Modification in Body Fat Content and Fatty Acid Profile of Wild Yellow Shortfin Eel, Anguilla australis, through Short‐term Fattening

Abstract

Wild‐catch eels with low fat content are either not accepted at all or accepted as a lower‐quality and less valuable product in the global eel market. This study was undertaken with the goal of increasing the fat content of yellow shortfin eel, Anguilla australis (104 ± 11 g initial weight), captured in the wild and kept in captivity for a short period, as well as assessing their rate of growth. An 86‐d feeding trial was conducted indoors in a recirculation aquaculture system, at 25.5 ± 1.6 C. Two commercial extruded dry feeds were tested; one formulated for European eel and one not specifically intended for use on eels. Good values of specific growth rate (1.10 and 1.12%/d) and feed conversion ratio (1.01 and 1.10) were achieved with both tested feeds. At the end of the trial, eels achieved 20–22% total fat, starting from wild fish with 7% fat content. Fat quality of the fattened eel was appreciably superior (higher proportion of omega‐3 fatty acids) than the fat of eels captured in the wild. The results of this study are encouraging for the prospect of fattening yellow shortfin eels and obtaining a market‐oriented eel product.

Conservation of freshwater eels in food‐web studies: Non‐lethal stable isotope analyses substitute fin for muscle tissue with lipid correction

“…We found no relationship of δ 13 C or δ 15 N with increasing eel length that might be expected with a trophic shift with increasing size but the geographical diversity of isotopic values in our data set limits this conclusion. Lipid content of eel muscle tissue can increase with increasing eel body size (Degani et al, 1986;Hirt-Chabbert & Young, 2012) but C:N ratios of untreated muscle in our study did not increase with eel size. C:N ratios of untreated fins, however, did show an increased range in eels >480 mm length, possibly indicating more diverse diets in larger eels.…”