Probiotics enhance resistance to Streptococcus iniae in Nile tilapia (Oreochromis niloticus) reared in biofloc systems
- PMID: 37422900
- DOI: 10.1111/jfd.13833
Probiotics enhance resistance to Streptococcus iniae in Nile tilapia (Oreochromis niloticus) reared in biofloc systems
Abstract
Biofloc technology is a rearing technique that maintains desired water quality by manipulating carbon and nitrogen and their inherent mixture of organic matter and microbes. Beneficial microorganisms in biofloc systems produce bioactive metabolites that may deter the growth of pathogenic microbes. As little is known about the interaction of biofloc systems and the addition of probiotics, this study focused on this integration to manipulate the microbial community and its interactions within biofloc systems. The present study evaluated two probiotics (B. velezensis AP193 and BiOWiSH FeedBuilder Syn 3) for use in Nile tilapia (Oreochromis niloticus) culture in a biofloc system. Nine independent 3785 L circular tanks were stocked with 120 juveniles (71.4 ± 4.4 g). Tilapia were fed for 16 weeks and randomly assigned three diets: a commercial control diet or a commercial diet top-coated with either AP193 or BiOWiSH FeedBuilder Syn3. At 14 weeks, the fish were challenged with a low dose of Streptococcus iniae (ARS-98-60, 7.2 × 107 CFU mL-1 , via intraperitoneal injection) in a common garden experimental design. At 16 weeks, the fish were challenged with a high dose of S. iniae (6.6 × 108 CFU mL-1 ) in the same manner. At the end of each challenge trial, cumulative per cent mortality, lysozyme activity and expression of 4 genes (il-1β, il6, il8 and tnfα) from the spleen were measured. In both challenges, the mortalities of the probiotic-fed groups were significantly lower (p < .05) than in the control diet. Although there were some strong trends, probiotic applications did not result in significant immune gene expression changes related to diet during the pre-trial period and following exposure to S. iniae. Nonetheless, overall il6 expression was lower in fish challenged with a high dose of ARS-98-60, while tnfα expression was lower in fish subjected to a lower pathogen dose. Study findings demonstrate the applicability of probiotics as a dietary supplement for tilapia reared in biofloc systems.
Keywords: Bacillus spp.; gene expression; lysozyme activity; pathogen challenge.
© 2023 John Wiley & Sons Ltd.
References
REFERENCES
-
- Abumourad, I. M. K., Abbas, W. T., Awaad, E. S., Authman, M. M. N., El-Shafei, K., Sharaf, O. M., Ibrahim, G. A., Sadek, Z. I., & El-Sayed, H. S. (2013). Evaluation of Lactobacillus plantarum as a probiotic in aquaculture: Emphasis on growth performance and innate immunity. Journal of Applied Sciences Research, 9(1), 572-582.
-
- Addo, S., Carrias, A. A., Williams, M. A., Liles, M. R., Terhune, J. S., & Davis, D. A. (2017). Effects of Bacillus subtilis strains on growth, immune parameters, and Streptococcus iniae susceptibility in Nile tilapia, Oreochromis niloticus. Journal of the World Aquaculture Society, 48(2), 257-267. https://doi.org/10.1111/jwas.12380
-
- Agnew, W., & Barnes, A. C. (2007). Streptococcus iniae: An aquatic pathogen of global veterinary significance and a challenging candidate for reliable vaccination. Veterinary Microbiology, 122(1-2), 1-15. https://doi.org/10.1016/j.vetmic.2007.03.002
-
- Al-Harbi, A. H. (2011). Molecular characterization of Streptococcus iniae isolated from hybrid tilapia (Oreochromis niloticus× Oreochromis aureus). Aquaculture, 312(1-4), 15-18. https://doi.org/10.1016/j.aquaculture.2010.12.014
-
- Avnimelech, Y. (2007). Feeding with microbial flocs by tilapia in minimal discharge bio-flocs technology ponds. Aquaculture, 264(1-4), 140-147. https://doi.org/10.1016/j.aquaculture.2006.11.025
Publication types
MeSH terms
Substances
Grants and funding
LinkOut - more resources
Full Text Sources
Medical
Research Materials
Miscellaneous