Theimmunemodulatoryeffectoforegano(Origanum
vulgare L.) essential oil on Tilapia zillii following
intraperitoneal infection with Vibrio anguillarum
Mahmoud Abd Elaziz Mabrok
1
&
Ali Wahdan
2
Received: 18 August 2017 / Accepted: 10 May 2018
#
Springer International Publishing AG, part of Springer Nature 2018
Abstract The current study aimed to evaluate the possible effect of Origanum essential oil on
innate immune parameters as well as the hematological profiles of Tilapia zillii following
challenge with Vibrio anguillarum.Fifty-fourofTilapia zillii weighing 180 ± 10.2 g were
randomly distributed into three identical closed recirculating seawater systems. The study
included three groups (G1, G2, and G3) repeated in triplicates. Fish of the first two groups
were fed on a basal diet without herbs, whereas fish of the last group were fed on a basal diet
supplemented with Origanum essential oil at concentration 1 g kg
−1
for 15 days. Subsequently,
fish of G2 and G3 subjected to a peritoneal inflammation by intraperitoneally injecting
V. anguillarum (5.5 × 10
5
CFU mL
−1
), whereas fish of G1 injected with saline and served as
control. Fish of all groups were then sampled at 4, 12, and 24 h post injection. No mortalities
were observed in both basal and Origanum fed groups. However, some specimens of fish fed
basal diet showed dorsal fin erosions, eroded mouth, and detached skin. Although the kinetics
of RBCs, WBCs, Hb, and differential leukocyte values remained unchanged in fish fed
different diets at the beginning of the trial, significant increases in those values were observed
in fish fed Origanum essential oil at 12 and 24 h post injection. Similarly, an augmentation of
plasma proteases, antiproteases, and lysozyme activities were recorded in fish fed Origanum
essential oil at the same particular sampling points. A significant enhancement in plasma
bactericidal capacity was only recorded in fish fed Origanum essential oil at 12 and 24 h post
challenge compared to those fed basal diet. In conclusion, Origanum essential oil had a
pronounced influence on the innate immunity and increased the fish resistance to
V. anguillarum. These data gave insight into the potential use of Origanum in prophylactic
strategies against threatening pathogens.
Aquacult Int
https://doi.org/10.1007/s10499-018-0274-y
* Mahmoud Abd Elaziz Mabrok
dr.mahmoudmabrok@yahoo.com
1
Department of Fish Diseases and Management, Faculty of Veterinary Medicine, Suez Canal
University, Ismailia, Egypt
2
Department of Bacteriology, Immunology and Mycology, Faculty of Veterinary Medicine, Suez
Canal University, Ismailia, Egypt
@Phil_Robichaud
@deepthiw
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