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  • Effect of fish feeds with high vegetable oil and low fish oil content on the growth performance and innate immune system of common carp (preliminary results)
    7-12
    Views:
    96

    Fish meal and fish oil are very important components of fish feeds used by aquaculture. They contain poly-unsaturated fatty acids, which are essential nutrients both for fish and human nutrition. However, sources of fish meal and fish oil are limited, there is a need for new feed components to supply the increasing fish production and the increasing demand for fish feed. The aim of AQUAMAX project, supported by the European Union is to replace the fish meal and fish oil with vegetable oils. As a participant of this project, group of immunology in Research
    Institute for Fisheries, Aquaculture and Irrigation (HAKI) examined the effect of three different fish feeds on the growth performance, innate immune response and resistance against Aeromonas hydrophila infection of common carp in an in vivo experiment. Fish feed supplemented with Camelina oil, but still containing fish oil significantly increased growth performance of experimental fish and their resistance against the infection. Fish feed containing linseed oil only did not enhance the growth performance, and it had a negative effect on resistance against infection. Based on the experimental results it can be concluded that fish oil used in fish feeds cannot be replaced effectively with vegetable oils, but can be supplemented with them. 

  • Effect of different n-6/n-3 fatty acid proportion oil sources on reproduction performance and fatty acid profile of milk in modern genotype sows - Pleminary results: Preliminary results
    121-128
    Views:
    160

    This study was conducted to investigate the effects of supplemental n-6 and n-3 fatty acids on sow’s milk fatty acid composition during the lactation period and on reproductive efficiency of sows in the subsequent gestation period. Data were collected on a total of 213 DanBred sows (108 control and 105 experimental) representing parity of 2–7, respectively. Control and experimental sows were placed in the same housing conditions during lactation and gestation period. Control group received 6.3 g of sunflower oil (SO) per kg feed as n-6 fatty acid supplementation, whilst experimental animals received the same amount of fish oil (FO) as n-3 fatty acid source. Diets were corn meal-extracted soybean meal based. The experiment was conducted in one replication as being a part of a longer and more comprehensive trial. It was found that the consumed long-chain polyunsaturated fatty acids (LC-PUFAs) appeared in the sow’s milk and changed its fatty acid profile. With this alteration, the n-6/n-3 ratio of experimental (FO) sows’ milk were narrower than in SO group (SO: 13.82 vs. FO: 5.89). The benefits of n-3 fatty acids supplementation were evident for the subsequent reproduction cycle, when experimental sows heated more reliable and earlier than control (weaning to oestrus interval: SO: 5.86 vs. FO: 4.48 days). Only 2.33% of experimental sows (FO) did not heat within 7 days after weaning, but this was 12.36% in the control group (SO). The present study requires further research to evaluate the effect of n-3 fatty acids on maintenance of pregnancy and improved subsequent litter size.

  • The changes of the ichthiofauna of river Berettyó and tributaries
    106-112
    Views:
    66

    In the spring and summer of 2005 I made ichtiologic research on the Barcau river in the area of Nusfalau – Saniob, as well as on its affluents.
    The results obtained were compared to those of the previous research performed on the Barcau river and partially on its affluents. Wenoticed a decrease of the fish lot both from the qualitative and the quantitative point of view, although the oil industry -the main source of pollution from this area – is in a temporary regress.
    Given the fact that upstream Suplacu-de-Barcau there are construction works for a dam and an artificiallakewhichwillinfluencetheriver fauna, the current research shall allow the repeat of the research and the comparison between the results, the identification of the effects of these works on the fish population from this area.