Ahiflower seed and its press cake as sources of nutrients for laying hens and omega-3 fatty acids in their eggs

240 64-week-old Lohman LSL-Lite laying hens were used to evaluate the effect of ahiflower seed (AS) and its press cake (APC) on egg yolk fatty acid profile, production performance, apparent total tract nutrient digestibility (ATTD), egg quality, eggshell mineral content, and fecal microbiota composition for 12 weeks in a completely randomized design, with 6 replicates of 5 birds in a cage. The diets included a control (CD), CD supplemented with 10 % flaxseed (FS), and CD supplemented with AS at 1, 5, and 10 % inclusion levels and APC at 5, 10, and 15 % inclusion levels. Diet did not affect eggshell Ca (P=0.1168) and P (P=0.8212) levels, and feed conversion ratio (P=0.136), but the 10 % FS reduced body weight gain (P=0.044), hen day egg production (P= 0.000) and feed intake (P<.0001) compared to other treatments. The yolk lightness L* was reduced (P=0.030) by 5 % APC compared to 10 % APC, redness a* was reduced (P= 0.002) by 10 % FS and 15 %APC compared to 10 %APC, CD, and 1 % AS. The 10 % FS and 15 %APC also reduced (P<0.001) yellowness *b compared to 1 %AS and 5 %APC. Apparent metabolizable energy (AME) and nitrogen-corrected apparent metabolizable energy (AME_n) increased (P<0.001) in 10 %FS and all AS and APC levels compared to CD. Compared to CD (87 %), ATTD of energy was increased (P<0.001) in hens fed 10 %FS (93 %), 1 %AS (93 %), and 15 %APC (92 %). However, 10 %FS (78.7 %) and 1 %AS (81.7 %) had higher (P=0.011) ATTD of P than 10 %APC (64.6 %). Similarly, ATTD of Ca was reduced (P<0.001) in hens fed 10 %APC compared to CD and 10 %AS. Compared to other treatments, total n-3 and stearidonic acids were increased (P<0.001) by 10 %FS and 10 %AS, respectively, and the total n-6 FAs and linoleic acid were highest (P=0.001) in 15 %APC. Both 10 %AS and 10 %FS increased (P<0.001) eicosapentaenoic, docosahexaenoic, and alpha-linolenic acid, compared to CD. The n-6/n-3 ratio was reduced (P<0.001) by 10 %FS and 10 %AS compared to APC and CD. Dietary treatments modulated fecal microbiota differently, but notably, Lactobacillus was more abundant when hens were fed 5 %AS compared to other treatments. In conclusion, the dietary supplementation of 10 %AS increased n3-FAs deposition in eggs similar to 10 %FS. However, 10 %FS reduced production performance. All levels of AS and APC increased diet metabolizable energy with no negative effect on production performance.