Vet World   Vol.12   February-2019  Article-14

Stimulation of non-specific immunity, gene expression, and disease resistance in Nile Tilapia, Oreochromis niloticus (Linnaeus, 1758), by the methanolic extract of the marine macroalga, Caulerpa scalpelliformis

Background and Aim: The objective of the present study was to test the immunostimulating potential of marine macroalga, Caulerpa scalpelliformis, in terms of non-specific immune responses, gene expression, and disease resistance of Nile tilapia, Oreochromis niloticus (Linnaeus, 1758).

Materials and Methods: O. niloticus was injected intraperitoneally with three different doses of methanol extract of C. scalpelliformis (CSME) (2 mg/kg, 20 mg/kg, or 200 mg/kg body weight), or MacroGardTM (commercial immunostimulant, positive control, and 20 mg/kg body weight), or distilled water (untreated control). In one set of fish, 5 days post-injection, serum lysozyme, myeloperoxidase, and antiprotease activities were assayed. 24 h after injection, gene expression was analyzed in a separate set of fish. To another set of fish, 1 week post-administration of the products, fish were challenged with lethal dose 50 (LD50) dose of a live virulent pathogen, Aeromonas hydrophila and subsequent resistance to it was noted in terms of cumulative percent mortality.

Results: CSME increased serum lysozyme, myeloperoxidase, and antiprotease activities. There was an increase in the expression of lysozyme gene in the spleen of treated fish. Mid dose of CSME caused the minimum mortality of 10% (consequent relative percentage survival = 73) which is comparable to that of the positive control.

Conclusion: CSME is considered to have the potential to be developed into an immunostimulant for finfish aquaculture. Keywords: Aeromonas hydrophila, Caulerpa scalpelliformis, immunostimulant, macroalga, Oreochromis niloticus.

Keywords: Aeromonas hydrophila, Caulerpa scalpelliformis, immunostimulant, macroalga, Oreochromis niloticus.

How to cite this article: Yengkhom O, Shalini KS, Subramani PA, Michael RD (2019) Stimulation of non-specific immunity, gene expression, and disease resistance in Nile Tilapia, Oreochromis niloticus (Linnaeus, 1758), by the methanolic extract of the marine macroalga, Caulerpa scalpelliformis, Veterinary World, 12(2): 271-276.

Received: 15-11-2018  Accepted: 11-01-2019     Published online: 16-02-2019

Corresponding author: R. Dinakaran Michael   E-mail: dean.sls@velsuniv.ac.in

DOI: 10.14202/vetworld.2019.271-276

Copyright: Yengkhom, et al. This article is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.