Comparison of the lipid properties of captive, healthy wild, and pansteatitis-affected wild Nile crocodiles (Crocodylus niloticus)

Abstract: The results presented describe and compare the fatty acid composition and melting properties of captive, healthy wild, and pansteatitis-affected wild crocodiles (Crocodylus niloticus). Differences in fatty acid composition between intramuscular and adipose fat is noted in captive crocodiles, and the latter differs from wild crocodiles as a result of different diets. Adipose fat of healthy wild crocodiles differs minimally from diseased ones, respectively with 37.3±2.6% vs. 43.2±2.3% monounsaturated fatty acids, and 43.2±2.9% in dead crocodiles, while polyunsaturated fatty acids decrease from 27.3±1.9% to as low as 21.9±3.6% respectively. Of the unsaturated fatty acids 18:2n−6 decreased from 6.5±2.6% in unaffected crocodiles to 3.5±0.6% in highly affected and 3.2±0.4% in dead crocodiles, and 22:5n−3 from 2.8±0.6% to 1.8±0.3% and 2.2±0.3% respectively. The melting properties as determined by differential scanning calorimetry show that extracted adipose fat is a small degree softer in pansteatitis-affected tissue, specifically in the temperature range 7–36°C, and does not contribute to the hard texture noted for adipose fat tissue of pansteatitis-affected animals. A high moisture content of 51.0±19.7% of the fat tissue of pansteatitis-affected animals vs.17.1±8.0% of healthy ones, suggests that physiological changes due to interstitial inflammation may contribute to the hard texture. [Copyright &y& Elsevier]