UNIVERSITY OF PANNONIA GEORGIKON FACULTY KESZTHELY Department of Animal Sciences and Animal Husbandry
Doctoral School of Animal and Agricultural Environmental Sciences Head of the doctoral school: Dr. Angéla Anda, D.Sc.
Foundation of plant protein based feeding of European catfish (Silurus glanis) in intensive systems Doctor of Philosophy (PhD) thesis
Written by: Máté Havasi
Supervisors: Dr. Miklós Bercsényi university professor and Dr. Szabolcs Nagy university docent
Keszthely, Hungary 2014
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Introduction and objectives The growing demand of fish due to the growing population can be secured only if the aquaculture sector develops and grows in the future. At the same time the market and trade require constant and reliable production. This could primarily be provided from intensive rearing facilities. The costs of an intensive production system are very high therefore only the production of valuable (e. g. predatory) fish species can prove economical in such systems. For this purpose the native, predatory European catfish species the wels (Silurus glanis, Linnaeus, 1758) is appropriate according to Hungarian studies and examples from Western Europe. Wels production in Hungary has unexploited possibilities as, in spite of its numerous fortunate properties, it covers only 1-2% of total cultured fish in pond culture. Nowadays fish in intensive rearing facilities are usually fed with feeds containing fish meal as primary protein source. The catches of marine species which provide the raw material of the fish meal, have been stagnating or decreasing globally since the beginning of the 90’s. Due to the still growing demand for fish meal the sustainability of this practice has become uncertain, as the price of fish meal could become too expensive in the future. Therefore it is an urgent and common interest in aquaculture to reduce the amount of the fish meal in commercial fish diets or substitute it with alternative protein sources e. g. other animal proteins, plant protein or fermentation products. For intensive wels culture in Hungary a combined intensive-extensive system could be appropriate, in which benefits of both types are utilized. In such systems administration of cheaper, even less protein containing feeds can be economic. Adopting a new technology for the production of a species requires the clarification of many technological details. As a remarkable part of the production costs is the feed cost, the thrift is dependant on this factor. It is of primary interest to optimize feeding issues. Regarding sustainability it is also important to develop feeds, which provide good growth and flesh quality, but on the other hand are made of cheap, inland ingredients and contain none or very small amounts of fishmeal. Feed consumption of fish occurs hidden from our eyes; we have only indirect information about actual feed portion demand. In order to reduce feed waste it is paramount to know the effects of optimal daily feed portions and feeding frequencies on producing parameters.
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According to this the aims of this study: The determination of optimal daily feed portion in cases of one-summer old wels. The determination of optimal feeding frequency in cases of one-summer old wels. The determination of passing time of feed through the digestive tract at different temperatures. Rearing wels on plant protein based feeds. Substitution of fish meal in the feeds of wels. Materials and Methods The experiments in this dissertation are highly related however, for ease of understanding they are shown separately. Regarding the subject the experiments can be divided into two major categories: Examinations of feeding-technology parameters Examinations of the possibilities of fishmeal substitution Common features of the different experiments are that, they were conducted in small scale recirculation systems. Due to the reduced experimental space, young, one-summer old specimens were used. The lights in the room were dimmed and the temperature was held at between 20-25 oC. Water temperature and oxygen saturation were measured daily and the concentration of harmful inorganic N-forms were measured weekly. Examinations of feeding-technology parameters Determination of optimal daily feed portion Eight individuals (mmean±SD: 48.8 ± 13.5 g) were stocked in each fish tank. Four treatments were applied in triplicates. The treatments differed from each other in the daily feed portion, which were the following expressed in the percentage of body weight: 1%, 2.5%, 4%, 5.5%. Feed was offered with automatic belt feeders over 12 hours a day. The feed was the same in each treatment (AQUAGARANT). The amount of offered feed was increased weekly according to the measured body weight gain.
