Biopsy-based normalizations of gill monogenean-infected European catfish (Silurus glanis L., 1758) stocks for laboratory-based experiments

András Bognár; Muhammad Hafiz Borkhanuddin; Shion Nagase; Boglárka Sellyei

doi:10.7717/peerj.18288

Biopsy-based normalizations of gill monogenean-infected European catfish (Silurus glanis L., 1758) stocks for laboratory-based experiments

PeerJ. 2024 Nov 14:12:e18288. doi: 10.7717/peerj.18288. eCollection 2024.

Authors

András Bognár¹, Muhammad Hafiz Borkhanuddin^{2

3}, Shion Nagase^{1

4}, Boglárka Sellyei³

Affiliations

¹ Frontline Fish Genomics Research Group, Department of Applied Fish Biology, Institute of Aquaculture and Environmental Safety, Hungarian University of Agriculture and Life Sciences, Keszthely, Hungary.
² Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, Kuala Nerus, Terengganu, Malaysia.
³ HUN-REN Veterinary Medical Research Institute, Budapest, Hungary.
⁴ Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Tokyo, Japan.

Abstract

Ectoparasites cause serious problems during the aquaculture production of food fishes. In this study, we set out to develop and test protocols for maintenance and sampling European catfish (Silurus glanis L., 1758) stocks infected with a gill monogenean, Thaparocleidus vistulensis (Siwak 1932) Lim 1996. When we compared the feasibility of two cohabitation-based parasite culture systems (i.e., static vs. flow-through), we found that the life cycle of T. vistulensis was completed in both habitats. In our experience, static tank systems with regular water exchange allowed better daily quality control of the parasite culture than continuous flow-through systems. We investigated the microhabitat preference of T. vistulensis on the gills of infected European catfish. A balanced distribution on the two lateral gill sets and a decreasing trend in parasite numbers from anterior gill holobranches towards the posterior ones was observed. Using these results, we developed a minimally invasive sampling protocol to estimate the parasite load of individuals. The biopsy aimed at four sectors (#6, #7, #10, and #11) situated within the distal and middle zones of the first holobranch on the left side, encompassing both rows of filaments. Biopsy-based estimates of parasite loads were validated by comparing them to full parasite counts of the same individuals and showed statistically significant correlations. Our biopsy-based method is designed to identify experimental animals with similar parasite loads and create groups of hosts with comparable burdens. This setup is expected to generate reduced between-group differences for expensive experiments (e.g., high throughput transcriptomic or epigenetic studies). We propose that the biopsy-based pre-sorting procedure should be considered in similar experiments with other cultured fish species and their gill monogeneans following a thorough fine-tuning of the experimental conditions.

Keywords: Experimental group formation; Gill biopsy; Gill parasite; Monogeneans; Parasite culture; Total parasite count estimation.

MeSH terms

Animals
Aquaculture / methods
Biopsy / methods
Catfishes* / parasitology
Fish Diseases* / parasitology
Gills* / parasitology
Parasite Load
Trematoda / physiology
Trematode Infections / parasitology
Trematode Infections / veterinary

Grants and funding

András Bognár was supported by the Frontline Research Grant of the National Research, Development and Innovation Office of Hungary (KKP 140353). Muhammad Hafiz Borkhanuddin recieved support from the Ministry of Higher Education, Malaysia (MOHE) for the MHB Postdoctoral Program. Shion Nagase received financial support of the Tobitate! (Leap for Tomorrow) Study Abroad Initiative by the Ministry of Education, Culture, Sports, Science and Technology, Japan, and the support of Prof. Carlos Strüssmann with the arrangement of her study trip to Hungary. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.