National Repository of Grey Literature 2 records found  Search took 0.00 seconds. 
The lipid quality of our economically significant fish species
KREJSA, Jakub
The level of fish consumption in the Czech Republic is very low. One of the possible factors influencing this situation is low awareness of the customer or consumer. The thesis "The Lipid Quality of our economically significant fish species" works with the list of nineteen economically most significant fish species not only including fish from the semi-intensive and intensive breeding, but also such species that are interesting for the consumption from the sport fishing point of view. The samples taken from particular fish were primarily used for the analysis of the fat content and fatty acid composition. The analysis established very interesting results in this field and created basis for further analysis for establishing atherogenic and thrombogenic index or for formation of nutritive values mentioned as "Big 7" (fat content and the ratio of fatty acid out of it, sacharide content and the sugar ratio in it, protein content, ash content and energy value) by particular fish species according to the regulation ES 1169/2011. The results of this work confirmed that the fat content and its composition are highly influenced by the type of ingested nourishment. The fish bred in semi-intensive way with the highest fat content are Common carp (7,62 ? 2,9 %) and Silver carp (6,87 ? 1,37 %). On the contrary the predatory fish evinced the fat content usually within 1%. The fish from extensive breeding or the types caught in sport fishing are in the fat con-tent more balanced. The fattest fish in this group is Silver Bream (5,52 ? 0,44 %) and the lowest content evinced Goldfish (1,14 ? 0,38 %). Also the species living in the aquaculture and living in the free waters as well were compared (Common carp, Rainbow trout, Peled, Tench, Wels catfish). The fatty acid composition significantly depends on the fat content. The predatory fish contain 195 - 219 mg×100 g-1, the most (p0,05) was found by the peled from the extensive breed (1048 mg×100 g-1 EPA + DHA). The participation of SFA by the most of the fish was under 30%, the content of MUFA was the highest by the Common carp (52,71 ? 7,75 %), the lowest by the European perch (18,83 ? 1,12 %). Pike, Zander and European perch contain relatively the most of PUFA, this is over 50%. All the fish species (Nile tilapia excluded) show in this study the values of atherogenic index below 0,5 and thrombogenic index below 0,4. The total energetic value was counted from the results of nutritional values presented in the "Big 7" list. The higher energetic value is directly proportional to the increasing fat content. The fish species included in this thesis show the total energetic value in the range of 500 - 900 kJ×100 g-1. The results of this study bring complete, laboratory proven information about the nutrition composition of our fish. This data can be appli-cable not only to increase the knowledge of the customers but mainly to be used by breeders and manufacturers of fish as an implement of fulfilling the duty of stating the nutrition facts on their products according to ES 1169/2011 on the providing infor-mation about the eatables to the consumers.
Effect of alternative feed on content of omega 3 fatty acids in fish muscles
KREJSA, Jakub
The aim of my bachelor thesis was to evaluate the effect of fish oil substitution for rapeseed oil in the feed on the fat content and fatty acid composition in the flesh of Brook trout (Salvelinus fontinalis) in the finishing feeding technology. The experiment was conducted in 2012 for the period of 135 days. The individuals of Brook trout were divided into four groups. The first two groups were fed with the feed containing only rapeseed or fish oil. The feeding of the remaining two groups was divided into two phases. In the first phase the fish oil was partly replaced by the rapeseed oil. In the second phase the fish oil was replaced by the feed which contained fish oil only. It was proved that a half replacement of the fish oil with the rapeseed oil does not influence the content of fat in the flesh of Brook trout. We observed that the fish had the higher content of MUFA and n-6 PUFA and lower content of n-3 PUFA, DHA, EPA and n-3/n-6 with increasing period where the feed with rapeseed oil was served. Following application of the finishing feeding technology with the use of feed with fish oil had the opposite effects. Furthermore, the dilution model was proved to be highly reliable for the prediction of the fatty acids composition. Based on these findings, it is possible to predict changes of fatty acid composition in the flesh of Brook trout as well as to predict how long is needed to apply finishing feeding to reach required content of EPA+DHA or n-3 HUFA.

See also: similar author names
14 KREJSA, Jan
33 KREJSA, Jiří
14 Krejsa, Jan
33 Krejsa, Jiří
1 Krejsa, Josef
Interested in being notified about new results for this query?
Subscribe to the RSS feed.