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Determination of optimal feeding frequency Fifteen catfish were stocked in each of the nine aquariums with an average initial weight of 59.9±12.8 g (mean±SD). Therefore the stocking density was 2.81±0.12 gL-1. Three different treatments were applied in 3-3 replicates In the case of the first treatment fish were fed continuously during a 12-hr period daily with automatic belt feeders. The second group of fish was hand fed once a day (1x fed group), while the third group was hand fed three times a day (3x fed group). In the latter case the portion was divided into three equal quantities. The daily portion (COPPENS Steco Supreme-10) was 2.5% in each group expressed as the percentage of the actual stock body weight. The portion was adjusted weekly according to the actual body weight. Examination of passing times of different feeds Eleven catfish specimens were stocked into each tank (66 altogether, weight (mean ± SD): 38.03 ± 8.04 g). Fish were individually marked by passive integrated transponder tags (PIT), which were injected abdominally. Two treatments were applied in 3–3 replicates. One group (D group) was fed by artificial dry feed (Skretting Alterna Marine), while the other (F group) received sliced forage fish (Carassius auratus). The temperature was set to 15 º C Four days before the experiment, feeding was suspended, in order to avoid the presence of any gut content from previous feeds. Weight of the fish with empty guts was measured, and they were then fed once by ad libitum hand feeding. After feeding, individual body weight was measured on a regular basis. The elapsed time between two measurements varied between 2 and 5 h. Fish can suffer harmful distress during measuring, which can highly affect the metabolic processes. Therefore, we tried to reduce stress by measuring only one replicate in each treatment at one time. So, each specimen was measured at only every third measuring occasion. Graphs were drawn as functions of time and body weight, before and after feeding. Passing time was calculated as time between feeding and time point when the body weights of specimens started to decrease. After the gut content was excreted, feeding was ceased for another 4 days. This whole process was repeated at 20 and 24 º C with the same stock
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without changing groups. Possibilities of fish meal replacement The effect of different admixtures on the growth performance of wels, administering plant protein based feeds. 120 specimens were used (mmean±SD: 42.9±6.8 g) in this experiment. Four different treatments were applied. First group was fed with squealer feed (BabyPro Classic 35) (S), the second one (SB) was fed with a mixture of squealer feed and blood meal (9:1), the third group (SF) fed on a mixture of squealer feed and fermented grains (5:5), the fourth group (CF) was fed with a mixture of granulated feed (HALTÁP Ltd.) and fermented grains (7:3). Squealer feed contained almost exclusively plant derived protein (wheat, corn, soy bean). The fermented grain consisted of corn, wheat and rye in the ratio 2:1:1. The treatments were conducted in triplicates. Fish were fed to satiation three times daily. Fish meal substitution with meat meal and plant protein. Fifteen specimens were placed in each aquarium (mmean±SD: 70.9±9.4 g). The following three treatments were applied: fish meal contained feed, meat meal contained feed and plant protein based feed. Latter consisted of only plant derived ingredients. The three different feeds were isonitrogenous and the amino acid profiles were similar. The constitution of the experimental feeds was based on the demand of channel catfish. Treatments were conducted in triplicates. The experimental feeds were distributed with automatic belt feeders over 12 hours a day. The daily feed portion was 2.5% of the actual body weight in each treatment. At the closing of the six weeks long experiment five specimens were dissected from each treatment. The weights of liver and abdominal fat were measured, and a homogenous squash was made of fish from each treatment. Full body analysis was conducted from these squashes regarding the dry matter-, protein-, fat-, ash- Ca- and P-content. Measures, calculations, statistical analysis
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Individual body weight was measured in water with 0.1g precision; the body length was measured with 0.5 cm precision. From measured values feed conversion ratio (FCR), daily growth (G), specific growth rate (SGR), condition factor (K) and relative weight gain were calculated. The size variation within stock was demonstrated with the calculation of coefficient of variance (CV). SPSS 14.0 for Windows and Statistica 8.0 programs were used for statistical analysis. The criteria of significance were determined at 95% profitability. To evaluate the measured data the following statistical probes and methods were applied: Shapiro-Wilk test, Kolmogorov-Smirnov probe, Levene test, Kruskal-Wallis test, Mann-Whitney u-probe, univariate analysis of variance (ANOVA), repeated Measures ANOVA, Tukey, Tamhane and Newman-Keuls post hoc tests. The conformance of functions was examined using the determination coefficient (R2) with Microsoft Office Excel 2007. Results Examinations of feeding-technology parameters Determination of optimal daily feed portion By the end of the experiment fish doubled their initial body weight (Figure 1.). The 1% group is an exception. The growth rate of this group was significantly lower than in the two other groups (p<0.01). At the end of the experiment mean weight was the highest in the 4% and 5.5% groups; there was not any difference between these treatments. The growing intensity of the 2.5% group was significantly lower than the previous ones (p<0.01). Values of daily weight gain and specific growth rate show the same. Data in the 1% group was lower than data of the other three treatments in cases of both indexes (p<0.05). From the first week of the study the growth rate of the 4% group was the highest expressed in absolute value or also by percentage. At the last stage the growth rate of 2.5% group differed significantly from the growth rate of the 4% group (p<0.05) (Figure 2.).
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160
mean weight (g)
140 120
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Figure 1.: Individual mean weight during the experiment. Different letters indicate significant differences (p<0.05).
specific growth rate (%)
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Figure 2.: Specific growth rate. Different letters indicate significant differences (p<0.05).
