Effects of "Bioactive" amino acids leucine, glutamate, arginine and tryptophan on feed intake and mRNA expression of relative neuropeptides in broiler chicks

Wang Songbo, Khondowe Paul, Chen Shengfeng, Yu Jianjian, Shu Gang, Zhu Xiaotong, Wang Lina, Gao Ping, Xi Qianyun, Zhang Yongliang, Jiang Qingyan

Description

Feed intake control is vital to ensuring optimal nutrition and achieving full potential for growth and development in poultry. The aim of the present study was to investigate the effects of L-leucine, L-glutamate, L-tryptophan and L-arginine on feed intake and the mRNA expression levels of hypothalamic Neuropeptide involved in feed intake regulation in broiler chicks. Leucine, glutamate, tryptophan or arginine was intra-cerebroventricularly (ICV) administrated to 4d-old broiler chicks respectively and the feed intake were recorded at various time points. Quantitative PCR was performed to determine the hypothalamic mRNA expression levels of Neuropeptide Y (NPY), agouti related protein (AgRP), pro-opiomelanocortin (POMC), melanocortin receptor 4 (MC4R) and corticotrophin releasing factor (CRF). Our results showed that ICV administration of L-leucine (0.15 or 1.5 μmol) significantly ( P < 0.05) increased feed intake up to 2 h post-administration period and elevated both hypothalamic NPY and AgRP mRNA expression levels. In contrast, ICV administration of L-glutamate (1.6 μmol) significantly ( P < 0.05) decreased feed intake 0.25, 0.5 and 2 h post-injection, and increased hypothalamic CRF and MC4R mRNA expression levels. Meanwhile, both L-tryptophan (10 or 100 μg) and L-arginine (20 or 200 μg) had no significant effect on feed intake. These findings suggested that L-leucine and L-glutamate could act within the hypothalamus to influence food intake, and that both orexigenic and anorexigenic Neuropeptide genes might contribute directly to these effects.

Sujets

• Hypothalamus
• Leucine
• Glutamic acid

Informations

• Publié par: biomed
• Publié le: 01 janvier 2012
• Nombre de lectures: 15
• Langue: English

Extrait

Wanget al. Journal of Animal Science and Biotechnology2012,3:27 http://www.jasbsci.com/content/3/1/27

JOURNAL OF ANIMAL SCIENCE AND BIOTECHNOLOGY

R E S E A R C HOpen Access Effects of“Bioactive”amino acids leucine, glutamate, arginine and tryptophan on feed intake and mRNA expression of relative neuropeptides in broiler chicks 1†1,2†1 11 11 Songbo Wang, Paul Khondowe, Shengfeng Chen , Jianjian Yu , Gang Shu , Xiaotong Zhu , Lina Wang , 1 11 1* Ping Gao , Qianyun Xi , Yongliang Zhangand Qingyan Jiang

Abstract Feed intake control is vital to ensuring optimal nutrition and achieving full potential for growth and development in poultry. The aim of the present study was to investigate the effects of Lleucine, Lglutamate, Ltryptophan and Larginine on feed intake and the mRNA expression levels of hypothalamic Neuropeptide involved in feed intake regulation in broiler chicks. Leucine, glutamate, tryptophan or arginine was intracerebroventricularly (ICV) administrated to 4dold broiler chicks respectively and the feed intake were recorded at various time points. Quantitative PCR was performed to determine the hypothalamic mRNA expression levels of Neuropeptide Y (NPY), agouti related protein (AgRP), proopiomelanocortin (POMC), melanocortin receptor 4 (MC4R) and corticotrophin releasing factor (CRF). Our results showed that ICV administration of Lleucine (0.15 or 1.5μmol) significantly (P< 0.05)increased feed intake up to 2 h postadministration period and elevated both hypothalamic NPY and AgRP mRNA expression levels. In contrast, ICV administration of Lglutamate (1.6μmol) significantly (P< 0.05) decreased feed intake 0.25, 0.5 and 2 h postinjection, and increased hypothalamic CRF and MC4R mRNA expression levels. Meanwhile, both Ltryptophan (10 or 100μg) and Larginine (20 or 200μg) had no significant effect on feed intake. These findings suggested that Lleucine and Lglutamate could act within the hypothalamus to influence food intake, and that both orexigenic and anorexigenic Neuropeptide genes might contribute directly to these effects. Keywords:Broiler chicks, Feed intake, Hypothalamus, Intracerebroventricular (ICV), Lleucine, Lglutamate

Background Metabolic fuels, including amino acids, could act on hypo thalamic neurons to regulate feeding behavior and energy homeostasis, but the signaling mechanisms mediating these effects are not fully clear [1]. The arcuate nucleus (ARC) of the hypothalamus contains at least two distinct groups of neurons controlling feeding behavior and energy balance, which are, neurons that contain the orexigenic Neuropeptide (including NPY and AgRP) and neurons that contain the anorexigenic Neuropeptide (including

* Correspondence: [e-mail] † Equal contributors 1 College of Animal Sciences, South China Agricultural University, Guangzhou 510642, P. R. China Full list of author information is available at the end of the article

POMC) [2,3]; and from theARC, neurons project to ‘second order neurons’in the paraventricular nucleus (PVN) (responsible for producing corticotrophinreleasing factor (CRF), a potent anorexigenic peptide), ventromedial hypothalamus area (VMH), and lateral hypothalamic area (LHA) to orchestrate feeding behavior [3,4]. In mammals, recent data indicated that brain amino acid sensing also contributed to the homeostatic regula tion of food intake and body weight [5]. In avian, many of the classic neurotransmitters, including amino acids, had been shown to affect food intake when injected dir ectly into the central nervous system [6,7]. Leucine, glutamate, tryptophan and arginine are among the important‘bioactive amino acids,’and participate in many important and diverse biochemical reactions

© 2012 Wang et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.