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Estudou-se o sistema porta hepático do bagre africano Clarias gariepinus Burchell, 1822, sob o ponto de vista da anatomia macroscópica e microscópica, utilizando-se várias técnicas anatômicas, que envolveram anestesia, injeção de substâncias recomendadas ao estudo do sistema vascular (látex, nanquim, cloreto de polivinil e substância radiopaca), dissecação, corrosão ou radiografia, conforme a exigência de cada técnica, como meio de compreensão da anatomia vascular do fígado deste peixe. Foram utilizados 16 exemplares do sexo feminino, com comprimento total entre 45 e 53,5 centímetros e massa corpórea entre 575 e 1068 gramas. Para a execução dessas técnicas, os peixes foram devidamente anestesiados com benzocaína, garantindo a narcose profunda e evitando qualquer tipo de sofrimento a eles. Os resultados obtidos com essas técnicas mostram que o fígado de Clarias gariepinus ocupa a cavidade abdominal cranial e apresenta uma lobação bem definida, sendo constituído por dois grandes lobos, denominados direito e esquerdo, conectados cranialmente por uma ponte dorsal à transição entre o esôfago e o estômago. O lobo esquerdo apresenta-se ligeiramente maior que o contralateral. Em suas extremidades caudais, os lobos esquerdo e direito formam um ápice pontiagudo, de formato triangular, que continua tenuemente através de um istmo eminentemente vascular que liga esses ápices a dois outros lobos, chamados acessórios direito e esquerdo, bem menores que os demais, e que ficam seqüestrados em um recesso peritoneal, lateral à cavidade abdominal. Os resultados indicam ainda que o sistema porta hepático de Clarias gariepinus está representado por duas veias portas principais denominadas direita e esquerda, levemente assimétricas em diâmetro, que drenam o sangue das vísceras abdominais (baço, estômago, vesícula biliar, intestino e gônadas) através dos tributários viscerais desse sistema. Ainda, devido a uma situação peculiar dos lobos acessórios, definem-se mais duas veias portas secundárias ligadas às principais e designadas igualmente por acessórias, uma esquerda e outra direita. Ambas as vv. portas principais se ramificam, atingindo o hilo da face visceral, enquanto que as vv. acessórias penetram por uma região restrita do lobo. Através de ramos interlobares, ambas as vv. portas principais se anastomosam no parênquima hepático. A v. porta esquerda, com discreto aumento de diâmetro, forma-se pela terminação da v. intestinal, concomitante à desembocadura da v. gastrointestinal e da v. porta acessória esquerda. A v. porta direita se define pela terminação da v. intestinal cranial, simultaneamente à chegada da v. porta acessória ipsilateral, drenando sangue do intestino médio, estômago e vesícula biliar. Nessa espécie, também estão caracterizados dois sítios de comunicação entre o sistema porta hepático e o sistema porta renal através de anastomoses em cada v. porta. Sob as condições em que o trabalho foi desenvolvido e considerando-se a metodologia proposta e a análise dos resultados, conclui-se que todos os métodos foram adequados ao estudo do aparelho circulatório de Clarias gariepinus, sendo recomendados para experimentos futuros sobre o mesmo assunto em outras espécies piscícolas; porém, dentre as três metodologias utilizadas para análises macroscópicas, a injeção de cloreto de polivinil seguida de corrosão das peças e subseqüente obtenção de moldes vasculares mostrou-se mais eficiente na marcação e identificação dos vasos que compõem o sistema porta hepático deste peixe. Conclui-se também que, devido à presença dos lobos acessórios, a lobação hepática é peculiar nesta espécie, em virtude da posição ocupada por estes lobos, assim como a circulação porta, em função das duas veias porta acessórias, e ainda a anastomose entre as duas veias porta principais, característica que deve ser considerada em trabalhos que envolvam cirurgia hepática no bagre africano / The hepatic portal system of the African catfish Clarias gariepinus Burchell, 1822, was studied considering the macroscopic and microscopic anatomy, by means of several anatomic techniques, including anesthesia, injection of substances recommended to the study of the vascular system (latex, Indian ink, polyvinyl chloride and radiopaque substance), dissection, corrosion or radiography, according to the requirement of each technique, as a way of understanding the hepatic circulatory pathway in the African catfish. Sixteen female specimen were used, being the entire length between 45 and 53.5 centimeters and the corporal mass between 575 and 1068 grams. To perform these techniques, the fishes were adequately anesthetized with benzocaine, assuring the deep narcosis and preventing them from