Feed conversion was the most preferable in the case of 2.5% group throughout the whole experiment (Figure 3.). This treatment differed significantly from the 1% group at the end of experiment (p<0.05). The least satisfactory conversion occurred in the 1% and the 5.5% groups. Significant differences were not found between these groups, neither
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feed conversion ratio (g/g)
between the feed conversion of the 4% and 2.5% groups. However values in the 2.5% were better throughout the whole period. 3.5
d
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Figure 3.: Changes of feed conversion during the experiment. Different letters indicate significant differences (p<0.05).
The size differentiation of the experimental stock was the most obvious in the 1% treatment. In this group the coefficient of variance doubled its value during the study. This phenomenon occurred the least in the 5.5% treatment.
Determination of optimal feeding frequency During the five weeks experiment the specimens have doubled their body weight. There were not any significant differences observed between the treatments regarding mean body weight (Figure 4.). The intensity of growth was the lowest in the 3x fed group initial value increased only to its 1.8-fold. This increase was twofold in the other two treatments. Therefore the differences which were present during the first part of the experiment equalized later, and the differences between the treatments were non significant (Figure 5.).
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mean weight (g)
170 160 150 140 130 120 110 100 90 80 70 60 50 40
continous 1X/day 3X/day
1
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3 4 weeks
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Figure 4.: Changes of mean body weight during the experiment in the three treatments.
daily weght gain (g/day)
3.0 2.5
2.0
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1.5
1X/day
1.0 0.5
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Figure 5.: The daily weight gain expressed in g/day.
Feed conversion ratio was the least satisfactory in the 1x fed group at the start of the experiment. In this group the utilization improved progressively over time (p<0.05). There was no difference between the other two groups, neither changing over time. At the end of the experiment there were no differences between the feed conversion ratios of the three treatments (Figure 6.).
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feed conversion (g/g)
1.2 1.0 0.8
0.6
continous 1X/day
0.4
3X/day 0.2
0.0 1
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3 weeks
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Figure 6.: Changes of feed conversion ratio during the experiment.
It is demonstrated that the treatments did not affect the size variation. The maximum alternation within one group during the experiment was only 2%. Size difference among fish of the 1x fed group increased by only 1%. The initial and final values were the same in the cases of the other two treatments.
Examinations of passing times of different feeds The appetite of fish was highly influenced by water temperature At 20 and 24 ºC, the whole stock accepted the offered feeds. At 15 º C, only 90.9 % of the fish of F group and only 42.4 % of the fish of D group consumed the feed. The quantity of consumed feed increased as water temperature increased. This value varied between 3.20 and 10.68 % of the body weight in the F group and between 1.36 and 4.46 % in the D group (Figure 7.). There was a significant difference between the feed uptake of F and D groups at all of the three temperatures (p<0.05). At 20 º C, the evacuation occured between the 36th hour and the 49th o hour after feeding (Figure 8.). At 24 C the metabolism of fish accelerated notably. The evacuation already begun after the 19th hour after feeding and completed by the 35th hour (Figure 9.).
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feed uptake (body weight %)
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10.68 3.27
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Figure 7.: The amount of consumed feed expressed in the fish body weight. D group: dry feed: F group: forage fish. Different letters indicate significant differences (p<0.05).
116%
body weight (%*)
114%
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Figure 8.: The changes of body weight in percentage at 20oC. * 100% is the body weight of fish with empty gut. D group: dry feed: F group: forage fish. Different letters indicate significant differences within a treatment (p<0.05).
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116% body weight (%*)
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Figure 9.: The changes of body weight in percentage at 24oC. * 100% is the body weight of fish with empty gut.. D group: dry feed: F group: forage fish. Different letters indicate significant differences within a treatment (p<0.05).
Possibilities of fish meal replacement The effect of different admixtures on the growth performance of wels, administering plant protein based feeds
mean body weight (g)
At the end of the experiment mean weight of the CF group was significantly higher than the three other treatments (p<0.01). There were not any significant differences found between the performance of S and SB groups (Figure 10.). The worst growing potential occurred in the SF group (p<0.01). 235 215 195 175 155 135 115 95 75 55 35
a
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S SF SB CF
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6 8 10 weeks Figure 10.: Mean body weight of wels during the experiment. S: squealer feed, SF: squealer feed + fermented grain (5:5), SB: squealer feed + blood meal (9:1), CF: granulated feed + fermented grain (7:3). Different letters indicate significant differences (p<0.05).
