The influence of dietary supplementation with fermented agro-industrial residue of faba bean on Japanese quail performance, immunity, gut microbiota, blood chemistry, and antioxidant status

Antibiotic overuse in poultry feeds has disastrous implications; consequently, long-term alternatives must be developed. As a result, the current study aims to assess the impact of Aspergillus niger filtrate (ANF) high in organic acids grown on agro-industrial residue of faba bean (AIRFB) on quail diet, as well as their influence on bird productivity, digestion, carcass yield, blood chemistry, and intestinal microbiota. A total of 240 Japanese quails (aged 7 d) were used in this study, divided equally among 5 experimental groups with 48 quails each. Group 1 (G1) received a basal diet without any ANF, group 2 (G2) received a basal diet supplemented with 0.5 mL ANF/kg diet, group 3 (G3) received a basal diet supplemented with 1.0 mL ANF/kg diet, group 4 (G4) received a basal diet supplemented with 1.5 mL ANF/kg diet, and group 5 (G5) received a basal diet supplemented with 2 mL ANF/kg diet. The performance parameters were monitored at 1 to 3, 3 to 5, and 1 to 5 wk. Adding ANF increased body weight at 3 and 5 wk, as well as body weight gain at 1 to 3, 3 to 5, and 1 to 5 wk, compared to the control diet. The ANF fed quails had the highest feed conversion ratio compared to the control group. The addition of ANF to the quail diet had no effect on the weight of the carcass, gizzard, heart, liver, giblets, or dressing; however, it did lower triglycerides, low-density lipoprotein, and very low-density lipoprotein while increasing high-density lipoprotein levels. The quail groups that received ANF had enhanced immunological indices such as IgG, IgM, IgA, and lysozymes. It also increased the levels of superoxide dismutase and total antioxidant contents, as well as catalase, and digestive enzymes such as protease, amylase, and lipase. However, it lowered the blood MDA levels compared to control. It has been demonstrated that the total gut microbiota, Escherichia coli, total coliforms, and the population of Salmonella are all reduced in ANF-fed quails. Histological examination of ANF quails' liver and intestinal sections revealed normal hepatic parenchyma, typical leaf-like intestinal villi, and comparatively short and frequently free lumina. In conclusion, Japanese quail showed improvements in performance, digestive enzymes, antioxidant indices, immunity, and capacity to reduce intestinal pathogenic bacteria after consuming diet supplemented with ANF.