Improving the Antioxidant Status, Meat Quality, and Immune Response of Broilers by Fermented Feather Meal

Background: Feather biodegradation is an effective alternative to other processing methods. Objectives: This study aims to investigate the effects of hydrolyzed feather meal (HFM) on broilers’ antioxidant status, meat quality, and immune response. Methods: In October 2022, 480-day-old Ross 308 male broilers were used for 42 days in a completely randomized design with eight treatments and five replicates (12 chicks/replicate) in the research farm of Agriculture Faculty, Guilan University (Rasht City, Iran). The experimental diets were as follows: (1) control diet (without feather meal [FM]), (2), (3), (4), (5), (6), (7), and (8) all containing 4% raw FM (RFM), HFM by autoclave (Au-HFM), fermented FM (FFM) by Bacillus licheniformis (Bl-FFM), FFM by Bacillus subtilis (Bs-FFM), FFM by Aspergillus niger (An-FFM), FFM by B. licheniformis+B. subtilis+A. niger (Co-FFM), and HFM by an enzyme (En-HFM), respectively. Results: The results of the in vitro experiment showed that 2,2-diphenyl-1-picrylhydrazl (DPPH) and 2, 2ʹ-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical-scavenging activities, as well as microorganism count of FFM, increased with increasing fermentation time (P≤0.05). Also, the pH of FFM significantly decreased by increasing the fermentation time (P≤0.05). The DPPH and ABTS radical-scavenging activities of FFM were higher than those of RFM, Au-HFM, and En-HFM (P≤0.05). The in vivo experiment results showed that the total antioxidant capacity (TAC) serum levels, glutathione peroxidase (GPX), superoxide dismutase (SOD), and catalase (CAT) in the FFM were higher than those in the control and other treatments (P≤0.05). Compared to control and other treatments, broilers fed FFM had lower meat malondialdehyde (MDA) levels, higher meat pH, and higher water-holding capacity at 0, 7, and 14 d of the breast meat storage, as well as lower serum MDA levels (P≤0.05). Broilers fed FFM had higher antibody titers against Newcastle disease virus, lower heterophil count, and lower heterophil-to-lymphocyte ratio, as well as higher total anti-sheep red blood cell (anti-SRBC) titer, immunoglobulin G (IgG), and immunoglobulin M (IgM), compared to the control and other treatments (P≤0.05). Conclusion: Fermentation of FM increased its antioxidant properties, improved the body’s antioxidative status, and contributing to improved the meat quality and immune response of broilers.