Effects of dietary supplementation of Lactobacillus plantarum and Bacillus subtilis on growth performance, survival, immune response, antioxidant capacity and digestive enzyme activity in olive flounder (Paralichthys olivaceus)

Abstract

In present study, a 10-month feeding trial was carried out to investigate effects of dietary Lactobacillus plantarum and Bacillus subtilis supplementation singly on growth performance, innate immune response, antioxidant capacity and digestive enzyme activity of olive flounder under a commercial production environment. Two experimental groups fed basal diet with supplementation of L. plantarum (5.0 × 107 CFU/g diet) and B. subtilis (1.0 × 108 CFU/g diet) respectively, and control group fed with basal diet without probiotics supplement. At harvest, serum immune parameters, liver antioxidant indices and digestive enzyme activities in liver, stomach and intestines were measured. Fish fed with B. subtilis supplemented diet showed the highest growth rate which was significantly higher than L. plantarum supplemented group (P < 0.05) which was also significantly higher than control group (P < 0.05). Survival rate were significantly elevated by feeding diet with L. plantarum supplementation (P < 0.05), while the improvement was not significant for B. subtilis supplemented diet compared to control group. All the studied immune parameters in serum were substantially enhanced in both experimental groups. Similar results were observed for the antioxidant capacity in liver. Besides, the activities of digestive enzymes increased substantially in both experimental groups compared to control group and the detected improvement in dietary B. subtilis supplemented group were all higher than in L. plantarum supplemented group, though not all the improvements were significant. In summary, the separate supplementation of B. subtilis and L. plantarum in diet is more beneficial for growth performance and healthy status respectively. Hence, in olive flounder aquaculture, favorable effects of compounded supplementation of L. plantarum and B. subtilis are expected.

Keywords

• Antioxidant capacity
• Digestive enzyme
• Growth performance
• Immune response
• Olive flounder
• Probiotics