Fatty acid profile and oxidative stability of pork as influenced by duration and time of dietary linseed or fish oil supplementation

¹ Laboratory for Animal Nutrition and Animal Product Quality, Department of Animal Production, Ghent University, 9090 Melle, Belgium
² Faculty of Biosciences and Landscape Architecture, University College of Ghent, 9000 Gent, Belgium

^* To whom correspondence should be addressed. E-mail: Stefaan.DeSmet{at}UGent.be.

	Abstract

In this experiment, the effect of duration and time of feeding n-3 PUFA sources on the fatty acid composition and oxidative stability of the Longissimus thoracis (LT) was investigated. Linseed (L) and fish oil (F), rich in -linolenic acid (-LNA) and eicosapentaenoic and docosahexaenoic acid (EPA and DHA) respectively, were supplied equivalent to a level of 1.2% of oil, either during the whole fattening period or only during the first (P1; 8 wk) or second (P2; 6 to 9 wk till slaughter) fattening phase. All diets were based on barley, wheat, and soybean meal and were fed ad libitum. Crossbred pigs (n = 154; Topigs 40 x Piétrain) were randomly allotted to the 7 feeding groups. In the basal diet (B), only animal fat was used as supplementary fat source. Three dietary groups were supplied the same fatty acid source during both fattening phases, i.e. group BB, LL, and FF. For the other 4 dietary groups, the fatty acid source was switched after the first phase (groups BL, BF, LF, and FL; the first and second letter indicating the diet in P1 and P2 respectively). Twelve animals per feeding group were selected based on average live weight. The LT was analysed for fatty acid composition; lipid stability (thiobarbituric acid-reactive substances, TBARS) and color stability (a* value, % of myoglobin pigments) were determined on the LT after illuminated chill storage up to 8 d. The -LNA, EPA, and docosapentaenoic acid (DPA) incorporation was independent of the duration of linseed feeding (respectively 1.24, 0.54, and 0.75% of total fatty acids for group LL). Supplying fish oil during both phases resulted in the greatest EPA and DHA proportions (1.37 and 1.02% of total fatty acids) (P < 0.05), but the content of DPA was not affected. The proportion of DHA was greater when fish oil was administered during P2 as compared to P1 (P < 0.05). There was no effect of diet on meat ultimate pH and drip loss, nor on lipid or color oxidation.

Key Words: Fish oil, Linseed, Omega-3 fatty acids, Oxidative stability, Pork