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Možnosti zvýšení adaptability a prevence negativních změn v chování u násady jesetera sibiřského (Acipenser baerii)
KODRAS, Marek
The experiment was performed to assess the impact of a modification in feed technology in the intensive rearing of Siberian sturgeon (Acipenser baerii) on the fish behavior. Four feeding regimes were tested in three repetitions: surface feeding during the day (DFSF), surface feeding at night (NFSF), bottom feeding during the day (DFBF), bottom feeding at night (NFBF). Sturgeon behavior was recorded using a video system in experimental observation tank before the application of different feeding regimens at 48th days post-hatching (dph) and every 20 days therafter (68th, 88th and 108th dph). In addition, the effect of five and ten-day starvation on fish behavior was determinated. Five parameters were tested: the total time spent in the lowest 10 and 25 % of the observation tank, the total time spent in the uppermost 10 and 25 % of the observation tank and the total activity. The whole experiment including larval rearing lasted 100 days and videos were analyzed using MATLAB software. Statistical differences were observed among the tested groups during our experiment. Experimental group NFBF at 88th dph showed the highest spending time in the lowest 25 % of the tank. Furthermore, NFBF at 68th and 88th dph displayed the lowest spending time in the uppermost 25 % of tank (only NFSF was not significantly different from NFBF at 68th dph). No statistical differences were observed in the uppermost or the lowest 10 % of the tank after all-day videorecording. After starvation, some differences were observed among the groups, however no clear trend or continuity with the data obtained before the starvation were found. In conclusion, the tested group NFBF showed better preconditions for intensive rearing of sturgeons, which might be subsequently stocked in open waters due to the lowest movement in the uppermost part of the tank (68th and 88th dph) than other tested groups. This could increase survival of the fish in the wild due to lower predation risk.
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Možnosti využití hmyzí moučky v krmivech pro candáta obecného (Sander lucioperca)
KODRAS, Marek
A feeding trial was carried out to assess the effect of replacing fish meal by partially deffated black soldier fly pre-pupae meal in feed for pikeperch (Sander lucioperca). A diet with fish meal, that covered 30 % of total protein, was used as a control. Three other diets contained 7,5%, 15% and 30% of insect meal, which coresponded to 25% (H25), 50% (H50) and 100% (H100) replacement of fish meal. Each tested group had 3 repetitions and experiment lasted 63 days. At the end of the trial, groups H25 and H50 did not show any significant statistical differences in growth and lenght performance compared to CON. There were no differences among groups in coefficient of variation, condition factor, hematocrit, feed conversion ratio, economic conversion ratio, fat and ash content in muscle. On the other hand, significant differences were observed in specific growth rate, contain of proteins in muscles, dry matter, somatic indexes and economic profit index. No differences in survival were found until 42. day. However, between 42. a 63. day of rearing high mortality caused by bacterial infection was observed in two of three tanks fed with H100 diet. This fact influenced this parameter for group H100. In conclusion, 7,5 % inclusion of insect meal from partially deffated black soldier fly pre-pupae meal, corresponding to 25% replacement of fish meal, may successfully replace fish meal in diet for pikeperch, as this substitution did not have negative influence on any parameter.
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Effective use RAS technolgy for breeding of ornamental fish in garden tanks.
MITÁŠ, Jaromír
The aim of this thesis was to evaluate the efficiency of the technology RAS for water cleaning and conditioning for ornamental tanks with an emphasis on sustainable conservation of water transparency. Initial costs for building the tank, operational costs and costs of purchasing fish were compared. Results include measurements that have been carried out on private property of the author, who breeds ornamental koi carp (Cyprinus carpio). The filtration of breeding tank was formed by vortex, by chamber with brushes, chamber with bioblocks and bioaquacitem. Tentative and 24 hours measurements of selected variables were used for data obtaining. The results indicate that the filter system is effective, but it had insufficient capacity. Transparency of water and elimination of glaucoma was solid by involving of UV lamp into the system of filtration. Available commercial resources were successfully used for controlling of filamentous algae. This thesis also includes a brief overview of ornamental fish species of our region, Moreover we mentioned the most common diseases, causative agents, symptoms and treatments. Overall, monitoring of the system of the garden's ornamental tank confirmed that water quality is dependent on the right choice and dimensioning of the filtration system and that current technology of recirculating of aquaculture systems can be successfully and effectively used within the construction and operation of tanks used for breeding of ornamental fish species.
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