Kinetics of phosphorus absorption in ligated small intestinal segments of broilers1

Abstract

Two experiments were conducted using 22-d-old Arbor Acres male broilers to study the kinetics of inorganic P absorption and the effect of P treatment on Type IIb sodium-phosphate cotransporter (NaP-IIb) mRNA and protein levels in ligated segments from different intestinal regions. In Exp. 1, the P absorption in different small intestinal segments at different postperfusion times (0, 2.5, 5, 10, 20, or 40 min) were compared. In Exp. 2, different small intestinal loops were perfused with solutions containing 0, 1.5, 3, 6, 12, 24, or 48 mmol P/L as KHPO, and P concentrations in perfusates were determined at 20 min after perfusion. The mRNA levels of NaP-IIb in different small intestinal loops and protein expression levels in the duodenums from the control group and the 6 or 48 mmol P/L group were analyzed. The results from Exp. 1 showed that P absorption increased in an asymptotic response to postperfusion time within 40 min in all the intestinal segments and P absorption was greater ( < 0.04) in the duodenum than in the other 2 segments at 20 min after perfusion, indicating that the duodenum is the main site of P absorption in the small intestine of chicks. In Exp. 2, the kinetic curves showed that P absorption in the duodenum was a saturated carrier mediated process and in the jejunum or ileum occurred with a nonsaturated diffusion process. In addition, the b mRNA levels were greater ( < 0.0001) in the duodenum than in the other 2 segments in the 3 groups (0, 6, or 48 mmol P/L), further indicating that P absorption in the duodenum occurred mainly by a saturated carrier mediated process. However, no significant differences ( = 0.20) in the NaP-IIb protein levels of the duodenum were observed among the 0, 6, and 48 mmol P/L groups. In conclusion, this study suggests by our criteria in ligated intestinal loops that the duodenum is the main site of P absorption and that P absorption may be a saturated carrier mediated process in the duodenum but a nonsaturated diffusion process in the jejunum or ileum of broilers.

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

“…The decreased concentration of P in excreta may re ect both enhanced intestinal absorption and renal reabsorption. Much of the intestinal absorption of P is accomplished by the sodium-dependent transporter NaP-IIb, which is primarily expressed in the duodenum of broilers and is considered to be the most important P transporter in the small intestine [40]. In our study, mRNA expression levels of NaP-b were increased in the small intestine of E. faecium treated broilers; indicating that increased P absorption occurred in this study.…”

Association between the gut microbiota and mineral metabolism

“…56 Phosphorus is a structural element of bones, nucleic acids and energy transfer compounds such as adenosine triphosphate (ATP). Its absorption takes place in the upper parts of the small intestine by active transport regulated by growth hormone, parathormone (PTH) and vitamin C. 57 Copper is a structural part of a number of enzymes, takes part in neuronal transmission and stabilizes the cell membrane of neurons. It is absorbed in the small intestine with participation of protein transporters CTR1 and ATP7A.…”

“…The main factors affecting mineral bioavailability are the content of minerals in the food, synergistic and antagonistic interactions between minerals in the food and in the GI tract, the presence of complexing or chelating compounds in the food, the health state of the organism and its age, environment pollution and technical processing of the food. [54][55][56][57][58][59][60][61][62] The intestinal microflora, probiotics and prebiotics significantly influence the bioavailability of minerals. The intestinal microbiota, probiotics and prebiotics can increase the absorption of minerals, 63 especially iron 4,14,64 and calcium, 17,18,65 or decrease it.…”

“…Minerals are absorbed mainly in the GI tract, especially in the intestine. The main factors affecting mineral bioavailability are the content of minerals in the food, synergistic and antagonistic interactions between minerals in the food and in the GI tract, the presence of complexing or chelating compounds in the food, the health state of the organism and its age, environment pollution and technical processing of the food . The intestinal microflora, probiotics and prebiotics significantly influence the bioavailability of minerals.…”

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

“…Transcellular permeation is the dominant mechanism for intestinal P absorption (5,6,8) and involves three types of phosphate co-transporters (6) : type IIb Na-dependent phosphate co-transporter (NaPi-IIb); inorganic phosphate transporter 1 (PiT-1); and inorganic phosphate transporter 2 (PiT-2). The NaPi-IIb is primarily expressed in the duodenum of broilers and is considered to be the most important P transporter in their small intestine (9)(10)(11) . The PiT-1 and PiT-2 may play a potential role in intestinal P absorption in the mouse (6) and rat (12) ; however, no information is available on the expression levels and physiological roles of PiT-1 and PiT-2 in the small intestine of broilers.…”