scholarly journals Dietary Agaricus blazei Spent Substrate Improves Disease Resistance of Nile Tilapia (Oreochromis niloticus) against Streptococcus agalactiae In Vivo

2022 ◽  
Vol 10 (1) ◽  
pp. 100
Author(s):  
Po-Tsang Lee ◽  
Yu-Sheng Wu ◽  
Chung-Chih Tseng ◽  
Jia-Yu Lu ◽  
Meng-Chou Lee

This study evaluated the effects of the feeding of spent mushroom substrate from Agaricus blazei on Nile tilapia (Oreochromis niloticus). The safety of 0–1000 μg/mL A. blazei spent substrate water extract (ABSSE) was demonstrated in the primary hepatic and splenic macrophages and the THK cell line (a cell line with characteristics of melanomacrophages) using a cytotoxicity assay. Here, 10 μg/mL of crude ABSSE promoted the phagocytic activity of macrophages and THK cells. Stimulating ABSSE-primed THK cells with lipopolysaccharides or peptidoglycan resulted in higher expression levels of four cytokine genes (e.g., interleukinz (IL)-1β, IL-12b, IL-8 and tumor necrosis factor α (TNFα)) and one cytokine gene (TNFα), respectively. An in vitro bacterial growth inhibition assay demonstrated that ABSSE could inhibit the growth of Streptococcus agalactiae. In the first feeding trial, Nile tilapia were fed with experimental feed containing 0, 1, or 5% of A. blazei spent substrate (ABSS) for seven and fourteen days followed by bacterial challenge assay. The best result was obtained when Nile tilapia were continuously fed for seven days on a diet containing 1% ABSS, with the survival rate being higher than in groups with 0% and 5% ABSS after challenge with S. agalactiae. In the second trial, fish were fed diets supplemented with 0% or 1% ABSS for seven days, and then all the groups were given the control feed for several days prior to bacterial challenge in order to investigate the duration of the protective effect provided by ABSS. The results showed that the protective effects were sustained at day 7 after the feed was switched. Overall, spent mushroom substrate from A. blazei is a cost-effective feed additive for Nile tilapia that protects fish from S. agalactiae infection.

Aquaculture ◽  
2016 ◽  
Vol 454 ◽  
pp. 237-242 ◽  
Author(s):  
Guilherme Campos Tavares ◽  
Frederico Augusto de Alcântara Costa ◽  
Raquel Ribeiro Dias Santos ◽  
Gustavo Morais Barony ◽  
Carlos Augusto Gomes Leal ◽  
...  

2018 ◽  
Vol 6 (1) ◽  
Author(s):  
Anita Jaglarz ◽  
Artur Gurgul ◽  
William J. Leigh ◽  
Janina Z. Costa ◽  
Kim D. Thompson

ABSTRACT This paper describes the whole-genome sequences for three Streptococcus agalactiae serotype Ia isolates. The isolates were recovered from the brains of clinically sick tilapia, Oreochromis niloticus, that were suffering from streptococcosis. One isolate was from tilapia in the United States and the other two from fish in China.


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