Role of diet complexity in feed formulation for broilers and nursery pigs

Two studies were conducted to determine the role of diet complexity using specialty protein sources in early chick and nursery pig diets. In Study 1, a total of 720 day-old, straight-run Cobb 500 broiler chicks were randomly allotted to six treatments following a randomized complete block design RCBD) with 12 replicate cages per treatment and 10 birds per cage. The experimental treatments were: 1) Corn-soy diet (Negative control, NC), 2) NC+5% enzymatically-treated soybean meal (ESBM1) at booster stage, 3) NC+5% hydrolyzed peptone (HP), 4) NC+5% pork meal (PM), 5) NC+5% soy protein concentrate (SPC), and 6) NC+5% ESBM at booster and 2.5% at starter stages (ESBM2). Broilers fed diets with various specialty protein sources did not significantly affect BW, ADG, ADFI, viability, PEI, excreta scores, and carcass characteristics (P0.05). Supplementing SPC, HP, and ESBM2 in broiler diets improved F/G (P0.01) at the finisher stage. Feed cost was lesser for broilers fed diets with ESBM at booster and SPC (P0.05). Broilers fed specialty protein sources showed no significant differences in MEI, caloric efficiency, value gain, and MOFC. In Study 2, a total of 128 weanling pigs (8.90 kg and 35 days of age, PIC L337 x C24) were used in a 24-day growth assay and were randomly allotted to one of four experimental treatments with 2 x 2 factorial combinations of nursery diet complexity and dietary supplementation with growth promoters (GP), which was a combination of 35 ppm of tiamulin, 400 ppm of chlortetracycline HCl, and 3000 ppm of zinc oxide. Diets with high (HC) and low complexity (LC) were formulated to contain 20% or 25% soybean meal, 13% or 9.5% specialty protein sources, and 11% or 7.5% dietary lactose, respectively. All the experimental diets were formulated to contain 2,540 kcal NE/kg and 1.37% standardized ileal digestible Lys. Overall (day 0 to 24), nursery pigs fed the HC diets and the LC+GP had greater (p0.01) ADG and ADFI compared with those fed the LC diet, Feeding HC diets also resulted in better (p