Comparing the effects of tranquilisation with long-acting neuroleptics on blue wildebeest (Connochaetes taurinus) behaviour and physiology

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Stellenbosch : Stellenbosch University
ENGLISH ABSTRACT: In South Africa, large numbers of game animals are translocated annually. These animals are subjected to a great amount of stress and the use of long-acting neuroleptics (LANs) has become a common practice to minimize animal stress. Long-acting neuroleptics suppress behavioural responses without affecting spinal and other reflexes, and can be administered in such a manner that a single dose results in a therapeutically effective tissue concentration for anywhere between three to seven days. The mammalian stress response consists of a variety of physiological responses, and the study aimed to quantify a number of these responses in blue wildebeest (Connochaetes taurinus). This was done in order to compare the effects of a commonly used LAN, Acuphase® (zuclopenthixol acetate in vegetable oil), with a newly developed LAN, Acunil® (zuclopenthixol acetate in a low-release polymer), in minimizing the stress response of blue wildebeest in captivity. A human biotelemetry belt, Equivital™ EQ02, was modified to fit this species, and the results from a validation study indicated that the belt accurately measured heart and respiration rate, respectively, in blue wildebeest. The belt also measured motion accurately, and this made the monitoring of conscious animals prior to and after being treated with a LAN, possible. A faecal glucocorticoid metabolite (FGM) assay was also validated for use in blue wildebeest. Three sets of trials were performed in which animals received one of three treatments; Acuphase®, Acunil® or a placebo in order to evaluate the effect of each. Animals were monitored for 12 hours before and 12 hours after treatment. The results showed that although both Acuphase® and Acunil® resulted in a decrease in vigilant behaviour and an increase in resting behaviour, similar results were observed when animals received a placebo. Animals treated with Acunil®, however, exhibited a decrease in explorative behaviour as well as an increase in the time they spent eating. Heart rate was unaffected by any of the three treatments, and this lack of effect by either of the LANs may potentially be due to reflex tachycardia in response to hypotension. Respiration rate was lowered by both LANs, specifically during certain behaviours, with this effect being absent in placebo-treated animals. In addition, the motion of the animals indicated that LAN-treated animals had a lowered flight response to a person entering the enclosure. Endocrine parameters measured in the blood and faeces of the animals before and after treatment revealed a minimal effect. Neither the acute nor the chronic stress response appeared to be significantly reduced by treatment with Acuphase® or Acunil®. In addition, immune function (as quantified by white blood cell count and neutrophil response) revealed that the chronic stress of captivity lowered the immune response of the animals. This decrease in immunocompetence, however, could not be ascribed to any of the LAN treatments. In conclusion, the most pronounced effects observed with the administration of both LANs included a decrease in respiration rate, and responsiveness of the animals. Long term studies on the effect of LAN administration on immune function and endocrine responses may yield more conclusive results regarding the stress responses of wild animals in captivity.
AFRIKAANSE OPSOMMING: In Suid-Afrika word ’n groot aantal wild jaarliks verskuif. Hierdie diere is onderhewig aan ’n groot hoeveelheid stres en die gebruik van langwerkende neuroleptika (LWN) is ’n algemene praktyk om stres te verminder. Langwerkende neuroleptika onderdruk gedragsresponse sonder om spinale en ander reflekse te beïnvloed en kan op so ʼn wyse toegedien word dat ʼn enkel dosis toediening ʼn terapeuties effektiewe weefsel-konsentrasie vir drie tot sewe dae kan handhaaf. By soogdiere bestaan die stres respons uit verskillende fisiologiese reaksies en hierdie studie het beoog om ʼn aantal van hierdie reaksies in blouwildebeeste (Connochætes taurinus) te kwantifiseer. Dit is gedoen om die gevolge van ʼn algemeen gebruikte LWN, Acuphase® (zuklopentiksol-asetaat in groente-olie) te vergelyk met ʼn nuut ontwikkelde LWN, Acunil® (zuklopentiksol-asetaat in ʼn stadig-vrystellende polimeer) om die voorkoms van stres by blouwildebeeste in aanhouding te verlaag. ʼn Biotelemetrie gordel, Equivital™ EQ02, ontwikkel vir menslike gebruik, is aangepas om hierdie spesie te pas. Die resultate van ʼn valideringstudie het aangedui dat die gordel hart- en respirasietempo’s presies in blouwildebeeste kon meet. Beweging kon ook presies deur die gordel gemeet word, wat die monitering van bewuste diere voor en nadat hulle met ʼn LWN behandel is, moontlik gemaak het. ʼn Toets vir fekale glukokortikoïed metaboliete (FGM) is ook gevalideer vir gebruik by blouwildebeeste. Drie stelle proewe is uitgevoer waarin diere een van drie behandelings ontvang het: Acuphase®, Acunil® of ʼn plasebo. Diere is vir 12 uur voor en 12 uur ná behandeling gemoniteer. Die resultate het getoon dat, alhoewel beide Acuphase® en Acunil® tot ʼn afname in waaksame gedrag en ʼn toename in rusgedrag gelei het, dat soortgelyke resultate ook waargeneem is wanneer diere ʼn plasebo ontvang het. Maar die diere wat met Acunil® behandel is, het ʼn afname in ondersoekende gedrag en ʼn toename in die tyd wat hulle aan vreet bestee het, getoon. Hartklop was nie deur enige van die drie behandelings beïnvloed nie, alhoewel die gebrek aan ʼn invloed van albei LWN’s moontlik aan reflekstagikardie in reaksie op hipotensie, toegeskryf kan word. Asemhalingstempo is deur beide LWN’s verlaag met sekere soorte gedrag - dié effek is nie by plasebo-behandelde diere waargeneem nie. Daarbenewens het die beweging van die diere ook aangedui dat LWN-behandelde diere ʼn minder prominente vlugreaksie getoon het wanneer ʼn persoon in die boma ingestap het. Endokriene parameters gemeet in die bloed en mis van die diere voor en ná behandeling het ʼn minimale effek van die neuroleptika getoon. Nie die akute of die chroniese stresreaksie is aansienlik deur behandeling met Acuphase® of Acunil® geïnhibeer nie. Immuunfunksie (gekwantifiseer d.m.v. witbloedseltellings en neutrofielreaksies) is deur die chroniese stres van aanhouding beïnvloed, soos waargeneem in ʼn verlaagde immuunrespons. Die kompromie van immuunrespons is nie beduidend deur LWN behandeling beïnvloed nie. In samevatting – die mees beduidende invloed van beide LWN’s is waargeneem as ʼn afname in onderskeidleik die asemhalingstempo en die vlugreaksie van die diere. Langertermynstudies oor die uitwerking van hierdie LWN’s op immuunfunksie en endokriene reaksies op stres kan moontlik meer insig gee in hoe diere op stres a.g.v. aanhouding reageer.
Thesis (PhD)--Stellenbosch University, 2015.
Game and game-birds -- Conservation, Long-acting neuroleptics (LANs), Blue wildebeest (Connochaetes taurinus) -- Stress responses, Blue wildebeest (Connochaetes taurinus) -- Tranquilisation, UCTD