Utjecaj različite razine linolenske masne kiseline (18:3[omega]3) u hrani na rezultate intenzivne proizvodnje mlađi linjak (Tinca tinca L.) : doktorska disertacija - Opačak, Anđelko; Treer, Tomislav; Černy, Tajana; Stević, Ivan (Zagreb : A. Opačak, 1996)
Sažetak: U radu je istražen utjecaj različite razine linolenske masne kiseline (18:3[omega]3) u hrani na rezultate intenzivne proizvodnje mlađi linjaka (Tinca tinca L.). Itraživanje je provedeno na šest pokusnih skupina riba sa po tri ponavljanja. Prosječna individualna nasadna masa linjaka iznosila je 32,5 g*kom-1. Ribe su hranjene peletiranom krmnom smjesom s 45% bjelančevina. Hrana za kontrolnu skupinu sadržavala je ukupno 0,39% linolenske kiseline iz ingrdijenata, dok je u istu tu krmnu smjesu za P1 pokusnu skupinu riba ugrađeno 0,50% linolenske kiseline, za P2 0,75% za P3 1,00%, za P4 1,25% te P5 pokusnu skupini 1,50% ove esencijalne kiseline. U sklopu eksperimentalnih istraživanja koja su trajala 18 tjedana, izvršno je 9 mjerenja (svakih 14 dana) proizvodnih pokazatelja iz svakog kaveza svake pokusne skupine riba.
Uz to, tijekom istraživanja praćeni su fizikalno-kemijski pokazatelji vode. Kakvoća fileta linjaka nakon eksperimentalnog dijela istraživanja, utvrđena je kemijskim analizama, a sastav masti na masne kiseline plinskom kromatografijom. Sadržaj linolenske kiseline u hrani od 0.39% u kontrolnoj do 1,88% u P5 pokusnoj skupini, izvršila je diferencijaciju kako proizvodnih pokazatelja tako i u kakvoći fileta linjaka te građi masti obzirom na masne kiseline između pojedinih pokusnih skupina. Značajne promjene s porastom linolenske kiseline u hrani, mogu se smatrati povećanje individualnog prirasta linjaka (g*kom-1) za maksimalnih 11,00%, povećanje SGRind.(%dan-1) za 6.18%, dok se hranidbeni koeficijent smanjio za 6,75%.
S druge strane, različita razina linolenske kiseline u hrani značajno je utjecala na kemijska svojstva mišića linjaka i građu mišićnih masti. Utvrđeno je osjetno smanjenje vode u mišićima za 1,34% i masti za 14,71%. Bjelančevine su porasle za 5,64%, a pepeo se neznatno mijenjao. Obzirom na masne kiseline u mastima pokazalo se da porastom linolenske masne kiseline u hrani od 0,39% do 1,88%, raste njen sadržaj u mišićima od 2,8%[plus minus]0,3 do 10,8%[plus minus]0,7% te sadržaj najznačajnije polinezasićene masne kiseline za ribe, docosaheksaenske (22,6[omega]3) i to od 3,4%[plus minus]0,2% do 11,8%[plus minus]0,2%.
Isto tako znatno niži sadržaj ovih te ostalih polizasićenih masnih kiselina u mišićju kontrolne skupine, kao i povećani sadržaj monozasićene, oleinske (18:3[omega]) te eicosatrienionske (20:3[omega]9) masne kiseline, pokazuje da je 0,39% linolenske kiseline u hrani nedovoljna količina za intenzivni uzgoj linjaka i da minimalna količina ove masne kiseline u hrani mora iznositi 0,9%.
Summary: The influence of different level of linoleic fatty acid (18:3[omega]3) in the food on the results of tench (Tinca tinca L.) intensive production has been researched in this study. The research was carried out on 6 experimental groups of fish with 3 repetirions. Average individual starting weight of tench was 32,5 g,5 g*kom-1. Fish was fed with peleted foodstuff containing 45% proteins. Food for control group contained the total of 0,39% linoleic acid from ingrediens, while for eksperimental groups P1,P2,P3,P4 and P5 it contained 0,50%, 0,75%, 1,00%, 1,25% and 1,50% respectivly. During the research wich lasted for 18 weeks 9 measurements of productive indicators have been done (each 14 days) for each cage from each group of fish. Beside, physical and chemical characteristics of the water was examined during the researches.
Tench file quality was determined after experimental part of the research by chemical analysis. Fatty acids contained in the fat was determined by gas chromatography. The content of the linoleic acid in the food from 0.39% in the control group to 1,88% in P5 eksperimental group has differentiated productive indicators as well as quality of the tench file and structure of the fat concerning fatty acids between eksperimental groups.Significant changes influenced by increased linoleic acid in the food could are: increase of idividual grain of tench (g*piece-1) for 11.0% maximum, increase of SGRind. (%*day-1) for 6.18%, while feed coeficient decreased for 6,75%. On the other hand, different level of linoleic acide in food significantly influenced the chemical characteristic of the tench muscle and the structureof muscle fats.
It was observed that the water and fat evidently decreased in the muscles for 1,34% and 14,71%, respectively. Proteins increased for 5,64% and ash was insignificantly volatile. Concerning the fatty acidis in the fat it showed up that by the increase of linoleic acid in the food, the content of this fatty acid in the muscles also increases from 2,8%[plus minus]0,3 to 10,8%[plus minus]0,7%. This can be stated for docosahexaeinic acid (22:6[omega]) as well, which is the most important polyunsaturated fatty acid for fish from 3,4%[plus minus]0,2% to 11,8%[plus minus]0,2%. Significantly lower content of these as well as higher content of monounastrated, oleinic (18:3[omega]1 and eicosatrienoinic (20:3[omega]9) fatty acid show that 0,39% of linoleic acid in the food is insufficient for intensive rear and that minimal amount of this fatty acid in the
Mentor: Tomislav Treer; Komisija za ocjenu: Tomislav Treer, Tajana Černy, Ivan Stević; Komisija za obranu: Tomislav Treer, Tajana Černy, Ivan Stević; datum obrane: 26.04.1996.
Sveučilište u Zagrebu, Agronomski fakultet, Zagreb, 1996
Bibliografija: str. 139-157
Summary
Keywords: Linjaci -- Hranidba -- Linolenska kiselina