Influência de diferentes sistemas nutricionais na pré e peripuberdade de borregas sobre a abundância relativa de RNAm DE IGF1/IGFBP3 enzimas esteroidogênicas e receptor de leptina em corpo lúteo

Abstract

The main objective of this study was to investigate the influence of 3 nutritional systems in pre and peripuberty of ewe lambs on the gene of insulin growth factor 1 (IGF1), IGF binding protein 3 (IGFBP3), the acute insulin regulatory protein steroidogenesis (STAR), 3β-hydroxysteroid dehydrogenase (HSD3B) and leptin receptor (LEPR) in diestrus corpus luteum (CLs). Nutritional status is the main factor influencing an animal's ability to protect itself. The onset of puberty and the maintenance of reproductive function are physiologically linked to nutrition and body condition. Modified variations of metabolism, with consequent reflection on consequences and their receptors. To survive the CLs, 24 ewe lambs (7/8 Dorper), aged between 6 and 7 months, were used. As lambs, groups were randomly assigned to 1 of 3 foods. G-Sub (70%-80% of the National Research Council [NRC] requirement); G-Control (100-110% [NRC] and G-Super (140% [NRC]).G-Sub (n=8) and G-Control (n=8) ewes were kept on Panicum maximum cv.Tanzania pasture with access to water and mineral salt and only as from the G-Super group 1.5% twice the weight of commercial live feed (8) were confined throughout the experimental period, receiving the total diet, in the proportion of rough weight concentration of 20:80, containing 16 % of CP and 72% of TDN, aiming at a daily weight gain of 200g/day according to NRC, with access to water and mineral salt ad libitum. average 5% of live weight. When they reached a body weight of 35 kg, the ewes were synchronized by the insertion of a vaginal device for slow release of progesterone (CIDR®) for 12 days. On the day of implant removal (D12), 0.075mg of cloprostenol and 300IU of equine chorionic gonadotropin were administered intramuscularly and eight days later the sheep were slaughtered and the reproductive system removed for weighing and processing of CL samples for later gene expression analysis. Fragments of LCs that were deposited in liquid nitrogen (-196oC) and stored in a freezer at -80oC were used to perform RT-qPCR. These fragments (approximately 40mg) were submitted to the total extraction protocol of Trizol® (ThermoFisherScientific®). Reverse transcription was performed using the Superscript® III protocol (Invitrogen TM, Termo Fisher Scientific, Brazil), following the manufacturer's protocol. qPCR was performed for the quantitative analysis of relative gene expression. From the statistical analysis, it was noted that there was an effect of nutritional management on the relative abundance of the leptin receptor, which was higher in ewes of the G-Super group. The enzymes HSD3B1 (p=0.1085), STAR (p=0.6516), IGF (p=0.3277) and IGBP3 (p=0.12) did not differ according to the nutritional plan. It was concluded that the different nutritional plans offered to ewes in pre and peripuberty had a significant impact on body weight and consequently on the relative abundance of Leptin receptors.