Total replacement of soy with alternative plant-based ingredients, feed enzymes and a probiotic in a mixed-cereal broiler diet fed during an entire growth cycle

Total replacement of soybean meal (SBM) and soy oil with alternative plant ingredients (rapeseed meal, sunflower meal, corn gluten meal, faba beans, lupins, pea flour and potato protein concentrate) plus feed additives was evaluated in broilers. A completely randomized design employed 1,440 Ross 308 males (30 birds/pen). Diets were fed ad libitum in 3 phases. Treatments comprised a SBM-control containing phytase (PhyG) at 1,000 phytase units (FTU)/kg and xylanase at 1,200 xylanase units (XU)/kg, and three alternative (ALT) diets without SBM or soy oil. The three ALT diets contained PhyG at 2,000/1,500/1,000 FTU/kg during starter/grower/finisher phases, respectively, and a probiotic (150,000 colony forming units (CFU)/g), as well as either: 1) a xylanase and β -glucanase co-granule (XB, containing 1,200 XU/kg xylanase and 152 U/kg β-glucanase) and 4,000 U/kg protease (ALTa); 2) XB at double dose and 2,000 U/kg protease (ALTb), or; 3) XB as in 2) and 4,000 U/kg protease (ALTc). Increasing both XB and protease dose in ALTc achieved final BW did not differ from the SBM-control, though overall FCR remained higher (P < 0.05), ALTc conferred a ~57% reduction in the carbon footprint of production (P < 0.05) and ALTc birds had a more diverse cecal microbiota at family level (P < 0.01, Shannon Diversity Index). Supplementation of these feed additives can enable complete replacement of SBM and soy oil with alternative plant ingredients in an all-vegetable diet, achieving final body weight comparable to a soybean meal- based diet while reducing the carbon footprint of production.