Acta Vet. Brno 2021, 90: 233-253

Plant-based and immunostimulant-enhanced diets modulate oxidative stress, immune and haematological indices in rainbow trout (Oncorhynchus mykiss)

Hana Minářová1,2, Lucie Bláhová3, Jiří Kalina3, Ivana Papežíková1,4, Jan Mareš4, Radovan Kopp4, Libor Vojtek5, Pavel Hyršl5, Stanislava Reschová2, Miroslava Palíková1,4

1University of Veterinary Sciences Brno, Faculty of Veterinary Hygiene and Ecology, Department of Ecology & Diseases of Zoo Animals, Game, Fish and Bees, Brno, Czech Republic
2Veterinary Research Institute, Department of Infectious Diseases and Preventive Medicine, Brno, Czech Republic
3Masaryk University, Faculty of Science, RECETOX, Brno, Czech Republic
4Mendel University in Brno, Faculty of AgriSciences, Department of Zoology, Fisheries, Hydrobiology and Apiculture, Brno, Czech Republic
5Masaryk University, Faculty of Science, Department of Experimental Biology, Brno, Czech Republic

Received September 14, 2020
Accepted May 26, 2021

The aim of this study was to investigate the effects of three commercial diets, standard, immunostimulant-supplemented (β-glucan, vitamins C and E) and plant-based, on the degree of oxidative stress in tissues of rainbow trout (Oncorhynchus mykiss). Selected immune and haematological indices were measured and challenge with Aeromonas salmonicida was conducted. The plant-based diet systemically modulated all oxidative stress biomarkers (thiobarbituric acid reactive substances; reduced and oxidised glutathione and their ratio) in the intestine. The ratio was elevated in all organs (liver, kidney, muscle and intestine) and an enhancement of respiratory burst and complement activity was observed even in the control fish. With the standard diet, an elevation of thiobarbituric acid reactive substances in the intestine and a decrease in some immune indices appeared after challenge. Less distinctive changes and the lowest mortality rate (the highest being with the plant-based feed) were obtained with immunostimulants. Increased total immunoglobulin, relative lymphocytosis and a decrease in the phagocyte count were observed. This study contributes especially by a thorough examination of oxidative stress indices in different tissues. The exact composition of these commercial diets is a trade secret; however, knowledge of their effects is extremely important for fish farmers using them; therefore, this study has a great practical impact.


This study was supported by the Ministry of Agriculture of the Czech Republic (MZe NAZV QJ 1510077), the Ministry of Education, Youth and Sports of the Czech Republic (LM2018121 and CZ.02.1.01/0.0/0.0/17_043/0009632) and by the project PROFISH CZ.02.1.01/0.0/0.0/16_019/0000869. The project is financed by the European Regional Development Fund in the operational programme VVV MŠMT. The authors would also like to thank Dr. Kevin Roche for his linguistic assistance and Dr. Kristýna Jánová for technical support.


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