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Možnosti léčby smíšených infekcí ryb
KOCOUR, Jakub
Fish diseases can be one of the factors slowing down the current development of aquaculture. Frequent causes of these diseases are pathogenic bacteria and parasites. The aim of this study was to test the effects of peracetic acid (PAA) and hydrogen peroxide (H2O2) on haematological and biochemical indicators as well as on the bacterial and parasitic load in fish. Common carp (Cyprinus carpio L.) were exposed to PAA (1.5 mg?l-1 ) and H2O2 (5 mg?l-1 ) for a period of 4 days. After the test ended, blood was collected from the fish to determine haematological and biochemical indicators, and swabs from gills and skin were taken for bacterial and parasitological examination. Haematologically, the following were determined: haematocrit (PCV), haemoglobin content (Hb), mean erythrocyte count (RBC), mean erythrocyte volume (MCV), erythrocyte haemoglobin (MCH), and mean corpuscular haemoglobin concentration (MCHC). From the blood plasma, the following biochemical indicators were assessed: glucose (GLU), total protein (TP), albumin (ALB), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), inorganic phosphate (PHOS), calcium (Ca), triglycerides (TRIG), and globulins (GLOB). The haematological examination showed a statistically significant difference only in the mean erythrocyte volume (P<0.05), with an increase in MCV for the tested substances. Biochemical examination revealed statistically significant (P<0.01) increases in GLU, ALT, ALP, and PHOS levels. In TRIG, a statistically significant increase (P<0.05) occurred only in the group of fish exposed to H2O2. The last statistically significant (P<0.05) difference was observed in GLOB, with a decrease in the group of fish exposed to PAA and an increase in those exposed to H2O2. Bacteriological examination showed a statistically significant (P<0.05) difference in the reduction of bacterial counts on the skin of the fish for both tested substances. Parasitological examination revealed a statistically significant (P<0.05) effect of PAA on the occurrence of Trichodina sp., leading to the complete elimination of these parasites on both the skin and gills. The results showed that the haematological and biochemical indicators were only slightly altered compared to the control. It can be inferred that the application of PAA and H2O2 at the tested concentrations does not significantly stress the fish organism. It was also confirmed that PAA has antibacterial and antiparasitic effects, while H2O2 has only antibacterial effects.
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Histology of fish gills - processing and evaluation of preparations
KOCOUR, Jakub
Histology is the science that deals with the microscopic structure and structure of the tissues of organisms. This science is unique in that it deals with the study of tissues cut into very thin sections. This allows us to look into microscopic structures that may not be visible to the naked eye. The aim of this work was to develop a literature review where the main task was to describe the structure of the gills, the critical points in their histological processing and to classify the gill changes. The aim was also to create a photographic documentation of the histological preparation process. The first part of this thesis is devoted to fish gills. The gills are a multifunctional organ that is constantly in contact with the surrounding water. It is a medium for the exchange of gases and other substances and is very sensitive to external stimuli. Through the gills of fish, various ions and substances are exchanged, taken in and excreted. An interesting feature is, for example, the passage of nitrite ions, which enter the body of the fish through the Cl-/HCO3- exchanger. Such passage is prevented by chloride ions, which are competitively excreted with nitrite ions. In the next part of this thesis are the topic of methods of histological processing of fish. Several histological processing options are described in this thesis, which lead to the same goal, i.e. a histological, mostly also permanent preparation. During preparation, one step is staining. The most common dye is haematoxylin-eosin. This dye shows the cellular structures very well. However, some structures are more difficult to distinguish from each other, in which case special staining methods can be used. All these properties of gills make it an organ that is suitable for many fish health evaluation. Despite this, the gills, specifically the histological evaluation of the gills, are usually only an additional evaluation.
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