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Probiotic organisms are used in fish culture to accelerate growth, improve the absorption of nutrients, enhance immune resistance, and reduce negative effects of stress. Probiotic microorganisms used in aquaculture include gram positive bacteria (Lactobacillus, Lactococcus, Enterococcus, Carnobacterium, Streptococcus, Bacillus), gram negative bacteria (Shewanella, Aeromonas, Vibrio, Enterobacter, Pseudomonas), fungi (Saccharomyces, Debaryomyces, Phaffia), and algae (Tetraselmis). Probiotics increase the expression of cytokines and affect the cellular and humoral defence mechanisms of the host by increasing the activity of phagocytic cells, complement, and lisozyme level. Probiotic bacteria in the intestines stimulate the immune system through the gut-associated lymphoid tissue (GALT). Probiotic bacteria can be used for protection against bacterial fish pathogens (Aeromonas salmonicida, Vibrio anguillarum, Vibrio ordalii, Yersinia ruckeri). Some publications also report anti-viral, anti-parasitic, and anti-fungal affect of probiotics. This study reviews the results of research on the efficiency of selected probiotics in various fish species. Probiotics may make it possible to achieve better results in fish culture without the need to use harmful and expensive chemotherapeutic products.
Anaesthetics are needed when handling fish, especially during tagging. However, most anaesthetics applied at present have a strong toxic effect on fish. For this reason it is only permissible to keep fish anaesthetized for a short time. A new anaesthetic, Propiscin, which allows fish to be anaesthetized for up to 0.5 h, has been successfully tested. It contains a 0.2% stabilized solution of etomidate and can be used as a bath. When administered correctly, the required disappearance of sense perception and motor reflexes in the fish can be obtained in about 2 - 4 min. The low toxicity of this pharmacological confection has been proved according to a full set of clinical, toxicological, hematological and biochemical criteria. Clinical tests have been conducted on with many fish species, mainly salmonids.
Shrimp farming is an economically important part of aquaculture. Shrimps constitute the largest portion of shellfish intended for human consumption. According to the World Organization for Animal Health (OIE), viral diseases pose the most serious threat to shrimp farming. There are currently six viral and two bacterial diseases on the OIE list. The most serious viral diseases are white spot disease (WSD), Taura syndrome (TS), infection with yellow head virus genotype 1 (YHV), infectious hypodermal and haematopoietic necrosis (IHHN), infectious myonecrosis (IMN) and white tail disease (WTD), whereas the most dangerous bacterial diseases are acute hepatopancreatic necrosis disease (AHPND) and necrotizing hepatopancreatitis (NHP). All these diseases result in high mortality, thus limiting shrimp production and causing large economic losses. Therefore, effective preparations are constantly sought to control infectious diseases in shrimps. Probiotics and immunostimulants, thanks to their demonstrated antibacterial and antiviral effects, as well their positive impact on the immune system, may play a crucial role in protecting the health of shrimps.
Despite great advances in new technologies for breeding and rearing fish, little progress is noted in prophylactic technologies for spawners, particularly those used in carp rearing. The condition and non-specific immunity of males and females has a decisive impact on the quality and fertilization of spawn, on the course of rearing larvae and fry in the first weeks of life, and on the subsequent stages of rearing. The aim of the current study was to determine the level of lysosome and ceruloplasmin activities and on the level of gamma globulin in the females of three carp lines reared in Poland- starzawski, zatorski, and węgierski. The results of the study indicated unequivocally that the highest non-specific humoral immunity potential was noted in the females from the starzawski line. The highest statistically significant levels of lysosome and gamma globulin activity were noted in selects from this line in comparison to those of the zatorski or węgierski lines. However, no significant differences were noted in the ceruloplasmin activities or total protein levels among the lines studied. This informs the direction of further study, which should focus on identifying lines and their cross-breeds that have the highest potential immunity to viral, bacterial, and fungal infections.
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