Curcumin-based nanotherapeutics for colibacillosis in chickens: advances in veterinary microbiology

One of the most important bacterial agents of colibacillosis is Avian Pathogenic Escherichia coli (APEC), which affects the poultry industry by increasing mortality, reducing growth performance, and ultimately decreasing production efficiency. According the surveillance studies carried out in the European Union during the period of 2019-21, resistance to antibiotics has increased in E. coli due to transfer of genes between bacteria and humans. The rapid emergence of high antimicrobial resistance has accelerated research towards effective, natural, and antibiotic-free substitutes. Curcumin is a bioactive polyphenol extracted from Curcuma longa, has been widely studied for its antioxidant, immunomodulatory, antimicrobial, and anti-inflammatory properties. But, its use as a feed additive for chickens is limited because of the low bioavailability, rapid metabolism, and poor solubility. By applying nanotechnology techniques, researchers have successfully developed formulations that counteract these disadvantages and improve their bioavailability and stability. Curcumin nanoparticles work by causing damage to bacterial cell membrane, production of reactive oxygen species, and impeding bacterial cytokinesis by preventing the assembly of the FtsZ protein. Applications of nanoformulations of curcumin as a therapeutic agent for increasing the production of chicken, the various methods of delivering them to the birds, their pharmacokinetic studies and their effect on the growth performance of poultry birds have been critically and thoroughly analyzed in this review. Nanocurcumin at a concentration of 100 mg per kilogram of feed has demonstrated the best results for body weight gain, feed conversion ratio and feed intake. Despite the positive results, there are unsolved queries about the toxicokinetics, signaling molecular pathways, long-term safety, and dose standardization. For nanocurcumin to be logically incorporated into chicken health management, these obstacles must be overcome.