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New Possibilities of Brown Bullhead (Ictalurus nebulosus) Farming
55-57Views:102The brown bullhead (Ictalurus nebulosus) has been settled in Europe at the end of Century XIX from North America. In Hungary it has been brought in 1902. The naturalization of this species was successful because the brown bullhead found adequate conditions for its life and reproduction in Hungary. But it was unsuccessful because lost its excellent growth.
In inland water habitats-and that’s why also fishponds-extraordinarily multiplied, but because of its slight growth this species is undesirable for the native farmers. The brown bullhead is concurrent for domestic fish species, on the other hand its weight not more than 150-200 g. Occasionally it was exterminated, but multiplied again and again.
In 1999 we placed out black bullhead offspring in a pool of a new intensive fish farm, in order to breed at least 300-350 g weight for the customers. The accidental trial was surprisingly successful. Consequently, the black bullhead prefers the artificial food, and produces excellent growth parameters and specific feed-live weight conversation ratio.
On the 20th of September 1999 there was placed 23 300 pieces of brown bullhead offspring, with 28 g average weight and 625 kg gross weight. When we sold them on the 22nd of February 2000, the gross weight was 3387 and the live weight gain was 2735 kg. The gross weight of the feed was 3041,8 kg, and the feed-live weight conversation ratio was 1,11 kg/kg.
Because of this successful trial the managers of the farm wanted to start systematic experiments to work out the details of the intensive farming of brown bullhead. We undertook to help to find the right place of the species in the Hungarian fish processing because of the increasing native and foreign demand. -
Effect of different weaning time on the growth and survival ofCommon carp (Cyprinus carpio L.) larvae
55-59Views:385Within our experiment, we studied the combined effect of live food application and feed training on the production parameters of carp larvae. In addition, we examined whether there is a difference in the growth rate and survival rate of the specimens of Szeged mirror landrace reared in similar stocking density but with different treatments.
Specimens of Szeged mirror landrace from induced propagation were placed into 12 pieces of 40-liter aquaria. For the 4 different treatments, (K, A3, A6, A9), live food (Artemia salina) was fed, as well as feed training was applied.
We also sought to find an answer as to how our feeding and rearing conditions can affect the production parameters of common carp fries and what impact these conditions may have on their survival rates. At the end of the 2-week experiment we determined the individual weight gain of the carp fries, their survival rate and the biomass growth. The purpose of the study is to examine the optimum timing of shifting from live food to feed for carp larvae.
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Goose Production Responses to Grass-Based Diets
26-28Views:125A feeding trial with 4 week-old goslings was conducted in 2003 using different proportions of chopped grass and grain pellets in the diet. Proportions of chopped grass and grain pellets in diets for Treatments 1, 2, 3 and 4 were 25:75; 50:50; 75:25 and 0:100, respectively. Weekly and final live weights of geese and the feather quality were measured. Treatments with higher grain contents produced higher live weights, and better feather quality.
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Associations analysis of production traits with leptin gene T3469C polymorphisms in pig
39-43Views:201The aim of this study was to define the connection between the leptin (LEP) gene T3469C polymorphism and its potential association with production traits in improved hybrid pigs. The study included data from 397 gilts and barrows from 2 different sample. The polymorphism was identified by using the polymerase chain reaction-restriction fragment-length polymorphism (PCR–RFLP) method with HinfI restriction enzyme. Two alleles of LEP gene were identified: T (0.93) an C (0.07). The analysis of values of production traits, depending on LEP genotype did not reveal significant (P≤0.05) differences. In the examination the loin diameter (between the 2nd and 3rd ribs), the live weight at slaughter and the averege daily gain during fattening were higher at pigs with C allele than pigs with TT genotipe. Accordingt to our data the effect of C allele was favourable in this population, because these animals had bigger bodyweight without valuable change of lean meat percent.