any suffering. The results obtained through such techniques show that the liver of Clarias gariepinus occupies the cranial abdominal cavity and shows a clear lobation, the liver consisting of two large lobes, called right and left, cranially connected by a bridge dorsal to the transition between the esophagus and the stomach. The left lobe is slightly larger than the contralateral lobe. At their caudal ends, the left and the right lobes form a sharp triangle-like apex that tenuously passes through a strip eminently vascular that links these apexes with two other lobes, called right and left accessories, much smaller than the others, these lobes being wrapped in a peritoneal recess, situated at the side of the abdominal cavity. The results still show that the hepatic portal system of Clarias gariepinus is represented by two main portal veins named right and left, slightly asymmetric in diameter, that empty the blood out of the abdominal viscera (spleen, stomach, gall bladder, intestine and gonads) through the visceral tributaries of this system. Furthermore, due to a peculiar situation of the accessory lobes, two other secondary portal veins were defined; they are connected to the main veins and are equally called right and left accessories. Both the main portal veins branch, reaching the hilum of the visceral face, whereas the accessory veins go into a restricted region of the lobe. Through interlobar branches, both the main portal veins anastomose in the hepatic parenchyma. The left portal vein, with a slight increase in diameter, is formed by the terminatio of the intestinal vein, accompanying the discharge of the gastrointestinal vein and the accessory left portal vein. The right portal vein is defined by the terminatio of the cranial intestinal vein, simultaneously with the accessory ipsilateral portal vein, emptying the blood out of the medial intestine, stomach and gall bladder. In this species it is also possible to distinguish two connecting sites between the hepatic portal system and the renal portal system by means of anastomoses in each portal vein. Under the conditions in which the experiment was carried out and considering the methodology suggested and the analysis of the results, it is concluded that all the methods were suitable for the study of the circulatory system of Clarias gariepinus, being recommended for future tests on the same subject in other fish species; however, among the three methodologies used in the macroscopic analyses, the injection of polyvinyl chloride followed by the corrosion of pieces and subsequent getting of vascular moulds was believed to be more efficient at the marking and identification of the vessels that compose the hepatic portal system of this fish. It was also concluded that, due to the presence of the accessory lobes, the hepatic lobation is peculiar in this species because of the position occupied by these lobes, as well as the portal circulation, caused by the two accessory portal veins, in addition to the anastomose between the two main portal veins, a characteristic that must be thought of in studies of hepatic surgery in the African catfish

In order to investigate the interactions of dietary protein and energy and their utilisation by African catfish, Clarias gariepinus (Burchell, 1822) (12.43 ± 0.05 g), a series of four nutritional experiments (triplicate groups of 20 fish per 30-L tank at 28 ± 1°C, for 8 weeks) were carried out using fish meal based diets. Optimum dietary protein to energy ratio (P/E ratio) and optimum lipid to carbohydrate ratio (L/CHO ratio) were investigated. Based on optimised dietary P/E ratio and L/CHO ratio, optimum feeding regime and compensatory growth were also investigated in this species. In the experiments to optimise P/E ratio and L/CHO ratio fish were offered each diet at 5% of their body weight per day adjusted fortnightly. In the optimum feeding regime experiments, fish were offered each diet to appetite or to a restricted level. The restricted regimes were achieved by offering fish decreasing fixed feeding rates with increasing dietary protein level. Studies on compensatory growth were conducted in two phases each of 4 weeks. In the first phase, triplicate groups of 30 fish and in the second phase triplicate groups of 20 fish (per 30-L tank) were offered the diet in six mixed feeding schedules at two feeding regimes i.e. appetite and restricted. The restricted regime was achieved by offering fish 1% (maintenance ration) of their body weight per day adjusted after fortnightly weighing. Optimum dietary P/E and L/CHO ratios were 20.54-mg protein/kJ of GE and 0.40 g/g respectively, with a crude protein level over 40% and gross energy of more than 20 kJ/g GE. The results of investigating