Wyniki wyszukiwania - Biblioteka Nauki

1

Nitrogenous compounds and oxygen concentration as the key density dependent factors to optimize growth of beluga, Huso huso (Actinopterygii: Acipenseriformes: Acipenseridae), in circular fiberglass tanks

100%

Rafatnezhad S. , Falahatkar B.

Acta Ichthyologica et Piscatoria

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2011

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tom 41

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nr 4

XX

Background. Beluga, Huso huso, known also as the great sturgeon, is a valuable fish in terms of meat and caviar production. It has been implicated that intensive fish culture is a major culprit for deterioration of water quality through metabolic excretion of fish in the aquatic environment. The aims of this study were: to determine the effect of the stocking density on the water quality, to assess the effect of water quality changes on growth of beluga juveniles, and also to determine the optimum density for culture in fiberglass tanks. Materials and methods. Fish were randomly distributed into 15 tanks at 5 different densities including 1 kg · m–2 (3.90 kg m–3), 2 kg · m–2 (7.09 kg · m–3), 4 kg · m–2 (14.54 kg · m–3), 6 kg · m–2 (21.19 kg · m–3), and 8 kg · m–2 (28.64 kg · m–3) with 3 replicates. Specific growth rate (SGR), yield (Y), average daily growth (ADG), absolute weight gain (AWG), and relative weight gain (RWG) were calculated. Throughout the experiment, water quality parameters including ammonia (NH3), nitrite (NO2), nitrate (NO3) dissolved oxygen (DO), and oxygen saturation (OS) were also measured. Results. Stocking density considerably influences the growth of beluga juveniles and water quality during 56 days of rearing. DO, OS, NO2, NO3, and NH3 were significantly different among treatments. pH and temperature showed no significant effect under different stocking densities. NO2 and NO3 increased, while DO decrease as the stocking density of fish increased. At the end of the 56 days of rearing, all the growth parameters (final weight, total length, SGR, Y, ADG, AWG, and RWG) were significantly different among treatments. Survival was 100% in all of the rearing densities. Conclusion. Results of this study showed that the density of fish had a significant effect on water quality and a high density culture accompanied by intensive feeding may result in high concentrations of nitrogen compounds, and low concentrations of dissolved oxygen in the water of culture tanks. Each of the factors (increase nitrogenous compounds and decrease in oxygen) could suppress the growth of Huso huso juveniles.

2

Optimization of artificial reproduction of asp, Aspius aspius (L.) under controlled conditions

70%

Targonska K. , Kucharczyk D. , Zarski D. , Mamcarz A. , Falahatkar B.

Polish Journal of Natural Sciences

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2011

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tom 26

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nr 2

EN

Artificial reproduction of asp under controlled conditions was done using two different spawning agents based on GnRH analogues and dopamine antagonists (Ovopel and Ovaprim). Fish in the Ovopel and Ovaprim and combined treatment groups were treated with a dose equivalent to 1.2 pellets (0.2 and 1.0), 0.5 cm³ liquid (0.1 and 0.4) and 0.2 pellets and 0.4 cm³ liquid per kg of body weight respectively. The highest percentage of ovulation (100%) and embryo-survival to the eyed-egg-stage (81.3%) was recorded after the application of a combination of Ovopel and Ovaprim in comparison with other groups. Fish from the control group did not ovulate. The latency time was shorter in the groups where Ovopel and Ovopel with Ovaprim was applied (40) than in Ovaprim group (42–44 hrs). The obtained results indicates that combination of Ovopel with Ovaprim might be successfully used for artificial reproduction of asp.

PL

Kontrolowany rozród bolenia przeprowadzono z zastosowaniem dwóch różnych preparatów opartych na analogach GnRH i inhibitorach dopaminy (Ovopel i Ovaprim). U ryb z grupy kontrolnej nie stwierdzono owulacji. Najwyższy odsetek owulacji (100%) oraz przeżywalność embrionów do stadium zaoczkowania (81.3%) zaobserwowano po zastosowaniu kombinacji Ovopelu i Ovaprimu. Krótszy czas owulacji odnotowano w grupach, w których aplikowano Ovopel oraz Ovopel z Ovaprimem (40 godzin) niż w grupie, w której zastosowano tylko Ovaprim (42–44 godziny). Uzyskane wyniki wskazują, że Ovopel w kombinacji z Ovaprimem mogą być z powodzeniem używane w kontrolowanym rozrodzie bolenia.

3

Spawning induction in Kutum, Rutilus frisii kutum (Kamensky), with different hormones: Analysis of hormone profiles and induced spawning success

61%

Falahatkar B. , Poursaeid S. , Langroudi H. E. , Efatpanah I. , Meknatkhah B. , Rahmati M.

Archives of Polish Fisheries

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2013

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tom 21

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nr 4