Varying digestible isoleucine level to determine effects on performance, egg quality, serum biochemistry, and ileal protein digestibility in diets of young laying hens

<p class="CxSpFirst">To ascertain an appropriate level of isoleucine for LSL-LITE layers (23- to 30-week-old), diets containing total isoleucine concentrations (levels) of 0.66 (Control), 0.69, 0.72, 0.75, 0.78, 0.81, and 0.84% were fed as 7 treatments (2730 kcal/kg metabolizable energy) x 7 replicates x 10 birds per replicate.  Significance for performance, egg quality, serum bioc Level, week, and level*week (L*W) were significant for production, egg mass, and feed intake.  Level and week were significant for FCR. Week was significant for weight gain.</p> <p>Level was significant for egg weight, specific gravity, and shell thickness; week was also significant for these external egg parameters as well as shape index and proportional shell thickness.  L*W was significant for all except shape index.  For internal egg measurements, level was significant for proportional yolk, proportional albumen, yolk index, and yolk:albumen. Week was significant for internal egg parameters while L*W significantly affected Haugh unit, proportional albumen weight, yolk index, albumen index, and yolk color.  Level was significant for <span class="Heading1Char"><span>globulin and glucose in serum. </span></span></p> <p><span class="Heading1Char"><span>Is</span></span>oluecine at 0.72%, 0.81% and 0.84% produced the lowest FCR, an important standard in the poultry industry.  Considering the low FCR of 1.45 and cost for inclusion as a dietary ingredients, 0.72% isoleucine was chosen for further study.</p>