Yeast Rhodoturula glutinis as a modulator of innate immune and oxidative stress-related genes in Oreochromis niloticus cultured in a Biofloc system

Abstract

The effect of live yeast Rhodoturula glutinis was evaluated on juvenile Oreochromis niloticus cultivated in a Biofloc system. Growth performance and the expression of innate response and relevant oxidative stress genes were evaluated after a 12-week feeding trial. Three experimental treatments were evaluated in a conventional tilapia culture (control), Biofloc culture (BFT), and Biofloc with the addition of the live yeast R. glutinis 1×106 CFU g-1 (BFT+Rg), with four replicates per treatment. In all cases, commercial food was supplied to the organisms (32% protein and 5% lipids). O. niloticus juveniles (7.02 ± 0.04 g) were randomly distributed in 12 tanks, each with 15 animals. BFT+Rg treatment showed a significant increase in weight gain compared with the other treatments. Significant improvements were found in Fulton's condition factor, feed conversion rate, and hepatosomatic index under Biofloc conditions, BFT, and BFT+Rg treatments. No significant differences were observed in survival. R. glutinis directly influenced gene expression in the liver and intestine. The expression of tnfa, tgfb, hsp70, and gpx, genes in the liver significantly increased in the BFT+Rg treatment compared with the other treatments. Similarly, a significant increase was found in intestinal il1b, tnfa, tgfb, trf, hsp70 gpx, and cat expression patterns in the BFT+Rg treatment. Based on the performance and immune response, the present study suggests the use of R. glutinis as a strategy to increase the productivity of tilapia in Biofloc culture.

Effect of C/N Ratio Levels and Stocking Density of Catla Spawn (Gibelion catla) on Water Quality, Growth Performance, and Biofloc Nutritional Composition in an Indoor Biofloc System

“…Higher crude protein in the C/N20 treatment could be due to the richness of microorganism in the treatment [56], but diferences in nutritional compositions among diferent treatments might be due to diference in microbial community [81]. In the present study, the crude lipid and ash content were in the range as observed by Becerril-Cortés et al [57] in rice bran-developed biofoc except for lower crude protein. Lipid is the important source of metabolic energy for growth of fsh.…”

“…Te presence of more nitrifying bacteria converts ammonia to nitrite and then nitrite to nitrate which might have resulted in increased nitrate-N concentration at a higher stocking density in BFT [28,56]. Becerril-Cortés et al [57] recorded similar nitrate-N concentration for tilapia fry. Te C/N ratio and stocking density have a signifcant efect on the TSS and foc volume.…”