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Vliv délky světelného dne na příjem krmiva a růst síha peledě (Coregonus peled) v intenzivním chovu
KOS, Martin
The effect of the length of the daylight on growth of in peled (Coregonus peled) juveniles was tested in the intensive culture. Fish of mean body weight 1.82 +- 0.48 g and total length of 65 +- 7 mm were divided into four groups (the ratio of light and darkness 12k12, 16k8, 20k4, 24k0). The experiment lasted for sixty-three days. Every twenty-one days fishes were sampled for biometric measurements. Fish reached mean body weight of 15 +- 4.9 g (12k12); 15.6 +- 4.5 g (16k8); 16.7 +- 4.5 g (20k4); 16.8 +- 5 g (24k0) in experimental groups. The longest total body length was detected in both 20k4 and 24k0 groups (127 +- 11 mm). The lowest one was registered in the 16k8 (114 +- 11 mm). The highest condition coefficient had group 16k8 and lowest was found out in group 20k4. Specific growth rate during the course of the experiment was 3.33 %xday -1 (12k12); 3.28 %xday -1 (16k8); 3.49 %xday -1 (20k4) and 3.43 % xday -1 (24k0). The highest final survival (95.8 +- 1.4 %) was achieved in group 12k12. On the contrary, group 16k8 showed lowest survival of 90.0 +- 4.6 %. There were no significant differences in final survival rate.
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The effect of feeding frequency on feed intake and growth for Peled whitefish (Coregonus peled) in intensive aquaculture.
DOFEK, Jan
Frequency influence of animal feed has been tested (6×, 4×, 2× and 1× per day). Food income and new arrival experiment was repeat in three phases after every 21 days. Fish age after 124 - 187 days from the beginning till the end of the experiment. Average weight in all tanks was 1.86 + - 0.5 g in first experiment phase (0. 21. days). At the end of first experiment fishes with the biggest weight were the one with frequency influence of animal feed 6 times a day. Individual weight at the end of first fishing was 4.21 + - 1.31 g (6× a day), 3.74 + - 1.24 g (4× a day), 3.6 + - 0.46 g (2× a day), 2.89 + - 1.29 (1× a day). The best growth group become group with frequency influence (6× a day and 4× a day) and on the other hand group with the smallest growth was the group with frequency influence (1× a day). Fishes achieved weight of 15.9 + - 4.5 g (6× per day), 15.1 + - 4.9 g (4× per day), 12.19 + - 5.4 g (2× per day), 5.54 + - 4.05 g (1× per day). Chance of survival (96 %) was the best in group with frequency influence of animal feed (4× a day) and the last (89 %) was the group with frequency influence (6× a day). The highest rate of heterogeneity (74 + - 9 %) was in third phase of experiment in fish group with frequency influence (1× a day) as compared to group (28 + - 2 %) with frequency influence of animal feed (6× a day).
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The effect of temperature on feed intake and growth of peled (Coregonus peled) in intensive culture.
VÁLEK, Pavel
The effect of water temperature within the range from 13 to 25 °C was tested on two weight cohorts of fish (age 74 and 230 days post hatch) during two subsequent growing experiments. Significantly better growth rate within the temperature range from 19 to 22 °C was observed in younger fish (initial body weight 0.60 +- 0.04 g). The mean individual weight at the end of the experiment was followed 5.19 +- 1.59 (13°C), 8.16 +- 2.08 (16 °C), 9.78 +- 2.50 (19 °C), 9.06 +- 2.75 (22 °C) and 4.70 +- 2.13 g (25 °C). Significantly lower survival (29.6 +- 6.3 %) was monitored in fish reared at 25 °C. Significantly higher growth heterogeneity (CV 50.1 +- 5.1 %) was observed in fish reared at 25 °C in comparison with the other groups. Significantly better growth rate within the temperature range from 16 to 22 °C was observed during second experiment on older juveniles (initial body weight 13.7 +- 2.9 g). Final mean body weight in appropriate group was observed as followed 25.2 +- 6.8 (13 °C), 30.3 +- 7.1 (16 °C), 29.7 +- 8.0 (19 °C), 30 3 +- 8.8 (22 ° C) and 23.9 +- 5.5 g (25 °C) at the end of the experiment. Fish reared at temperatures 22 and 25 °C showed significantly lower survival rate (70.8 +- 18.8 and 40.8 +- 6.3 % respective) in comparison with the other groups.
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