Gene expression in the adipose tissue of pre pubertal and pubertal Nelore heifers

• Grant number: 15/15642-3
• Support Opportunities: Scholarships in Brazil - Master
• Start date: November 01, 2015
• End date: February 28, 2017
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Genetics and Improvement of Domestic Animals
• Principal Investigator: Luiz Lehmann Coutinho
• Grantee: Paula Suarez Henriques
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated research grant: 14/14136-4 - Technological innovations to increase productivity in beef cattle: nutritional and genetic interrelationships about puberty, reproduction and production. Protocols for TAI. Gene expression in reproductive processes, AP.TEM

Abstract

The onset of puberty and with it, the beginning of a fertile reproductive stage in heifers has great economic impact for cattle breeders because when heifers reach puberty later, there is less calves bred in the course of a cow's productive life. On the other hand, the reduction of age at first pregnancy from 3 to 2 years old, a consequence of an early puberty, may increase financial gain in 16%. The mechanisms controlling puberty in Bos taurus indicus heifers seem to be similar to the ones described for Bos taurus taurus heifers however, the age at which they reach puberty differs considerably from 12-15 months old in European cattle to 16-40 months old in Zebu cattle. Among the factors contributing to sexual maturity is genetic heritability that varies from 0.52 to 0.57. The present study aims at finding the difference in gene expression for Nelore heifers who reach puberty in either early or late fashion, and, by comparing these differences, to discover genes that may be used as markers for the selection of genetically superior animals, aiding the genetic improvement of Brazilian's national herd. We will assess 30 Nelore heifers, monitored weekly from 230 kg live weight until the onset of puberty. The onset of puberty will be defined by gynecological ultrasound examination detecting the presence of corpus luteum in the ovary and through measurement of blood's progesterone concentration higher than 1ng/ml. Adipose tissue will be collected through subcutaneous biopsy, and used for extracting RNA and subsequent gene expression analysis through RNA sequencing. The first biopsy will be done when heifers are 10 months old and subsequently once a month until they reach puberty. We will collect biopsies from each heifer that reaches puberty alongside with a contemporary heifer who has not reached puberty so we will have samples of six early heifers and their six late contemporary ones in pre and post pubertal stages. (AU)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

HENRIQUES, Paula Suarez. Gene expression analyses on adipose tissue of Nellore peripubertal heifers reveal genes that have an impact on reproductive physiology. 2017. Master's Dissertation - Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) Piracicaba.