Synthesis and application of the antimicrobial peptide Ctx(Ile21)-Ha and its conjugates in different formulations as a nutritional additive in swines

Abstract

Swine production is one of the most important economic activities in the world, since it is the second most consumed animal protein, being only behind the fish. The consumption of pork has been growing steadily, becoming an attractive and promising activity for Brazil, in the international scope. Lately, concern about animal welfare and banning antibiotics has led to changes in swine farming around the world. Thus, one of the biggest problems and challenges of swine farming in the early days of the animal is the frequent diarrhea, usually caused by strains of Escherichia coli and Salmonella spp. In this sense, the antimicrobial peptide Ctx(Ile21)-Ha, which has been extensively studied by the present research group, has demonstrated, in previous studies with laying hens, a biological activity against these pathogenic bacteria. Thus, the present 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, this new conjugate molecule will be formulated into microparticles with two different types of coating (HPMC phthalate and acetate/succinate) for direct release into the intestine in piglets during the maternity phase, for the treatment of diarrhea. Specific doses of peptosanas will be applied daily in piglets from the first day to the 21 days of age, the period in which the piglets are in the maternity sector. The application will be oral, since the intake of food in this period is still low. The zootechnical indexes, such as daily weight gain, weight at 21 days and mortality, as well as the occurrence or not of the pathogens mentioned above, confirmed by microbiological techniques will be evaluated. It is expected that, after administration of peptosanes, the diarrhea will decrease or stopped and if the registered zootechnical indexes are positive, this study can enables the Ctx(Ile21)-Ha peptide and its conjugates (peptosanas) as a new nutritional additive in swines. (AU)