Effects of dietary levan on growth performance, nonspecific immunity, pathogen resistance and body composition of orange-spotted grouper (Epinephelus coioidesH.)

Abstract

This study investigated the effects of levan produced by Bacillus licheniformis FRI MY‐55 on growth performance, intestinal count of viable bacteria, immune status, pathogen resistance and body composition of orange‐spotted grouper (Epinephelus coioides). Orange‐spotted grouper were fed diets supplemented with levan at concentrations of 0 (control), 5.0, 10.0, 25.0 and 50.0 g kg−1 for 12 weeks. The final weight and per cent weight gain were significantly higher in the 25.0 g kg−1 levan‐supplemented group than in the control group (p < 0.05). All levan‐supplemented diets significantly decreased the count of total viable aerobic bacteria and Vibrio spp. in the intestines of groupers (p < 0.05). Serum total protein levels, globulin levels, lysozyme activity and survival rate of orange‐spotted grouper after challenge with V. harveyi were significantly higher in the 25.0 g kg−1 levan‐supplemented group than in the control group (p < 0.05). This study also found that the 10.0, 25.0 and 50.0 g kg−1 levan‐supplemented diets significantly increased the crude protein level in the body composition of orange‐spotted grouper. Overall, the results of this study indicate that dietary levan (25.0 g kg−1) could be an effective method for enhancing the growth performance and disease resistance in orange‐spotted grouper.

Prebiotics and Fish Immune Response: A Review of Current Knowledge and Future Perspectives

“…The juveniles of another carp variety, L. rohita were found to have high serum lysozyme activity and highest relative survival percentage against Aeromonas hydrophila upon levan inclusion in the feed at 12.5 g kg ¡1 (Gupta et al, 2008). In a recent investigation, serum lysozyme activity and survival rate of orangespotted grouper (Epinephelus coioides H.) after challenge with Vibrio harveyi were significantly, higher in the 25 g kg ¡1 levan supplemented group compared to the control group (Huang et al, 2014).…”

Fructans As DAMPs or MAMPs: Evolutionary Prospects, Cross-Tolerance, and Multistress Resistance Potential

“…Dietary fructans are degraded by fructan-degrading enzymes from microbes in the colon, since animals lack fructan-degrading enzymes (Capitán-Cañadas et al, 2014; Peshev and Van den Ende, 2014). Dietary supplements of bacterial levans are also known to improve growth and defense responses in different animal species (Li and Kim, 2013; Huang et al, 2015). Anti-tumor and immunomodulatory effects have been ascribed to some bacterial levans (Yoo et al, 2004; Xu et al, 2006).…”

The Efficacy of Inactivated Photobacterium damselae subsp. piscicida Combined with Levan/Alum as Vaccine against Photobacteriosis in Cobia, Rachycentron canadum

“…is a suitable nanocarrier system for the potential delivery of macromolecular drugs. Levan can be used as a dietary immunostimulant and fish fed a levan‐supplemented diet had significantly high protection in both Cyprinus carpio and Labeo rohita against Aeromonas hydrophila (Rairakhwada et al ; Gupta et al ) and Vibrio harveyi in Epinephelus coioides (Huang et al ). Gupta et al () suggested that microbial levan is an ideal prebiotic and immunostimulant for use in aquaculture.…”