Enzymatically prepared alginate oligosaccharides improve broiler chicken growth performance by modulating the gut microbiota and growth hormone signals

The coding sequences of five alginate lyases from bacteria were cloned into Pichia pastoris GS115 and the hydrolysis characteristics of the expressed enzymes were evaluated. Animal trials were carried out using 320 1-day-old male Arbor Acres broilers (four groups) receiving either a basal diet or the same diet supplemented with 100, 200 and 400 mg/kg AOS for 42 d. The effects of AOS were evaluated by broiler growth performance, intestinal morphology and associated enzyme activities, barrier function, immunity, and integrated microbiome analysis. Assays of AOS in vitro fermentation, pathogen inhibition, and growth promotion of selected gut bacterium were performed.