Egg Quality and Yolk Polyunsaturated Fatty Acid Status in Relation to Broiler Breeder Hen Age and Dietary n-3 Oils

Abstract

The effects of broiler breeder hen age and dietary n-3 oils on yolk n-3 and n-6 fatty acid composition, egg quality, fertility, and hatchability were investigated. A total of 2,200 eggs were collected from wk 26 through 62 from Cobb breeder hens fed diets containing 1.75% fish oil + 1.75% yellow grease (low n-3) or 3.5% fish oil (high n-3). Eggs obtained from a commercial source were used as the control for n-6 and n-3 fatty acid composition and hatchability studies. A significant decrease in egg weight, yolk weight, shell weight, and yolk color was observed for high n-3 when compared with low n-3 eggs (P < 0.05). No difference was noted in egg total fat content due to dietary treatments. However, egg fat was highest at 42 wk for high and low n-3 eggs when compared with other weeks (P < 0.05). Total n-3 fatty acids, docosahexaenoic acid (DHA, 22:6 n-3), and the DHA:arachidonic acid (AA, 20:4 n-6) ratios were higher in high n-3 eggs when compared with low n-3 eggs. The incorporation of DHA was lowest at wk 26 and highest at wk 38 for low and high n-3 eggs (P < 0.05). Low n-3 and high n-3 eggs at the oldest age had the highest level of AA (P < 0.05). A positive correlation between hen age and egg yolk AA content was observed. The r2 values for AA in low n-3 and high n-3 eggs were 0.91 and 0.90, respectively (P < 0.05). The total content of long-chain (>18-C) n-6 PUFA (AA+ 22:4 n-6+22:5 n-6) constituted over 0.3 g per commercial egg when compared with 0.09 and 0.07 g in low and high n-3 eggs, respectively. The content of DHA in commercial eggs was negligible (<0.5%) when compared with low and high n-3 (P < 0.05). The overall fertility was 98.6 and 97.4%, and hatchability of fertile eggs was 80 and 83.8% for low and high n-3 eggs, respectively (P > 0.05). The overall fertility was 96%, and hatchability of fertile eggs was 80% for commercial eggs.