Expression of genes associated with nutrient uptake in intestines of chickens with different growth potentials show temporal changes but are not correlated with growth

Abstract

ABSTRACT 1. The study was designed to compare the expression of genes that encode proteins located at either the brush border (BB) or basolateral (BL) of the gut epithelium among fast and slow-growing broilers. 2. Six broiler breeds with different growth capacities were used: Ross 708, Hubbard H1 (HH1), Cobb 500, Longenecker’s Heritage (LHR), Red-Bro, and the Athens Canadian Randombred Control (ACRB). Birds were sampled between embryonic day (ED) 19 and day 35 post-hatch (PH). 3. Performance parameters indicated that Ross 708, HH1, and Cobb 500 had the highest body weights (BW) while ACRBs had the lowest. 4. Quantitative RT-PCR was performed on 13 genes encoding proteins associated with nutrient processing and uptake. Statistical analysis was carried out (ANOVA) for eight BB genes: Aminopeptidase N (APN), four amino acid transporters, (ATBo,+, BoAT, bo,+AT, EAAT3) a di- and tri-peptide transporter (PepT1), and two sugar transporters (GLUT5 and SGLT1). Analysis of four amino acid transporters (CAT1, CAT2, LAT1, and γ+LAT1), and a single sugar transporter (GLUT2) associated with BL was carried out. 5. Four BB associated genes (APN, EAAT3, BoAT, and b0,+AT) in the small intestine were negatively correlated with growth. 6. In most cases, genes encoding BB proteins increased in expression over time (P < 0.05) in the small intestine, while, in the caeca, the expression decreased (P < 0.05). The mRNA of BL-associated proteins showed decreased (P < 0.05) expression over time in all gut segments, with exception of GLUT2, which increased in expression in the small intestine. 7. The temporal changes in gene expression were consistent among bird lines and BB associated genes tended to increase over time, while BL associated genes tended to decrease over time. Correlation analysis indicated that mRNA expression of nutrient transporter genes may not be a good predictor of growth potential.