The effect of reducing dietary energy on performance, intestinal morphology and intestinal peptide and amino acid transporters in broiler chicks

Abstract

Abstract Background Previous research has investigated the impact of different factors such as gender and age of birds, protein and amino acid levels, protein origin and the physical form of the diet, on the mRNA expression of intestinal peptides and amino acid transporters. Nevertheless, there have been no attempts to examine the impact of dietary energy density on the mRNA abundance of intestinal amino acid and peptide transporters in humans or animals. This is the first reported case in both humans and animals. Objectives This experiment aimed to evaluate the influence of two levels of metabolizable energy ([ME]; 2950 and 2850 kcal ME/kg diet) on performance and jejunal morphology and mRNA expression of amino acid (B0AT, b0,+AT, CAT1 and y+LAT1) and peptide (PepT1) transporters in broiler chickens during the starter period (0–10 days of age). Methods Two hundred and seventy day‐old male Ross 308 broiler chickens were randomly assigned to two dietary treatments with nine replicates and fifteen birds in each replicate. At 10 days of age, the outcome variables were measured, which included the assessment of the mRNA abundance of PepT1, b0,+AT, B0AT, y+LAT1 and CAT1 in the jejunal section using real‐time PCR. Results The findings of this study revealed no significant impact of the dietary treatments on feed intake, body weight gain, feed conversion ratio and the jejunal mRNA abundance of PepT1, CAT1 and y+LAT1 (p > 0.05). However, a reduction in dietary ME level from 2950 to 2850 kcal ME/kg diet resulted in a decrease in the mRNA level of B0AT and b0,+AT (p ≤ 0.05). The reduction in dietary energy level did not lead to any significant changes in villus width, villus height, crypt depth, villus surface area and villus height to crypt depth ratio (p > 0.05). Conclusion The results demonstrated that decreasing dietary energy density may alter the expression of amino acid transporters in the intestine while having no impact on the growth performance and morphometric structure of the intestine.

Keywords

• amino acid transporters
• broilers
• intestinal morphology
• metabolizable energy
• peptide transporter