Anti-inflammatory and analgesic effects of egg yolk: a comparison between organic and machine made

Yolk composition may be influenced by the bird's dietary intake. Quality of egg yolk from different sources is also varied. Especially egg yolk from organic sources, those prepared by the hen and duck were naturally fed. Traditional medicine users in north of Iran believe the oil extracted by direct heat from egg yolk has analgesic activity. In this work anti-inflammatory and antinociceptive activities of organic and machine made hen yolk and duck yolk were evaluated.

Three various sources of egg yolk (organic hens, duck and machine made) were chosen. Each yolk was extracted by two methods, solvent extraction (hexane) and direct heating. In order to investigate the analgesic and anti-inflammatory activity, carageenan, hot plate and writhing tests were carried out.

The organic hen and duck oil extracted by direct heat method showed the highest activity compared to other types. Organic sources may contain some special components which are not existed in machine made eggs. Oil samples obtained by direct heat from three different kinds of egg yolk showed significant anti-inflammatory activity at 100-300 mg/kg compared to controls (p < 0.001). All samples indicated analgesic properties at all doses in writhing test. The highest activity was seen at 300 mg/kg of organic hen egg yolk oil prepared by heat (HO) and hexane extract of duck egg yolk (ED) which was similar to 5 mg/kg morphine (p > 0.001). In hot plate test all of the oil samples did not show significant difference with controls. Hexane extract of organic egg yolk (EO) (300 mg/kg) and ED (200 and 300 mg/kg) showed significant analgesic activity in hot plate test.

This study confirms anti-inflammatory and analgesic scheme of yolk. We can also claim environmental and dietary condition is very important in yolk contents. In order to improve life quality of human beings and better efficiency for egg yolk components we suggest considering the way of feeding for poultry. We can propose organic yolk oil prepared by direct heat as an alternative remedy for inflammatory joint conditions.