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Škůdci krmných substrátů - druhové složení, význam a možnosti likvidace
Hustá, Valérie
This bachelor thesis examines pests of feed stuff. The literary research describes the most important pests, the extent of their influence in agriculture, food industry and methods of pest control with an emphasis on further use of the substrate. This work focuses on non-chemical methods which do not have a negative impact on the safety of feed stuff, food and the environment. The next part describes the effect of low temperatures as physical method of disruption on the life manifestations of insects and mites. To test this, one of the most common pests, Tenebrio molitor, were exposed to different low temperatures (0 °C, 3 °C, and 6 °C) for durations of 5 min, 10 min and 20 min. The feed intake, weight gain and feed conversion were measured. The results show decreasing temperature and increasing expose interval increased the feed intake. This experiment indicates that low temperature do not eliminate pests or mitigate damages but can stimulate pests to take more feed stuff resulting in more damage and losses.
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The influence of the amount of the daily feed ration on growth Northern whitefish (Coregonus peled) in intensive conditions.
MORAVA, Jakub
Influence of the amount of the daily ration in juvenile whitefish peled was tested at doses of 1,5 %, 2,5 %, 3,5 % and 4,5 % fish biomass using feed BioMar Inicio 1,1 mm. The experiment lasted 63 days. At the beginning of the experiment were seeded fish with an average weight of 1,82 +- 0,48 g, and a total length of 65 +- 6 mm. After the first phase of the rearing (0 - 21 days) were observed significant differences between test groups. Fish showed the highest growth of the group fed 4,5 % (80 mm). Specific growth rate was 1,5 % 1,1 %.day-1, 2,5 % 2,6 %.day-1, 3,5 % 4,4 %.day-1, 4,5 % 4,7 %.day-1. In the second period of the rearing (21 - 42) significantly lagged growth in the fish group fed 1,5 % over the rest, and their growth was a mere 9 % of the total length. In other groups, there were significant changes in body length with the highest values in the group fed 4,5 % of the biomass of fish where the specific growth rate moved 1,5 % 1,9 %.day-1, 2,5 % 3,1 %.day-1, 3,5 % 3,9 %.day-1, 4,5 % 4 %.day-1. In the last part of rearing (42 - 63) the highest growth was confirmed again in the group fed 4,5 %. This group achieved an increase of 60 % body length compared to the group fed 1,5 %. The specific growth rate over that period was of the lowest value. The highest growth rate was calculated for the group of 4,5 % 3,7%.day-1, 3,5 % 3,6 %.day-1, 2,5 % 2,9 %.day-1 and 1,5 % 1,6 %.day-1. At the end of the experiment measured the average individual fish in the group fed 1,5 % 84 +- 7 mm, 2,5 % 106 +- 10 mm, 3,5 % 122 +- 10, 4,5 % 148 +- 11 mm.
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