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The daily weight gain in the CF group was two times greater than growing intensity of the plant protein based treatments during the whole experimental period (Figure 11.). At the end the growing intensity of fish in the CF group significantly exceeded the growth rate of the three other treatments (p<0.01). daily weight gain (g/day)
3.50 a
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Figure 11.: Daily weight gain in two weeks periods. S: squealer feed, SF: squealer feed + fermented grain (5:5), SB: squealer feed + blood meal (9:1), CF: granulated feed + fermented grain (7:3). Different letters indicate significant differences (p<0.05).
Mean value of the feed conversion ratio (FCR) for the whole period was the lowest in the CF group and the least satisfactory in the SF group. There were no significant differences found between the feed conversion of S and SB treatments (Table I.). Table I.: Changes of feed conversion ratio (FCR) during the experiment. Different letters indicate significant differences (p<0.05). weeks S SF SB CF 1 1.53±0.06ab 1.98±0.23a 1.53±0.18ab 0.95±0.04b 2 1.73±0.30a 1.75±0.15a 1.47±0.23ab 1.00±0.03b 3 1.75±0.12a 2.25±0.54a 1.87±0.27a 1.01±0.16b 4 1.45±0.50a 1.86±0.19a 1.72±0.10a 1.26±0.26a mean±SD 1.61±0.15 1.96±0.22 1.64±0.18 1.05±0.14 S: squealer feed, SF: squealer feed + fermented grain (5:5), SB: squealer feed + blood meal (9:1), CF: granulated feed + fermented grain (7:3).
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Fish meal substitution with meat meal and plant protein. Mean weight increased from 70.9±9.4 g to 117.0±24.0 g during the six week long experiment. By the third week the growth rate of the vegetable diet group significantly lagged behind from the two other groups (p<0.05). There was no difference found between the growth rate of fish meal and meat meal groups, although the growing intensity of fish meal group was bigger (Figure 12.). 160.0
mean body weight (g)
150.0 140.0
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vegetable diet
meat meal
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Figure 12.: Changes of individual mean body weight. Different letters indicate significant differences (p<0.05).
The individual daily weight gain was lowest in the vegetable diet group during the whole experimental period (Figure 13.). The biggest daily growth was observed in the fish meal group with 1.82 g/day value. The growth performance of the vegetable diet group significantly lagged behind the two other treatments by the end of the experiment (p<0.01). The feed conversion ratio was the best in the fish meal group. The feed conversion in the meat meal group was 1.6, while it was 2.1 in the case of the weakest vegetable diet treatment. There was no significant difference between the treatments in this issue (Figure 14.).
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daily weight gain (g/day)
2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0
a a a ab
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vegetable diet
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fish meal
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Figure 13.: Individual weight gain during the experiment. Different letters indicate significant differences (p<0.05).
feed conversion ratio (g/g)
12.0
b 10.0 8.0 b
6.0 a
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aa
a aa
a
a aa aa
meat meal a
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fish meal
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vegetable diet
0.0 1
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3 4 weeks
5
6
Figure 14.: Changes of feed conversion ratio during the experiment. Different letters indicate significant differences (p<0.05).
Coefficient of variance showed slight alterations in the case of vegetable diet group. In cases of the other two treatments explicit increase was observable regarding size variation (Figure 15.).
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CV%
20.0 bb
18.0 16.0 14.0
a aa
aa a
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a aa
a a
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ab ab ab a
vegetable diet
a
fish meal meat meal
10.0 8.0 1
2
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4 5 weeks
6
7
Figure 15.: The coefficient of variance in the different treatments. Different letters indicate significant differences within a treatment (p<0.05).
Weight of liver was highest in the meat meal group. Within the treatments the size of liver was very similar and showed little deviation. The ratio of abdominal fat was almost the same in the three different treatments, although it showed large deviation. There were no significant differences between the groups regarding neither the ratio of abdominal fat nor the weight of liver. The fat- and protein-content were the lowest in vegetable diet group and highest in the meat meal group (Figure 16.).
3.0 % 2.5 2.0
0.9 0.5
1.1 0.3 0.8 0.5
1.5
abdominal fat liver
1.0
1.3 0.1
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meat meal
vegetable diet
Figure 16.: The ratio of the liver and abdominal fat to the total body weight.
