Protein turnover, amino acid
profile and amino acid flux in juvenile shrimp Litopenaeus vannamei: effects
of dietary protein source
E.
Mente, P. Coutteau, D. Houlihan, I. Davidson, P. Sorgeloos-2002
Journal
of Experimental Biology, 205(20): 3107-3122
Abstract:
The effect of dietary protein on protein synthesis and growth of juvenile
shrimps Litopenaeus vannamei was investigated using three different diets
with equivalent protein content. Protein synthesis was investigated by a
flooding dose of tritiated phenylalanine. Survival, specific growth and
protein synthesis rates were higher, and protein degradation was lower, in
shrimps fed a fish/squid/shrimp meal diet, or a 50% laboratory diet/50%
soybean meal variant diet, than in those fed a casein-based diet. The
efficiency of retention of synthesized protein as growth was 94% for shrimps
fed the fish meal diet, suggesting a very low protein turnover rate; by
contrast, the retention of synthesized protein was only 80 for shrimps fed
the casein diet. The amino acid profile of the casein diet was poorly
correlated with that of the shrimps. 4 h after a single meal the protein
synthesis rates increased following an increase in RNA activity. A model was
developed for amino acid flux, suggesting that high growth rates involve a
reduction in the turnover of proteins, while amino acid loss appears to be
high.
(Univ. of Aberdeen, Dept. of Zoology, Tillydrone Avenue, AB24 2TZ, Aberdeen, Scotland, UK, e-mail: e.mente@abdn.ac.uk)