The chicken is an interesting animal for study of the functional role of ghrelin in the gastrointestinal tract

Effects of chronic heat exposure on growth performance, intestinal epithelial histology, appetite‐related hormones and genes expression in broilers

“…Most of the intestinal hormones, including appetite inhibitors of CCK, ghrelin, PYY, and SS that are mainly released by intestinal epithelial cells, have a strong inhibition of appetite and can hamper intestinal movements . Ghrelin, originally identified as a growth‐hormone‐releasing peptide released from the stomach of mammals, is an interesting hormone owing to its adverse function on appetite between mammals and poultry, which might be involved in inhibiting feed intake, particularly in young growing chickens .…”

“…30 Most of the intestinal hormones, including appetite inhibitors of CCK, ghrelin, PYY, and SS that are mainly released by intestinal epithelial cells, have a strong inhibition of appetite and can hamper intestinal movements. [31][32][33][34] Ghrelin, originally identified as a growth-hormone-releasing peptide released from the stomach of mammals, is an interesting hormone owing to its adverse function on appetite between mammals and poultry, which might be involved in inhibiting feed intake, particularly in young growing chickens. [35][36][37] The current results showed that heat exposure significantly elevated the intestinal hormone levels of SS, ghrelin, CCK and PYY in the duodenum, as well as SS and ghrelin in the jejunum for 35-day-old broilers, and increased the intestinal hormone levels of SS and PYY in the intestine, as well as ghrelin in the jejunum on day 42 compared with the NC and PF groups.…”

Regulation of Gastrointestinal Motility by Motilin and Ghrelin in Vertebrates

“…Interestingly, pharmacological analysis indicated different contractile mechanisms depending on the region: in the crop, GHRL acts on smooth muscle cells directly, and in the proventriculus, GHRL stimulates both smooth muscle cells and enteric neurons (77). Direct action of GHRL on smooth muscle cells is a characteristic of the chicken GI tract that has never been reported in mammals [Table 2, (136)]. The region-dependent contractile responses correlate to the expression level of GHS-R1a mRNAs, indicating that the different degrees of responsiveness of the GI tract to GHRL are due to the heterogeneous expression of GHS-R1a (76).…”

Screening of reliable reference genes for the normalization of RT-qPCR in chicken gastrointestinal tract

“…RT-qPCR is a widely employed method in contemporary molecular biology research ( Gadkar and Filion, 2014 ), and the precise quantification of RT-qPCR relies on the identification of stable internal reference genes ( Huggett et al, 2005 ; Sanders et al, 2014 ). The GI tract of chickens holds significant importance in terms of food digestion and nutrient absorption, exhibiting distinct morphological variations from mammals, particularly in the anterior GI tract ( Gao et al, 2012 ; Kitazawa et al, 2017 ). Each segment of the chicken GI tract serves a distinct functional purpose, which is attributable to the selective expression of genes.…”

“…In recent years, the focus on the intestinal microbiome has further propelled this research ( Clavijo and Florez, 2018 ; Wen et al, 2021 ; Zhang et al, 2022 ). The GI tract, being a lengthy and complex system, undergoes similar developmental stages ( Gao et al, 2012 ; Kitazawa et al, 2017 ), making it crucial to compare the variations in gene expression profiles across different sections. Presently, there is a dearth of reference primers tailored specifically for targeting the GI tract.…”