Effect of waste milk on microbiome, immunity and gut health in dairy calves

• Grant number: 20/14761-7
• Support Opportunities: Regular Research Grants
• Start date: August 01, 2022
• End date: July 31, 2024
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Clinics and Surgery
• Principal Investigator: Viviani Gomes
• Grantee: Viviani Gomes
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: Andrea Micke Moreno ; Christian Hoffmann ; Richard Van Vleck Pereira

Abstract

Waste milk is all milk produced that cannot be sold commercially, due to the presence of antimicrobials residues and bacterias from cows manifesting mastitis, colostrum and transition milk. Despite the presence of antimicrobials residues, biological risk and variations in chemical composition, most farms in Brazil and in the world have using waste milk to feed dairy calves in order to reduce the production costs. Based on this scenario, the general objective of this research is to evaluate the effect of the use of waste milk on the relationship between gut microbiome with immunity and metabolism in the health and disease balance, as well as to determine the antimicrobial resistance profile developed during the pre-weaned period. The study will be carried out in an experimental restrict area at FMVZ / USP, in which 30 male dairy calves will be raised and distributed into three experimental groups: group receiving whole milk (GLI, n = 10), group receiving waste milk (GLD, n = 10) and group receiving pasteurized waste milk (GLDP, n = 10). It will be performed clinical examination daily, performance weekly, and sampling of biological material in weeks S1, S3, S5, S7 and S9 in relation to the age of the animals included in the study. Blood samples (60mL) will be obtained to perform the specific immune response against the bacteria Escherichia coli and Lactobaccilus acydophilus. For this purpose, pheripheral blood mononuclear cells (PBMC) will be isolated and stimulated with different concentrations of antigens to evaluate cellular proliferation, immunophenotyping of CD4, CD8, CD14, CD25 and WC1 lymphocytes and measurement of cytokines IL-4, IL-10, IL-17 and IFN-y from the cell culture supernatant. In addition, fecal samples will be collected for the isolation of Escherichia coli and other enterobacterias to analyze the antimicrobial resistance profile; for the analysis of pH and fecal concentration of short and branched chain fatty acids; and for the analysis of the microbiome. At the end of the experiment (S9), calves will be euthanized for the realization of necroscope, histopathological and immunohistochemical examination of the gut tissue. The results will be tabulated and stored in excell spreadsheets for further statistical analysis using appropriate tests according to the data distribution. (AU)