Long-term supplementation of dietary omega-6/omega-3 ratios alters bone marrow fatty acid and biomarkers of bone metabolism in growing rabbits

Abstract

The long-term effects of different dietary lipid sources with varying ratios of omega-6/omega-3 (ω6/ω3) polyunsaturated fatty acids (PUFAs) on the bone marrow fatty acid profile, ex vivo prostaglandin E2 (PGE2) release in bone, and plasma biomarkers of bone metabolism were evaluated in rabbits. Weanling male and female New Zealand white rabbits were randomly assigned to five groups and fed ad libitum on diets containing 70g/kg of added oil for 100days as follow: soy bean oil (SBO control), sesame oil (SO), fish oil (FO), DHA algae oil (DHA), and DHA and ARA algae oils (DHA/ARA). The dietary lipid treatments were formulated to provide the following ratios of ω6/ω3 fatty acids: 8.7 (SBO), 21.8 (SO), 0.4 (FO), 0.6 (DHA), and 0.7 (DHA/ARA). The bone marrow fatty acid profile of rabbits was significantly influenced by and reflected the dietary lipid treatments. Rabbits fed the FO diet had the highest ω3 PUFA concentration, and those fed the SBO diet were highest in ω6 PUFA. Ex vivo PGE2 level declined progressively as the ω6/ω3 dietary ratio declined. Plasma alkaline phosphatase (ALP) activity was significantly higher in male and female rabbits fed the DHA/ARA diet compared with those fed the control, SO, FO, or DHA diets. These results demonstrated that the dietary ω6/ω3 ratio modulates bone PGE2 production and plasma ALP activity in growing rabbits. In addition, the significant elevation in ALP activity in the DHA/ARA fed group proved that algae oils may be promising dietary sources for promoting bone formation during the growing stage.