Pansteatitis in African sharptooth catfish, Clarias gariepinus (Burchell), in the Kruger National Park, South Africa

Show simple item record

dc.contributor.advisor Steyl, Johan Christian Abraham en
dc.contributor.advisor Myburgh, Jan G. en
dc.contributor.advisor Lawrence, John A. en
dc.contributor.postgraduate Huchzermeyer, Karl David August en
dc.date.accessioned 2013-09-06T18:58:57Z
dc.date.available 2013-05-29 en
dc.date.available 2013-09-06T18:58:57Z
dc.date.created 2013-04-13 en
dc.date.issued 2012 en
dc.date.submitted 2013-05-25 en
dc.description Thesis (PhD)--University of Pretoria, 2012. en
dc.description.abstract In the Kruger National Park (KNP), pansteatitis in sharptooth catfish, Clarias gariepinus (Burchell), was shown to be a serious problem in the inlets to large man-made lakes fed by rivers arising in the polluted catchments of the Olifants and Sabie rivers. An increasing prevalence of pansteatitis was recorded in catfish from the Olifants River gorge. A low prevalence was found in catfish upstream of the gorge at two further sites. No pansteatitis was detected in catfish from a rain-filled dam distant from the potential pollution sources affecting the Olifants River and in rivers arising outside of the park that were not dammed. Analysis of stomach content indicated a higher prevalence of fish in the diet of catfish affected by pansteatitis than in those not affected. Significant pathology in catfish was limited to changes associated with a generalised necrosis and inflammation of adipose tissues (pansteatitis), and there was evidence that lesions accumulated over time. Similar pathology was found in a captive population of catfish with known nutritional pansteatitis. Pathology in other organs that might have been attributed to pollution could not be demonstrated. Examination of blood smears and measurement of haematocrit, blood haemoglobin, serum vitamin E and erythrocyte glutathione peroxidase values did not prove useful as monitoring tools, probably because of the episodic exposure to oxidative stress and the chronic nature of the condition. Pansteatitis-affected catfish, kept in an experimental pond for 11 months after the inciting nutritional cause had been removed, retained steatitis lesions almost unaltered. Whereas lipolysis appeared to be reduced by pansteatitis, adipogenesis appeared to be unaffected. Juvenile catfish confined in experimental tanks with sediments from sites where pansteatitis occurred remained healthy, and no pathology developed after 14 months, suggesting that sediments were not directly toxic. The results of the study present the first record of pansteatitis in both wild and farmed African sharptooth catfish and emphasize the ecological importance and complexity of nutritional oxidative stress in a disturbed aquatic environment. Nutrient entrapment and the consumption of phytoplankton-feeding fish rich in polyunsaturated fats, particularly silver carp, Hypophthalmichthys molitrix (Valenciennes), a species alien to Africa but present in the Olifants River, is proposed as the dietary cause of the pansteatitis. en
dc.description.availability unrestricted en
dc.description.department Paraclinical Sciences en
dc.identifier.citation Huchzermeyer, KDA 2012, Pansteatitis in African sharptooth catfish, Clarias gariepinus (Burchell), in the Kruger National Park, South Africa, PhD thesis, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/24994 > en
dc.identifier.other D13/4/653/ag en
dc.identifier.upetdurl http://upetd.up.ac.za/thesis/available/etd-05252013-162530/ en
dc.identifier.uri http://hdl.handle.net/2263/24994
dc.language.iso en
dc.publisher University of Pretoria en_ZA
dc.rights © 2012 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. en
dc.subject African sharptooth catfish en
dc.subject Kruger National Park (South Africa) en
dc.subject Pansteatitis en
dc.subject UCTD en_US
dc.title Pansteatitis in African sharptooth catfish, Clarias gariepinus (Burchell), in the Kruger National Park, South Africa en
dc.type Thesis en


Files in this item

This item appears in the following Collection(s)

Show simple item record