Lysozyme activity as an indicator of innate immunity of tilapia (Oreochromis niloticus) when challenged with LPS and Streptococcus agalactiae

Author(s)

Jaqueline Dalbello Biller ^[1] ; Gustavo do Valle Polycarpo ^[2] ; Basia Schlichting Moromizato ^[3] ; Ana Paula Diogo Sidekerskis ^[4] ; Thaís Daltoso da Silva ^[5] ; Ingrid Camargo dos Reis ^[6] ; Camino Fierro-Castro ^[7]

Affiliation

^[1] Universidade Estadual Paulista “Júlio de Mesquita Filho”. Faculdade de Ciências Agrárias e Tecnológicas - Brasil

^[2] Universidade Estadual Paulista “Júlio de Mesquita Filho”. Faculdade de Ciências Agrárias e Tecnológicas - Brasil

^[3] Universidade Estadual Paulista “Júlio de Mesquita Filho”. Faculdade de Ciências Agrárias e Tecnológicas - Brasil

^[4] Universidade Estadual Paulista “Júlio de Mesquita Filho”. Faculdade de Ciências Agrárias e Tecnológicas - Brasil

^[5] Universidade Estadual Paulista “Júlio de Mesquita Filho”. Programa de Pós-Graduação em Aquicultura - Brasil

^[6] Universidade Estadual Paulista “Júlio de Mesquita Filho”. Programa de Pós-Graduação em Ciência e Tecnologia Animal - Brasil

^[7] Universidad de León. Facultad de Ciencias Biológicas y Ambientales. Departamento de Biología Molecular

• Document type: Journal article
• Source: REVISTA BRASILEIRA DE ZOOTECNIA-BRAZILIAN JOURNAL OF ANIMAL SCIENCE; v. 50, 2021-11-29.

Abstract

ABSTRACT The objective of this study was to fully describe the protocol with standardized modifications and evaluate the lysozyme activity, an indicator of innate immunity in tilapia, to compare lipopolysaccharide (LPS) with Streptococcus agalactiae injections. Lysozyme was determined in serum using the turbidimetric method, in which lysozyme activity was evaluated by Micrococcus lysodeikticus lysis, with modifications for microplate assay. The experiment was conducted in a completely randomized design. Juvenile tilapia was divided in the following six treatments: challenged with phosphate buffer PBS (control) and 100, 250, 500, and 600 μg kg−1 LPS and S. agalactiae. All treatments were challenged for 72 h and seven days and then sampled to determine lysozyme activity. After 72 h or seven days, concentrations of LPS promoted changes in lysozyme production, either lesser or equal, depending on concentration when compared with fish injected with S. agalactiae. It was possible to standardize the analysis and determine that the treatment with LPS promotes immunomodulation at a concentration of 250 μg kg−1 LPS, this response being similar to challenge with S. agalactiae. (AU)

• FAPESP's process: 12/22016-3 - Study of the immunostimulating potential of b-glucan and its mode of action aiming at new administration protocols in tilapia, Oreochromis niloticus
• Grantee: Jaqueline Dalbello Biller Takahashi
• Support Opportunities: Research Grants - Young Investigators Grants