Immunohistochemical Study on Glucagon-Like Peptide-1(GLP-1) and Pituitary Adenylate Cyclase Activating Peptide (PACAP) in the Small Intestine of <i>Muscovy </i>Duck during the Prehatching and Posthatching Periods

Abstract

The distributions and frequencies of some endocrine cells in the small intestine of Muscovy duck during development were studied with immunohistochemical method using two types of antisera against Glucagon-like peptide-1 (GLP-1) and Pituitary adenylate cyclase activating peptide (PACAP). In the small intestine, GLP-1 was first observed in the jejunum at E24 and in the duodenum at E30. However PACAP labeled fibers were first noted in the jejunum and the ileum at E30. The density of GLP-1immunoreactive cells reached the peak at hatch in the duodenum, while in the jejunum and ileum got the peak at 2d (P＜0.05). The density of PACAP positive cells reached the peak in the jejunum and ileum at hatch and in the proximal duodenum at 2d and in the distal duodenum at 9d (P＜0.05). The distribution of different endocrine cell type in the small intestine exhibit some particularities in the Muscovy duckling.These results can represent an useful information for future physiological investigations that will explore the exact role of PACAP and GLP-1 in the avian intestine during a critical period like the prehatch and posthatch.

Changes in expression of neuropeptides and their receptors in the hypothalamus and gastrointestinal tract of calorie restricted hens

“…Feeding state has a great effect on gastrointestinal tract motility [6]. Along with glucagon-like peptide-1 (GLP-1), PACAP is present in the avian intestine [9,36] and takes part in the regulation of intestinal motility as a smooth muscle relaxant [30,45]. This PACAP function has been confirmed as gastric motility is reduced when PACAP is injected peripherally [33].…”

Gut Hormones and Regulation of Food Intake in Birds

“…In chickens, frequencies of occurrence of GLP-1-immunoreactive cells were influenced by food deprivation ( Monir et al , 2014a ), dietary protein levels ( Monir et al , 2014b ), and dietary amino acids ( Nishimura et al , 2015 ). GLP-1 immunoreactive cells were detected in the small intestine of ducks ( Ding et al , 2013 ). GLP-1 receptor mRNA is widely distributed in both the brain and gastrointestinal tract of chickens ( Huang et al , 2012 ).…”