In Vitro Efficacy of Chicken Egg Yolk Antibodies Immunoglobulin Y (IgY) against Mastitis-Causing Escherichia coli (E. Coli)

Abstract Background The dairy goat farming industry in Indonesia holds significant economic potential, but its productivity is frequently hindered by major health issues like mastitis, an inflammation of the mammary glands. This disease is often caused by bacterial infections, particularly Escherichia coli (E. coli), leading to substantial financial losses for farmers. Historically, treatment relied on antibiotics, but this approach faces concerns regarding antimicrobial resistance and antibiotic residues in milk. Therefore, this study proposes an innovative, safe, and sustainable therapeutic alternative: Immunoglobulin Y (IgY), a natural antibody derived from chicken egg yolks. IgY can be efficiently and noninvasively produced to specifically target and inhibit mastitis-causing E. coli antigens. Aim This study investigated the potential of Immunoglobulin Y (IgY) extracted from the egg yolks of immunized free-range chickens as a safe and sustainable alternative for treating E. coli-induced mastitis in dairy goats. The heavy reliance on antibiotics for this condition has raised global concerns regarding antimicrobial resistance and drug residues in dairy products. Methods This study involved the immunization of 20 native chickens with inactivated E. coli to produce specific IgY. The IgY was purified from the egg yolks using the caprylic acid method. Purity and concentration were tested with SDS-PAGE and spectrophotometry. Finally, the antibody's efficacy was evaluated in vitro using a Growth Inhibition Assay to measure the E. coli growth inhibition zone. Results IgY was successfully purified using the caprylic acid method, and SDS-PAGE analysis confirmed the presence of an intact IgY protein band at approximately 180 kDa, along with its heavy and light chains. Spectrophotometric analysis showed that IgY concentration peaked on day 40, with a value of 80.54 mg/ml. In a growth inhibition assay, IgY demonstrated antibacterial activity against E. coli, with a 4 ml concentration yielding the largest inhibition zone of 9.67 mm diameter. However, this was less effective than the amoxicillin positive control, which had a zone of 18.67 mm, and the result was classified as resistant according to the general standards. These findings provide strong initial evidence for the potential of IgY as a natural antibacterial agent, highlighting the need for further optimization of immunization and purification protocols to enhance its efficacy. Conclusion This study successfully demonstrated that IgY purified from the egg yolks of immunized free-range chickens has in vitro antibacterial activity against E. coli, the main causative agent of mastitis in dairy goats. IgY production is considered a safe and sustainable alternative for treating mastitis, addressing concerns regarding antimicrobial resistance and antibiotic residues.