Optimizing feeding formulations to improve fish farming protocols

• Autor(a) principal: Carrilho, Raquel Vaz
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/12568
• topic: Dourada; Baixa temperatura; Nutrição; Razão proteína:energia; Resposta ao stress; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

The aquaculture provides millions of tonnes of food for human consumption and with the expected increase in the population it is important that aquaculture production continues to grow in a sustainable way. Gilthead seabream (Sparus aurata) is one of the most produced fish species in the Mediterranean, mainly in off-shore cages, and since it is very susceptible to low temperature, reducing feed intake and growth, it is necessary to improve formulations for the Winter, focusing on minimising the dietary protein content and the fishmeal inclusion level. Furthermore, during production gilthead seabream can be exposed to stressful events, as high densities during sorting procedures, that can affect negatively the fish. Therefore, the aim of this thesis was to optimize feed formulations that benefits gilthead seabream at low temperature (14°-15°C) in the Mediterranean Sea and assess the potential of nutritional strategies to help the fish cope with stressful events. The fish were fed with three experimental diets, the Control diet with high protein:energy ratio (48P:19L), the Low diet with low protein:energy ratio (45P:19L) and the LowMix diet with low protein:energy ratio (44P:19L) but supplemented with a mix of additives, for 84 days. At day 84, fish were exposed to a simulated sorting procedure, and blood samples were collected at different times (T=0 min, T=30 min, T=90 min). At the end of the experiment, the fish fed the LowMix diet had similar final weight and growth performance than fish fed the Control diet. The Low diet fish had a lower weight when compared with the Control fish. Furthermore, the viscerosomatic index was lower in the fish fed the LowMix diet compared with the Control fish. In the stress experiment, the stress indicators were not significantly different among diets. These results indicate that the Winter formulation for gilthead seabream juveniles may present a low protein content and a low fishmeal inclusion, provided that the adequate dietary supplements are included, without negative consequences in fish welfare and growth performance.