Nutritionally important fatty acids in hen egg yolks from different sources.

Egg samples were collected from six different sources across Canada, and the yolks from those samples were analyzed for fatty acid composition using gas chromatography. Three yolk samples were from regularly fed chickens from three different Canadian egg processing plants, and the other three samples were from chickens fed with special diets. The specially fed chicken yolk samples were collected from three different Canadian egg producers. The three egg yolk samples from specially fed chickens had a significantly higher linolenic acid and docosahexaenoic acid content than the three regularly fed chicken yolk samples (P < 0.05). However, the arachidonic acid levels in the regularly fed chicken yolk samples were significantly higher (P < 0.05). In general, there was no significant difference among the three egg sources in each group. There was some variation in the fatty acid levels during different seasons for each source, but the difference was not statistically significant in most cases.