Gene Expression of the Intestinal Peptide Transporter 1 and Peroxisome Proliferator-Activated Receptor alpha Following Fasting/Refeeding and Ligand Administration in Chickens
Madsen, Sara Lindsly
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The uptake of amino acids is mediated by amino acid transporters and the peptide transporter, PepT1. The nuclear receptor PPARÎ± may play a role in the activation of PepT1. The objectives of this study were to evaluate the effect of a fasting/refeeding regimen and gavaging a PPARÎ± ligand on expression of chicken PepT1 and PPARÎ±. During the fasting/refeeding trial, chicks were placed on a 24h fast and then divided into 3 groups (Continuously Fasted (CF), Refed/Food Withdrawn, and Refed Adlib) and sampled 1, 2, 3, 5 and 7h post-fast. Expression of PepT1 and PPARÎ± increased almost 2-fold post-24h fast (P < 0.002). The CF group had highest expression for both genes (P < 0.0001) suggesting a coordinate change in PepT1 and PPARÎ± expression during fasting, indicating a possible regulatory role for PPARÎ± of PepT1. Oral gavage trials utilizing PPARÎ± ligand WY- 14643 were conducted with layers and broilers. For the layer trial birds were gavaged daily for 3 d with 50 mg WY-14643/kg in carrier (Ligand) or with just carrier (No Ligand) and sampled on d4. For the broiler trial, birds were gavaged daily with 25 or 50 mg WY-14643/kg or just carrier and sampled on d2 or d3 post gavage. No difference in PepT1 was observed between the Ligand and No Ligand groups. In the layer trial, PPARÎ± decreased 6-fold (P = 0.005) in the Ligand group. Broilers treated with WY-14643 showed no effect of ligand. These results indicate a difference between layers and broilers in response to WY-14643.
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