Fatty acid composition, cholesterol and total fat content in rainbow trout (Oncorhynchus mykiss) as influenced by fatty acids in diet | Uticaj masnih kiselina u hrani na sastav masnih kiselina i količinu holesterola kod kalifornijske pastrmke (Oncorhynchus mykiss)

Long-term and uncontrolled exploitation of sea resources, as well as awareness of positive influence of n-3 polyunsaturated fatty acids (PUFA) on health of humans, contributed recently to increased demand for aquaculture which resulted in certain demands in respect to fish quality and nutritive value, i.e. n-3 PUFA composition. The aim of this paper was to investigate basic chemical parameters, cholesterol content and fatty acids content of Rainbow trout (Oncorhynchus mykiss) during the breeding in winter season (December 2008 and March 2009) as well as to investigate basic chemical composition and fatty acids content of feed. In order to determine correlation of obtained results for fish and feed, we used modern statistical methods. The samples were collected in full-system breeding facility with independent water supply, situated in the mountains area of Central Serbia. Using correlational analysis of fatty acids composition in food and trout samples, Parsons correlation coefficient was calculated for measurements carried out in March and December : r = 0.9422 and r = 0.9584. Respective values of t-parameter were 11.933 and 14.253 (t sub(crit) = 2.10), which point to the statistical significance of both correlation coefficients at the significance level of p = 0.05. Obtained results show that there is statistically significant correlation between fatty acids composition of feed and fatty acids composition of trout samples, although statistical data for feed (comparative t-test) show no statistical difference in feed composition. By applying principal component analysis (PCA), two groups of results for fatty acids composition of trout filets were obtained, depending on time of experiment (December and March). Hottelings T**2 test for comparison of two populations of multivariate objects was performed in order to objectively confirm the difference between the two groups of results. Value of T**2 is 331.6, while critical value for significance level of p = 0.05 is 15.3. This clearly indicates significant difference between two groups of samples.