Acta Vet. Brno 2006, 75: 571-577

Effects of Oxytetracycline Containing Feed on Pond Ecosystem and Health of Carp (Cyprinus carpio L.)

Z. Svobodová1,2, E. Sudová1, L. Nepejchalová3, S. Červinka4, B. Vykusová1, H. Modrá2, J. Kolářová1

1University of South Bohemia České Budějovice, Research Institute of Fish Culture and Hydrobiology, Vodňany, Czech Republic
2University of Veterinary and Pharmaceutical Sciences Brno, Czech Republic
3Institute for State Control of Veterinary Biomedical and Medicaments, Brno, Czech Republic
4State Veterinary Institute České Budějovice, České Budějovice, Czech Republic

Received June 30, 2006
Accepted September 5, 2006

The aim of the present study was to assess the effects of medicated feed, Rupin Special gran. ad us. vet. with oxytetracyclini chloridum as active ingredient (5 g kg-1 feed), on physical and chemical characteristics of a pond ecosystem and the health of carp of two age groups in a pilot operation. The medicated feed was administered in 8 doses (15 g kg-1 live weight). In the study, temperature, oxygen concentration, pH, microbiological, hydrobiological and hydrochemical variables of pond water were monitored. The fish health assessment was based on clinical, pathological-morphological and haematological examinations of 80 individuals in total. The examinations were made before, during, immediately after and 15 days after the administration of medicated feed. No effects on water quality were found. An important histological change after the application of 8 doses was the loss of haematopoietic tissue from the spleen, and dystrophic changes in the renal duct epithelium. A decrease in leukocyte and lymphocyte counts and in total blood plasma protein concentrations (P < 0.05) were observed already after the 3rd dose of Rupin Special. It follows from the results of the study that Rupin Special should be used in only 4 (exceptionally 6) doses, compared to the originally recommended 8 doses.