A new method
to estimate the relative bioavailability of individual amino acids in fish
larvae using C-13-NMR spectroscopy
L.E.C. Conceição, H. Grasdalen, M.T. Dinis-2003
Comparative Biochemistry and Physiology B –
Biochemistry & Molecular Biology, 134(1): 103-109 (via Current Contents)
Abstract:
In comparison to mammals, fish, and in particular
young stages, are thought to have higher amino acid (AA) requirements.
Still, little is known about AA requirements of fish larvae, largely due to
difficulties in applying traditional methodologies to these fast growing
small animals. This study presents a new method to study the qualitative AA
requirements of fish larvae. This method combines the use of C-13-labelled
live food and C-13-NMR spectroscopy. It allows the simultaneous estimation
of the relative bioavailability of several individual AAs. The present study
shows that the relative bioavailabilies of various AAs do differ between AAs
in larval seabream. (Sparus aurata). Threonine has a low relative
bioavailability, while aspartate, glutamate and lysine had high relative
bioavailabilies compared to other AAs. These results are here attributed to
differences in absorption rates by the gut, and/or selective catabolism. The
results from the present study suggest that when rotifers are used as the
diet for larval seabream, they should be enriched with products rich in
threonine and leucine. Information on the relative bioavailability of
individual AAs together with the AA profile of the larval protein should
allow defining the ideal dietary AA profile for a given species. (
(Univ. Algarve, Ctr. Ciencias Mar. CCMAR, Campus Gambelas, P-8000117,
Faro, Portugal, e-mail: lconcei@ualg.pt)