Dietary Lactobacillus plantarum Supplementation Improves Growth Performance and Antioxidant Status and Upregulates Genes Related to the Toll/Imd and JAK-STAT Signaling Pathways in Red Claw Crayfish (Cherax quadricarinatus)

This study conducted a 70-day feeding trial to evaluate the effects of dietary Lactobacillus plantarum supplementation (0, 0.1, 1.0, and 10.0 g/kg) in red claw crayfish (Cherax quadricarinatus). Growth performance, hepatopancreatic antioxidant-related parameters, and the expression of genes related to the Toll/Imd and JAK-STAT pathways were determined. Results showed that dietary L. plantarum supplementation significantly improved weight gain rate, specific growth rate, daily growth index, and feed efficiency, which were increased by 23.57%, 5.10%, 9.67%, and 7.90%, respectively, and reduced mortality rate by 60.00% compared with the control group (p < 0.05), enhanced the activities of glutathione peroxidase, catalase, superoxide dismutase and total antioxidant capacity, and reduced malondialdehyde levels in the hepatopancreas (p < 0.05). Furthermore, dietary L. plantarum supplementation was associated with the upregulated expression of key genes related to the Toll/Imd and JAK-STAT signaling pathways (p < 0.05). The expression levels of tumor necrosis factor-α, interleukin-1β, and transforming growth factor-β1 were also significantly increased (p < 0.05). Overall, these findings suggest that dietary L. plantarum supplementation improved growth performance and antioxidant-related and immune-related parameters in red claw crayfish, and that these effects were associated with the upregulated expression of genes involved in the Toll/Imd and JAK-STAT pathways. Among the tested treatments, 1.0 g/kg L. plantarum produced the most favorable overall response.