feeding regimes suggest that dietary protein level could be reduced from over 40% to 35% by feeding to appetite based on the above optimised dietary P/E and L/CHO ratios. Addition of dietary energy as lipid at varying protein levels resulted in increased growth, protein and energy utilisation in C. gariepinus. Based on optimised dietary P/E ratio, dietary carbohydrate levels were increased (with concomitant reduction in dietary lipid levels) resulting in a trend towards higher growth performance, protein and energy utilisation. Protein and energy utilisation did not vary (P > 0.05) with feeding regime or dietary protein level. C. gariepinus showed partial compensatory growth under alternating periods of feeding a restricted (maintenance requirements) and appetite ration and also showed higher feed, protein, lipid and energy utilisation efficiencies in comparison to appetite feeding.Increase in dietary lipid produced an increment in carcass lipid deposition, both in whole body and liver in all studies. Fish in all treatments did not show significant differences (P < 0.05) in body protein content. Optimum P/E ratio studies, with varying dietary protein and energy level, produced higher liver glycogen, plasma glucose and plasma triglycerides at higher dietary carbohydrate level with lower protein diets. In the studies to optimise lipid to CHO ratio comparatively lower (P < 0.05) plasma glucose and plasma cholesterol deposition were observed while no consistent trends were found in liver glycogen deposition in fish fed higher dietary lipid with concomitant lower CHO levels. Studies on optimising feeding regime, with varying protein levels, did not show any significant differences (P < 0.05) in liver glycogen, plasma glucose, plasma triglycerides and plasma cholesterol in response to dietary treatment. In all studies fish fed the experimental diets showed insignificant differences (P > 0.05) in plasma amino acid levels and digestive enzyme activities (protease and lipase) while intestinal a-amylase activity increased with increasing dietary carbohydrate level. Histological examination of intestine & liver in all studies showed no abnormalities. In conclusion, these studies suggest that manipulation and optimisation of dietary protein and energy intakes plays a very significant role in African catfish, Clarias gariepinus nutrition.

When hormonally induced artificial spawning of african catfish (Clarias gariepinus), was several female injected intraperitoneally in one dose preparation Ovopel at doses of 1.5 pellet × kg-1. Females were kept separately in the tanks at a temperature of 21.5 °C. All females were spawned at the same time latency 19.2 hours. Eggs from three spawned females were mixed and divided into 6 doses. Each batch was placed into thermoboxes at temperature 5 °C, 10 °C, 15 °C, 20 °C, 25 °C and 30 °C. These eggs were stored in thermoboxes and after times of storage 0.5 h, 1 h, 1.5 h, 2 h, 3 h, 4 h, 6 h, 8 h, 10h, part of the eggs (approximately 50 to 100 pieces) were taken out from each thermoboxes in three replications and was placed into individuals cups and fertilized by adding 5 drops of sperm and 20 ml of water. In these samples were subsequently observed fertilization, hatching rate and survival rate. When watching fertilization was in individual temperature the highest values and also statistically non-significant difference ( = 0.05) achieved: at 5 °C in times of fertilization 0.5 2 hrs. (61.6 +- 5.81 % - 47.7 +- 1.48 %), at 10 °C in times 0.5 - 1.5 hrs. (70 +- 6.7 % - 62.1 +- 8.9 %), at 15 °C in times 0.5 - 3 hrs. (59.6 +- 9.4 % - 59.6 +- 2.9 %), at 20 °C in times 0.5 - 3 hrs. (61.4 +- 3.6 % - 56.1 +- 2.5 %), at 25 °C in times 0.5 - 4 hrs. (55.5 +- 7.2 % - 49.7 +- 9.3 %) and at 30 °C in times 0,5 - 3 hrs. (61.6 +- 10.3 % - 51.8 +- 17.8 %). When watching hatching rate was in individual temperature the highest values and also statistically non-significant difference ( = 0.05) achieved: at 5 °C in times of fertilization 0.5 - 1 hrs. (28.4 +- 2.9 % - 21.1 +- 9.5 %), at 10 °C in times 0.5 - 1 hrs. (36.6 +- 17.3 % - 22.1 +- 7 %), at 15 °C in times 0.5 - 2 hrs. (34.1 +- 5.5 % - 26.9 +- 5.1 %), at 20 °C in times 0.5 - 2 hrs. (33 +- 8.2 % - 28.8 +- 1.6 %), at 25 °C in times 0.5 - 4 hrs. (31.4 +- 6.2 % - 15.3 +- 13.5 %) and at 30 °C in times 0.5 - 2 hrs. (33.1 +- 9.2 % - 21.2 +- 8 %). When watching survival rate was in individual temperature the highest values and also statistically non-significant difference ( = 0.05) achieved: at 5 °C in times of fertilization 0.5 - 1 hrs. (20.1 +- 6 % - 13 +- 3.3 %), at 10 °C in times 0.5 - 3 hrs. (19.8 +- 15.31 % - 3.1 +- 3 %), at 15 °C in times 0.5 - 6 hrs. (23.3 +- 9 % - 5 +- 2.8 %), at 20 °C in times 0.5 - 2 hrs. (22.4 +- 1.9 % - 15.1 +- 5.2 %), at 25 °C in times 0.5 - 4 hrs. (18.7 +- 4.4 % - 4.1 +- 1.9 %) and at 30 °C in times 0.5 - 1.5 hrs. (26.2 +- 5.5 % - 21.4 +- 6.8 %). Suitable temperatures for the storage of unfertilized eggs after spawning are two hours before fertilization at temperatures from 15 to 30 °C. Other suitable temperatures which are useful for storage are temperatures 15 to 25 °C, for preservation after 3 hrs. and longer after fertilization.

