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Influence of 17-alpha methyl testosterone on the production parameters of common carp (Cyprinus carpio L.) fry
Published December 28, 2018
37-43

During our research we aimed at finding an answer as to what extent the different concentrations of 17-alpha methyl testosterone incorporated in the diet of common carp fries can influence the production parameters of the species, as well as how efficient their sexreversal can be with the use of this method. To this end, an aquarium experiment ...was conducted in the course of which four different hormone treatments were set and monitored. The fish feed was enriched with 17-alpha methyl testosterone in 50 ppm, 75 ppm, 100 ppm, 500 ppm dosages.

The obtained figures revealed that the hormone treatments had no influence on the production parameters and conservation of the common carp fries. Further on, our team is to determine the sex of the fish through the examination of gonads during autopsy when they reach the 500 g average weight.

Furthermore, a male specific test method which was supposed to be of great help in our attempt to select the sex-reversed specimens in the subsequent processes was also put to the trial. During the experiment the DNA-isolation of different sample types (muscle tissue, fin, mucus) of common carp with identified sex was successfully carried out. The extracted PCR product was examined with agarose gel. Our results indicated that the ccmf2 marker was applicable, however, the obtained figures were not reliable.

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The use of essential trace elements in the juvenile rearing of barramundi (Lates calcarifer
Published March 20, 2014
33-38

Barramundi (Lates calcarifer L.) is a predatory fish species native in Southeast Asia and Australia. Based on the geothermal potentiality of Hungary the warm-water fish can be reared successfully. Zooplankton in the wild contains minerals in a higher concentration than the usually fed newly hatched Artemia nauplii, therefore essential trace ele...ments, such as cobalt, zinc and manganese play an important role in the larviculture of barramundi. Cobalt is vital in trace amount for many living functions of vertebrates, however, lower number of papers are available considering the nutritional aspects. Nevertheless. improved growth performance was observed in cases of some fish species when diet was supplemented with CoCl2. Zinc and manganese are also vital for optimal growth and accordingly are investigated and applied diet supplements in aquaculture.

The main aim of the recent study is to investigate the effects of cobalt, manganese and zinc on the growth performance and homogeneity of fish when a commercially available dry diet is supplemented with trace elements individually and in combined treatments. A total of 6 treatments were set in a randomized blocked design where the concentrations of the applied elements were 50 mg kg-1 for CoCl2, for ZnSO4 and for MnCl2 individually, as well as for CoCl2 along with ZnSO4 and for CoCl2 along with MnCl2 in combination. Although the production parameters of larval barramundi were positively affected by the addition of trace elements when the retention of minerals occurred through nourishment living organisms, statistically no differences were found between the treatments considering the growth performance of barramundi juveniles either when dry feed was supplemented with cobalt, manganese or zinc (p>0.05). While the use of cobalt and manganese in combined treatments produced a less uniform larvae in size and as a consequence of increased heterogeneity, survival was significantly reduced by the cannibalism, the sizes distribution of barramundi juveniles wasn’t affected by the dry diet supplementation of these elements.

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The applied mechanical equipments for wastewater treatment in the észak-Alföld region
Published May 16, 2017
171-178

In this study we presented the results of a survey research, which was performed during 2015 at 34 sewage treatment works, operating in Észak-alföld region (Hungary). The survey focused on applied mechanical equipment and works of art of the sewage treatment establishments.

The results of the survey showed that the majority of the exa...mined sites (approx 65%) are working with capacity utilization of 50–100%,merely the 12% of plants was overload. It was found analyzing of specific energy consumption of the sites that the largest value (1.1 kWh per m3) was at the plants with smaller capacity (0–1000 m3 per day). It was clear during the questionnaire processing of the survey that almost all of the works applied activated sludge for sewage treatment The sludge treatment of the sewage plants is conducted by two methods; aerobic- and mixed (anaerobic and aerobic) sludge stabilization. We suggest for the plants with small capacity to use deep aerators, since anachronistic method used the at 3% of the settlements.

