EFFECT OF WASTE MILK USE ON METABOLOME, INFLAMMATORY PROFILE, OXIDATIVE STRESS IN HOLSTEIN CALVES

Abstract

The use of waste milk in the liquid diet of heifers is a common practice in several farms in Brazil and around the world to reduce costs in milk production systems, despite the biological risk and variations in the bromatological composition and nutritional values of this food. The hypothesis of this research is that the consumption of waste milk, with a high microbial load and antimicrobial residues, can change the profile of the intestinal microbiota and its by-products, with consequences on the metabolome and modulation of the immune response of calves towards a pro-inflammatory associated with the state of oxidative stress. Given this context, the general objective of this work is to evaluate the effect of using waste milk on the relationship of the metabolome with innate immunity and inflammatory response in the balance between health and disease, as well as determining the oxidative stress of calves from birth to weaning. The study will be carried out in an experimental animal facility at FMVZ/USP, where 30 calves will be reared, distributed into three experimental groups according to the liquid diet they will receive: whole milk group (GLI, n=10), waste milk group (GLD, n=10) and pasteurized waste milk group (GLDP, n=10). The intestinal health of calves will be evaluated by the daily fecal score and intestinal permeability thesis. Blood samples will be collected in weeks S1, S3, S5, S7 and S9 for metabolome evaluation; innate immune response by macrophage activity and neutrophil function and production of reactive oxygen species against Escherichia coli and Staphylococcus aureus bacteria; analysis of oxidative stress biomarkers; and serum haptoglobin dosage. Fecal samples will be collected for metabolome, pH, lactate and fecal concentration of short-chain and branched fatty acids, as well as for quantification of dry matter. At the end of the experiment (S9) the animals will be euthanized and a necroscopic, histopathological and immunohistochemical examination of the intestine will be performed. The results will be tabulated and stored in Excel spreadsheets for further statistical analysis with appropriate tests, according to data distribution.