Solubility and peptide
profile affect the utilization of dietary protein by common carp (Cyprinus
carpio) during early larval stages
A.P. Carvalho, R. Sá, A. Oliva-Teles, P. Bergot-2004
Aquaculture, 234(1-4): 319-333
Abstract:
The present work aimed at evaluating whether
solubility and peptide profile of dietary protein can affect survival and
growth performance of common carp during early stages of life.
Water-insoluble casein and two forms of soluble casein (non-hydrolysed and
hydrolysed) were used as protein sources at different proportions in the
experimental diets for first-feeding carp larvae. When provided as the only
protein source water-insoluble casein led to high mortality and depressed
growth after 21 days. The partial or total substitution of water-insoluble
casein by soluble non-hydrolysed casein effectively improved survival and
enhanced growth of larvae. An optimum level of soluble non-hydrolysed
protein was found at 25% of total protein. The addition of some hydrolysed
casein (25% of soluble protein) further improved results. However, high
dietary levels of hydrolysed casein led to negative effects on larval
performance, which would be related with a surplus of di-/tripeptides or/and
amino acids. Protein solubility appears to have only a temporary effect on
larval performance, probably related with the ontogeny of the digestive
tract, since about 2 weeks after the onset of exogenous feeding larvae
became able to use efficiently water-insoluble protein. Results also suggest
the need for a balance in the peptide profile to optimise the utilization of
dietary protein by fish larvae.
(Departamento de Zoologia e Antropologia/CIIMAR
(Centro Interdisciplinar de Investigação Marinha e Ambiental), Faculdade
de Ciências da Universidade do Porto, Pr. Gomes Teixeira, 4099-002, Porto,
Portugal, e-mail: apcarval@fc.up.pt)