Estudou-se o sistema porta hepático do bagre africano Clarias gariepinus Burchell, 1822, sob o ponto de vista da anatomia macroscópica e microscópica, utilizando-se várias técnicas anatômicas, que envolveram anestesia, injeção de substâncias recomendadas ao estudo do sistema vascular (látex, nanquim, cloreto de polivinil e substância radiopaca), dissecação, corrosão ou radiografia, conforme a exigência de cada técnica, como meio de compreensão da anatomia vascular do fígado deste peixe. Foram utilizados 16 exemplares do sexo feminino, com comprimento total entre 45 e 53,5 centímetros e massa corpórea entre 575 e 1068 gramas. Para a execução dessas técnicas, os peixes foram devidamente anestesiados com benzocaína, garantindo a narcose profunda e evitando qualquer tipo de sofrimento a eles. Os resultados obtidos com essas técnicas mostram que o fígado de Clarias gariepinus ocupa a cavidade abdominal cranial e apresenta uma lobação bem definida, sendo constituído por dois grandes lobos, denominados direito e esquerdo, conectados cranialmente por uma ponte dorsal à transição entre o esôfago e o estômago. O lobo esquerdo apresenta-se ligeiramente maior que o contralateral. Em suas extremidades caudais, os lobos esquerdo e direito formam um ápice pontiagudo, de formato triangular, que continua tenuemente através de um istmo eminentemente vascular que liga esses ápices a dois outros lobos, chamados acessórios direito e esquerdo, bem menores que os demais, e que ficam seqüestrados em um recesso peritoneal, lateral à cavidade abdominal. Os resultados indicam ainda que o sistema porta hepático de Clarias gariepinus está representado por duas veias portas principais denominadas direita e esquerda, levemente assimétricas em diâmetro, que drenam o sangue das vísceras abdominais (baço, estômago, vesícula biliar, intestino e gônadas) através dos tributários viscerais desse sistema. Ainda, devido a uma situação peculiar dos lobos acessórios, definem-se mais duas veias portas secundárias ligadas às principais e designadas igualmente por acessórias, uma esquerda e outra direita. Ambas as vv. portas principais se ramificam, atingindo o hilo da face visceral, enquanto que as vv. acessórias penetram por uma região restrita do lobo. Através de ramos interlobares, ambas as vv. portas principais se anastomosam no parênquima hepático. A v. porta esquerda, com discreto aumento de diâmetro, forma-se pela terminação da v. intestinal, concomitante à desembocadura da v. gastrointestinal e da v. porta acessória esquerda. A v. porta direita se define pela terminação da v. intestinal cranial, simultaneamente à chegada da v. porta acessória ipsilateral, drenando sangue do intestino médio, estômago e vesícula biliar. Nessa espécie, também estão caracterizados dois sítios de comunicação entre o sistema porta hepático e o sistema porta renal através de anastomoses em cada v. porta. Sob as condições em que o trabalho foi desenvolvido e considerando-se a metodologia proposta e a análise dos resultados, conclui-se que todos os métodos foram adequados ao estudo do aparelho circulatório de Clarias gariepinus, sendo recomendados para experimentos futuros sobre o mesmo assunto em outras espécies piscícolas; porém, dentre as três metodologias utilizadas para análises macroscópicas, a injeção de cloreto de polivinil seguida de corrosão das peças e subseqüente obtenção de moldes vasculares mostrou-se mais eficiente na marcação e identificação dos vasos que compõem o sistema porta hepático deste peixe. Conclui-se também que, devido à presença dos lobos acessórios, a lobação hepática é peculiar nesta espécie, em virtude da posição ocupada por estes lobos, assim como a circulação porta, em função das duas veias porta acessórias, e ainda a anastomose entre as duas veias porta principais, característica que deve ser considerada em trabalhos que envolvam cirurgia hepática no bagre africano / The hepatic portal system of the African catfish Clarias gariepinus Burchell, 1822, was studied considering the macroscopic and microscopic anatomy, by means of several anatomic techniques, including anesthesia, injection of substances recommended to the study of the vascular system (latex, Indian ink, polyvinyl chloride and radiopaque substance), dissection, corrosion or radiography, according to