|
|
Vliv nasycení kyslíku ve vodě na efektivitu intenzivního chovu candáta obecného (Sander lucioperca) v recirkulačním akvakulturním systému
VOJTA, Petr
This thesis deals with an issue of Zander (Sander lucioperca) production in a recirculating aquaculture system RAS in different oxygen rates (50-80% O-, 80-110% Os and O+ 110-150%). Zander weighted W=22,98?15g was planted into two identical recirculating systems with different water temperature. SGR, FCR and FC of survival and general health condition of kept fish in hematology, biochemistry as well as stress indicators were evaluated. The results proved a negative influence of hypoxia (50-80%) on the food reception, growth and general survival of experimental fish kept in this environment in both the recirculating systems with water temperature 20 and 23°C. In the group O- kept in RAS 20°C, higher coefficient of FCR=1,11 was proved in comparison with group O (normoxia) and group O+ (hyperoxia), where no significant difference (p0,05) was recorded. The health condition showed a significant difference (p0,05) of O group in comparison with group O+ and O in RAS 20°C during the TBARS evaluation (brain, gills, muscle), assessing SOD in liver, and GPx (brain and muscle). By determining the HSI, SSI and VSI indexes, the significant differences (p0,05) of HSI and VSI for O+ and O groups in comparison with O- were proved.
|
|
| |
|
|
Converting of juvenile zander (Sander lucioperca) to artificial diet (preliminary results)
Baránek, V. ; Mareš, J. ; Prokeš, Miroslav ; Jirásek, J. ; Spurný, P.
Weaning success of pond-reared zander (Zander lucioperca) fry was evaluated using three different converting methods: direct converting to dry feed (Bio-Optimal Start 0.5-0.8 mm) – variant A, three– day application of semi-moist feeding mixture on the base of fish – variant B and three-day application of semi-moist mixture + three-day co-feeding of semi-moist mixture and dry feed. These methods were evaluated regarding specific growth rate (SGR), Fulton´s factor of weight condition (FWC), survival and cannibalism. The average onset total length of fish was 35.22 ± 2.15 mm and the average individual weight was 0.31 ± 0.05 g. There were 600 individuals in each circular tank. The initial stock density was 0.62 g.l-1 (2 fish.l-1). The water temperature during this experiment fluctuated in intervals 22 – 24oC. Fish survival during a 14-day period of rearing ranged from 34.33% [C] to 50.33% [A]. Variant A and B were achieved better weaning performance than variant C regarding all parameters.
|
|
|
Rearing of the zander (Sander lucioperca) stock material under controlled conditions (preliminary results)
Baránek, V. ; Mareš, J. ; Spurný, P. ; Prokeš, Miroslav ; Baruš, Vlastimil ; Němec, M.
The aim of this study was to check the possibilities of exploitation of summer zander (Sander lucioperca) fry for production of stock material under controlled conditions. Two groups of these fish were converted from natural diet to artificial diet using the semi-moist feeding mixtures (variant A) and trout feed (Dan-Ex 1352 - variant B). The average total length of imported fish was 44,3 mm and the average idividual weight was 0,606 g. There were 255 individuals in each tank. The initial stock density was 2,34 g.l-1 (3,86 ks.l-1). The water temperarute during this experiment fluctuated in intervals 21 ů 23 oC. Our simple experiment confirmed possibility of exploitation of summer zander fry to intensive rearing of stock material.
|
guest ::