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Discussion According to my results the conclusions are the following. For feeding of one-summer old wels 2.5-4% daily feed portion (body weight %) is appropriate depending on the water temperature and production strategy. In cold water and if the aim is better feed conversion, smaller amounts of feed is suggestible. In cases of warmer water and if the priority is rapid growth, larger feed portions is advisable. During the experiment no effects of feeding frequency on growth, feed conversion and size variation became apparent. According to the publications of other authors 3 times daily or more frequent feeding is recommended, in order to avoid sudden water quality changes and harmful distress due to feeding. The temperature dependency of the appetite and metabolic intensity of wels was verified. The amount of consumed feed increased as the temperature was raised. Specimens consumed twice and a half as much from the natural feed (sliced fish) than from dry feed. One of the causes is that the dry matter content of the fish is much less than it is of dry feeds. The evacuation time of digestinal tract shortened as the temperature increased. At 20°C occurrence was after 36-49 hours, at 24°C after 19-35 hours post feeding. According to my results it can be stated, that wels can also be reared exclusively on plant protein, however, in this case its growing performance is much less than is acceptable. From the animal derived ingredients I have examined, meat meal seems usable for substitution fish meal. The utilization of plant originated feeds in my experiments was not sufficient to reach satisfying growth performance. Further studies are needed to reach improved digestibility e.g. with enzymes or probiotics. Moreover the protein – and amino acid demand of wels and the optimal protein : energy ratio require determination.
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Thesis Points 1.
It was determined, that 2.5-4% daily feed ration (body weight %) is appropriate for the one-summer old wels in cases of dry feed, at 2223°C.
2.
It was stated, that feeding frequency has no significant effect on growth rate or feed conversion in cases of one-summer old wels.
3.
A numerical definition of temperature dependency of feed uptake was made in wels at 15°C, 20°C and 24°C, in the case of dry feed and forage fish. It was determined, that the evacuation of gut content occurs within 36-49 hours following feeding at 20°C and within 1935 hours at 24°C.
4.
It was verified in an experimental way, that one-summer old catfish can also be reared almost solely on plant protein. However in this case the growth rate is significantly lower. On the other hand, the fat content of the filet and the amount of visceral fat is lower when administering plant based feeds.
5.
It has been demonstrated, that blood meal addition in 10% did not improve the effect of plant protein based feed on the growth performance of wels.
6.
The author has shown, that 100% of fishmeal can be replaced with meat meal in the feeds of wels without any significant decrease in growing intensity or feed conversion.
List of publications Scientific presentations relevant to dissertation 1.
2.
HAVASI M., FELFÖLDI Z., SZŰCS R., MERTH J., NÉMETH S. (2010) Harcsa (Silurus glanis L.) intenzív nevelése tápon, halkiegészítéssel, XVI. Ifjúsági Tudományos Fórum, Keszthely, 2010. 03. 25. HAVASI M., FELFÖLDI Z., GORZÁS A., LÉVAI P., MERTH J., NÉMETH S. (2010) Harcsa (Silurus glanis L.) intenzív nevelése növényi fehérje
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alapú tápon, XXXIV. Halászati Tudományos Tanácskozás, Szarvas, 2010. 05. 13. 3. HAVASI M., FELFÖLDI Z., GORZÁS A., LÉVAI P., MERTH J. (2010) Növényi alapú táp alkalmazása egy ragadozó hal, a lesőharcsa (Silurus glanis) nevelésében. LII. Georgikon Napok, Keszthely, 2010. 09. 31.2010. 10.01. 4. HAVASI M., GORZÁS A.,LÉVAI P., MERTH J., BERCSÉNYI M. (2010) Intensive rearing of wels (Silurus glanis) fed with plant protein based feed. Acvapedia 2010, Kolozsvár, Románia, 2010. 12.03-04. 5. HAVASI M., OLÁH T., FELFÖLDI Z., BERCSÉNYI M. (2011) Passing times of two types of feeds in wels (Silurus glanis) at three different temperatures. Diversification in Inland Finfish Aquaculture, Písek, Cseh Köztársaság, 2011. 05. 16.-18. 6. HAVASI M., OLÁH T., FELFÖLDI Z., BERCSÉNYI M. (2011) Két különböző takarmány kiürülési sebessége három hőmérsékleten lesőharcsánál (Silurus glanis). XXXV. Halászati Tudományos Tanácskozás, Szarvas, 2011. május 25-26. 7. HAVASI M., OLÁH T., FELFÖLDI Z., BERCSÉNYI M. (2011) A béltartalom kiürülési sebessége a hőmérséklet függvényében, lesőharcsán. Doktoranduszok Kaposvári Workshopja, Kaposvár, 2011. 06.08. 8. HAVASI M. (2011) Lesőharcsa (Silurus glanis). Ragadozóhal nevelési ismeretek gyakorlati bemutatása, Keszthely, 2011. 06.10. 9. HAVASI M., NÉMETH S., LÉVAI P. (2011) Különböző adalékok alkalmazása lesőharcsa növényi tápon való nevelése során. LIII. Georgikon Napok, Keszthely, 2011. 09. 29.-30. 10. BELICZKY G., HAVASI M., NÉMETH S., BERCSÉNYI M., GÁL D. (2012) Környezeti terhelés harcsa (Silurus glanis) eltérő fehérje tartalmú tápokon történő takarmányozása során. LIV. Georgikon Napok, 2012.október 11-12, Keszthely, Abstract kötet, 36. 11. HAVASI M., BALIKÓ T., NÉMETH S., FELFÖLDI Z., BERCSÉNYI M. (2012) Kísérletek a harcsa (Silurus glanis) optimális napi takarmányadagjának meghatározására. XXXVI. Halászati Tudományos Tanácskozás, Szarvas, 2012. május 23-24. 12. HAVASI M., BALIKÓ T., NÉMETH S., FELFÖLDI Z., BERCSÉNYI M. (2012) Kísérletek a harcsa (Silurus glanis) optimális napi takarmányadagjának meghatározására. Takarmányozást Oktatók és Kutatók Találkozója, Keszthely, 2012. 08. 27.