the requirement of each technique, as a way of understanding the hepatic circulatory pathway in the African catfish. Sixteen female specimen were used, being the entire length between 45 and 53.5 centimeters and the corporal mass between 575 and 1068 grams. To perform these techniques, the fishes were adequately anesthetized with benzocaine, assuring the deep narcosis and preventing them from any suffering. The results obtained through such techniques show that the liver of Clarias gariepinus occupies the cranial abdominal cavity and shows a clear lobation, the liver consisting of two large lobes, called right and left, cranially connected by a bridge dorsal to the transition between the esophagus and the stomach. The left lobe is slightly larger than the contralateral lobe. At their caudal ends, the left and the right lobes form a sharp triangle-like apex that tenuously passes through a strip eminently vascular that links these apexes with two other lobes, called right and left accessories, much smaller than the others, these lobes being wrapped in a peritoneal recess, situated at the side of the abdominal cavity. The results still show that the hepatic portal system of Clarias gariepinus is represented by two main portal veins named right and left, slightly asymmetric in diameter, that empty the blood out of the abdominal viscera (spleen, stomach, gall bladder, intestine and gonads) through the visceral tributaries of this system. Furthermore, due to a peculiar situation of the accessory lobes, two other secondary portal veins were defined; they are connected to the main veins and are equally called right and left accessories. Both the main portal veins branch, reaching the hilum of the visceral face, whereas the accessory veins go into a restricted region of the lobe. Through interlobar branches, both the main portal veins anastomose in the hepatic parenchyma. The left portal vein, with a slight increase in diameter, is formed by the terminatio of the intestinal vein, accompanying the discharge of the gastrointestinal vein and the accessory left portal vein. The right portal vein is defined by the terminatio of the cranial intestinal vein, simultaneously with the accessory ipsilateral portal vein, emptying the blood out of the medial intestine, stomach and gall bladder. In this species it is also possible to distinguish two connecting sites between the hepatic portal system and the renal portal system by means of anastomoses in each portal vein. Under the conditions in which the experiment was carried out and considering the methodology suggested and the analysis of the results, it is concluded that all the methods were suitable for the study of the circulatory system of Clarias gariepinus, being recommended for future tests on the same subject in other fish species; however, among the three methodologies used in the macroscopic analyses, the injection of polyvinyl chloride followed by the corrosion of pieces and subsequent getting of vascular moulds was believed to be more efficient at the marking and identification of the vessels that compose the hepatic portal system of this fish. It was also concluded that, due to the presence of the accessory lobes, the hepatic lobation is peculiar in this species because of the position occupied by these lobes, as well as the portal circulation, caused by the two accessory portal veins, in addition to the anastomose between the two main portal veins, a characteristic that must be thought of in studies of hepatic surgery in the African catfish

The object of this study is to design demembranation method on four freshwater species and its application on study of the influence of HgCl2 on the axoneme and motity sperm motility parameters. Demembranation was designed and examined for all investigated species common carp (Cyprinus carpio), sterlet (Acipenser ruthenus), perch (Perca fluviatilis) and african catfish (Clarias gariepinus). One-step and two-step method was designed and tested for common carp. One-step method was designed for sterlet and perch. Two-step method of demembranation was designed for african catfish. Demembranation was designed and examined for all species under examination. Sperm motility was evidently increased above normal physiological value. Other sperm motility parameters (velocity, percent of motile cells) slightly decreased. HgCl2 in concentration 0,01 mM to the demembranation medium didn't show effect on flagellar microtubule aparat and then to the motility parameters, except sterlet; demembranated sterlet sperm was inhibited at all used concentration of HgCl2. Concentration 0,1 mM had inhibition effect on carp and africant catfish spermatozoa. Concentration 1 mM HgCl2 inhibited sperm of all tested species.

