Impact of Sel-Plex dietary supplementation on growth performance, physiological response, oxidative status, and immunity-linked gene expression in Nile tilapia () fingerlings challenged with .

BACKGROUND

Organic selenium (Sel-Plex) supplementation holds considerable promise for improving the effectiveness of fish production.

AIM

This experiment was accomplished to judge the potential benefits of Sel-Plex nutritional additive on growth outcomes, physiological response, oxidative status, and immunity-linked gene expression in Nile tilapia () fingerlings exposed to bacterial infection with .

METHODS

Utilizing a basal diet of 30% protein, four experimental diets were prepared, each of which contained Sel-Plex at concentrations of 0.0, 0.5, 1, and 2 mg/kg, respectively. Three replicates of 20 fish/treatment were used using 240 healthy Nile tilapia fingerlings. Fish were placed in 12 glass aquariums and separated into 4 groups at random. For the entire span of 8 weeks, diets were admitted to fish at a 3% rate of fish biomass/aquarium. After the feeding trial, pathogenic was intraperitoneally injected into fish of each treatment, and fish were observed for 15 days to track the survival rate (SR) after the challenge.

RESULTS

Growth performance, physiological response, immunological parameters (phagocytic activity, phagocytic index, and lysozyme), and antioxidant parameters [catalase, superoxide dismutase (SOD), malondialdehyde, and glutathione peroxidase (GPx)] were noticeably improved in Sel-Plex treated groups. Moreover, Sel-Plex increased gene expression linked with the immune system in the liver (tumor necrosis factor-alpha and interleukin 1β), to growth (insulin-like growth factor 1 and growth hormone receptor), and antioxidants (SOD and GPx). Under pathogen-challenge conditions, the employed dietary Sel-Plex supplementation could successfully lower fish oxidative stress, offering a potential preventive additive for Nile tilapia instead of antibiotics. On the other hand, Sel-Plex significantly enhanced each of three intestinal morphological measurements (villus width, villus length, and crypt depth), demonstrating the greatest influence on the improvement of intestinal structure overall. In the Nile tilapia control group, the infection with caused noticeable degenerative alterations in the gut, hepatopancreas, spleen, and posterior kidney. The severity of the lesion was significantly reduced and significantly improved with higher Sel-Plex concentrations. Sel-Plex supplemented groups had 100% SRs among the -challenged groups.

CONCLUSION

It could be advised to enrich the diets of Nile tilapia fingerlings with 1-2 mg.kg of Sel-Plex to enhance growth rate, physiological response, immunological reaction, and intestinal absorptive capacity.