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Alginate micro particles as symbiotic carriers in diets for Nile tilapia

Grant number: 20/04215-5
Support type:Regular Research Grants
Duration: April 01, 2021 - March 31, 2023
Field of knowledge:Agronomical Sciences - Fishery Resources and Fishery Engineering - Aquaculture
Principal researcher:José Eurico Possebon Cyrino
Grantee:José Eurico Possebon Cyrino
Home Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
Assoc. researchers: Angélica Priscila do Carmo Alves ; Brunno da Silva Cerozi ; Rodney Alexandre Ferreira Rodrigues ; Tamira Maria Orlando

Abstract

Probiotics are several classes of functional foods beneficial to the health and performance of animals. However, the viability of microorganisms with probiotic action may be impaired during passage through the host's gastrointestinal tract or by the form and length of food storage period. Therefore, microencapsulation appears as a promising technique in the protection of probiotics, promoting a favorable microenvironment for the encapsulated microorganism. However, there is still no complete map on the effects of using microencapsulation to extend the viability of probiotics. Considering these factors, this project aims at investigating the effects of a ²-glucan plus Bacillus subtilis symbiotic, free and microencapsulated by the spray-drying technique, in diets for Nile tilapia (Oreochromis niloticus) in a performance assay in a completely randomized design with five treatments (n = 5): T1 - no symbiotic added; T2 - 0.1% of non-encapsulated symbiotic; T3 - 0.2% of non-encapsulated symbiotic; T4 - 0.1% encapsulated symbiotic; T5 - 0.2% encapsulated symbiotic, starting on a pre-test characterizing the microcapsules containing symbiotic to evaluate the probiotic's recovering rate after the microencapsulation process and their resistance to simulated gastrointestinal fluids. At the end of the performance test, histological analysis of the animals' intestines will be performed to characterize possible beneficial effects of dietary symbiotics on the integrity and immunological patterns of the intestinal epithelium. Finally, the fish will be submitted to an immunological challenge by the bacterium Aeromonas hydrophila in order to assess the survival rate, the innate immune system and characterize the intestinal microbiota to detect the action of the symbiotic in free or microencapsulated form, thus filling in the gaps in the knowledge of the action of these substances in teleosts. (AU)