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In pigs, where the fatty acid (FA) profile of body lipids reflects dietary lipids to a substantial extent, enrichment of meat products by feeding polyunsaturated FA (PUFA), especially the long-chain n-3 (omega-3) PUFA like eicosapentaenoic acid and docosahexaenoic acid, is an interesting strategy, as these FA have repeatedly been shown to be beneficial to human health, especially in the prevention of cardiovascular disease. The objectives of the present study were to compare, based on the pork material harvested in an extensive fattening study, (i) the level of enrichment of long-chain n-3 FA in three different pork products to be achieved by supplementing a total of 1.6 kg unrefined tuna oil (TO) to pigs, (ii) the potential consequence for shelf life, and (iii) the importance the TO feeding period has for this trait. Pork products were selected which deliberately differed in designated shelf life, formulation and processing technology. Belly, lean from the shoulder and backfat obtained from 80 pigs, fed either no or 1.6 kg TO during fattening (35-90 kg body weight), were used to prepare bacon, Chinese-style sausage and Vienna-style sausage. The TO had been supplemented either initially, at the end, or continuously during fattening.
In all meat products, TO supplementation clearly increased contents of n-3 FA (P < 0.001), especially of the long-chain n-3 PUFA. Differences among supplementation periods were pronounced only in the n-3 FA proportion of total FA (P < 0.05), being lower with early TO feeding. Thiobarbituric acid value, which was high in dry Chinese-style sausage (P < 0.001), was mostly enhanced by TO, whereas the period of TO supplementation had no systematic influence.
In conclusion, the present study shows that any of the tested modes of non-food grade TO supplementation of pigs is basically suitable for the strategic enrichment of pork products with n-3 FA. This allows farmers to choose the most convenient feeding period in terms of tuna oil price and other conditions. Certain reductions in shelf life seem unavoidable, but this was critical only in a dry type sausage, due to their susceptibility to rancidity during storage time.
R Khiaosa-ard, P Chungsiriwat, N Chommanart, M Kreuzer and S Jaturasitha, 2011. Canadian Journal of Animal Science, 91: 87-95.