Varying Ratios of Omega-6:Omega-3 Fatty Acids on the Pre-and Postmortem Bone Mineral Density, Bone Ash, and Bone Breaking Strength of Laying Chickens
2008
Baird, H.T. | Eggett, D.L. | Fullmer, S.
The purpose of this study was to investigate the effects of varying ratios of n-6 to n-3 fatty acids in the diets of White Leghorn chickens on tibia bone characteristics [bone mineral density, bone mineral content (BMC), ash bone mineral content, bone morphology, and cortical thickness] and tibia bone strength parameters (ultimate force, bending stress, maximum strain, Young's modulus of elasticity, area under the curve, and moment of inertia). Seventy-five 16-wk-old female White Leghorn chickens were randomly assigned to 1 of 5 dietary ratios of n-6 to n-3 fatty acids: 47.8:1, 18.0:1, 7.6:1, 5.9:1, or 4.7:1. Corn oil was the n-6 fatty acid source, whereas flax oil provided the n-3 fatty acids. Bone density was measured on the left tibia via dual-energy x-ray absorptiometry (DXA) prior to killing and after excision. Bones were ashed in a muffle furnace at 500°F. Tibia bones were broken by using a 3-point bending rig. Results showed no significant effect of diet on bone characteristics. There were no significant differences among diet groups for parameters of bone strength except cortical thickness (P <= 0.01). Bone mineral content determined by ashing was significantly different by 9.2% (P <= 0.0001) from BMC determined in vivo by DXA; however, there were no differences in ex vivo BMC and BMC ash, although they were highly correlated (r = 0.99, P <= 0.0001). We concluded that there was no effect of n-3 fatty acids on tibia bone in mature White Leghorn chickens. The GE Lunar Prodigy DXA instrument significantly underestimated the in vivo BMC in chickens.
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