Approach to circular economy through the inclusion of local agriculture by-products in fish feedstuff: consumer health risk assessment due to heavy metal accumulation and effects on fish health by study of liver and gut morphology
- Autores: Selwan Mohamed Harb Rabia Hamad
- Directores de la Tesis: R. Ginés (dir. tes.), Pedro Castro Alonso (codir. tes.)
- Lectura: En la Universidad de Las Palmas de Gran Canaria ( España ) en 2023
- Idioma: inglés
- Tribunal Calificador de la Tesis: María Jesús Zamorano Serrano (presid.), Mohamed Soula (secret.), Moustafa Abdel Latif Abbassy (voc.)
- Programa de doctorado: Programa de Doctorado en Acuicultura Sostenible y Ecosistemas Marinos por la Universidad de Las Palmas de Gran Canaria
- Materias:
- Enlaces
- Tesis en acceso abierto en: acceda
- Resumen
The circular economy refers to an industrial economy that is restorative by intention, designed for reducing the carbon footprint and employing a more sustainable and eco-friendly use of resources. The recycling of materials that still are valuable in their end-of-life phase and closing production loops are one way to use resources more efficiently and minimize the impact on the environment. This new way of thinking will promote bio-based industries for the recovery, transformation and revalue of by-products from the primary and secondary sectors.
The current study aimed to determine the metal content of Aloe vera and banana byproducts as sustainable alternatives to standard ingredients in aquaculture diets, develop diets with varying levels of inclusion of these byproducts in accordance with the circular economy concept, validate diets for fish, and assess the accumulation of pollutants as well as various risk management strategies and nutritional value. Also, assess the effects of adding banana meal to the diet on the growth, biochemistry, and histomorphology of the liver and intestine in juvenile tilapia.
In our study, two different plant by-products Aloe vera and banana crop by-products, as well as golden mullet (Liza aurata) and tilapia were evaluated (Oreochromis niloticus). For each of the by-products, four isocaloric and isoproteic diets were made: one of them was a commercial diet customized to the species being studied, and the other three contained increasing amounts of the raw material. All diets were analyzed both for biochemical composition and content in metals. risks arising from fish metal content has been measured using various parameters as Estimated Daily Intake (EDI), Maximum Safe Consumption (MSCA), Target Hazard quotient (THQ), Hazard Index (HI) Carcinogenic risk of As (As- CR), the Value Selenium Health Benefit (Se HBV) and also the Nutritional Values has been evaluated.
In both trails it was found that in the various ratios of Aloe vera and banana by product in diets, the content of all elements was less than the upper limits permitted. According to the different risk-benefit analyses used by national and international authorities, consuming Liza aurata and Oreochromis niloticus is generally safe.
In the third trail, the same technique by using the banana by product with different inclusions in Nile tilapia diets but to evaluate the growth rate, proximal composition of the fish fillet and the effect on liver and gut histology. Moreover, the various fatty acids identification and quantitation was performed.
The finding of this study clarified that the banana ensure that the tilapia would grow and perform adequately and had a positive effect on growth parameters. During histological study, the feeding conditions had no adverse impacts on growth or proximal composition, and neither the liver nor the gut seemed to have any unusual effects.
As a result, the banana byproduct was shown to be an effective and environmentally safe way to feed Nile tilapia, which helps to reduce food loss and waste from a circular economy perspective.
