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Studie siamských dvojčat morčete domácího
NAVRÁTIL, Vojtěch
This diploma thesis deals with a unique case of a newborn Siamese guinea pig. Conjoined twins are always very rare, and concerning guinea pigs only a few previous cases have been described. The main subject of this study are the Siamese twins of the domestic guinea pig (Cavia aperea f. Porcellus), born in hobby breeding in the Czech Republic in 2019. The publication examines the external and internal structure of the body and the type of connection of both bodies in detail. Then it compares with other cases of born Siamese twin guinea pigs in the past. In general, it addresses the issue of domestic guinea pig reproduction and anatomy. It compares the weights of selected internal organs of the Siamese twin with normally developed youngs. From the results, conclusions are then drawn indicating the possible causes and consequences of the unusual case of Siamese twins.
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Testování háďátka octového (Turbatrix aceti) a substrátů pro eliminaci olejových látek z povrchové blanky pro raná stádia okouna říčního (Perca fluviatilis)
PŘIBYL, Tadeáš
This thesis evaluates an alternative life food Turbatrix aceti for feeding of European perch in its early life stages and the possibility of oily substances elimination from the surface water layer in perch aquaculture. It is of crucial importance to provide perch live food up to 20 days after hatching. Artemia sp. is commonly used for perch feeding in its early life stages. Five different feeding treatments with six replicates in each treatment were performed. The main investigated parameters were fish survival and growth (weight). Average survival (expressed as the number of fish survived) in each of five feeding treatments were: T 107, A5T1 5 145, A10T10 150, A 196 and A15T5 207. Treatment A and A15T5 were not significantly different. After termination of the experiment, the average weights in mg ? standard deviations after 20 days of rearing in given treatment were: A - 28.0 ? 7.7; T 2.9 ? 1.4; A5T15 4.4 ? 3.3; A10T10 7.4 ? 1.1 and A15T5 - 15.9 ? 2.7. The results indicate that Turbatrix aceti cannot be used for rearing of perch early life stages, since mortality was higher and weight lower than in control group, where Artemia sp. was used as a live food. The second experiment tested the possibility to reduce amount of swim bladder inflation failures in perch intensive aquaculture using several types of surface substrates. Swim bladder inflation rates in each treatment were as follows: O 55%, S 40 %, MT 58 %, ML 38 %, PP 65 %, C 48 %. The treatments were not significantly different from each other. Used surface layer collectors of oily substances have not been proved successful, since the percentage of successfully inflated swim bladders were not different from the control treatment, where no surface layer collector of oily substances was used.
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Indukce triploidie u candáta obecného (Sander lucioperca)
RŮŽEK, Martin
The aim of this study was to induce the triploidy in pikeperch (Sander lucioperca) with use of a cold shock. To induce the triploidy, fertilised egg were (spawning temperature 14,5 °C) submerged in a cold bath at the temperature of 2 °C. Time of initiation was 1; 3; 5; 7 and 10 minutes post activation. The exposure time was 20 and 40 minutes. Ploidy level of freshly hatched larvae was assessed with use of the flow cytometry. In both exposure times, the hatching rate was getting lower with later time of initiation (20 minutes exposure, hatching rate: 58,4-13,4 %; 40 minutes exposure, hatching rate: 28- 9,6 %). Number of malformed larvae increased with later time of initiation and longer exposure time (20 minutes exposure, malformed larvae 0-47,2 %; 40 minutes exposure, malformed larvae 0-58,8 %). None of the tested combination of exposure time and time of initiation led to a population containing 100 % triploid larvae. However, percentage of triploid larvae grew up with longer exposure time and later time of initiation. The best cold shock combination with highest yield of triploids were after 20 minutes long treatment initiated 10 minutes post activation (57,1 +- 14,2 %) and after 40 minutes long treatment initiated 10 minutes post activation (61,9 +- 8,2 %). The most important finding of this study is that cold shock treatment leads to triploidy in pikeperch. To obtain 100% triploid larvae, shorter exposure time and different shock temperature might be applied. It may also eliminate low hatching rate and high appearance of malformed larvae.
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