Zoltán Nagy

Magyar Agrár- és Élettudományi Egyetem

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Georgina Fazekas

Magyar Agrár- és Élettudományi Egyetem

Uroš Ljubobratović

Magyar Agrár- és Élettudományi Egyetem

Dénes Gál

Research Institute for Fisheries and Aquaculture

ÁH

Ákos Horváth

Magyar Agrár- és Élettudományi Egyetem

Zsuzsanna J. Sándor

Research Institute for Fisheries and Aquaculture

J. Czakó

Budapest Institute

Csaba Hancz

Magyar Agrár- és Élettudományi Egyetem

Jelena Stanivuk

Magyar Agrár- és Élettudományi Egyetem

Máté Havasi

Research Institute for Fisheries and Aquaculture

Shivendra Kumar

Central Agricultural University

Cooperative Institutions

University College London

Magyar Agrár- és Élettudományi Egyetem

Birkbeck, University of London

Research Institute for Fisheries and Aquaculture

National Agricultural Research and Innovation Centre

University College Hospital

King's College London

Imperial College London

Cancer Research UK

Royal London Hospital

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DNA barcoding of Congolese freshwater fish collections

Erik Verheyen F. Breman Célestin Danadu Mizani M. Hanssens A. Ibala-Zamba

DNA Barcoding

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Evaluation of Biotechnology Tools – Polyploidization and Hybridization – for Improvement of Pikeperch (Sander Lucioperca) Larviculture and Juvenile On-Grow with Special Regard to Morphological Traits and Gonadal Development

Jelena Stanivuk Zoran Marinović Nevena Kitanović Attila Mozsár Jenő Káldy

Basic morphological and reproductive traits of diploid and triploid pikeperch (Sander lucioperca), as well as its diploid and triploid hybrids with the Volga pikeperch (S. volgensis), were investigated in closed larviculture for up to 350 days post-hatch. Biotechnological interventions enhance aquaculture production over time, with proven benefits in other species, improving growth, survival, feed efficiency, and reducing intracohort cannibalism. This study evaluated four experimental groups: diploid pikeperch (PD), triploid pikeperch-autotriploid (PT), diploid hybrid (S. lucioperca ♀ × S. volgensis) (HD), and their triploid-allotriploid (HT). Triploidization was induced via hydrostatic pressure. Larval ploidy and hybrid status were verified. Subsequent larviculture and juvenile growth trials spanned from 5-40 and 89-145 days post-hatch (DPH), respectively. Hybrid larvae in both ploidy levels exhibited superior swim bladder inflation compared to diploids but lagged in growth. Triploidization did not enhance growth performance but decreased fish viability. However, allotriploids have proven to be more vigorous than autotriploids. Gonadal analyses indicated that PD and HD developed fully functional gonads. PT histological samples showed many germ cells that did not enter meiosis, with sporadic oocytes and spermatocytes. HT displayed two gonadal phenotypes: pro-male, resembling juvenile diploid testes, and pro-female, characterized by intersex traits, likely rendering them infertile. These findings provide valuable insights into the phenotypic effects of triploidization and hybridization.

Sander

10.2139/ssrn.5082029

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Concentrate mixtures with dried skimmed milk for rearing calves.

Allattenyesztes (1963)

J. Czakó Zoltán Nagy S. Guba

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EFFECTS OF FEEDING REGIME ON GROWTH FEED CONVERSION AND SIZE VARIATION OF Silurus glanis

Croatian Journal of Fisheries (2015)

M�t� Havasi Shivendra Kumar Zoltán Nagy G. Beliczky Szabolcs Nagy

The present study was carried out to investigate the effects of feeding frequency on the growth, feed utilization, condition and size variation of European catfish.Triplicate groups of fish (45 specimens per treatment) weighing 59.9±12.8g (mean ± S. D.) were fed a commercial diet (18 MJ DE kg -1 ).Three different treatments were applied in 3-3 replicates.One group of fish was fed continuously with automatic belt feeders over 12 hrs (C).The second group of fish was fed by hand once a day (1x).The third group got three hand-fed meals per day (3x).In this case the portion was divided into three equal quantities.Feeding levels were 2.5% of actual stock weight in each group.During the 5-week trial, the final body weight (FBW), weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER), condition factor (CF) and coefficient of variance CV% were determined.In the first week, remarkable differences in specific growth rate and feed conversion ratio were observed between different treatments, however, all of the differences were ceased at the end of experiment.No significant difference in growth rate, feed conversion ratio, protein efficiency ratio, size variation and condition factor were recorded between different treatments.Overall, our findings conclude that feeding frequency had no significant effect on any of the indices in Silurus glanis.Despite this, three times daily or more frequent feeding could be suggested, as frequent feeding regimes mitigate the harmful effects of rapid water quality changes.r%& '% ()'0 1232456

Variation (astronomy)

10.14798/73.4.846

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Effect of different planes of feeding on growth, efficiency of feed conversion and carcase quality of young bulls.

