Antimicrobial activity of tilapia protein hydrolysate against pathogenic bacteria in aquaculture

• Grant number: 25/09724-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2025
• End date: July 31, 2026
• Field of knowledge: Agronomical Sciences - Food Science and Technology
• Principal Investigator: Clariana Zanutto Paulino da Cruz
• Grantee: Maria Luisa de Araujo Alcantara
• Host Institution: Faculdade de Medicina Veterinária (FMVA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil

Abstract

Nile tilapia (Oreochromis niloticus) has emerged as one of the most prominent species in global aquaculture, and Brazil is currently positioned as the fourth largest producer worldwide. Despite its high growth potential, the fish production chain faces major challenges, such as the large volume of waste and the frequent occurrence of bacterial diseases, which often require the use of antibiotics as a control measure. However, the indiscriminate use of these drugs promotes microbial resistance, with significant impacts on animal, environmental, and human health, highlighting the urgent need for alternative strategies. Among fish by-products, tilapia skin is a rich source of collagen, which can be thermally converted into gelatin. During the extraction process, gelatin derived from tilapia skin collagen may be enzymatically hydrolyzed into smaller fragments, resulting in tilapia protein hydrolysate (TPH), which can contain peptides with bioactive properties. Antimicrobial peptides (AMPs) represent a potential alternative to conventional antimicrobials. The main objective of the present study is to evaluate the antimicrobial activity of TPH against pathogenic microorganisms of importance in aquaculture and its potential application as an alternative to conventional antibiotics used in tilapia farming. The following steps will be carried out: a) preparation and extraction of collagen from tilapia skin; b) hydrolysis of tilapia skin collagen using alcalase®; c) evaluation of the antimicrobial activity of TPH against Streptococcus agalactiae (Gram-positive) and Aeromonas hydrophila (Gram-negative) using the disk diffusion and microdilution methods; d) comparison of the antimicrobial activity of TPH with the antibiotic florfenicol. This study aims to promote the reuse of tilapia skin, a by-product of fish processing, to generate high value-added TPH containing AMPs with potential applications in aquaculture.