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The effect of cobalt-chloride on the production parameters and homogenity of barramundi (Lates calcarifer) larvae
Published February 10, 2013
21-25

...5); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">Barramundi (Lates calcarifer) is a predatory fish species native in Southeast Asia and Australia. Based on the geothermal potentiality of Hungary the high market potential warm-water fish barramundi can be produced economically. Living nourishment organisms such as Artemia nauplii play an essential role in the larval rearing of barrramundi. However, zooplanktons in natural aquatic enviroments contain minerals in a higher concentration than the usually fed newly hatched Artemia. Therefore the goal of recent study was to investigate the effect of cobaltchloride on the larval growth and survival of barramundi when fed individually and combined with Zn and Mn supplemented Artemia.

In our experiment a 24 hours period was used for the enrichment of newly hatched Artemia nauplii with cobalt chloride in itself, as well as in combination with zinc sulphate and manganese chloride. A total of 1900 barramundi larvae from 15–30 day post hatching were fed with supplemented Artemia in 9 groups of treatments in duplicate. The growth performance and elemental concentration of 40 larvae from each group was determined. All the groups produced significantly improved growth compared to the control (p<0.05). The lower concentration of individual Co supplementation resulted in a higher growth performance while the opposite dose relation occured when combined the Co with Mn. Cobalt had a significant negative effect on the Mn uptake of the larvae – significantly higher Mn accumulation compared to the control group was only observed when Mn was fed in itself (p<0.05). In case of Co-Zn-1 and Co-Zn-2 treatments significantly higher Zn concentration was measured than in the others (p<0.05).

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Investigation of Chromium(III)-Picolinate Adsorption on Some Soil Types
Published May 11, 2003
190-193

In the experiment adsorption characteristics of different soil types (humic sand, meadow soil, leached chernozem and meadow solonec) was examined on the basis of adsorption isotherms for Cr(III)-picolinate. The Langmuir equation was used to describe the isotherms by which the amounts of metal ions actually and maximally adsorbed by the soils we...re determined concerning the given complex. A comparison was made among the organically bound Cr(III)-picolinate, an inorganic Cr(III) compound and a Cr(VI) form examined in a previous study. Based on the adsorption isotherms, adsorption capacity of the Cr(III)-picolinate was found 20 times smaller on sandy soil and 50 times smaller on the chernozem comparing to that of the inorganic Cr(III)-chloride, thus, the bio-availability of the chromium for the plants is 20 and 50 times higher in case of the given soil types. For the well-known toxic Cr(VI)-form, the adsorption was 2 times higher in case of sandy soil and 5 times higher for chernozem than in case of the organic Cr(III)-complex compound.

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Changes in weed flora of basket willow (Salix viminalis L.) under different soil nutrient supply
Published November 10, 2010
116-120

The world is in a continuous progress, as a result of which energy consumption and with this the release of gases with adverse impact show rapid increase. As a result of the survey conducted by the International Energy Agency, if the major economic powers do not initiate a change in their energy policy, the increase of energy consumption may as... well reach 40 % by 2030. This increased energy demand is getting more and more difficult to fulfill with the fossil energy resources, which is to lead to an increasing significance of renewable energy resources. In Hungary, these energy resources are the best to provide with biomass growth. Biomass growth for energetic purpose can mostly be provided by energy plants, out of which “energy willow” (Salix viminalis L.) is outstanding with its high yield and with its excellent burning technology characteristics of its timber. The willow’s cropping technology is being established in our country. One of our tasks is to work out an adequate weed control plan. The professional and safe use of herbicides can increase the success of production. In our paper, we discuss the weed flora data collected on  treatments applied in the different fertilizer and compost. We started our survey in 2010. We examined twelve different fertilizer and compost treated areas. The dominant weeds were: Amaranthus retroflexus, Chenopodium album, Echinochloa crus-galli among annuals; Cirsium arvense and Agropyron repens among the perennials. 

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Novel Applications of Microwave Techniques in the Food and Environmental Industries
Published March 4, 2005
29-34

During the microwave processing, despite the conventional heating, the material heats consistently inside. This property of microwave is utilized by drying and dehydration processes. The thermal sensitivity of raw materials of food industry requires development of gentle, fast and controllable technologies, which is realizable by means of combi...nation of conventional and microwave techniques. The other important application area of the microwave technique is food industrial practice is enhancing the microbial safety of products, mainly by pasteurization processes. In recent time the strict environmental regulation necessitate developing more effective treatment of wastes, waste waters and sewage sludge. Because a part of these techniques are heat and power demanded, the microwave technique may be an alternative process in execution of sludge conditioning, drying or gasification and pyrolysis.

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