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13. HAVASI M., NÉMETH S., FELFÖLDI Z., LÉVAI P., OLÁH T., BERCSÉNYI M. (2012) Studies on the intensive feeding of Silurus glanis: Substitution of fish meal with plant proteins, passing time of different feeds and daily feeding rate. AQUA 2012, Prága, Cseh Köztársaság, 2012.09.05. 14. HAVASI M., BALIKÓ T., NÉMETH S., FELFÖLDI Z., BERCSÉNYI M. (2012) Kísérletek a harcsa (Silurus glanis) optimális napi takarmányadagjának meghatározására. LIV. Georgikon Napok, Keszthely, 2012. 10. 11. 15. BELICZKY G., HAVASI M., NÉMETH S., BERCSÉNYI M., GÁL D. (2013) Environmental load of wels (Silurus glanis) fed by feeds of different protein levels. Acvapedia 2012, Szarvas, 2012. 11. 27. 16. HAVASI M. (2013) Harcsanevelés: ismeretek, lehetőségek, kérdések. III. Gödöllői Halászati-Horgászati Szakember Találkozó, 2013. 01. 24. 17. HAVASI M., BELICZKY G., NÉMETH S., BERCSÉNYI M., NAGY SZ. (2013) Különböző etetési gyakoriság hatásának vizsgálata lesőharcsán, recirkulációs rendszerben. XXXVII. Halászati Tudományos Tanácskozás, Szarvas, 2013. május 22.-23. 18. HAVASI M., BELICZKY G., PÁL L., BERCSÉNYI M., NAGY SZ. (2013) A halliszt kiválthatósága húsliszttel, illetve növényi fehérjével lesőharcsa (Silurus glanis) takarmányában. II. ATK Tudományos Nap, Martonvásár, 2013. 11. 08., poszter szekció 19. BERCSÉNYI M., HAVASI M., BELICZKY G., GÁL D., BALIKÓ T., SZÉKELY CS., MERTH J., PÁL L. (2013) Kísérletek a lesőharcsa (Silurus glanis) intenzív tömegtermelésének megalapozására I-II (N-formák megjelenése, etetési gyakoriság hatásai). II. ATK Tudományos Nap, Martonvásár, 2013. 11. 08. Scientific publications relevant to the dissertation 1.
2.
