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Vliv alternativních zdrojů bílkovin v rybím krmivu na růst ryb a rostlin ve dvousmyčkovém akvaponickém systému
NIKL, Ondřej
The objective of this thesis was to evaluate the production efficiency of feeds which were designed with the intention of developing a special aquaponic feed. Further, to evaluate the content of nutrients in water, sludge and nutrient solutions and their influence on plant growth and finally suggest possible modifications to the feed composition. Aquaponic feed should respect nutritional requirements of fishes and plants, not put burden on the environment by not used nutrients and with regards to sustainability, use alternative sources of protein instead of marine fish meal. Because of that, three experimental isoprotein and isocaloric feeds were proposed. Feed A contained conventional ingredients including marine fish meal. Feed B used freshwater fish meal and exclusively plant proteins not regarding its origin. Feed C was made of sustainable and local sources of protein. The experiment was conducted in the aquaponic hall of Faculty of Fisheries and Protection of Waters, University of South Bohemia. As experimental material was used Nile tilapia (Oreochromis niloticus) and lettuce (Lactuca sativa). Feed B shown similar values of all production indicators as conventional feed A. Weight of fishes in system A after thirteen weeks increased by 143,68 % and in system B by 136,56 %. Weight of fishes in system B was at the end of experiment inconclusively lower by 4,08 %. Feed conversion ratio (FCR) of feed B (1,92?0,10) was inconclusively higher by 8,47 % against FCR of feed A (1,77?0,13). Average weight of aerial parts of plants growing in nutrient solution created from mineralized sludge gathered from system B, supplemented with missing nutrients reached value 221,8?33,9 g after four weeks. That was inconclusively more by 44,21 % than average weight of plants grown in special hydroponic solution and by 8,62 % more than weight of plants grown in enriched solution gathered from system A. Experimentally it was proven that in aquaponic feeds it is possible to substitute marine fish meal by alternative source of protein and using these feeds ensure an effective nutrition for fish and plants in a two-loop aquaponic system.
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Využití produktů ze zpracování konopí ve výživě ryb
Žejdl, Matěj
The aim of this bachelor‘s thesis was to create a literary review on the utilization of cannabis products in fish diets, mainly of common carp (Cyprinus carpio L.) and Nile tilapia (Oreochromis niloticus L.). Other plant-based feeds and their possible use in fish nutrition and nutrition of different farm animals were also studied. Furthermore, the issue of fish digestion and their nutrient requirements in feed was outlined. Part of the work contains a method for the conduction of a feed test, which will be performed on fish species Cyprinus carpio and Oreochromis niloticus in a recirculating aquaculture system at the Department of Fisheries and Hydrobiology at the Mendel University in Brno. Fish will be fed granulated mixtures, with the addition of products from processed cannabis. Lenght-weight parameters, production parameters and the effect of feed on fish organism and chemical composition of their tissues will be determined.
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Hematological changes in fish exposed to nitrites
FRANĚK, Roman
The aim of the thesis was to determine the effect of nitrite on hematological indices of rainbow trout (Oncorhynchus mykiss) and Nile tilapia (Oreochromis niloticus). After the fish were exposed to various concentrations of nitrites were determined 48hLC50. For the main test only fractional concentrations of these values were used. For rainbow trout it was 8 mg.l-1 NO2?, for Nile tilapia 11 mg.l-1 NO2?. The exposure of both species lasted for 48 hours. From fish blood were made blood smears to determine the influence of nitrite on size changes of erythrocytes and hematological parameters were set also. The effect of nitrite on changes in the ultrastructure of erythrocytes was determined by the electron microscopy. The erythrocyte nuclei of rainbow trout showed significant (p <0.05) shrinkage. The images of the electron microscope showed an increased amount of changes, especially in the form of various units within the cytoplasm of erythrocytes, was also visible nuclei shrinkage. There was significant (p < 0.01) reduction in the amount of hemoglobin and significant (p < 0.01) increase in the concentration of methemoglobin levels of the exposed groups. In the number of erythrocytes and hematocrit were not detected any changes. Hematological parameters of Nile tilapia did not show any size changes in the measured parameters, no changes were detected in the count of erythrocytes, hemoglobin and hematocrit values.
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