Effect of Zinc on the resistance of Haemonchus contortus in in vitro tests and expression of the P-Glycoprotein resistance gene.

• Grant number: 23/14846-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): January 01, 2024
• Effective date (End): June 30, 2025
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Preventive Veterinary Medicine
• Principal Investigator: Luciana Morita Katiki
• Grantee: Rillary Moscardine Schuindt
• Host Institution: Instituto de Zootecnia. Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). Nova Odessa , SP, Brazil

Abstract

Haemonchus contortus parasitizes sheep and causes serious losses due to loss of productivity. The parasite is anthelmintic resistant to most anthelmintic drugs on the market. The stimulation of host immune resistance to parasites has been the target of many studies because there is an established relationship between host immunity and parasite load by H. contortus. Nutritional supplementation of Zinc (Zn) is recognized for its ability to induce immunity in vertebrates. However, little is known about the effect of Zn on parasites. The nanoparticulate Zn (Zn-NP) has high bioavailability and longer permanence in the animal organism and consequently in the parasite organism. The effect of Zn on the immune system of sheep is being studied as part of a thematic project (FAPESP 2019/26042-8) and the transcriptomic study of genes related to immunity in a regular project (FAPESP 2022/15638-0). The aim of this study will be to evaluate H. contortus obtained from artificially infected animals and supplemented with micronized Zn (conventional) and Zn-NP. It will be an evaluation of the indirect exposure of Zn on H. contortus (the parasite receives Zn from sheep tissues and fluids). Thus, the sensitivity/resistance of eggs, L3 (third stage larva) and adults of H. contortus will be evaluated in in vitro hatchability and motility tests with sensitivity/resistance challenge to albendazole (eggs) and ivermectin (L3 and adults). At 3 months of age, naïve lambs from mothers supplemented or not during gestation will be divided into treatments: 1. without Zn supplementation with infection (n=10); 2.com micronized Zn supplementation with infection (n=10); 3.com Zn-NP supplementation and with infection (n=10). The animals will be infected weekly with 1200 L3 H. contortus from 2rd to 7th month of age. Eggs and L3 will be recovered from the infected groups for in vitro susceptibility/resistance tests. All animals will be euthanized at the 8th month and the adult parasites from each group will be selected for in vitro test and P-glycoprotein gene expression. It is expected that this work will make sure that the Zn consumed by the sheep will not interfere with the resistance mechanisms of H. contortus.