Government Publishing Service: Canberra.)

Clarke, E. G. C. (1976). Species differences in toxicology. The Veterinary Record 98, 215–218.
|  CAS | PubMed | Cowled B. , and O’Connor C. (2004). A project that investigates current options for managing feral pigs in Australia and assesses the need for the development of more effective and humane techniques and strategies – Stage 3 Report. Pest Animal Control Cooperative Research Centre, Canberra, Australia. Available from http://www.environment.gov.au/biodiversity/invasive/publications/feral-pig/stage3.html

Cowled, B. D. , Gifford, E. , Smith, M. , Staples, L. , and Lapidge, S. J. (2006a). Efficacy of manufactured PIGOUT® baits for localised control of feral pigs in the semiarid Queensland rangelands. Wildlife Research 33, 427–437.
| Crossref | GoogleScholarGoogle Scholar | Littin K. E. , and O’Connor C. E. (2002). Guidelines for assessing the welfare impacts of vertebrate poisons. Landcare Research Contract Report: LC0203/006. Landcare Research, Lincoln, New Zealand.

London, W. T. , Henderson, W. , and Cross, R. F. (1967). An attempt to produce chronic nitrite toxicosis in swine. Journal of the American Veterinary Medical Association 150, 398–402.
|  CAS | PubMed | Mitchell J. (2003). Alternative baiting strategies for feral pig control and disease monitoring, final report to the Bureau of Rural Sciences National Feral Animal Control Program. Unpublished report.

Nebbia, C. , Ceppa, L. , Dacasto, M. , Nachtmann, C. , and Carletti, M. (2001). Oxidative monensin metabolism and cytochrome P450 3A content and functions in liver microsomes from horses, pigs, broiler chicks, cattle and rats. Journal of Veterinary Pharmacology and Therapeutics 24, 399–403.
| Crossref | GoogleScholarGoogle Scholar | CAS | PubMed | Bartik M. , and Piskac A. (1981). ‘Veterinary Toxicology.’ (Elsevier: Amsterdam.)

Plumlee, K. H. , Johnson, B. , and Galey, F. D. (1995). Acute salinomycin toxicosis of pigs. Journal of Veterinary Diagnostic Investigation 7, 419–420.
|  CAS | PubMed | Prescott J. F. (2000). Miscellaneous antibiotics: ionophores, nitrofurans, nitroimidazoles, rifamycins and others. In ‘Antimicrobial Therapy in Veterinary Medicine’. 3rd edn. (Eds J. F. Prescott, J. D. Baggot and R. D. Walker.) pp. 339–366. (Iowa State University Press: Ames, IA.)

Radostits O. M. , Gay C. C. , Blood D. C. , and Hinchcliff K. W. (2000). ‘Veterinary Medicine: A Textbook of the Diseases of Cattle, Sheep, Pigs, Goats and Horses.’ 9th edn. (W.B. Saunders Co.: Philadelphia, PA.)

Ratz, V. , Laczay, P. , Mora, Z. , Csiko, G. , Monostori, K. , Vereczkey, L. , Lehel, J. , and Semjen, G. (1997). Recent studies on the effects of tiamulin and monensin on hepatic cytochrome P450 activities in chickens and turkeys. Journal of Veterinary Pharmacology and Therapeutics 20, 415–418.
| Crossref | GoogleScholarGoogle Scholar | CAS | PubMed | Sharp T. , and Saunders G. (2004). Model code of practice for the humane control of feral pigs. NSW Department of Primary Industries, Orange.

Shimada, T. , Mimura, M. , Inoue, K. , Nakamura, S. , Oda, H. , Ohmori, S. , and Yamazaki, H. (1997). Cytochrome P450-dependent drug oxidation activities in liver microsomes of various animal species including rats, guinea pigs, dogs, monkeys, and humans. Archives of Toxicology 71, 401–408.
| Crossref | GoogleScholarGoogle Scholar | CAS | PubMed | StatsDirect Ltd (2005). StatsDirect Statistical Software. Accessed online 21 June 2007 at http://www.statsdirect.com England: StatsDirect Ltd. 2005.

Twigg, E. L. , Lowe, T. , Martin, G. , and Everett, M. (2005). Feral pigs in north-western Australia: basic biology, bait consumption, and the efficacy of 1080 baits. Wildlife Research 32, 281–296.
| Crossref | GoogleScholarGoogle Scholar | Wanntorp H. , and Swahn O. (1953). The toxicity of whey for swine in conjunction with bacterial reduction of nitrate to nitrite. In ‘Proceedings of the XVth International Veterinary Congress, Stockholm. Part 1’. pp. 496–501.

Wickstrom, M. L. , and Eason, C. T. (1999). Literature search for mustelid-specific toxicants. Science for Conservation 127, 57–65.
Williams A. T. (1948). Sodium fluoracetate poisoning. Hospital Corps Quarterly. United States Government Printing Office, Navy Department, Washington, DC.

Winks, W. R. , Sutherland, A. K. , and Salisbury, R. M. (1950). Nitrite poisoning of pigs. The Queensland Journal of Agricultural Science 7, 1–14.
|  CAS |