There is an increased interest among poultry nutritionists to increase the linoleic acid (LA) content
of the egg, which possesses many benefits for human health. This fatty acid must be provided
by the diet as the bird’s body cannot synthesise it. The present study evaluated the
influence of different levels of dietary LA on the productive performance, egg quality and yolk
lipid profile of Longyan laying ducks. In total, 900 Longyan female laying ducks aged 24 weeks
were assigned to six dietary treatments, each containing 6 replicates of 25 ducks. The six dietary
treatments contained six incremental levels of LA (analysed content: 0.36, 0.66, 0.80, 1.07, 1.28,
and 1.45%) and the experimental diets were offered for the following 20 weeks. The results
showed that different supplemental levels of dietary LA had no effects on egg production traits,
concentrations of plasma cholesterol and triglycerides, or low or high-density lipoprotein cholesterol
(p>.05). There was a linear increase in yolk colour (p<.001) and yolk cholesterol (p<.005)
with increasing dietary LA. With increased intake of LA, the yolk content in C18:1, C20:1 and
total monounsaturated fatty acids decreased linearly (all p<.005), but the concentrations of
C18:2, C18:3, C20:2, C20:3, C20:4, C20:6, and total polyunsaturated fatty acids were linearly
increased (p<.008 to <.0001). The results of the present work show that LA dietary supplementation
of Longyan duck layers positively modified the yolk fatty acid profile, increased the yolk
cholesterol, and enhanced the yolk colour.
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