Celentano, Carmela (2025) Harnessing natural products for sustainable aquaculture: an investigation using aquatic animal models. [Tesi di dottorato]

	Documento PDF 37_CICLO_TESI_CARMELA_CELENTANO_EMBARGO.pdf Visibile a [TBR] Amministratori dell'archivio Download (12MB) | Richiedi una copia
	Documento PDF 37_CICLO_TESI_CARMELA_CELENTANO.pdf Visibile a [TBR] Amministratori dell'archivio Download (18MB) | Richiedi una copia

Abstract

Marine algae and plants offer a sustainable solution for aquaculture by providing a cost-effective and environmentally friendly alternative to fishmeal and fish oil in feeds. They enhance the health and productivity of aquatic animals while improving water quality and mitigating environmental pollution, making them crucial for the sustainable growth of this vital food production sector. Unfortunately, our understanding of how specific bioactive chemical components in algae contribute to their positive nutraceutical effects remains limited. This PhD thesis aimed to investigate the activity of purified compounds to enhance the productivity and health of farmed animals, specifically by examining their effects on aquatic animal models. In particular, the research explored the potential of repurposing natural products from invasive marine species for possible applications in aquaculture. Specifically, we investigated the flavonoid apigenin (from Halophila stipulacea), the sesquiterpene caulerpenyne and the alkaloid caulerpin (both from Caulerpa spp.). The study aimed to evaluate their palatability, nutritional impact on fish, gut microbiota, metabolic and transcriptomic profiles, and their influence on fish flesh quality. Crustaceans initially accepted apigenin and caulerpenyne but developed a learned aversion after repeated exposure. This finding excludes a possible use of the two compounds in crustacean farming. In contrast, zebrafish and clownfish readily consumed both compounds during daily administrations for over a month, indicating sustained acceptance in both freshwater and marine models. Chronic treatment of zebrafish with apigenin and caulerpenyne resulted in subtle shifts in their fatty acid profiles, with a decrease in oleic acid and, in the case of apigenin, linoleic acid. These alterations, while not significantly impacting overall lipid quality, suggest potential modulations of lipid metabolism. Clownfish fed with caulerpin exhibited increased voracity, which later returned to normal feeding behaviour. However, their growth rates remained unaffected. Interestingly, caulerpin supplementation significantly altered the fish's lipid profile, resulting in decreased levels of certain fatty acids, notably omega-3s. This finding is further supported by the transcriptomic and metabolomic analysis, which revealed a significant downregulation of genes involved in the fatty acid synthesis and stimulation of energy metabolism, oxidative stress protection, and cellular signalling. Microbiome analysis revealed minor shifts in the gut microbiota of fish fed the different compounds, suggesting a limited impact on the gut microbial community. Despite these variations, the quality of the fish flesh, assessed through the use of specific indices, remains unaffected. Overall, the results support the potential of utilizing natural products from invasive species in aquaculture while providing valuable insights into their effects on fish physiology and the gut microbiome. Further research is necessary to fully understand the long-term implications of these compounds on fish health and productivity. As secondary aspects of this thesis, Appendix 1 presents the use of the zebrafish embryo model to assess the toxicity of compounds of pharmacological interest. Additionally, Appendix 2 explores the potential valorization of biomass from non-indigenous species, specifically investigating its application in developing materials for environmental decontamination of pollutants.

Downloads

Actions (login required)

Modifica documento