Development of alginate microparticles coated with HPMCAS containing the antimicrobial peptide Ctx(Ile²¹)-Ha for application as a natural oral additive in laying hens against systemic Salmonella Enteritidis infection

• Ano de defesa: 2021
• Autor(a) principal: Roque Borda, Cesar Augusto
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Additives; Enteric coating; Laying hens; Salmonella; Poultry health; Aditivos; Aves Poedeiras; Micropartículas; Revestimento entérico; Sanidade
• Link de acesso: http://hdl.handle.net/11449/204500

The search for new compounds that can increase and improve performance or reduce chemical residues in products of animal origin is becoming relevant and in demand. At the same time, the constant use of synthetic antibiotics as growth promoters causes great bacterial resistance in laying birds, as well as traces and residues in their products, which can affect animal health and, consequently, human health. In this sense, the antimicrobial peptide (AMP) Ctx(Ile21)-Ha, extracted and isolated from the Brazilian Cerrado frog Hypsiboas albopunctatus, is a very promising molecule in the control of pathogenic bacteria. However, AMPs applied in an in vivo system can undergo degradation or denaturation due to the presence of proteases or hydrolysis by the acidic environment. Thus, this study aimed at the synthesis and purification of the Ctx(Ile21)-Ha peptide, and the coating of alginate microparticles with hypromellose acetate/succinate (HPMCAS), in addition to its physicochemical characterization. Hemolytic activity and simulated in vitro gastrointestinal release of the coated microparticles were also evaluated. In vivo study was carried out with newly hatched laying hens, challenged with Salmonella Enteritidis and treated with microparticles in the feed. Bacterial counts were performed in liver, spleen, and cecum to verify the effects of peptide. The results obtained showed thermostable microparticles, with encapsulation efficiency greater than 70%, slight gastric release, excellent intestinal release, the hemolytic activity of peptide decreased by 95%, and in the in vivo experiment a significant difference was obtained in bacterial count, mainly in liver, followed by spleen. Therefore, this study demonstrated that the coated microparticles containing AMP Ctx(Ile21)-Ha have a high antimicrobial activity and serve as a tool for the prevention of systemic infections, without contaminating residues compared to conventional drugs.