Phosphorus absorption and gene expression levels of related transporters in the small intestine of broilers

Abstract

To investigate the P absorption and gene expression levels of related co-transporters, type IIb sodium-dependent phosphate co-transporter (NaPi-IIb), inorganic phosphate transporter 1 (PiT-1) and inorganic phosphate transporter 2 (PiT-2) in the small intestine of broilers, 450 1-d-old Arbor Acres male broilers were randomly allocated to one of three treatments with ten replicate cages of fifteen birds per cage for each treatment in a completely randomised design. Chickens were fed a diet with no added inorganic P (containing 0·06 % non-phytate P (NPP)) or with either 0·21 or 0·44 % NPP for 21 d. Plasma P concentration in the hepatic portal vein, mRNA and protein expression levels of NaPi-IIb, PiT-1 and PiT-2 were determined at 7, 14 and 21 d of age. The results showed that the concentration of P in plasma in the hepatic portal vein increased as dietary NPP increased (P<0·0001). At 14 and 21 d of age, the increase in dietary NPP inhibited (P<0·003) NaPi-IIb mRNA expression level in the duodenum, as well as PiT-1 mRNA and protein expression levels in the ileum, but promoted NaPi-IIb protein expression level (P<0·002) and PiT-2 mRNA and protein expression levels (P<0·04) in the duodenum. These results suggest that NaPi-IIb, PiT-1 and PiT-2 might be important P transporters in the small intestine of broilers. Higher intestinal P absorption may be achieved by up-regulating the protein expression levels of NaPi-IIb and PiT-2 and down-regulating the protein expression of PiT-1.

Dietary supplemental vitamin D3enhances phosphorus absorption and utilisation by regulating gene expression of related phosphate transporters in the small intestine of broilers

“…In addition, a post-transcriptional regulatory mechanisms including glycosylation or ubiquitination may be also involved in the NaP-IIb protein expression induced by P deficiency in this study (56) , but it needs to be investigated further. Hu et al (25) reported that a higher dietary NPP level promoted intestinal P absorption by increasing NaP-IIb protein expression, which was consistent with our results. Besides, dietary supplemental VD 3 enhanced NaP-IIb protein expression in the jejunum of the broilers fed the low NPP diets, suggesting that the increased absorption and utilisation of P induced by supplemental VD 3 might be partially associated with the enhanced NaP-IIb protein expression.…”

Enterococcus Faecium Modulates the Gut Microflora of Broilers and Enhances Phosphorus Absorption and Utilization

“…The elevation of NaP-b expression levels in the E. faecium group may have resulted from increased available P in the intestine. The expression of NaP-b mRNA increases when the level of dietary P increases and is concentration dependent [41]. Some probiotics produce phytase [42], which would enhance phytate digestibility, releasing P for absorption.…”

“…After the blood sampling on day 42, the duodenum (about 10 cm distal to the pylorus), jejunum (about 10 cm preceding the Meckel's diverticulum) and ileum (about 10 cm preceding the ileocecal junction) were separated [21], and ushed gently with saline solution. The mucosa samples were scraped with a coverslip and snap-frozen in liquid nitrogen for analysis of mRNA.…”

Kinetics of phosphorus absorption and expressions of related transporters in primary cultured duodenal epithelial cells of chick embryos

“…Many studies have demonstrated that phosphate cotransporters were involved in P absorption of broilers (Fang, Xiang, Cao, & He, ; Hu et al, ; Liu et al, ). Therefore, the present study investigated the mRNA and protein expressions of NaP‐IIb, PiT‐1 and PiT‐2 in primary cultured duodenal epithelial cells of broiler embryos.…”

“…Our previous study on P absorption in half in vivo in situ ligated small intestinal loops of broilers indicated that the duodenum was the main site of P absorption, and P absorption was a saturable carrier‐mediated process in the duodenum but a non‐saturable diffusion process in the jejunum or ileum of broilers (Liu et al, ). Furthermore, our in vivo study demonstrated that the increase in dietary non‐phytate P levels inhibited NaP‐IIb mRNA level in the duodenum, but promoted NaP‐IIb protein level and PiT‐2 mRNA and protein levels in the duodenum of broilers (Hu et al, ). More recently, we and other researchers have successfully established the in vitro primary cultured duodenal epithelial cell model of 18‐d‐old chick embryos for studying P absorption (Lin, Jiang, Jiang, Zheng, & Gou, ; Zhang, Liao, Lu, Zhang, & Luo, ), but it remains unclear about the kinetics of P absorption and whether these phosphate cotransporters are involved in P absorption in primary cultured duodenal epithelial cells of chick embryos.…”