Comparison of the lipid properties of healthy and pansteatitis‐affected African sharptooth catfish, Clarias gariepinus (Burchell), and the role of diet in pansteatitis outbreaks in the Olifants River in the Kruger National Park, South Africa

Abstract

Pansteatitis has been identified in wild populations of sharptooth catfish, Clarias gariepinus (Burchell), and Nile crocodiles, Crocodylus niloticus Laurenti, inhabiting the same waters in the Olifants River Gorge in the Kruger National Park, South Africa. Mesenteric and pectoral fat tissue was investigated microscopically and by fatty acid analysis in healthy and pansteatitis-affected catfish from both captive and wild populations. Variation in fatty acid composition between pectoral and mesenteric fat was noted. Composition of mesenteric fat differed between fish from various localities as a result of differences in diet. Pansteatitis in the captive population, resulting from ingestion of high amounts of dietary oxidized fat, reflected higher levels of unsaturated fatty acids within the mesenteric fat. Mesenteric fat of pansteatitisaffected wild catfish was characterized by an increase in moisture content, a decrease in fat content and a decrease in stearic and linoleic acids. The n-3 to n-6 fatty acid ratio of mesenteric fat was higher in pansteatitis-affected wild catfish than in healthy catfish from the same locality, reflecting higher polyunsaturated fat intake by pansteatitisaffected fish. The possible role of alien, invasive, phytoplankton-feeding silver carp, Hypophthalmichthys molitrix (Valenciennes), in the aetiology of pansteatitis in both catfish and crocodiles in the Olifants Gorge is discussed.

Perfluorinated alkyl acids in the plasma of South African crocodiles (Crocodylus niloticus)

“…In 2008, KNP in South Africa experienced numerous mortalities to its resident Nile crocodile population in the Olifants River, with another episode of mortalities following in the spring of 2009. The mortality events of the crocodiles, as well as other aquatic species, were attributed to environmental pansteatitis, a disease hallmarked by inflammation and subsequent hardening of adipose tissue (Osthoff et al, 2010; Huchzermeyer et al, 2013; Lane et al, 2013). To date, no definitive origin of for pansteatitis has yet been determined, though several hypotheses have been noted, which include possible contributions from anthropogenic sources (Larsen et al, 1983; Swanepoel et al, 2000; Ashton, 2010; Masango et al, 2010; Huchzermeyer et al, 2011; Oberholster et al, 2012; Woodborne et al, 2012; Dabrowski et al, 2013; Bouwman et al, 2014; Dabrowski et al, 2014).…”

Comparison of the Lipid Composition of Three Adipose Tissue Types of Male and Female Wild Nile Crocodiles (Crocodylus niloticus)

“…A similar effect has been reported for some birds such as the Domestic Chicken (Gallus gallus domesticus, Ferrini et al, 2008), pheasant (Phasianus colchicus mongolicus, Mustonen et al, 2009), King Penguin chicks (Aptenodytes patagonicus, Thil et al, 2003), Zebra Finches (Taeniopygia guttata, McCue, 2008), and Red-eyed Vireos (Vireo olivaceous, Pierce et al, 2004). Rainbow Trout (Oncorhyncus mykiss, Kiessling et al, 2001) and African Catfish (Clarias gariepinus, Huchzermeyer et al, 2013) have been investigated. Of the reptiles, the fat compositions of the American Alligator (Alligator mississippiensis, Staton et al, 1990), Agamid Lizard (Amphibolurus nuchalis, Geiser and Learmonth, 1994), Desert Iguana (Dipsosaurus dorsalis; Simandle et al, 2001), and Nile Crocodile (Crocodylus niloticus, Osthoff et al, 2010) have been investigated and the data published.…”

Pansteatitis in polluted Olifants River impoundments: nutritional perspectives on fish in a eutrophic lake, Lake Loskop, South Africa

“…Huchzermeyer et al . () and Woodborne et al . () were able to show that a concurrent trophic shift in sharptooth catfish and Nile crocodiles in the Olifants River Gorge was linked to an excessive assimilation of polyunsaturated fats in animals with pansteatitis when compared to healthy individuals from the same locality.…”

“…This appears to conflict with the perspective of Huchzermeyer (), Huchzermeyer et al . () and Woodborne et al . () who argue for a strong role of piscivory in the Olifants River Gorge.…”