The in ovo administration of l-trans pyrrolidine-2,4-dicarboxylic acid regulates small intestinal growth in chicks

Abstract

Glutamate, which is one of the most important contributors to oxidative metabolism in the intestinal mucosa, is mainly transported by the excitatory amino acids transporters (EAATs) that are expressed in enterocytes. The objective of this study was to evaluate the effects of in ovo administration of L-trans pyrrolidine-2,4-dicarboxylic acid (L-trans-PDC), a potent competitive inhibitor of glutamate uptake by EAATs, on the growth of the small intestine in chicks. Two series of experiments were conducted with hatching eggs; 100 μl of various L-trans-PDC solutions (0, 0.075 or 0.225 mg/egg for the Control group, low-dose L-trans pyrrolidine 2,4-dicarboxylic acid group (L-PDC) or high-dose L-trans pyrrolidine 2,4-dicarboxylic acid group (H-PDC), respectively) was injected into the albumen sac of these hatching eggs before incubation. Hatchlings were sacrificed by cervical dislocation to determine the embryonic development in Experiment I, whereas the birds in Experiment II were raised or sampled at hatching, days 7 and 14 (D7 and D14) for further study. Gene expression in the small intestines was determined by real-time RT-PCR; and serum concentration of free amino acids was determined by an amino acid analyzer. The results showed that the hatchability was decreased by in ovo administration of L-trans-PDC. The small intestinal weights of the H-PDC group were decreased ( P < 0.05) at hatching and increased ( P < 0.05) on D7 and D14 compared with those in the Control group. In addition, the gene expression of EAAT2 in the completed or segmental small intestines was not changed ( P > 0.05); EAAT3 gene expression in the duodenum ( P < 0.05), jejunum ( P = 0.084) and ileum ( P = 0.060) on D14 was lower in the H-PDC group than in the Control group. Furthermore, the serum concentrations of free proline, threonine and phenylalanine but not glutamate or aspartate were increased ( P < 0.06) in H-PDC group. In conclusion, this paper is the first to report that in ovo administration of L-trans-PDC induces small intestinal growth retardation during the embryonic period and catch-up growth after hatching.

EAAT3 promotes amino acid transport and proliferation of porcine intestinal epithelial cells

“…Glu absorption is mainly mediated by EAAT3 in the nervous system [16], gastrointestinal tract [5, 17] and skeletal muscle [18]. Our previous studies revealed that EAAT3 is a marker of intestinal growth during embryonic development in chicks [7, 19] and pigeons [20–22]. In addition, Glu deficiency or absorptive inhibition of EAAT3 decreased IPEC-1 cell proliferation [6].…”

“…Studies with pigs, rats and mice demonstrate that the excitatory amino acid transporter 3 (EAAT3), encoded by solute carrier family 1 member 1 ( SLC1A1 ), is the predominant anionic amino acid transporter in the intestine [5]. In our previous studies, EAAT3 inhibition decreased pig intestinal epithelial cell (IPEC-1) proliferation [6] and intestinal growth in chick embryos [7]. Landeghem, et al .…”

Growth of embryo and gene expression of nutrient transporters in the small intestine of the domestic pigeon (Columba livia)

“…Embryonic growth in precocial birds has been widely investigated, for instance duck (Tangara et al, 2010), turkey (Stepińska et al, 2012), and chicken (Li et al, 2014). In contrast to precocial poultry, young pigeons, a typical representative of altricial birds, are feed with pigeon milk from the crop by parents for a few days.…”

CDX2 increases SLC7A7 expression and proliferation of pig intestinal epithelial cells

“…Nutrient absorption, mediated by nutrient transporters, supports the growth of intestinal epithelial cells. Our previous studies have shown that the gene expression of SLC1A1 , SLC7A9 , and SLC15A1 in chicks [ 19 , 20 ] and SLC7A9 , SLC1A1, SLC43A2 , SLC15A1 , SLC9A2 , SLC9A3 , and SLC7A6 in pigeons positively correlates with the growth of embryonic intestines [ 21 , 22 ]. In addition, the inhibition of SLC1A1 decreased the proliferative activity of the IPEC-1 cells, as expected [ 23 ].…”