engleski

Growth and osteological development of two Croatian common carp (Cyprinus carpio L) strains – preliminary study

Introduction: Growth and osteological development of two Croatian common carp strains, Poljana mirror carp (PMC) and Poljana scaly carp (PSC) were studied. Comparative analysis was undertaken from the 4 to 26 day post hatching (dph). The aim of the present study was to collect data on developmental processes as a basis for further detailed research. Materials and Methods: Offspring of both strains were sampled after the artificial spawning at Poljana Fish Farm. Starting from 8 June (4 dph), larvae were transferred into the nursery ponds and first sample of eight specimens was taken. Further sampling of 8 fish per sample was conducted 6 times, at 15, 17, 19, 22, 24 and 26 dph respectively. Fish were euthanized by immersion in a solution of MS-222. Feeding of early fry in nursery ponds was based on natural food along with the additional feed (fish meal, wheat flour, corn flour and vitamin and mineral mixtures). Average total length (TL) and body mass were used for correlation with dph. Staining was carried out according to Dingerkus and Uhler (1977). Ontogenesis was observed under Olympus SZX7 stereoscopic microscope. Results: In both group, at 4 dph cartilaginous elements of the head and vertebral column were identified. In PMC at 15 dph the majority of the skull elements were ossified and ossification was started on fin bones. At 19 dph process of ossification is mostly finished. In PSC at 15 dph the ossification has started in majority of the skull elements but ossification of some bones (quadrate e.g.) finished at 22 dph. The beginning of fin ossification was noticed at 15 dph and finished at 26 dph. Conclusion: PMC in a shorter time achieves greater mass and TL than PSC. Proportionally, the process of ossification is much more rapid in that line. The results obtained indicate the need for more frequent sampling (every two days) at a distance of 4 to 15 dph.

common carp, osteological development

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