Effect of high energy intake on carcass composition and hypothalamic gene expression in Bos indicus heifers

Abstract

-The objective of this study was to evaluate the effect of high or low energy intake on carcass composition and expression of hypothalamic genes related to the onset of puberty. Twenty-four prepubertal Nellore heifers, 18-20-months-old, with 275.3±18.0 kg body weight (BW), and 4.9±0.2 (1-9 scale) body condition score (BCS) were randomly assigned to two treatments: high-energy diet (HE) and low-energy diet (LE). Heifers were housed in two collective pens and fed diets formulated to promote average daily gain of 0.4 (LE) or 1.2 kg (HE) BW/day. Eight heifers from each treatment were slaughtered after the first corpus luteum detection -considered as age of puberty. The 9-10-11th rib section was taken and prepared for carcass composition analyses. Samples from hypothalamus were collected, frozen in liquid nitrogen, and stored at −80 °C. Specific primers for targets (NPY, NPY1R, NPY4R, SOCS3, OXT, ARRB1, and IGFPB2) and control (RPL19 and RN18S1) genes were designed for real-time PCR and then the relative quantification of target gene expression was performed. High-energy diets increased body condition score, cold carcass weight, and Longissimus lumborum muscle area and decreased age at slaughter. High-energy diets decreased the expression of NPY1R and ARRB1 at 4.4-fold and 1.5-fold, respectively. In conclusion, the hastening of puberty with high energy intake is related with greater body fatness and lesser hypothalamic expression of NPY1 receptor and of β-arrestin1, suggesting a less sensitive hypothalamus to the negative effects of NPY signaling.Key Words: cattle, energy supplementation, neuropeptides, puberty, reproduction Revista Brasileira de Zootecnia

Análise de parâmetros fisiológicos e perfil de expressão de genes associados ao estresse térmico e eficiência alimentar em bovinos das raças Nelore e Caracu

“…According to , the NPY gene shows a strong marker significantly associated with growth and carcass traits in Hanwoo cattle. The importance of the NPY gene in cattle efficiency has been reported for different breeds, including Nelore (Santana et al, 2014;Diniz-Magalhães et al, 2017), Hanwoo , Yunling and Leiqiong , and Brahman (Cardoso et al, 2015).…”

“…The NPY gene influences several biological pathways that regulate appetite, ingestive behavior, and energy homeostasis in humans and animals Santana et al, 2014;Yu et al, 2017). Likewise, its expression is linked to increased plasma levels of insulin and corticosteroids, which mediate some actions of leptin in the hypothalamus (Anubhuti, 2006;Diniz-Magalhães et al, 2017). Several studies reported the importance of the LEP gene in animal growth, energy balance, immune system, fat deposition, reproductive traits, and heat stress (Casas and Kehrli, 2016;Foote et al, 2016;Kononoff et al, 2017;Woronuk et al, 2012).…”