Induction of hypothalamic GABA synthetic enzymes mRNA (Gad 1 and Gad 2) expression by negative energy balance in broiler and layer chicks. (1st November 2019)

• Record Type: Journal Article
• Authors: Zare, D.; Jonaidi, H.; Sadeghi, B.
• Is Part Of: Neuroscience letters. Volume 712(2019)
• Publication Date: 2019-11-01
• Subjects: GABA -- Gad 1 and Gad 2 -- Hypothalamus -- Energy balance -- Food intake -- Broiler and layer chicks; Neurology -- Periodicals; Neurology -- Periodicals; Research -- Periodicals; Neurologie -- Périodiques; Neuroanatomie -- Périodiques; Neuropharmacologie -- Périodiques; Neurophysiologie -- Périodiques; Neurology; Periodicals; Electronic journals; 617.48
• DOI: 10.1016/j.neulet.2019.134498
• Languages: English
• ISSNs: 0304-3940

Abstract

Highlights: Gad 1 and 2 genes were expressed within the hypothalamus of free fed broiler and layer chicks with the higher level in layers than broilers. Fasting induced hypothalamic Gad 1 and 2 mRNA levels in broilers and layers with the greater induction in broilers than layers. Gad 1 and 2 genes expression tended to return to the baseline in fasted/refed broilers and layers. ICV administration of GABA had no effect on food intake of broilers and layers with the exception of an increase in free fed broilers. Abstract: Broiler and layer chicks have been selected for higher and lower food intake and body weight gain, respectively. It has recently been reported that glutamate decarboxylase (Gad1) mRNA, a gamma-aminobutyric acid (GABA) synthetic enzyme gene, is a reliable proxy for GABA release. Previous studies have revealed that GABAergic system has a stimulatory role on food intake in both mammals and birds. Over the recent years, evidence has identified the presence of GABAergic neurons as either the first- or second-order neurons within the various feeding nuclei of hypothalamus of laboratory rodents. They respond to the negative energy balance representing a critical role for GABA in the regulation of food intake. In the current study, the mRNA abundance of Gad 1 and Gad 2 was measured within the hypothalamus of both broiler and layer free fed, 12 h-fasted and 12 h-fasted / 3 h refed chicks. Furthermore, the effect of intracerebroventricular (ICV) injection of GABA was studied on food intake of chicks. The results indicated an increase in both Gad 1 and 2 expressions during fasting which tended to return to the baseline after refeeding. However, this increase was greater in broilers than in layers. The results also showed that ICV injection of GABA had no effect on food intake with the exception of an increase in free fed broilers. This study suggests a role for hypothalamic GABAergic system in birds that respond to negative energy balance, which seems to be more considerable in broilers than in layers.