J. Czakó Zoltán Nagy S. Guba

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Predicting population's oocyte maturation competence and evaluating individual's latency time using in vitro oocyte maturation in pikeperch (Sander lucioperca)

Aquaculture (2022)

Uroš Ljubobratović Nevena Kitanović Sylvain Milla Zoran Marinović Georgina Fazekas

Artificial reproduction of pikeperch (Sander lucioperca) is characterized by the unpredictability of latency time (LT) as well as the variability of egg quality depending on the time of hormonal stimulation. To predict latency time and thus enhance fertilization outcomes, the present study evaluated whether in vitro maturation techniques could be utilized to assess the status of oocyte maturation competence (OMC). Oocyte samples from nine pond-reared females originating from the Czech Republic (CZECH) and 12 intensively cultured females originating from river Körös (HAKI) were catheterized at the time of hormonal stimulation and cultured in L15 medium supplied with 100 ng/mL of DHP. The stage of final oocyte maturation (FOM) was monitored both in vivo and in vitro and egg quality features were evaluated. HAKI group was characterized by larger oocytes at the time of stimulation (934.4 ± 32.9 μm vs. 860.0 ± 22.7 μm), as well as higher embryo survival (77.7 ± 10.4% vs 53.5 ± 28.8%), suggesting that artificial reproduction was performed prematurely for CZECH group. Oocytes from HAKI fish displayed a higher share of maturing oocytes (41.4 ± 9.1% vs. 13.8 ± 17.6%) and in all samples germinal vesicle breakdown was noticed, while in the CZECH group it was so only in oocytes of one fish. With respect that all fish ovulated after the gonadoliberin stimulation, gonadotropin-regulated OMC is assumed. A correlation was found between the in vivo and in vitro LTs in the HAKI group only (r = 0.791, P = 0.002), indicating a certain autonomy of ovarian follicle of other parts of the physiological axis after completed OMC. The in vitro techniques show great promise for practical application in hatcheries to evaluate the aptness for hormonal stimulation on both individual and population levels.

Germinal vesicle

Sander

In vitro maturation

10.1016/j.aquaculture.2022.738851

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Effect of different planes of nutrition on development and subsequent milk yield of heifers.

J. Czakó Zoltán Nagy

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Reusability check-based refinement of a biophysical fishpond model

Computers and Electronics in Agriculture (2024)

Priya Sharma Gergő Gyalog László Berzi-Nagy F Tóth Zoltán Nagy

Given the increasing importance of data- and model-driven design and control in food production systems, this paper addresses the need to improve the reproducibility, replicability, and reusability of datasets, models, and modeling frameworks. While sensor data and machine learning-based control and operation of agricultural and aquacultural systems face reproducibility and replicability challenges, reusability is becoming critical for computational model-based design and planning of complex processes. This study evaluates the reusability of an existing pond aquaculture model and outlines a systematic, stepwise approach for reusability enhancements. The suggested methodology starts with an established reference model of a typical production fishpond and improves its reusability through pilot-scale experiments, covering key aspects of pond farming technologies. The reference model is subjected to stepwise reusability checks using measured data from the respective pilot units, progressing from simpler (reduced) to more complex (extended) cases. Each step concludes with the necessary parameter or sub-model refinements, which remain unchanged in subsequent steps. The refined model is validated with the measured data from other pilot experiments. This process can be repeated until satisfactory results are obtained. The resulting model is then tested to scale up a production pond model using limited case-specific input data. In addition, a hypothetically modified scenario is studied to address discrepancies between measured and simulated data.

Reusability

10.1016/j.compag.2024.108664

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Nursing of Pike-Perch (Sander lucioperca) in Recirculating Aquaculture System (RAS) Provides Growth Advantage in Juvenile Growth Phase

Animals (2023)

Géza Péter Jovanka Lukić René Alvestad Zoltán Horváth Zoltán Nagy

This study aimed to estimate the efficacy of two pike-perch juvenile production technologies: exclusive Recirculating Aquaculture System (RAS) culture (the RAS group) and pond larviculture with a transfer to the RAS at the 42nd day post-hatch (DPH). Both direct weaning on dry feed (the Pond-D group) and 10-day gradual weaning using bloodworms (the Pond-B group) after transfer to the RAS were evaluated in pond-nursed fry. Their survival and morphometric indices were monitored after the RAS habituation period (first 10 days), after the 18-day post-habituation period and after an additional 30 days of on-grow. Our results indicate a negative allometric growth of the pond-nursed fish during the nursing period, which was slower (p < 0.0001) in comparison to the RAS-nursed fry (16.3 ± 0.4 vs. 17.8 ± 0.7%/day). After transfer, these fish grew faster than the RAS-nursed fry (7.7 ± 0.1, 4.9 ± 0.5 and 6.1 ± 0.6 during habituation, 8.5 ± 0.6, 9.3 ± 0.5 and 6.7 ± 0.1%/day during post-habituation period, in the Pond-B, Pond-D and RAS groups, respectively). However, four weeks afterwards, the RAS-nursed fry were again superior in terms of growth (4.0 ± 0.1, 3.6 ± 0.2 and 4.6 ± 0.2%/day, for the Pond-B, Pond-D and RAS groups, respectively), and this was accompanied by a significantly lower feed conversion ratio in this group. Although the survival of the RAS-nursed fry during the nursing period was lower in comparison to the pond-reared fry (11.3 vs. 67.3%), the RAS seems to provide a long-term growth advantage.

10.3390/ani13030347

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Examination of resistance against Aeromonas hydrophila infection on genetically different common carp variants (preliminary results)

Acta Agraria Debreceniensis (2008)

László Ardó J. Bakos Zoltán Nagy András Rónyai Dénes Gál

Septicemia disease caused by the bacterium Aeromonas hydrophila is a major problem for fish farmers around the world. In our experiment resistance to the disease was investigated on carp variants with diferent genetical backgrounds. 96 different genetic variants(„families”) were created by crossing various individuals of 4 carp strains (2 wild and 2 cultured ones). Families were reared until reaching the size of 10 gramms and 100 fish of each families were marked with an individual electronic identifier. Marked fish were divided into 5 groups. Fish from one group were infected with A. hydrophila and mortality were registered during 2 weeks. Based on mortality data, the most resistant and most susceptible families will be selected using population genetics methods.

Common carp

10.34101/actaagrar/31/2998

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