Incorporation of n-3 Long-chain Polyunsaturated Fatty Acids into Duck Egg Yolks

Tian-Fwu Chen,Jenn-Chung Hsu

doi:10.5713/ajas.2003.565

Abstract

The objective of this experiment was to determine the effects of different levels of refined cod liver oil (RCLO) on laying performance, n-3 polyunsaturated fatty acids composition (n-3 PUFAs) and the organoleptic evaluation of duck egg yolks. A total of 180 30 wk old laying Tsaiya ducks, at the beginning of peak production, were allotted into 6 treatments with 3 replicates each. Ducks were fed one of the 6 experimental diets, supplemented with 2% tallow (control) and graded levels of RCLO at 2, 3, 4, 5, and 6% to a corn-soybean diets, respectively, for 6 wks. All of the experimental diets were formulated to be both isocaloric and isonitrogenous. Feed and water were supplied ad libitum throughout the experimental period. The results indicated that the RCLO supplementation levels did not affect (p>0.05) egg production, egg mass, feed intake, feed efficiency or body weight change. Egg weight was the lightest when the ducks received the 6% RCLO diet. The eicosapentaenoic acid, docosahexaenoic acid, and total n-3 PUFAs contents in the yolks increased with increasing RCLO supplementation. The taste and general acceptability of the hard-boiled eggs were not significantly different among the treatments. However, a fishy flavor was much higher when ducks were fed diets supplemented with 5% and 6% RCLO diets. (Asian-Aust. J. Anim. Sci. 2003. Vol 16, No. 4 : 565-569)

Highlights

The importance of long-chain n-3 polyunsaturated fatty acids (n-3 PUFAs), mainly eicosapentaenoic acid (C20:5n3, EPA) and docosahexaenoic acid (C22:6n3, DHA), in human nutrition is gaining considerable attention due to their role in various physiological processes (Salem et al, 1996)
There is evidence of n-3 PUFA for its cardioprotective effect (Kinsella et al, 1990) and that these n-3 PUFAs are associated with a reduced incidence of coronary heart disease (Bang et al, 1980)
The reduction in AA content and its metabolites, such as thromboxane A2 in plasma, which had a potent proaggregatory effect on platelets, was suggested as one of the reason why n-3 PUFAs reduced the risk of coronary heart disease (Leaf and Weber, 1988)

Summary

INTRODUCTION

The importance of long-chain n-3 polyunsaturated fatty acids (n-3 PUFAs), mainly eicosapentaenoic acid (C20:5n3, EPA) and docosahexaenoic acid (C22:6n3, DHA), in human nutrition is gaining considerable attention due to their role in various physiological processes (Salem et al, 1996). The focus of studies exploring the means to alter the fatty acid composition in yolk has been the use of various dietary levels (3 to 10% of the diet) of fish oils in laying hen diets (Leskanich and Noble, 1997). Dietary fish oil inclusion resulted in significant increases in the n-3 fatty acids such as DHA and EPA in egg yolks (Adams et al, 1989; Huang et al, 1990; Hargis et al, 1991; Hargis and Van Elswyk, 1993; Oh et al., 1994). Fish oils are rich sources of EPA and DHA (Barlow and Pike, 1977) They could cause a fishy flavor in the egg and meat if included at high levels (Leskanich and Noble, 1997). We conducted the present experiment to determine the effects of dietary supplementation of different levels of refined cod liver oil (RCLO) on the n-3 PUFA composition and its effect on the taste of duck eggs

MATERIALS AND METHODS

Findings

CONCLUSION