Open AccessDietary supplementation of dry oregano leaves increases the innate immunity and resistance of Nile tilapia against Streptococcus agalactiae infection
Author(s) -
Espirito Santo Amanda H.,
Brito Túlio S.,
Brandão Laura L.,
Tavares Guilherme C.,
Leibowitz Márcia P.,
Prado Samuel A.,
Ferraz Vany P.,
Hoyos Daniela C. M.,
Turra Eduardo M.,
Teixeira Edgar A.,
Figueiredo Henrique C. P.,
Leal Carlos A. G.,
Ribeiro Paula A. P.
Publication year - 2020
Publication title -
journal of the world aquaculture society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.655
H-Index - 60
eISSN - 1749-7345
pISSN - 0893-8849
DOI - 10.1111/jwas.12602
Subject(s) - biology , nile tilapia , streptococcus agalactiae , lysozyme , tilapia , innate immune system , immunity , aquaculture , streptococcus iniae , plant disease resistance , microbiology and biotechnology , oreochromis , immune system , food science , zoology , immunology , fish <actinopterygii> , streptococcus , bacteria , fishery , genetics , biochemistry , gene
This study aimed to evaluate the influence of increasing concentrations of dietary dry oregano leaves (DOL), ranging from 0 to 0.15%, on different performance parameters of Nile tilapia. Hence, two separate experimental trials testing growth factors (Trial 1) and innate immunity and disease resistance against Streptococcus agalactiae infection (Trial 2) were conducted with a total of 464 tilapia juveniles and two to four replicates. As a result, dietary inclusion of DOL did not induce significant effects on growth performance, hematological parameters, and fillet composition. However, there were significant differences in lysozyme activity between groups of DOL at 0.075% and the control (0%). Moreover, the bactericidal index of the positive control and groups supplemented with DOL were significantly higher than baseline treatment groups. For disease resistance, there was a reduction of 15% in the relative risk of streptococcosis in fish juveniles after dietary inclusion of oregano at 0.15%. In conclusion, the inclusion of DOL in tilapia diets resulted in no significant gains in terms of growth; nevertheless, the immune system and resistance of tilapia against S. agalactiae infection were significantly improved.