HAVASI M., FELFÖLDI Z., SZŰCS R., MERTH J., NÉMETH S. (2010) Harcsa (Silurus glanis L.) intenzív nevelése tápon, halkiegészítéssel. XVI. Ifjúsági Tudományos Fórum, digitális konferencia-kiadvány, ISBN 978-963-9639-36-2 HAVASI M., FELFÖLDI Z., GORZÁS A., LÉVAI P., MERTH J. (2010) Növényi alapú táp alkalmazása egy ragadozó hal, a lesőharcsa (Silurus glanis) nevelésében. LII. Georgikon Napok, elektronikus konferencia kiadvány, ISBN 978-963-9639-39-3
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HAVASI M., GORZÁS A., LÉVAI P., MERTH J., BERCSÉNYI M. (2010) Intensive rearing of wels (Silurus glanis) fed with plant protein based feed. AACL Bioflux, 3 (5), 347-353. HAVASI M., Oláh T., Felföldi Z., Bercsényi M. (2011) Táplálékhal és száraz táp áthaladási idejének vizsgálata lesőharcsa (Silurus glanis L.) béltraktusában. Halászat, 2011/1, 29-32. HAVASI M., NÉMETH S., LÉVAI P. (2011) Különböző adalékok alkalmazása lesőharcsa növényi tápon való nevelése során. LIII. Georgikon Napok,elektronikus konferencia kiadvány, ISBN 978-9639639-44-7, pp. 355-362. BELICZKY G., HAVASI M., NÉMETH S., NAGY G., BERCSÉNYI M., GÁL D. (2012) Környezeti terhelés harcsa (Silurus glanis) eltérő fehérje tartalmú tápokon történő takarmányozása során. Halászat, Vol. 105/4. pp.25-28. HAVASI M., FELFÖLDI Z., GORZÁS A., LÉVAI P., MERTH J., BERCSÉNYI M. (2012) Intensive rearing of wels (Silurus glanis L.) using plant protein based feed. Georgikon for Agriculture, 15/1, 19-31. HAVASI M., OLÁH T., FELFÖLDI Z., NAGY SZ., BERCSÉNYI M. (2012) Passing times of two types of feeds in wels (Silurus glanis) at three different temperatures. Aquaculture International, 15 (5), DOI: 10.1007/s10499-012-9564-y, IF= 0,912 BELICZKY G., HAVASI M., NÉMETH S., BERCSÉNYI M., GÁL D. (2013) Environmental load of wels (Silurus glanis) fed by feeds of different protein levels. AACL Bioflux 6(1):12-17.
Other scientific publications 1.
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TÁTRAI I., JÓZSA V., GYÖRGY Á.I., HAVASI M., SZABÓ I. (2006) A busa biológiai szerepének és hatásának vizsgálata a Balatonban. In: Mahunka S., Banczerowski J. (szerk.) A Balaton kutatásának 2005. évi eredményei Magyar Tudományos Akadémia, Budapest, 73-83. TÁTRAI I., KORPONAI J., MÁTYÁS K., POMOGYI P., HAVASI M., KUCSERKA T. (2006) Importance of the Crustacean plankton in the regulation of phytoplankton biomass in a shallow wetland lake with abundant submerged vegetation, as a part of the water quality reservoir. The 5th Internat. Conf. on Resl. Limnol. And Water Quality, Brno. Book of Abstracts, 238-242.
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HAVASI M., TÁTRAI I., KORPONAI J., KUCSERKA T. (2007) A domináns Cladocera plankton méret- és termékenységváltozása a Kis-Balaton tározó I. ütemén. Hidrol. Közl. 87/6., 64-66. 4. KUCSERKA T., TÁTRAI I., HAVASI M. (2007) Halállományok hatása a makrozoobentosz populáció dinamikájára a Kis-Balaton tározó I-es ütemén. Hidrol. Közl. 87/6., 93-96. 5. GYÖRGY Á.I., HAVASI M., BOROS G. (2008) A halállomány összetételének változása 2005-2007 során a Kis-Balaton tározó Majortaván. Hidrológiai Közlöny, 88/6., 64-65. 6. HAVASI M., TÁTRAI I., KORPONAI J., KUCSERKA T. (2008) A Bosmina longirostris méret- és termékenységváltozása a Major-tóban. Hidrol. Közl. 88/6., 76-96. 7. HAVASI M. (2009) A Bosmina longirostris dinamikája és táplálékhálózatban betöltött szerepe a Major-tóban. Hidrológiai Tájékoztató, 2009: 24-25. 8. TÁTRAI I., BOROS G., GYÖRGY Á. I., MÁTYÁS K., KORPONAI J., POMOGYI P., HAVASI M., KUCSERKA T. (2009) Abrupt shift from clear to turbid state in a shallow, eutrophic, biomanipulated lake. Hydrobiologia, 620/1.,149-161. IF=1.754 9. TÁTRAI I. MÁTYÁS K., KORPONAI J., POMOGYI P., GYÖRGY Á. I., HAVASI M., KUCSERKA T. (2009) Changes in water clarity during fishmanipulation and post-manipulation periods in a shallow eutrophic lake. Fundamental and Applied Limnology, 174: 135-145. IF= 0.989 10. FELFÖLDI Z., ARDÓ L., HAVASI M., NÉMETH S. (2011) Immunstimulátorok vizsgálata csapó sügéren (Perca fluviatilis). XVII. Ifjúsági Tudományos Fórum, digitális konferencia-kiadvány, ISBN 978-963-9639-36-2 11. ÜVEGES V., ANDIRKÓ V., ÁCS A., BÍRÓ R., DRÁVECZ E., HAJNAL E., HAVASI M., HUBAI K. E., KACSALA I., KOVÁCS K., KOVÁTS N., KUCSERKA T., LENGYEL E., MATULKA A. SELMECZY G. B., STENGERKOVÁCS CS., SZABÓ B., TEKE G., VASS M., PADISÁK J. (2011) A vörösiszap katasztrófa hatása a Torna-patak és a Marcal élővilágára, a regeneráció első időszaka. Economica, 12: 95-139. 3.
