Abstract
The nutritional quality of feather meal (FM) is constrained owing to its elevated keratin content and unbalanced amino acid (AA) composition, while small peptide substances have beneficial effects on animal growth promotion, immune enhancement, and intestinal function modulation. Herein, the goal of this work was to fabricate bioactive peptides by microbial-enzyme co-fermentation of feather meal and to explore the effects of fermented feather meal (FFM) rich in bioactive peptides on the growth performance and intestinal health of broilers. In total, 450 healthy one-day-old Arbor Acres broilers were randomly divided into 5 dietary treatments, including 6 replicates per treatment and 15 birds per replicate for 42 d. The treatments were as follows: a basal diet (CON), 2 % (FM1) and 4 % (FM2) feather meal, and 2 % (FFM1) and 4 % (FFM2) fermented feather meal, with soybean meal (SBM) replaced under isonitrogenous conditions. Dietary supplementation with 4 % FM reduced broiler body weight, average daily gain, and thigh muscle percentage while increasing feed conversion ratio, and these adverse effects were notably alleviated by FFM relative to the FM2 group (P < 0.05). Moreover, relative to the FM2 group treatment with 4 % FFM improved serum immunoglobulin and antioxidant indices (P < 0.05), and both FM and FFM supplementation resulted in higher serum IL-10 concentrations relative to the CON group (P < 0.05). In addition, relative to the CON and FM groups, supplementation with 4 % FFM markedly improved intestinal morphology, reduced intestinal permeability, upregulated the expression of intestinal barrier-related genes and proteins, regulated the Nrf2/PI3K/NF-κB pathways and activated intestinal peptide/AA transporters (P < 0.05). FFM also effectively increased the cecal probiotics such as Lactobacillus and reduced the pathogenic taxa including Escherichia-Shigella (P < 0.05). Overall, intestinal health can be effectively improved by FFM through the synergistic action of multiple pathways, with 4 % inclusion showing the best effects among the tested levels. These findings provide a scientific reference for the high-value utilization of feather resources.