Flaxseed fed pork: n3 fatty acid enrichment and contribution to dietary recommendations

January 1, 2014 Human Health and Nutrition Data 0 Comments

Flaxseed fed pork: n3 fatty acid enrichment and contribution to dietary recommendations

Year: 2014
Authors: Turner, T.D. Mapive, C. Aalhus, J.L. Beaulieu, A.D. Patience, J.F. Zilstra, R.T. Dugan, M.E.R.
Publication Name: Meat Sci.
Publication Details: /dx.doi.org/10.1016/j.meatsci.2013.08.021


The potential to increase n3 fatty acid (FA) intake via flaxseed fed pork is underestimated when restricted to pure longissimus muscle, whereas a combination of muscle and adipose tissue is typically consumed. Presently, the FA content of pigs fed 0percent, 5percent and 10percent dietary flaxseed for 11 weeks was measured in loin, picnic and butt primals (lean muscle with epimysium (L), L plus seam fat (LS), and LS plus 5 mm backfat (LSS)). The n3 FA content necessary for an enrichment claim in Canada (300 mg/100 g serving) was exceeded in L from all primals when feeding 5percent flaxseed, being 4 fold that of controls with further enrichment from inclusion of associated adipose tissues. Increasing flaxseed feeding levels in combination with adipose tissue inclusion amplified total long chain n3 FA, particularly 20:5n3 and 22:5n3. Flaxseed fed n3 FA enriched pork can contribute substantially to daily long chain n−3 FA intakes, particularly for societies with typically low seafood consumption. (Authors abstract)

In recent years emphasis has been placed on enriching pork and pork products with n−3 fatty acids due to their positive effects on human health. Increasing n3 fatty acids in pork by feeding flaxseed to pigs has been demonstrated by several groups as reviewed by. Flaxseed supplementation invokes a rapid response, with 18:3n3 and 20:5n3 levels increasing notably in muscle after seven days of feeding. Maximum polyunsaturated fatty acid (PUFA) effects are reportedly achievable after 40 days of feeding, with most effects occurring in the first two weeks. Feeding flaxseed to pigs to yield enough n3 fatty acids for enrichment claims, however, presents some challenges. The present study is an extension of, and investigates the fatty acid composition of tissue and tissue combinations found in various cuts of pork when feeding increasing levels of optimally processed flaxseed. Gender effects on fatty acid composition were also investigated due to barrows having greater rates of endogenous fat synthesis, whereas gilts have a greater capacity for long-chain (LC, greater than 20 carbon) n3 fatty acid synthesis. Effects of feeding flaxseed on levels of 18:3n3 elongation and desaturation products in pork were also investigated in anticipation that separate enrichment or health claims for LC n3 fatty acids will eventually be possible.

The present results highlight the differences in tissue fat content, fatty acid composition and the potential to enrich the n−3 fatty acid composition of pork products. Levels of n3 fatty acids attained in LSS cuts when feeding flaxseed far exceeded requirements necessary for an enrichment claim, and unlike intermuscular fat, subcutaneous fat would likely be trimmed by the consumer.  Present findings show that retail cuts from different primals can easily meet requirements for n3 fatty acid enrichment when associated adipose tissue depots are retained with the lean cuts. Moreover, the LC n3 fatty acid content attained when feeding flaxseed can provide a considerable proportion of the daily recommended intake. Feeding strategies will, therefore, need to be tailored to address end product uses, whether sold as a fresh retail cut, or if excess adipose tissue trimmed at slaughter is used for enrichment of other processed products, including enriched lard.(Editors comments)


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