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Influence of water temperature on toxicity of free ammonia for fish and on amount of ammonia produced by fish
MECKO, Jozef
Determination of acute toxicity of free ammonia for fish in dependence on water temperature and determination of production of ammonia by fish in dependence of water temperature It was made a test of acute toxicity on akutní toxicity on Poecilia reticulata according to ČSN EN ISO 7346-2 and determination of acute lethal toxicity of substances for fish. Next was made test on excretion of ammonia by common carp in different temperatures of water. Fish were divided after a two pieces into basins.The water temperature was kept in basins on two level. Next test was realized in a similar way with a difference, that an amyloid gel with an addition of NH4Cl was aplicated by a probe to the digestive tract of fish. To control fish were aplicated the amyloid gel without an addition of NH4Cl. It was observed concetration of ammonia in water and the fish were bleeded to set haematocrit and biochemical values. On grounds of these values will be analyzed production of ammonia by one species of fish in dependence on water temperature.
EVALUATE THE PERFORMANCE PARAMETERS OF THE BREEDS OF COMMON CARP AND ITS CROSSBREDS
KŘÍŽ, Michal
The aim of the thesis was to evaluate the performance parameters of the breeds of common carp and its crossbreds by using the top-crossing. On the maternal position the Hungarian synthetic mirror carp line (HSM) was used. On this line, males of HSM, Telč mirror carp (TeL), Northern mirror carp (M72) and Amur mirror carp (AL) were crossed and a hybrid of Ropsha carp (ROP) and Tata carp (TAT) was used as their control group. Rearing of the tested groups was monitored from larval stage until their market size in ponds with a semi-intensive way of management in three localities (2 organisations). In the first year, each tested group was bred individually with internal control group of a different scaly covering phenotype in order to correct the influence of the environment on the weight achieved. In the second and the third year, all the groups were group-labelled and bred together in triplicate (three ponds) localities. In the individual stages of testing, the weight and the survival rate were recorded. Moreover, in the market size stage the biometric measurement and slaughtering value were evaluated. In the overall assessment of the results from all the localities carried out by the ANCOVA procedure, the highest weight at the K3 age was achieved by the hybrid HSM x AL (1413 {$\pm$} 31.5 g; Last square means {$\pm$} S.E.), whose weight was statistically comparable to the other hybrids (HSM x M72 a HSM x TeL). However, it was the only noticeably higher weight in comparison with the HSM (1257 {$\pm$} 31.5 g) with its ordinary heterosis effect of growth on the level of 12.4%. During the third year of testing, the survival ranged from 69.0 % in HSM x Tel to 73.4% in HSM x AL and the values were statistically comparable. The yield parameters (the proportion of the processed body, the proportion of filets with skin and the skinless ones) were similar in all the groups. In the previous periods of testing the results reflected the situation in the market size. As a result, it is concluded that preferably the hybrid HSM x AL could be exploitable in commercial breeding.

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