Antioxidant and immune response of juvenile red tilapia (Oreochromis sp) cultured at different densities in sea water with biofloc plus probiotics

Scarce information is available about the benefits of adding probiotics to biofloc systems on the growth and health status of red tilapia reared in seawater. This study aimed to assess the growth performance, antioxidant and immune responses of red tilapia (Oreochromis sp.) reared in seawater with two stocking densities (D1, 120 fish/m(3); D2, 240 fish/m(3)) with biofloc plus probiotics. For each density, juvenile red tilapia (6.7 +/- 0.2 g) were cultured under three different experimental conditions: clear seawater (control group, C), seawater enriched with biofloc (B), and seawater enriched with biofloc plus probiotics (BP). The bioassay lasted 7 weeks. Fish reared in D2 showed the lowest specific growth rate value, protein efficiency ratio (PER), and superoxide dismutase (SOD) and catalase (CAT) activity but the highest feed conversion ratio (FCR) and viscerosomatic index (VSI). However, fish from BPD2 showed FCR and PER values similar to those of fish in D1. Fish from the control group showed the highest globulin concentration (GB) with the lowest albumin:globulin ratio (AL:GB), in contrast to fish from BPD2, which also showed the highest glutathione peroxidase (GPX) activities. In conclusion, a high culture density affects the growth performance of red tilapia regardless of biofloc and probiotics in the system; however, supplying biofloc plus probiotics into the cultures improves the feed efficiency as well as immune and antioxidant responses of hybrid red tilapia when reared at high densities in seawater.

Automated summary

This study found that a high culture density affects the growth performance of red tilapia, but adding biofloc and probiotics to the feed can improve feed efficiency as well as immune and antioxidant responses.