Folia Parasitologica 67:024 (2020) | DOI: 10.14411/fp.2020.024

Experimental infection model with the bivalvulid Enteromyxum leei (Myxidiidae) in the sharpsnout seabream, Diplodus puntazzo (Sparidae), and evaluation of the antiparasitic efficacy of a functional diet

Morgane A. Henry¹, Fotini Kokou^1,2, Oswaldo Palenzuela³, George Pyrenis¹, George Rigos¹

¹ Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research, Anavissos, Attiki, Greece;

² Aquaculture and Fisheries Group, Wageningen Institute of Animal Sciences, Wageningen University, Wageningen, The Netherlands;

³ Institute of Aquaculture Torre de la Sal (IATS-CSIC), Castellón, Spain.

An infection model for sharpsnout seabream Diplodus puntazzo (Walbaum) challenged with the myxosporean Enteromyxum leei (Diamant, Lom et Dyková, 1994), resembling the natural infection conditions, was used to evaluate the antiparasitic efficacy of a functional diet. Fish of an average weight of 12.5 ± 1.2 g were delivered either a functional (included as feed supplement at 0.3% levels) or a control extruded diet. After four weeks of administration of the experimental diets, fish were challenged with the parasites (cohabitation with infected donors; donor: recipient ratio 1 : 1). The experiment was terminated four weeks after the start of the challenge. At the end of the experiment, growth and feeding (specific growth rate and feed efficiency), as well as immunological parameters (respiratory burst activity, antibacterial activities, hemoglobin concentration, anti-protease activity and ceruloplasmin activity) were measured along with cumulative mortality and total parasitic count in the gut. No significant difference was evident with regard to growth and feeding performance, mortality, gut parasitic load or immunological parameters as the parasitical challenge significantly affected both the performance of the control and functional diet fed fish. However, there was a less prominent impact on antibacterial, anti-protease and ceruloplasmin activity in fish fed with the functional diet. Overall, the present study validated the experimental cohabitation infection model and evaluated the efficacy of a functional ingredient as an antiparasitic agent, showing some potential effects on the fish immune response.

Keywords: Cohabitation parasitical challenge, Myxosporea, immune response, hemoglobin, inflammation, gut parasite, parasite intensity, parasite prevalence, qPCR.

Received: January 27, 2020; Revised: May 6, 2020; Accepted: June 4, 2020; Published online: September 22, 2020  Show citation