In my diploma thesis I was tested six types of feed. I tested in 3 repetitions in the recirculating system with biological treatment of water. Tested fishes african catfish (Clarias gariepinus) weighted between 200 ? 800 g per piece, were deployed into 18 aquariums with volume of 190 litres per aquarium. The whole experiment took place in five partial 3-week periods in the intensive breeding of the laboratory - controlled reproduction of fishes FROV JCU. The average water temperature during the experiment was 27 °C. The main objective of the thesis was to observe production efficiency of tested types of feed, speed of the growth of fishes, feed rates and financial costs. Afterwards, determinativ of yield and organoleptic evaluation was determined, followed by laboratory examination of composition of meat. The results of production indicators (Specific Growth Rate, Relative Growth Rate, Food Conversation Ratio) were most favorable for 3 types of feed ? Haltáp (SGR=0,81 %; RGR=126 %; FCR=1,45), Coppens TROCO SUPREME-22 (SGR=0,73 %; RGR=105 %; FCR=1,19), Coppens TROCO PRIME-18 (SGR=0,68 %; RGR=97 %; FCR=1,26). The lowest costs for 1 kg of fish increment were achieved for these specific types of feed Haltáp and Aller Aqua Focus (45 Kč a 46 Kč). In the organoleptic analysis was found positive evaluation of meat of all tested fishes. Chemical composition of meat was (in term of proteins and fats content) most favorably documented for the hungarian feed called Haltáp (proteins=19,22 % and fats=4,85 %).

Einleitung Entsprechend der Tierschutz-Schlachtverordnung sind Wirbeltiere vor der Tötung grundsätzlich zu betäuben. Die für Fische zulässigen Betäubungsmethoden haben sich jedoch für die Betäubung Afrikanischer Welse (Clarias gariepinus) in der Praxis als problematisch erwiesen. Ziel der Untersuchungen Das Untersuchungsziel bestand in der Erprobung und Optimierung von Betäubungsverfahren für die Schlachtung Afrikanischer Welse. Verschiedene Varianten der Vorkühlung, Eiswasserbehandlung und Elektrobetäubung wurden einzeln oder in Kombination vergleichend geprüft. Materialien und Methoden Zur Beurteilung der Betäubungswirkung dienten klinische Tests: Atmung, Schwimmbewegungen, Reaktion auf Manipulation, Gleichgewicht mit und ohne Manipulation, Augendrehreflex, Schmerzreiz. Weiterhin erfolgten Blutuntersuchungen mit Bestimmung der Cortisol-, Glukose-, Laktat-, Natrium-, Kalium- und Chloridgehalte zur Beurteilung der Stressbelastung der Welse. Insgesamt wurden 378 Afrikanische Welse genutzt. Die Untersuchungen umfassten sechs Teilversuche: Im Vorversuch 0 fand die Prüfung der Untersuchungsmethoden statt. Versuch 1a diente dem Vergleich von drei Varianten der Eiswasserbehandlung: Variante 1: Eiswasser mit +0,1 ± 0,2 °C, Variante 2: Eiswasser mit zusätzlichem Crash-Eis bei gleicher Temperatur und Variante 3: Eiswasser mit Kochsalz bei -2,0 ± 0,5 °C. Im Versuch 1b wurden drei Vorkühltemperaturen getestet: 10 °C, 15 °C und 20 °C. Die Elektrobetäubung (Versuch 2 bzw. Versuche 3 und 4 als Kombinationsmethoden) erfolgte am Einzeltier per Kopfdurchströmung mit 250 bzw. 300 V und 1,3 bzw. 