Nutritional bases of microdiet development for the early stages of two crustacean species: whiteleg shrimp (Penaeus vannamei) and European lobster (Homarus gammarus)

• Autor(a) principal: Silva, Andreia Sofia Sardinha
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/15278
• topic: Camarão-de-patas-brancas; Penaeus vannamei; Lavagante europeu; Homarus gammarus; Microdietas; Requisitos de proteína; Domínio/Área Científica::Ciências Naturais::Outras Ciências Naturais

Crustaceans are an important source of aquatic food protein with a growing global demand leading to one of the fastest growing aquaculture sectors. Aquaculture of crustaceans is highly dependent on meeting their nutritional requirements and producing high quality stocks. However, knowledge on the nutrition, feeding ecology, body composition and nutrient requirements in crustacean larval culture is still limited. This thesis aimed at creating nutritional bases for the development of diets for two crustaceans species, whiteleg shrimp (Penaeus vannamei) and European lobster (Homarus gammarus), at their early development stages. A first feeding trial was conducted to study the dietary protein requirements of whiteleg shrimp postlarvae. For this trial, six experimental diets were formulated to include 34, 44, 49, 54, 58 and 63% protein levels, designated as treatments P34, P44, P49, P54, P58 and P63, respectively. In this trial, 3.18 mg initial mean body weight postlarvae were reared in triplicate groups for 21 days, being fed one of the experimental diets. Growth performance and survival of shrimp from different treatments were affected by the dietary protein levels, with shrimp fed diet P34 registering significantly lower results than the remaining treatments. Final weight, weight gain, RGR and survival of shrimp only increased until diet P44 and FCR decreased. Broken-line analysis of weight gain indicated that the optimal dietary level of crude protein is 47.1% for whiteleg shrimp postlarvae. This requirement level of protein is slightly higher than previous research on posterior stages of development. This can be due to higher growth rates in earlier stages of development. A second feeding trial was conducted to study the growth performance of European lobster juveniles fed on three different experimental diets. These diets were rich in protein, protein and calcium or in carbohydrates and calcium, designated as PROT, PROTCA and STASH, respectively. For this trial, 23 lobster juveniles were reared for 90 days fed one of the experimental diets with 8 replicates per diet, except diet PROT which had 7 replicates. Survival in this trial was 100%. Weight gain, FCR and RGR were not affected by the diet treatments. At the end of the trial, body weight and total body length showed to be significantly higher in juveniles fed PROTCA than in the remaining treatments. Cephalothorax length, colouration changes and molting were not affected by the diet treatments. This thesis concludes that a diet with a medium-high level of protein has shown good performance in shrimp postlarvae, with an optimal dietary level of crude protein estimated at 47.1%. Moreover, from the diets tested on European lobster juveniles, the diet rich in protein and calcium was considered the most suitable for early stages of development. This can be a result of this diet being the most related to the body composition of the lobster at the life stage studied.