Using of recirculation systems for rearing of fish is common practice in Western Europe countries. Benefits of this systems are utilized in recovering programs of endangered species of fish. In this work we had paid attention on suitability of RAS for rearing Nase, Vimba bream and Barbel. In the first part two six-month experiments were conducted. The five-month-old nase and vimba bream had been trained on pellet feed and acclimated to four different temperatures. The WT fluctuated in parallel with ambient outside conditions at an average of approximately 4 °C for the inflow system and approximately 15, 18 and 21°C in closed, recirculation systems. The total length and weight were measured at two-week intervals and SGRw, FCR and survival were monitored. We observed a positive effect of higher water temperatures on their growth rate of each species. Both groups (WT 21°C) had the most rapid growth and highest SGRw. Growth rate and SGRw were lowest for each species in group with the ambient temperature conditions. Lower temperature at the level of 18°C gave good results in comparison to rearing in cold water. Individual weight was 3.25 and 4.13 times higher for nase and vimba bream, respectively. The temperature 15°C was chosen with regard to the functioning of the biofilter and in this experiment, it proved to be a minimal temperature suitable for rearing of river fish species in RAS. The economic costs to maintain this temperature is low, but the effect of production considered this level of WT as very less effective in several aspects. To conclude this part, we found intensive winter rearing of nase and vimba bream is an effective way to prepare fish for spring restocking. In the second part we have tested suitability of Vimba bream as a trainer fish for adaptation of pikeperch for commercial pellet diet. One of the basic problems in pikeperch culture in RAS is adapting early life stages to pelleted feed (PF). Our work compares four different ways of adapting 6-week-old pikeperch fingerlings to feeding on a commercial diet. The methods were designated, A - use of trainer fish and direct application of PF; B - use of trainer fish and gradual addition of PF with natural food (NF, chironomid larvae); C - direct application of PF only; D - gradual addition of PF with NF. The growth trial experiment (including adaptation to PF) lasted 14 days by which time all experimental groups were accepting PF. Pikeperch fingerlings in group A grew significantly faster and PF was more readily accepted compared to other groups. Other characteristics observed (total weight increment, FCR) also support the use of trainer fish and direct application of PF for pikeperch in their adaptation to intensive culture. The aim of the final study were to compare the effect of anaesthetics MS 222, clove oil, 2- phenoxyethanol and Propiscin on haematological and blood biochemical profiles in vimba bream. The haematological and blood biochemical profiles of vimba bream anaesthetized with MS 222 (100 mg/l), clove oil (33 mg/l), 2- phenoxyethanol (0.4 ml/l), Propiscin (1.0 ml/l) and non-anaesthetized control group were tested. Each tested group was divided into two subgroups. The first subgroup was sampled immediately after 10-min anaesthesia. Second subgroup was sampled 24 h after 10-min anaesthesia. The 10-min of exposure to the anaesthetics had no effect on the haematological profile of vimba bream. The effect of anaesthetics on biochemical indices of blood plasma was demonstrated. The exposure of the anaesthetics 2-phenoxyethanol and Propiscin influenced levels of glucose, ammonia and the activity of aspartate aminotransferase compared with the control group. The level of triacylglycerols and the activity of lactate dehydrogenase was affected to exposure of MS 222. Based on the results only clove oil had no effect on the haematological and blood biochemical profiles. Other anaesthetics tested more or less affect value of blood biochemical profiles.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:364450 |
| Date | January 2017 |
| Creators | LEPIČ, Pavel |
| Source Sets | Czech ETDs |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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