1,8 A Wechselstrom. Bei der Prüfung der Kombination von Elektrobetäubung und Eiswasserbehandlung wurden die Welse nach der Kopfdurchströmung unmittelbar in ein mit Eiswasser gefülltes Becken umgesetzt. Versuch 4 diente der Überprüfung der Kombinationsmethode auf Praxistauglichkeit in einer Kreislaufanlage an 50 schlachtreifen Welsen. Ergebnisse Die maximalen Reaktionszeiten im Eiswasser lagen in den drei Varianten des Versuches 1a zwischen 3,8 und 4,7 Minuten (arithmetische Mittel). Die Eiswasserbehandlung ermöglichte kein schnelles Erreichen der Wahrnehmungs- und Empfindungslosigkeit. Die Variante 1 – Eiswasser mit +0,1 ± 0,2 °C – war mit den geringsten Belastungen verbunden. Gleiches trifft auf die Vorkühltemperatur von 15 °C zu. Mittels elektrischer Kopfdurchströmung wurde im Versuch 2 eine Betäubung der Welse erreicht, verbunden mit einer 30 bis 60 Sekunden andauernden Wahrnehmungslosigkeit. Die Betäubung geschah am Einzeltier nach vorheriger Separierung. In den Kombinationsversuchen 3 und 4 wurde kein durchgängiger Zustand der Wahrnehmungs- und Empfindungslosigkeit beobachtet. Die Welse zeigten im Mittel 2,7 bzw. 3,3 Minuten nach Umsetzen in das Eiswasser zuletzt Reaktionen auf klinische Tests. Schlussfolgerungen Die Eiswasserbehandlung ermöglicht keine tierschutzgerechte Betäubung entsprechend der Tierschutz-Schlachtverordnung. Eine Vorkühlung vor der Betäubung scheint notwendig. Vor der Elektrobetäubung schränkt sie die Beweglichkeit der Welse ein und ermöglicht somit ein besseres Ansetzen der Elektroden. Die Einzeltierbetäubung ist zeitaufwendig und setzt von der durchführenden Person ausreichend Erfahrung voraus, um Fehlbetäubungen zu vermeiden. Die kurze Wahrnehmungslosigkeit erfordert eine sich unmittelbar anschließende Entblutung bzw. Dekapitation. Für kleine Schlachtzahlen bzw. als Alternative zur Betäubung per Kopfschlag erscheint die untersuchte Methode mit der verwendeten gerätetechnischen Ausstattung bzw. unter Beachtung der elektrischen Betäubungsparameter geeignet. Zur Validierung der Kombination von Vorkühlung, Elektrobetäubung und Eiswasserbehandlung sind weitere Untersuchungen erforderlich. Es ist zu prüfen, ob durch eine Veränderung der Betäubungsparameter eine bis zum Tod anhaltende Wahrnehmungs- und Empfindungslosigkeit gewährleistet werden kann.

The main objective of this diploma thesis is compare the production efficiency of special types of feed for African catfish in experimental conditions in a recirculating system with biological treatment of water. It was tested four different types of floating feed, differing in the proportion of main components, the chemical composition and determining - for catfish (CatCo GROWER - 12 EF, CatCo SELECT - 13 EF and CatCo GROWER - 13 EF), respectively salmonid fish species (Dibaq Trout Evolution). The primary outcome indicators was the growth rate, individual weight (and it's variability), feed conversion ratio, the cost of feed consumed per unit of growth and product quality, evaluated according the average dress-out percentage of skinless fillets, organoleptic assessment and chemical composition of flesh.

