Application of the antimicrobial peptide Ctx(Ile21)-Ha and its conjugates in different formulations as a nutritional additive in laying hens

Abstract

Nowadays, markets are increasingly demanding more attention and requirements to the quality and safety of the food produced, also for the type of additives added for the animal feeding. In this way, the search for new compounds that can increase and improve productivity or reduce chemical residues in products of animal origin becomes relevant and demanded. In parallel, the constant use of synthetic antibiotics as growth promoters causes a high bacterial resistance in laying hens, as well as traces and residues in their products, which can affect animal health and, consequently, the human health. In this sense, the antimicrobial peptide Ctx(Ile21)-Ha, extracted and isolated from the Brazilian cerrado frog Hypsiboas albopunctatus, has been studied extensively by the present research group and has been shown, in previous studies, to be very active and promising molecule in the control of pathogenic bacteria in laying hens. Thus, this project aims the synthesis, purification and characterization of the peptide Ctx(Ile21)-Ha, in addition to its conjugation with chitosan, very known as natural antimicrobial molecules, for the formation of the conjugate here called peptosan. After this step, the new molecules will be formulated into microparticles with two different coating types (HPMC phthalate and acetate/succinate) for direct release into the bowel of the laying hens. By means of microbiological techniques, the bacterial colonies of Salmonella ssp. will be evaluated in the cecal and intestinal contents as a whole, after the addition of the molecules. In addition, it is expected to carry out the analysis of zootechnical performance (average daily intake, daily weight gain, weight at 28 days) and total digestibility. Thus, it is expected that the number of CFUs of the pathogenic bacteria decreases after the administration of peptosanes and if the registered zootechnical indexes are positive, this study can enabling the peptide Ctx(Ile21)-Ha and its conjugates (peptosanas) as a new nutritional additive in laying hens. (AU)