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Utilizing hydrophilic extracts of Amyloodinium ocellatum (Brown, 1931) in the development of new marine fish therapies
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Abstract(s)
Espera-se que a população global atinja os 9 mil milhões em 2050, desafiando o sector alimentar mundial a tornar-se mais produtivo, eficiente e sustentável para garantir a segurança alimentar às gerações futuras. Os oceanos, em todo o mundo, são sobre-explorados e a atividade de pesca é muitas vezes insuficiente para satisfazer a procura, pelo que a aquacultura representa uma solução para o problema. Um dos principais desafios ao desenvolvimento da aquacultura é proliferação de doenças que afetam os indivíduos em cultivo. Na região mediterrânica, no Sul da Europa, amyloodiniosis representa um grande risco para a aquacultura semi-intensiva e intensiva, afetando a maioria das explorações piscícolas em todos os sistemas de produção e causando elevada mortalidade. Embora existam métodos preventivos e desinfetantes, a maioria tem um custo elevado, é pouco prática de aplicar em sistemas semi-intensivos com tanques de terra e altamente prejudicial para o ambiente, tornando a inovação de novas terapias, tratamentos e vacinas de especial importância. Esta tese centra-se no desenvolvimento de uma possível vacina para o robalo (Dicentrarchus labrax), utilizando extratos hidrofílicos obtidos a partir do dinoflagelado Amyloodinium ocellatum. Os extratos foram injetados intraperitonealmente em robalos de 139.8 g de peso médio e as respostas imune, de stress e hematológica foram analisadas após 7, 14, 21 e 28 dias da vacinação. Vinte e oito dias após a vacinação procedeu-se ao desafio com duas concentrações de A. ocellatum (35 e 10 dinospores/mL), sobre o grupo controlo e o grupo vacinado. Para os parâmetros hematológicos, foi registada uma disparidade de resultados nos valores da hemoglobina (Hgb), hematócrito (Htc), lactato e pH, apresentando o grupo vacinado valores mais elevados de Hgb e Htc e valores mais baixos de lactato e pH no sangue. O grupo vacinado, também, apresentou um maior número de monócitos e um menor número de trombócitos. A nível histológico, não foram observadas diferenças no fígado e nas brânquias entre os dois grupos. Quanto aos resultados do desafio, conclui-se que, com a concentração utilizada, não existiu diferença significativa entre os peixes imunizados e o grupo de controlo.
The global population is expected to reach 9 billion before 2050, and the world food-producing sector must become more productive, efficient, and sustainable to provide food security for future generations. Fisheries worldwide are overfished, and stocks are often incapable of satisfying the demand, aquaculture represents a solution to the problem. However, the development of aquaculture is constrained by different causes, diseases being one of the most significant. In the Mediterranean area, Southern Europe, amyloodiniosis represents a key bottleneck for semi-intensive aquaculture production, affecting most fish farms across all production systems and causing high mortalities at precipitous rates. Although treatments exist, most are either expensive, unpractical, or highly harmful to the environment, making the innovation of new therapies, treatments, and vaccines of paramount importance. This thesis focuses on the development of a possible vaccine for seabass (Dicentrarchus labrax), using hydrophilic extracts obtained from the dinoflagellate (Amyloodinium ocellatum). The Extracts were injected intraperitoneally in seabasses with an average weight of 128.9 g and the immune, stress and haematological responses were evaluated at 7-, 14-, 21-, and 28-days post-injection. After 28 days the challenge started, where both the control and the vaccinated group were injected with two concentrations of A. ocellatum (35 and 10 dinospores/mL). For the haematological parameters, it was registered a difference in the values of haemoglobin (Hgb), haematocrit (Htc), lactate and pH, where the vaccinated fish showed higher values in Hgb and Htc and lower values in lactate and pH. Vaccinated fish also presented a higher number of monocytes and a lower number of thrombocytes. At the histological level, no significant differences were noted in the gills and liver. As for the results from the challenge, it was concluded that there were no differences between the vaccinated fish and the control with the selected concentration.
The global population is expected to reach 9 billion before 2050, and the world food-producing sector must become more productive, efficient, and sustainable to provide food security for future generations. Fisheries worldwide are overfished, and stocks are often incapable of satisfying the demand, aquaculture represents a solution to the problem. However, the development of aquaculture is constrained by different causes, diseases being one of the most significant. In the Mediterranean area, Southern Europe, amyloodiniosis represents a key bottleneck for semi-intensive aquaculture production, affecting most fish farms across all production systems and causing high mortalities at precipitous rates. Although treatments exist, most are either expensive, unpractical, or highly harmful to the environment, making the innovation of new therapies, treatments, and vaccines of paramount importance. This thesis focuses on the development of a possible vaccine for seabass (Dicentrarchus labrax), using hydrophilic extracts obtained from the dinoflagellate (Amyloodinium ocellatum). The Extracts were injected intraperitoneally in seabasses with an average weight of 128.9 g and the immune, stress and haematological responses were evaluated at 7-, 14-, 21-, and 28-days post-injection. After 28 days the challenge started, where both the control and the vaccinated group were injected with two concentrations of A. ocellatum (35 and 10 dinospores/mL). For the haematological parameters, it was registered a difference in the values of haemoglobin (Hgb), haematocrit (Htc), lactate and pH, where the vaccinated fish showed higher values in Hgb and Htc and lower values in lactate and pH. Vaccinated fish also presented a higher number of monocytes and a lower number of thrombocytes. At the histological level, no significant differences were noted in the gills and liver. As for the results from the challenge, it was concluded that there were no differences between the vaccinated fish and the control with the selected concentration.
Description
Keywords
Aquaculture Pathology Dicentrarchus labrax Amyloodinium ocellatum Immune response Sonication Vaccination