Abstract
The maned wolf (Chrysocyon brachyurus) is the largest canid native to South America. This endangered species is omnivorous, consuming 49% animal matter and 51% plant matter in the wild.4 Although this species has been kept in captivity in the US since the 1970s, managing ex situ populations has been challenging because captive animals often have suboptimal health, including loose stool, inflammatory bowel disease (IBD), unthriftiness (hair loss, poor coat condition), low reproduction, and cystinuria. It is suspected that nutrition plays a significant role in these problems because it is challenging to provide a captive diet that closely resembles what maned wolves eat in the wild. Preventative medicine (vaccination, flea and tick prevention) and babesiosis are additional medical issues in captive maned wolves that are currently under investigation.
Over the past ten years, investigating nutrition has been a priority of the Maned Wolf Species Survival Plan© (MWSSP). In 2011 the MWSSP collaborated with Mazuri® (Purina Animal Nutrition, 100 Danforth Drive, Gray Summit, MO 63039-1128, USA) to formulate a kibble to promote formed stools and prevent cystinuria. Although there has been a reduction in urethral obstruction since widespread implementation of this diet, other problems have been recognized, including poor palatability, gastric dilatation-volvulus (GDV), loss of muscle mass, and infanticide. After several maned wolves died from GDV while being fed the Mazuri® diet, the kibble size was increased, as small kibble size is a risk factor for GDV in domestic dogs.2,6
Serum nutritional assays on captive maned wolves compared values prior to and one year after the transition to the Mazuri® maned wolf diet. Several animals were noted to have slightly low iron and taurine prior to feeding this commercial maned wolf diet, with values increasing after transitioning to the new diet. Results show that there was no significant difference in other serum vitamins or minerals. Future studies will compare captive and wild maned wolf serum vitamin and mineral parameters.
Pending results of a new diet survey conducted over the past year, current diet recommendations include:
- For animals that are currently on the Mazuri® maned wolf diet and are not exhibiting health concerns, it is recommended to continue feeding this diet, along with mixed produce and whole prey items
- For animals with lean body conditions and/or breeding animals and those raising pups, an increase in whole prey items by 10–15% of the diet is recommended to provide additional protein
- For animals with active “disease” or inflammatory bowel disease-like clinical signs, the MWSSP recommends working with the nutrition advisor to formulate a homemade diet with limited ingredients (protein, starch, vitamins/minerals)
A recent study investigated a genetic component to IBD in maned wolves. In both the domestic dog and human, single nucleotide polymorphisms (SNP) in the Toll-like receptor (TLR) genes have been associated with IBD. A recent study characterized polymorphisms within two selected regions of the TLR5 gene in both wild (n=7) and captive maned wolves (n=24). Two polymorphic positions, both of which affect protein function, have been identified in the maned wolf. However, SNPs associated with domestic dog IBD (G727A, C805T and C2549T) were not polymorphic in maned wolves. Interestingly, maned wolves lacked the protective T allele in C805T and C2549T, suggesting that this species may be genetically predisposed to IBD.1
In addition to nutritional concerns, there have been nine cases of confirmed babesiosis in captive maned wolves since 2004, five of which were fatal. Babesia is a tick borne-disease but also may be transmitted through bite wounds or possibly transplacentally. One case documented raccoon-maned wolf interaction prior to the maned wolf dying from babesiosis. The raccoon tested positive for the same strain of Babesia.3,5 Current recommendations for prevention of babesiosis include tick control and limiting raccoon-maned wolf interaction, where possible. There have been several babesiosis cases that were successfully treated, but quick intervention is paramount.3
Preventative medicine, such as the use of domestic animal vaccines and flea and tick prevention, is another area of ongoing research with captive maned wolves.
Neoplasia and gastrointestinal disease have been found on post-mortem examination of captive maned wolves.
The MWSSP is in the process of updating the maned wolf husbandry manual and would like to promote the cross-sharing of information with international colleagues.
Acknowledgments
The authors would like to thank all institutions holding maned wolves and Mazuri® for their generous financial and technical support.
Literature Cited
1. Henson L, Songsasen N, Waddell W, Wolf K, Freeman E, Emmons L, Gonzalez S, Maldonado J. Characterization of genetic variation and basis of inflammatory bowel disease in the Toll-like receptor 5 gene of maned and red wolves. Endangered Species Research. 2017;32:135–144.
2. Hinton JD, Padilla LR, Joyner PH, Schnellbacher R, Walsh TF, Aitken-Palmer C. Gastric dilatation volvulus in adult maned wolves (Chrysocyon brachyurus). J Zoo Wildl Med. 2017;48(2):476–483.
3. Lipanovich E, Haefele HJ, Birkenheuer A, Thomas B, Hammond E, Rodden M, Songsasen N. Babesiosis in captive North American populations of maned wolves (Chrysocyon brachyurus). Proc Am Assoc Zoo Vet; 2014. p. 105–106.
4. Motta-Junior JC, Talamoni SA, Lombardi JA, Simokomaki K. Diet of the maned wolf, Chrysocyon brachyurus, in central Brazil. J Zool, London. 1996;240:277–284.
5. Phair KA, Carpenter JW, Smee N, Myers CB, Pohlman LM. Severe anemia caused by babesiosis in a maned wolf (Chrysocyon brachyurus). J Zoo Wildl Med. 2012;43(1):162–167.
6. Theyse LFH, van de Brom WE, van Sluijs FJ. Small size of food particles and age as risk factors for gastric dilatation and volvulus in great danes. Vet Rec. 1998;143;48–40.