Exopolysaccharide Derived From Bacillus pumilus As Dietary Supplement Improves Innate Immunity, Nutrient Metabolism, Antioxidant Status And Gut Microbiota In Zebrafish (Danio rerio)

Nurhadi, Tri and Prof. Dr. Ir. Arief Prajitno, MS (2023) Exopolysaccharide Derived From Bacillus pumilus As Dietary Supplement Improves Innate Immunity, Nutrient Metabolism, Antioxidant Status And Gut Microbiota In Zebrafish (Danio rerio). Magister thesis, Universitas Brawijaya.

Abstract

Microbial exopolysaccharides (EPS) as immunosaccharide provides immunomodulatory function to host. Previously Bacillus pumilus as probiotic has been evidenced exhibited multiple-beneficial effects to aquaculture, however the function of EPS derived from B. pumilus have not been fully explored. In the present study, the purification of EPS from B. pumilus cultured broth was performed by simple ethanol precipitation. The purity of extracted EPS is around 94.3%, and the average molecular weight of 291 kDa was determined by gel permeation chromatography. The efficacy of dietary EPS on nutrient metabolism, innate immunity, antioxidant status and gut microbiota in zebrafish was evaluated by feeding basal diet (control) and basal diet containing 0.5% and 1% (w/w) of EPS for 30 days. In the end of feeding trial, the mRNA expression of hepatic glycolysis-related genes such as hexokinase (HK), and growth-related genes such as growth hormone receptor (GHR) and insulin-like growth factor-1 (IGF-1) were significantly increased in EPS- supplemented fish. The hepatic antioxidant-related genes (SOD and NOS2A) were obviously increased in EPS-supplemented fish. A significant increasing of expression in anti-apoptotic gene (Bcl-2) and decreasing of expression in apoptotic gene (TP53) in EPS-supplemented fish. The results showed that immune-relevant genes IL-1β, TNF-α, Lysozyme and TLR-4a in intestine, and TNF-α and TLR-4a in whole body were significantly evoked in the EPS- supplemented fish. The cumulative mortality was significantly reduced in zebrafish fed a diet containing 0.5% and 1% of EPS after challenged with Aeromonas hydrophila and Streptococcus iniae, respectively. NGS analysis showed a significant difference of bacterial community in gut between control and EPS-supplemented groups. The relative abundances of potential pathogens, such as Vibrio and Aeromonas genus, were significantly reduced in EPS- supplemented fish. The present study elucidated that the administration of the EPS could improve innate immunity, disease resistance and gut microbiota in zebrafish, and a diet containing 0.5% of EPS is adequate. These results

Item Type:	Thesis (Magister)
Identification Number:	042308
Divisions:	S2/S3 > Doktor Ilmu Perikanan dan Kelautan, Fakultas Perikanan dan Ilmu Kelautan
Depositing User:	Nur Subchan
Date Deposited:	19 Jan 2024 08:08
Last Modified:	19 Jan 2024 08:08
URI:	http://repository.ub.ac.id/id/eprint/212240

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