Cumulative impact factor: IF=3.655
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Books, dissertations 1.
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HAVASI M. (2008) A Bosmina longirostris dinamikája és táplálékhálózatban betöltött szerepe a Major-tóban., Diplomadolgozat, Pannon Egyetem, Mérnöki Kar HAVASI M. (2010) Harcsa (Silurus glanis L.) intenzív nevelése tápon, halkiegészítéssel. Diplomadolgozat, Kaposvári Egyetem, Állattudományi Kar HAVASI M. (2010) A halak szaporodása a természetben. In: Ördög V.(szerk.) Haltenyésztés, elektronikus BSc jegyzet, pp. 33-38.
Other scientific presentations 1.
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HAVASI M., TÁTRAI I., KORPONAI J., KUCSERKA T. (2006) A domináns Cladocera plankton méret- és termékenységváltozása a Kis-Balaton tározó I. ütemén. XLVIII. Hidrobiológus Napok, Tihany, poszter szekció GYÖRGY Á.I., HAVASI M., BOROS G. (2007) A halászati hozam (CPUE) változása 2005-2007 évek során a Major-tóban. XLIX. Hidrobiológus Napok, Tihany, poszter szekció HAVASI M., TÁTRAI I., KORPONAI J., KUCSERKA T. (2007) A Bosmina longirostris méret- és termékenységváltozása a Major-tóban. XVIX. Hidrobiológus Napok, Tihany, poszter szekció HAVASI M. (2007) A Bosmina longirostris méret- és termékenység változása a Major-tóban. ITDK, Veszprém, dicséret, továbbjutás GYÖRGY Á. I., TÁTRAI I., BOROS G., KORPONAI J., HAVASI M., KUCSERKA T. (2008) Changes in fish community structure in an alternating shallow lake. Deutschen Gesellschaft für Limnologie (DGL)/ International Association of Theoretical and Applied Limnology (Societas Internationalis Limnologiae, SIL), Konstanz, Germany, Németország GYÖRGY Á. I., HAVASI M., KUCSERKA T. (2008) A halállomány összetételének (CPUE) és mennyiségének változása a Kis-Balaton Vízvédelmi Rendszer kísérleti taván. L. Hidrobiológus Napok, Tihany, poszter szekció GYÖRGY Á. I., TÁTRAI I., BOROS G. KORPONAI J., HAVASI M., KUCSERKA T. (2008) Changes in fish community structure in an
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alternating shallow lake. Shallow Lakes Conference, Punta del Este, Uruguay, poszter HAVASI M. (2008) A Bosmina longirostris dinamikája és táplálékhálózatban való szerepe a Major-tóban. Környezettudományi Hallgatói Kutatások, Veszprém HAVASI M. (2008) A Bosmina longirostris dinamikája és táplálékhálózatban való szerepe a Major-tóban. XI. Országos Felsőoktatási Környezettudományi Diákkonferencia, Nyíregyháza, vízi ökológia szekció, II. helyezés Havasi M. (2009) A Bosmina longirostris méret- és termékenység változása a Major-tóban. XXIX. OTDK, Veszprém, hidrobiológia szekció HAVASI M. (2010) A Balaton őszi-téli madárvilága. Balaton Szakkollégium, Pannon Egyetem, Keszthely, 2010. 12. 06. FELFÖLDI Z., ARDÓ L., HAVASI M., NÉMETH S. (2011) Immunstimulátorok vizsgálata csapó sügéren (Perca fluviatilis). XVII. Ifjúsági Tudományos Fórum, Keszthely, 2011. április 21. FELFÖLDI Z., ARDÓ L., HAVASI M., NÉMETH S. (2011) Gyógynövény alapú immunstimulátorok használata intenzív halnevelésben. XXXV. Halászati Tudományos Tanácskozás, Szarvas, 2011. május 25-26. HAVASI M. (2012) Examples of non-native aquatic species found in Lake Balaton. Learning for Lakes workshop, Valencia, Spanyolország, 2012. 02. 28. NAGY SZ., KAKASI B., HAVASI M., NÉMETH S., PÁL L., BERCSÉNYI M., HUSVÉTH F. (2013) Dynamic cellular changes during fish sperm activation as measured by flow cytometry. Diversification in Inland Finfish Aquaculture II., Vodňany, Cseh Köztársaság, 2013. 09. 24.
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