Abstract

BADILLO ZAPATA, Daniel  and  VIANA, Maria Teresa. Stable isotopes (δ¹⁵N) as a tool for quality estimation of commercial aquafeeds for striped bass (Morone saxatilis) in sea cages farming. Hidrobiológica [online]. 2015, vol.25, n.2, pp.303-306. ISSN 0188-8897.

Aquafeed quality for striped bass (Morone saxatilis) was evaluated under commercial conditions in sea cages using stable isotopes as tracers for nitrogen. Using a crossover experimental design, fish that were fed during 270 days with aquafeed "A" was switched to aquafeed "B" during the following 160 days. Samples of aquafeeds and of muscle, and liver tissues were analyzed before and during feeding with aquafeed "B". The isotopic value from diet "A" and muscle and liver tissues after being fed during 270 days were 10.3, 14.6 and 13.1‰ resulting in a discrimination factor of 4.3 and 2.7 for muscle and liver. At day 90 and 160 the discrimination factor reach the equilibrium both for muscle and liver tissues (2.3 and 0.0). It was concluded that diet "B" hadbetter quality as a result of a lower discrimination factor than that observed with diet "A". The nitrogen stable isotope is a reliable tool to evaluate aquafeeds quality under commercial conditions where the other estimations like feed intake and apparent digestibility are difficult to obtain.

Keywords : Cage culture; fish; nitrogen retention; nutrition stable isotopes.

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