Einleitung Entsprechend der Tierschutz-Schlachtverordnung sind Wirbeltiere vor der Tötung grundsätzlich zu betäuben. Die für Fische zulässigen Betäubungsmethoden haben sich jedoch für die Betäubung Afrikanischer Welse (Clarias gariepinus) in der Praxis als problematisch erwiesen. Ziel der Untersuchungen Das Untersuchungsziel bestand in der Erprobung und Optimierung von Betäubungsverfahren für die Schlachtung Afrikanischer Welse. Verschiedene Varianten der Vorkühlung, Eiswasserbehandlung und Elektrobetäubung wurden einzeln oder in Kombination vergleichend geprüft. Materialien und Methoden Zur Beurteilung der Betäubungswirkung dienten klinische Tests: Atmung, Schwimmbewegungen, Reaktion auf Manipulation, Gleichgewicht mit und ohne Manipulation, Augendrehreflex, Schmerzreiz. Weiterhin erfolgten Blutuntersuchungen mit Bestimmung der Cortisol-, Glukose-, Laktat-, Natrium-, Kalium- und Chloridgehalte zur Beurteilung der Stressbelastung der Welse. Insgesamt wurden 378 Afrikanische Welse genutzt. Die Untersuchungen umfassten sechs Teilversuche: Im Vorversuch 0 fand die Prüfung der Untersuchungsmethoden statt. Versuch 1a diente dem Vergleich von drei Varianten der Eiswasserbehandlung: Variante 1: Eiswasser mit +0,1 ± 0,2 °C, Variante 2: Eiswasser mit zusätzlichem Crash-Eis bei gleicher Temperatur und Variante 3: Eiswasser mit Kochsalz bei -2,0 ± 0,5 °C. Im Versuch 1b wurden drei Vorkühltemperaturen getestet: 10 °C, 15 °C und 20 °C. Die Elektrobetäubung (Versuch 2 bzw. Versuche 3 und 4 als Kombinationsmethoden) erfolgte am Einzeltier per Kopfdurchströmung mit 250 bzw. 300 V und 1,3 bzw. 1,8 A Wechselstrom. Bei der Prüfung der Kombination von Elektrobetäubung und Eiswasserbehandlung wurden die Welse nach der Kopfdurchströmung unmittelbar in ein mit Eiswasser gefülltes Becken umgesetzt. Versuch 4 diente der Überprüfung der Kombinationsmethode auf Praxistauglichkeit in einer Kreislaufanlage an 50 schlachtreifen Welsen. Ergebnisse Die maximalen Reaktionszeiten im Eiswasser lagen in den drei Varianten des Versuches 1a zwischen 3,8 und 4,7 Minuten (arithmetische Mittel). Die Eiswasserbehandlung ermöglichte kein schnelles Erreichen der Wahrnehmungs- und Empfindungslosigkeit. Die Variante 1 – Eiswasser mit +0,1 ± 0,2 °C – war mit den geringsten Belastungen verbunden. Gleiches trifft auf die Vorkühltemperatur von 15 °C zu. Mittels elektrischer Kopfdurchströmung wurde im Versuch 2 eine Betäubung der Welse erreicht, verbunden mit einer 30 bis 60 Sekunden andauernden Wahrnehmungslosigkeit. Die Betäubung geschah am Einzeltier nach vorheriger Separierung. In den Kombinationsversuchen 3 und 4 wurde kein durchgängiger Zustand der Wahrnehmungs- und Empfindungslosigkeit beobachtet. Die Welse zeigten im Mittel 2,7 bzw. 3,3 Minuten nach Umsetzen in das Eiswasser zuletzt Reaktionen auf klinische Tests. Schlussfolgerungen Die Eiswasserbehandlung ermöglicht keine tierschutzgerechte Betäubung entsprechend der Tierschutz-Schlachtverordnung. Eine Vorkühlung vor der Betäubung scheint notwendig. Vor der Elektrobetäubung schränkt sie die Beweglichkeit der Welse ein und ermöglicht somit ein besseres Ansetzen der Elektroden. Die Einzeltierbetäubung ist zeitaufwendig und setzt von der durchführenden Person ausreichend Erfahrung voraus, um Fehlbetäubungen zu vermeiden. Die kurze Wahrnehmungslosigkeit erfordert eine sich unmittelbar anschließende Entblutung bzw. Dekapitation. Für kleine Schlachtzahlen bzw. als Alternative zur Betäubung per Kopfschlag erscheint die untersuchte Methode mit der verwendeten gerätetechnischen Ausstattung bzw. unter Beachtung der elektrischen Betäubungsparameter geeignet. Zur Validierung der Kombination von Vorkühlung, Elektrobetäubung und Eiswasserbehandlung sind weitere Untersuchungen erforderlich. Es ist zu prüfen, ob durch eine Veränderung der Betäubungsparameter eine bis zum Tod anhaltende Wahrnehmungs- und Empfindungslosigkeit gewährleistet werden kann.