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PROVOZNÍ OVĚŘENÍ MONOSEXNÍCH OBSÁDEK V CHOVU TRŽNÍHO KEŘÍČKOVCE JIHOAFRICKÉHO (Clarias gariepinus)
JELÍNEK, Jaroslav
The objective of the present diploma thesis was to verify the influence of monosex populations in African catfish (Clarias gariepinus) fishfarming on growth rate, growth heterogeneity, feed conversion ratio, yield and product quality in the operating conditions of a small fish farm with a recirculating aquaculture system. In six tanks with a volume of 0,3 m-3, 60 individuals with an average unit weight of 614 ? 135 g, all-male, all-female and mixed- sex (in 2 repeats each) were deployed. The fish were fed with feed in the usual and registered feed doses 4 times a day. At the end of the experiment, 119 days average fish weight reached 1445 ? 911 g. The composition of the populations was found to have a statistically significant effect on the food conversion ratio, gonadosomal index, and fillet yield. Statistically significant differences were not found in specific growth ratio (SGR), growth heterogeneity, or muscle composition (fat and protein content). The yield of fillets without skin reached only 40.74 ? 1.81% for all-female group. An economically advantageous alternative to a mixed -sex groupe with a sex ratio of 1: 1 was a all-male fishfarning groupe where the yield of skinless fillets was 46.99 ? 1.12%. Food conversions were also more favorable for all-male groups (FCR = 1.08 ? 0.08 and 1.04 ? 0.12) compared to all-female (FCR = 1.18 ? 0.21 and 1.25 ? 0.19 ). The fat content of the muscle at the end of the experiment varied between 5.10-10.53% for each group without proven dependence on the type of the group, the protein content showed only minimal differences, varied between 15.18 and 16.46%, dry mass contained muscle from 24.23 to 27.95% without proven dependence on the type of occupancy. Significant economic impact has the composition of groups when evaluating the yield of fillets without skin as the final product.
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Testing the production efficiency of special types of feed fot catfish in a rearing of African catfish (Clarias gariepinus) in a recirculating system
ČTRNÁCT, Petr
The main objective of this diploma thesis is compare the production efficiency of special types of feed for African catfish in experimental conditions in a recirculating system with biological treatment of water. It was tested four different types of floating feed, differing in the proportion of main components, the chemical composition and determining - for catfish (CatCo GROWER - 12 EF, CatCo SELECT - 13 EF and CatCo GROWER - 13 EF), respectively salmonid fish species (Dibaq Trout Evolution). The primary outcome indicators was the growth rate, individual weight (and it's variability), feed conversion ratio, the cost of feed consumed per unit of growth and product quality, evaluated according the average dress-out percentage of skinless fillets, organoleptic assessment and chemical composition of flesh.
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