Assessing Polyunsaturated Fatty Acid Essentiality in Florida Pompano

We evaluated the growth performance and fatty acid composition of juvenile Florida Pompano Trachinotus carolinus that were fed diets containing different combinations of n-3 and n-6 polyunsaturated fatty acids (PUFAs) to assess the relative importance of C-18 PUFAs and long-chain (LC) PUFAs in meeting the essential fatty acid requirements of this species. Juvenile fish (mean +/- SD =47.4 +/- 0.6 g/fish) were fed diets containing different combinations of n-3 and n-6 PUFAs: a positive control containing menhaden fish oil, a negative control containing hydrogenated soybean oil, and experimental diets containing hydrogenated soybean oil amended with ethyl esters of 18:3(n-3); 18:3(n-3) and 18:2(n-6); 22:6(n-3); 22:6(n-3) and 20:4(n-6); or 20:5(n-3), 22:6(n-3), and 20:4(n-6). After 7 weeks, weight gain, feed conversion ratio, and specific growth rate were significantly greater among fish that were fed the positive control feed in comparison with those that received the negative control feed. The addition of n-3 and/or n-6 PUFAs to the negative control formulation did not significantly improve performance in any case, although numeric improvements observed for weight gain and feed conversion ratio appeared to suggest some advantage from providing a complement of both n-3 and n-6 LC-PUFAs in the diet. Fatty acid composition varied significantly between all tissues, generally reflecting dietary fatty acid profiles. Tissue fatty acid profiles suggest that Florida Pompano have some ability to elongate and desaturate fatty acids and may be able to survive on diets containing C-18 PUFAs, but they perform optimally when provided with LC-PUFAs directly.