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|Título:||Amino acid requirements of white seabream (Diplodus sargus) larvae: effects on growth and performance|
|Autor:||Saavedra, Maria Margarida Alves da Silva de Almeida|
|Orientador:||Dinis, Maria Teresa|
Conceição, L. E. C.
Alimentação dos peixes
|Data de Defesa:||2008|
|Resumo:||Diplodus sargus is a potential species for aquaculture. Constraints to its production are a high incidence of skeletal deformities and stagnation of the growth rate in juvenile stage, possibly caused by dietary imbalances. This thesis is focused on the amino acid (AA) requirements of Diplodus sargus larvae, on the formulation of diets with AA supplementation and also identifies larvae skeletal deformities patterns (Chapter 2). D. sargus AA requirements were estimated using the AA profiles from larval carcass. It was observed that the AA profiles were relatively constant during larval ontogeny, and dietary imbalances were identified in rotifers and Artemia (Chapter 3). Tyrosine, lysine, tryptophan and arginine supplementation was tested by tube feeding and lower gut absorptions efficiencies were observed for these AA. Also, these AA do not seem to be limiting D. sargus growth (Chapter 4 and 5). Based on the results from Chapter 3, a microencapsulated casein diet with a balanced AA profile was formulated and was compared to an unbalanced AA diet and to a live feed diet (control) (Chapter 6). Results showed lower ammonia excretion and less skeletal deformities in larvae fed a balanced diet. Tryptophan supplementation in the diet was tested because of its involvement in skeleton ossification (Chapter 7). However, a decrease on larval growth and no effect on skeletal deformities were observed. The effect of tyrosine and phenylalanine supplementation on D. sargus larvae was tested and a higher survival to a temperature stress test was observed in larvae fed a tyrosine supplementation (Chapter 8). Larvae given a phenylalanine supplementation had a decreased incidence on vertebral compressions. In conclusion, an AA balanced diet reduces skeletal deformities and improves nitrogen utilization. Skeletal deformities do not seem related to tryptophan deficiency. Supplementation of phenylalanine and tyrosine lead to a decrease on skeletal deformities and better resistance to a stress test, respectively. From the AA studied; tryptophan, lysine, phenylalanine, arginine and tyrosine; none seems to be limiting D. sargus larval growth|
|Descrição:||Tese dout., Aquacultura, Universidade do Algarve, 2008|
|Designação:||Doutoramento em Aquacultura|
|Aparece nas colecções:||FCT1-Teses|
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|Tese definitiva.pdf||1,13 MB||Adobe PDF||Ver/Abrir|
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