Strain and age effects on egg composition from hens fed diets rich in n-3 fatty acids.

A trial was conducted to study the effects of strain, age, and diet on egg production, egg composition, and yolk fatty acid incorporation. Three strains (six pens of eight hens per strain), [DeKalb Delta (D); Babcock B 300 (B); and Hy-Line W-36 (H)], were subjected to a 10% flax diet + oats from 30 to 50 wk of age. At 50 wk, hens were divided into two groups and one half were kept on flax + oats diets (three pens) or assigned to a second diet of flax - oats (three pens) to 60 wk of age. Eggs were collected at 36 and 58 wk of age for fatty acid and lipid analysis. Strain had an early effect (30 to 50 wk) on egg production with B (85.3) exceeding the other two strains D (81.0) and H (79.1). Strain D had greater feed consumption and egg weight than either B or H. Flax - oats increased percentage shell compared to flax + oats. Strain effect was significant for percentage albumin, which was greatest for D (61.2%) vs H (59.5%) and B (59.4%). Strain D had significantly lower total and percentage yolk lipids than the other two strains. Strain B eggs had more C16:0, but less C18:0 and C18:1 than D and H. No significant effect of strain on C18:2, C18:3, and C22:6 deposition was observed. Percentage C18:0 and C18:1 in the yolk was significantly affected by strain, diet, and strain x diet interaction. Dietary flax + oats increased C18:0 and C18:1 in all strains except H. A significant diet by strain interaction effect occurred such that C18:3 increased in D yolk but decreased in B yolk when flax + oats were fed. Deposition of C18:3 was greater at 58 wk (5.61%) than at 36 wk (2.52%) of age across all strains. Results from these trials indicate that strain, diet, and age can affect yolk lipids and composition.