in: Egg Innovation and Strategies for Improvement, Patricia Hester, Editor, Elsevier Science, Oxford/Amsterdam , London, pp.373-381, 2017
The fatty acid composition of egg yolk lipids can be
readily altered by modifying the type and quantity of fat in laying hen’s diet.
For this reason, there has been a recent interest in feeding fish oil to laying
hens in order to produce omega-3 (n-3) enriched eggs. The
n-3 refers to the third position from the methyl end of the fatty acid of the first
carbon-carbon double bond. Because
there are health benefits to humanswho consumeomega-3 fatty acids, various
governments and health organizations recommend dietary intakes for total n-3
polyunsaturated fatty acids (PUFA) of 1.4 to 2.5 g/day. The major n-3 PUFA in
fish oil are eicosapentaenoic (EPA, 20:5), docosapentaenoic (DPA, 22:5), and
docosahexaenoic acid (DHA, 22:6;Yalcin and Unal,
2010). In order to decrease the risk of cardiovascular disease, a dietary
reference intake for humans that ranges from 250 to 500mg/day of EPA+DHA should
be recommended according to Harris et al.(2009). Unfortunately, in
many countries, these recommendations are not met (Sioen et al., 2006).
Although fish oil is considered to be the richest dietary source of EPA and
DHA, manypeople do not consume fish regularlybecause of displeasure in its
taste or market access (Lewis et al., 2000). The presence of
pollutants such as heavy metals in fish may also discourage consumers from
eating fish (Domingo and Bocio, 2007). One
strategy to increase the n-3 PUFA content in the human diet without radically changing
eating habits is to enrich foods that are frequently consumed. Egg is one example
of a common food product that has wide acceptability amonghumans and is
available worldwide. With the exception to those individuals with allergies to
eggs or do not eat animal-based products (vegans), there are no known restrictionsdue
toreligion or culture. The price of eggs is economically more affordable to
many consumers compared to the cost of fish or its products (Lewis et al.,
2000).
In this chapter, enrichment of eggs through inclusion of fish oil in the hen's diet isdiscussed. The effect of hen's consumption of fish oil based diets on the n-3 fatty acid composition, cholesterol content, oxidative stability, and sensory characteristics of enriched eggs as well as the production parameters of henswill be discussed. Human health benefits with regard to consumption of omega-3 enriched eggs derived from hens fed fish oil will also be reviewed.