Evaluation of the use of calcium salts of fatty acids in the diet of Nellore cattle: association between fecal metabolome and feed efficiency.

• Grant number: 24/08643-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2024
• End date: November 30, 2025
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Josineudson Augusto Ii de Vasconcelos Silva
• Grantee: Marina Alves da Silva
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

The high production and export of beef cattle in Brazil resulted in an increasing number of feedlot-finished animals within the national territory and allowed the country to occupy a prominent position in the meat market worldwide. However, the high cost of feed still represents one of the biggest expenses in feedlots. Feed efficiency is directly related to the increase in meat production per unit of feed. Furthermore, the use of diets composed of inert lipids can improve carcass quality and the production of efficient animals. In this context, the objectives of this study are twofold: (1) to identify possible differences in the fecal metabolite profiles of Nelore cattle subjected to the incorporation of the calcium salts of fatty acids in their feed; and (2) identify metabolites associated with feed efficiency traits, morphometry, and carcass quality. To date, the experimental phase has been conducted using a population of 74 contemporary Nelore cattle (Bos taurus indicus). The animals were kept in collective pens equipped with Intergado® electronic feed bunks and body weighing scales for 87 days. Two experimental treatments were established: control (Con; n = 37): 0 grams of calcium salts of fatty acids; nutrifats (Nut; n = 37): 300 grams of calcium salts of fatty acids. After the feed efficiency test, fecal samples were collected directly from the rectal ampulla for metabolomic analysis, and morphometric evaluations and carcass ultrasound were performed. In the next stages, feed efficiency traits will be estimated such as dry matter intake (DMI, kg/day), average daily gain (ADG, kg/day), body weight (BW, kg), metabolic live weight (MBW, kg), residual feed intake (RFI, kg DM/day), residual average daily gain (RADG, kg/day), feed conversion ratio (FE, kg) and gross feed efficiency (GFE, kg). Fecal metabolomics analyses will be carried using Nuclear Magnetic Resonance (1H NMR). The 1H NMR spectra will be analyzed to identify and quantify fecal metabolites using Chenomx NMR Suite 8.2 software. Association analyses of fecal metabolites with feed efficiency traits, morphometry and carcass quality will be conducted. The results of this study will advance knowledge on the influence of calcium salts of fatty acids in the feed Nelore cattle. Additionally, it is expected to identify fecal metabolites that can serve as semi-invasive biomarkers for feed efficiency traits, morphometric and carcass quality. These biomarkers can offer new insights into beef production, assisting in the selection and nutritional management of animals.