Use of flaxseed oil for sustainable enrichment of chicken meat with omega-3 fatty acids for human consumption

Abstract

Chickens naturally possess the required enzymes to convert the omega-3 polyunsaturated fatty acids (n-3 PUFA) precursor α-linolenic acid (ALA, found at a high percentage in flaxseed oil) to the long chain n-3 PUFA (or n-3 LCPUFA). However, flaxseed oil is relatively expensive to be used in poultry feed. Therefore, a number of strategies have previously been studied to reduce the additional cost of the enriched n-3 LCPUFA chicken meat. Nevertheless further investigation is still needed before this approach can be commercially applied. This research aimed to: i. investigate the ability of a flaxseed oil based diet to enrich broiler tissues with n-3 LCPUFA and/or enhance growth performance, ii. clarify the relationship between the fatty acid profile (with emphasis on n-3 PUFA) of diet and excreta in broilers, iii. investigate the shortest required period for feeding broilers the flaxseed oil diet while maintaining an acceptable level of n-3 LCPUFA in meat tissues and iv. determine whether exposing the developing chicken embryo to higher levels of n-3 PUFA will subsequently modify the broilers ability to utilize ALA and/or deposit n-3 LCPUFA in meat. The dietary effect of six very different fats (including flaxseed oil) on changing the fatty acid profile of seven tissues in broilers was investigated. The strong correlations and regressions between diet and tissue (except brain) fatty acid levels (highest for the n-3 PUFA) validate the ability to predict the tissue fatty acid profile of broilers based on their dietary fat composition. However, unexpectedly none of the growth performance parameters or crude fat percentages of the tissues were influenced by changing dietary fat type suggesting that such effects may only become detectable when birds are under stress. Furthermore, the relationship between excreta fatty acid composition and dietary fatty acid intake showed positive linear correlations for all fatty acid groups. Comparing the fatty acid content of diet and excreta suggested that the broilers most preferentially utilized n-3 PUFA group. Oppositely, n-6 PUFA and some saturated fatty acids (C16:0 and C18:0) were under-utilized. Feeding broilers the flaxseed oil diet for different periods prior to slaughter showed a comparable level of n-3 LCPUFA in the meat by feeding broilers from week 3 as for the entire six week growth period. This strategy would result in a reduction of the required flaxseed oil amount by >9.4%. Thus, this is an economically-viable step towards commercializing n-3 LCPUFA-enriched chicken meat from using flaxseed oil diet. Exposing broiler embryos to high ALA or n-3 LCPUFA via the maternal diet did not enhance the ability of the progeny to deposit n-3 LCPUFA in their tissues when they were subsequently fed a flaxseed oil diet. Thus, this strategy was not effective in further elevating n-3 LCPUFA levels in the chicken meat. In summary, the outcomes of this research support the efficient use of a flaxseed oil-based diet to produce n-3 LCPUFA enriched chicken meat to offer a practical pathway to increase n-3 LCPUFA intake by a wide range of consumers without relying on further unsustainable exploitation of marine resources.