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Changes in the splenic melanomacrophage centre surface area in southern bluefin tuna (Thunnus maccoyii) are associated with blood fluke infections


Nowak, BF and Dang, TS and Webber, C and Neumann, L and Bridle, A and Bermudez, R and Evans, D, Changes in the splenic melanomacrophage centre surface area in southern bluefin tuna (Thunnus maccoyii) are associated with blood fluke infections, Pathogens, 10, (1) Article 79. ISSN 2076-0817 (2021) [Refereed Article]


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Copyright 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// 4.0/).

DOI: doi:10.3390/pathogens10010079


Melanomacrophage centres (MMCs) are aggregates of macrophages accumulating various pigments. They have been proposed as an indicator of fish immune response. Blood flukes are common parasites in farmed fish. Two cohorts of wild Southern Bluefin Tuna (Thunnus maccoyi) were examined at transfer, before treatment against blood flukes (pre-treatment) and at harvest. MMCs were assessed in histological sections using image analysis, while Cardicola forsteri and Cardicola orientalis infection severity was determined using qPCR, count of adult flukes in heart flushes and count of eggs in gill filaments. Fish from both cohorts showed the same pattern in the changes in the surface area of MMCs. The surface area of splenic MMCs increased over the ranching duration and was positively correlated to the PCR determined copy numbers of Cardicola forsteri ITS2 rDNA in the gills of those fish. However, the infection with blood fluke was more variable, both between cohorts and individuals within the same cohort. Eggs of blood fluke were detected in renal MMCs using histology. Cardicola forsteri had a higher prevalence than Cardicola orientalis. This study contributes to our understanding of blood fluke infections in Southern Bluefin Tuna and their interactions with MMCs.

Item Details

Item Type:Refereed Article
Keywords:parasite, melanomacrophage centre, tuna
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Fisheries sciences
Research Field:Fish pests and diseases
Objective Division:Animal Production and Animal Primary Products
Objective Group:Fisheries - aquaculture
Objective Field:Aquaculture tuna
UTAS Author:Nowak, BF (Professor Barbara Nowak)
UTAS Author:Dang, TS (Ms Thi Dang)
UTAS Author:Neumann, L (Mr Lukas Neumann)
UTAS Author:Bridle, A (Associate Professor Andrew Bridle)
ID Code:143435
Year Published:2021
Web of Science® Times Cited:2
Deposited By:Fisheries and Aquaculture
Deposited On:2021-03-17
Last Modified:2021-10-07
Downloads:18 View Download Statistics

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