Metabotype investigation of programmed heifers by early-weaning and its effect on puberty

• Grant number: 22/07906-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2022
• End date: November 30, 2023
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Production
• Principal Investigator: Nara Regina Brandão Cônsolo
• Grantee: Larissa Christina Montezano
• Host Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil
• Associated research grant: 20/08845-3 - The metabolomic approach to improve Nellore beef tenderness: a concept of metabotype and biomarkers, AP.JP

Abstract

The increasing need to improve efficiency in animal production systems has lead to a great search for technologies which might increase the producers and industry profitability. In this context, tools that allow us a better understanding on animal reproduction is indeed a promising way to increase its productivity and profitability. Thus, the aim of this study is to analyze the metabolomic profile of heifers Nellore, whose mothers had the previous offspring submitted to early or conventional weaning, looking for fetal programming of these females, and to deeply understand their metabolism and the development of reproductive tract up to the puberty. It will be used 57 Nellore females, with 14 to 16 months of age and 280 and 300 kg live weight. The animals will be divided according to the weaning time in two groups: ANT) calves from mothers whose previous calf was weaned early, at five months of age and NOR) calves from mothers whose previous calf was conventionally weaned. At 12-15 months of age, the females will be evaluated through ultrasound, the diameter of the dominant follicle, ovulation and luteinization will be checked to establish the precocity of these heifers using transrectal ultrasound. Heifers will be classified according to the estrous cyclicity pattern, adapting the scale of: prepubescent heifers (without corpus luteum), pubescent (with corpus luteum) and non-pubescent (without corpus luteum and dominant follicles). The same day, blood sample will be collected, puncture of the vein or jugular artery, centrifuged to obtain plasma and analyzed by nuclear magnetic resonance spectrometry (NMR) to obtain the metabolomic profile. The statistical analysis will be analyzed through the MetaboAnalyst platform, using uni and multivariate analysis on regards the ANT and NOR treatment. The present study will also establish the first metabotype of the heifers as a function of classification of prepubescent, pubescent and non-pubescent. Metabolic pathway and enrichment analysis will be performed to better understand how the weaning system affects the sexual precocity of programed heifers.