Effect of functional feed additive on symptoms reduction of enteromyxosis in gilthead seabream “sparus aurata” (field experiment)

• Autor(a) principal: Pierantozzi, Mirko
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/18782
• topic: Mediterranean aquaculture; Gilthead seabream; Enteromyxum leei; Functional feed; Sustainable aquaculture

Aquaculture is a fast-growing sector, very important for the food, nutrition, income, and livelihood of hundreds of millions of people. The demand for seafood is increasing and aquaculture plays an important role in satisfying that. The increasing number of fish farmed go at the same pace as the health and welfare problems especially because of the high density of the fish. One of the biggest sanitary problems for the gilthead seabream industry is Enteromyxum leei, a myxosporean parasite since the infection has a chronic course and is responsible for poor food conversion rate and difficulty to reach commercial size. Unfortunately, no treatments are authorized for this parasitosis, but a recent experimental study shows a good result using SANACORE® functional feed as a treatment for this parasitosis. This study aims to verify the efficacy and the feasibility of the functional feed as a possible treatment for E. leei. The trial was done in an important commercial facility of gilthead seabream in Tuscany (Italy) where enteromyxosis has been already diagnosed in the past. For this study, two different concentrations of SANACORE® are tested, respectively 0.5% and 0.7%. Prevalence and intensity of the parasite in the fish are evaluated using microscopy observation and molecular diagnosis (PCR) to combine qualitative and quantitative parasitological analyses comparing the groups under study. The weight and length of all the fish sampled were recorded and a biomass index was measured and compared along with the different fish groups. Unfortunately, the occurrence of a severe secondary bacterial infection influenced the evaluation of the efficacy of SANACORE's inclusion in fish feed. Concerning the comparison of the different diagnostic methods, the results showed that the qPCR is a more suitable method for the diagnosis of Enteromyxosis. Because of the possibility of a non-lethal technic to collect the samples (by rectal swab), it can be used as a valid screening test in a farm for newly introduced fish.