Effects of Rhodotorula mucilaginosa on Growth, Antioxidant, and Immune Function, and Toll/Imd and JAK-STAT Signaling Pathways in Red Claw Crayfish (Cherax quadricanatus)

Abstract

In aquaculture, the use of probiotics to improve growth, immunity, and stress resistance in crustaceans has gained increasing attention. This study examined the effects of incorporating different levels of Rhodotorula mucilaginosa (0.0, 0.1, 1.0, and 10.0 g/kg) into the diet on growth performance, antioxidant capacity (AOC), immune function, Toll/Imd, and JAK-STAT signaling pathways in red claw crayfish (Cherax quadricanatus). The investigation was conducted through a 56-day feeding trial. The main results are as follows: Compared with the control group (0.0 g/kg), different R. mucilaginosa levels significantly increased (p < 0.05) the specific growth rate (SGR) and weight gain rate (WGR) of red claw crayfish, significantly increased (p < 0.05) the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione S-transferase (GST), total AOC (T-AOC), and acid phosphatase (ACP) in hepatopancreas of red claw crayfish, and significantly upregulated (p < 0.05) the relative expression levels of tumor necrosis factor receptor-associated protein 6, akirin, immunodeficiency homolog, interferon regulatory factor 4, Toll-like receptor (TLR) 6, TLR 2, Janus kinase, signal transducer activator of transcription, tumor necrosis factor α, interleukin-1β, transforming growth factor-β1 genes in the hepatopancreas of red claw crayfish. In conclusion, R. mucilaginosa significantly enhanced red claw crayfish's growth, AOC, and immune function, and activated the Toll/Imd and JAK-STAT signaling pathways. In this experimental context, the ideal addition level of R. mucilaginosa is 1.0 g/kg.

Keywords: crustaceans; feed additive; hepatopancreas; probiotics; signal pathway activation.

Figure 1

The effects of Rhodotorula mucilaginosa on the weight gain rate (WGR; A), specific growth rate (SGR; B), and feed conversion rate (FCR; C) of red claw crayfish. All the data are presented as mean ± SE (n = 3). Within the same figure, different superscript letters indicate significant differences between the values (p < 0.05).

Figure 2

The effects of Rhodotorula mucilaginosa on the relative expression levels of tumor necrosis factor receptor-associated factor 6 (traf6), akirin, and immune deficiency homolog (imd) genes in the hepatopancreas of red claw crayfish. All the data are presented as mean ± SE (n = 3). Within the same figure, different superscript letters indicate significant differences between the values (p < 0.05).

Figure 3

The effects of Rhodotorula mucilaginosa on the relative expression levels of interferon regulatory factor 4 (irf4), Toll-like receptor 6 (tlr6), and Toll-like receptor 2 (tlr2) genes in the hepatopancreas of red claw crayfish. All the data are presented as mean ± SE (n = 3). Within the same figure, different superscript letters indicate significant differences between the values (p < 0.05).

Figure 4

The effects of Rhodotorula mucilaginosa on the relative expression levels of tumor necrosis factor α (tnf-α), interleukin-1β (il-1β), transforming growth factor-β1 (tgf-β1) genes in the hepatopancreas of red claw crayfish. All the data are presented as mean ± SE (n = 3). Within the same figure, different superscript letters indicate significant differences between the values (p < 0.05).

Figure 5

The effects of Rhodotorula mucilaginosa on the relative expression levels of Janus kinase (jak) and signal transducer activator of transcription (stat) genes in the hepatopancreas of red claw crayfish. All the data are presented as mean ± SE (n = 3). Within the same figure, different superscript letters indicate significant differences between the values (p < 0.05).