Modulation of growth, skin mucus and serum immunities, and disease resistance of Nile tilapia fed host-associated probiotic (Lactobacillus paracasei l61-27b)

Abstract

The experiment was performed to examine the effect of Lactobacillus paracasei l61-27b (LP) isolated from Nile tilapia intestine on the growth rate, skin mucus and serum immune parameters and disease resistance. Fish (25.40 ± 0.33 g) were distributed into glass tank (150 litres tank−1) at 20 fish tank−1 and fed with different levels of dietary L. paracasei l61-27b: 0 (LP1), 106 (LP2), 107 (LP3), 108 (LP4) and 109 CFU mL−1 (LP5) for 8 weeks. The results indicated that SGR, WG and FW significantly improved, while FCR significantly decreased, in fish fed LP supplemented. Dietary L. paracasei significantly increased SMLA and SMPA with the highest values recorded for fish in LP4 and LP5 groups. Similarly, SL, SP, ACH50, PI and RB were significantly stimulated in fish fed LP diet compared with fish fed control diet. Challenge study showed that in comparison with the control diet (20% survival), the survival rates of fish fed the L. paracasei were significantly (p < 0.05) higher; by 63.33% (LP2), 66.67% (LP3), 80.00% (LP4) and 83.33% for LP5. The relative per cent survival (RSP) was 54.17%, 58.33%, 75% and 79.17% in LP2, LP3, LP4 and LP5, respectively. In conclusion, the dietary inclusion of L. paracasei can be potentially used in Nile tilapia to improve its growth and health status.