Effects of dietary lipids on growth, fatty acid composition, intestinal absorption and hepatic storage in white sturgeon (Acipenser transmontanus R.) larvae

A. Gawlicka, M.A. Herold, F.T. Barrows, J. de la Noüe, S.S.O. Hung-2002

Journal of Applied Ichthyology, 18(4-6): 673-681

Abstract: 

White sturgeon larvae grew faster over a 24-day period (11-36 days post-hatch, dph) when fed a commercial diet (17% lipid, C17) as compared to fish fed experimental diets containing 25% (E25), 33% (E33) and 42% (E42) lipids with different fatty acid profiles but matching protein contents. The larvae fed the high lipid diets contained more fatty acids in the total triacylglycerol and phosphoacylglycerol but less moisture and ash than larvae on the commercial diet at the end of the 24-day feeding trial. Larvae fed the C17 diet had significantly (P < 0.05) lower levels of 18 : 2 n  - 6 but higher levels of 20 : 5 n - 3, 22 : 6 n - 3 and n - 3 polyunsaturated fatty acids (PUFA) and a higher n - 3/n - 6 ratio than larvae on the E25, E33 and E42 diets after 24 days of feeding. Larvae fed the high lipid diets showed increased activities of alkaline phosphatase, nonspecific esterase and lipase in the brush border and increased stores of lipid in the liver compared to larvae on the C17 diet after only two days of feeding (14 dph). After 24 days of feeding, glycogen stores had decreased in all larvae except those fed the E25 diet, whereas lipid stores had increased in larvae fed each of the four diets. These results indicate that the slower growth of larvae on the high lipid diets may have resulted in part from reduced food intake and therefore insufficient intake of protein as well as suboptimal levels of PUFA. Despite the slower growth, these larvae showed a marked capacity to assimilate and store lipids in the liver without loss of cell membrane integrity.

(University of California, One Shields Ave., Davis, CA 95616-8521, USA. E-mail of S.S.O. Hung: sshung@ucdavis.edu)

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