Thanks to refining, deodorisation and stabilisation techniques, fish products and by-products nowadays seem to be good components in the diets of layers and broilers. These contribute to producing healthy food at an affordable cost. Particularly enriched eggs are a healthy ingredient on the menu.
By Andrés Ross Burrows , technical director SPES SA, Santiago de Chile, Chile
Day by day consumers are getting increasingly interested in functional foods as an alternative to increase their health and wellbeing. To fulfil this demand there has been a huge development in the area of functional foods, meaning products that not only provide the classical nutrients but also contain other substances of healthy benefit. Among these substances are EPA (Eicosapentaenoic acid) and DHA (Docosahexaenoic acid), both Omega-3 essentials fatty acids.
These fatty acids have proven to reduce cardiac diseases, reduce cholesterol and triglycerides plasmatic levels, they also enhance the immune status and regulate inflammatory response, and through their structural-functional role in central nervous system development, growth and ageing affects neurotransmission and neuronal growth and survival, thus having a role in behaviour and cognitive function.
Incorporated in diet
As Omega-3 fatty acids cannot be synthesised d-novo by mammalian individuals they must be incorporated in our diet. EPA and DHA are found only on marine sources; even when vegetables sources contains the Omega 3 alfa-linolenic acid (ALA), this molecule is much shorter and has to be elongated and desaturated to become DHA, a process that is quite inefficient because most of ALA is an energetic substrate.
Here lies the problem, since the actual consumption of fish and marine derivative-meals has been dramatically reduced by an occidental diet with common cooking vegetable oils and processed foods with little or no EPA-DHA Omega-3 fatty acids, resulting in an unhealthy imbalance; in fact the FAO/WHO expert consultation recommend that individuals with a deficiency in n-3 fatty acids should be encouraged, if possible, to consume more n-3 PUFA-rich foods such as fish and other seafood.
It is well known that many vegetable sources also provide Omega-3 fatty acids, but short chain fatty acids. Those fatty acids should be elongated and desaturated to EPA and further DHA, but the fat conversion to these long chain fatty acids is reported to be very inefficient reaching approximately 6% for EPA and 3.8% DHA; with a diet rich in Omega 6 fatty acids, such as vegetables, this amount is further reduced by 40-50%. Fish oil is the best source of long chain Omega-3 fatty acids, but it is not the main source of consumption since it is not available for every person due to costs.
Thus alternative approaches have been made to modify fatty acid composition of natural foodstuff; by increasing the amounts of fish oils in the diet of laying hens and broilers, a substantial amount of EPA and DHA were incorporated into eggs and meat, and the most important thing: without the organoleptic problems in the final product, since the refining, deodorisation and stabilisation of these commercial products allows to overcome those problems.
Misconception about eggs
Although the incorporation of EPA and DHA using commercial fish oil by-products have been reported to occur in other meat species (beef cattle, lambs and pigs), EPA-DHA enriched eggs are the least expensive source of high quality protein and balanced distribution of most vitamins and minerals. However, there is a misconception of eggs being a major source of bad cholesterol, and therefore have been pointed out as the one food to avoid.
Those ideas contradict more than a decade of epidemiologic studies showing that dietary cholesterol is not a contributor to heart disease. Furthermore, eggs enriched with EPA and DHA have shown not to increase the plasma cholesterol concentrations when consumed four eggs per day.
Fish oil based products
The Omega-3 fatty acids EPA and DHA incorporated in the diet are deposited on the egg yolk as globules containing VLDL molecules, with fatty acids mainly being deposited as phosphatidylethanolamine, phosphoglycerides and triglycerides. The lipid profile modifies at seven days of consumption and the EPA-DHA levels on the eggs have shown to stabilise between 9-12 days.
In our experience an inclusion level of 2-3% of refined and deodorised fish oil-based product (Omega e-Blend) in the layer hen diet allows to produce eggs with an average EPA+DHA of 140 mg/egg, in other words one single egg would have 56% of the recommended daily intake of EPA+DHA for adults according to FAO recommendations and 46% of the recommended daily intake for pregnant and lactating women.
No fishy taste
The use of these commercial presentations of refined-deodorised fish oil based products stabilised with powerful antioxidants ensures a good fixation of EPA and DHA on egg yolk with no fishy taste on the final product thus adding more value to the final product. Seafood, the main source of EPA and DHA is becoming expensive and its consumption is falling. EPA/DHA enriched eggs are the least expensive source of Omega-3 enriched foodstuff and thus the easiest way to incorporate non-traditional Omega-3 sources in a daily diet.
The contribution of enriched eggs will become increasingly important, especially to vegetarians, whose diet has no EPA or DHA. Moreover, as maternal DHA status influences subsequent infant function, high-DHA eggs are an excellent means to increase the daily DHA intake by the mother and foetus.Other benefits such as improved fertility rates and promotion of health has been reported for fish oil supplementation in poultry, thus providing benefits to product, producer and consumer.
* References are available on request