The Expression of Amino Acid and Fatty Acid Receptors Show an Age-Dependent Pattern Involving Oral Cavity, Jejunum and Lower Gut Sensing in Broiler Chickens

Abstract

This work aimed to evaluate the gene expression of amino acids (AA) and fatty acids (FA) sensors in the gastrointestinal tract (GIT) of chickens at two different ages (7 and 26 days post-hatch). Sixteen broilers (Ross 308) were selected, and ten sections of the GIT, including upper (tongue base, upper palate, crop, proventriculus), middle (gizzard, duodenum, jejunum, ileum), and lower GIT section (cecum, colon) were collected for analysis. Relative gene expression of AA (T1R1, T1R3, mGluR1, mGluR4, CaSR, GPR139, GPRC6A, GPR92) and FA (FFAR2, FFAR3, FFAR4) sensors were assessed using qPCR. The statistical model included age, GIT section, and gene. In addition, the correlations between gene expressions were calculated. At day 7, a significantly (p = 0.004) higher expression of AA sensors in the oral cavity and FA sensors in the lower GIT section (i.e., cecum and colon) compared to the middle section was recorded. A higher expression of AA compared to FA sensors was detected at the upper GIT section in 7 (p p = 0.026). Thus, at day 7, AA sensors were predominantly (p p p p p < 0.050). It is concluded that the gene expression is greater in the oral cavity for AA sensors and the lower gut for FA sensors. On day 26, the role of jejunum regarding nutrient sensing is highlighted.

Keywords

• amino acids
• broiler chicken
• fatty acids
• gastrointestinal tract
• gene expression
• nutrient sensors