Nutritional evaluation of sunflower products for poultry as affected by the oil extraction process.

The nutritional value of sunflower seed (SFS) products was determined in two experiments using 180 adult Leghorn-type roosters (Hy-Line). In Experiment 1, press and solvent SFS oils were included in a basal diet at four graded levels (from 1.3 to 20%). Each diet was force-fed (30 g) to 10 roosters to determine their TMEn and true fat digestibility. Dietary TMEn and true digestible fat increased linearly (P < 0.0001) with oil inclusion. There were no differences in nutritional value between oils; their digestibility was 90%, which led to 8,385 +/- 39 kcal TME/kg DM. In Experiment 2, the effect of oil extraction on TMEn, true fat, and amino acid digestibility (TAAD) of SFS products was studied. Several products were derived from the oil extraction process: SFS, press extracted SFS (PESFS), and SFS meal (SFSM), as well as recombined products (mix of meal and oil) of SFS and PESFS, and were force-fed directly to 10 roosters each. Oil extraction produced a decrease (P < 0.0001) in true fat digestibility, TAAD, and TMEn (4,555, 2,591, and 1,754 +/- 59 kcal/kg DM for SFS, PESFS, and SFSM, respectively). Digestible fat content explained the difference between TME, of SFS and PESFS, whereas the difference between the TMEn of PESFS and SFSM was lower than expected. Recombined and original products had similar (P > 0.05) TMEn, despite solvent oil showing higher digestibility when released. Recombined SFS showed lower (P < 0.005) TAAD than original SFS (84.2 and 90.4%, respectively), indicating protein damage caused by heat and mechanical pressure. However, there were no differences, except for lysine, in TAAD between original and recombined PESFS (86.3 and 86.6%, respectively); both feeds showed higher (P < 0.05) TAAD than SFSM (83.9%), which indicates a positive effect of fat addition at this step.