Selenium(Se)is an essential trace element that has a large number of biological functions for broilers.However,the absorption kinetics of Se from sodium selenite in the small intestine of broilers remains unclear.Ther...Selenium(Se)is an essential trace element that has a large number of biological functions for broilers.However,the absorption kinetics of Se from sodium selenite in the small intestine of broilers remains unclear.Therefore,two experiments were conducted with 28-d-old commercial male broilers to study the kinetics of Se absorption in ligated small intestinal segments.In experiment 1,the Se absorption in duodenal,jejunal,and ileal segments at different post-perfusion time points(0,20,40,60,80,100 and 120 min)were compared.In experiment 2,a kinetic study of Se absorption was conducted with the duodenal,jejunal,and ileal loops perfused with solutions containing 0,0.0375,0.075,0.15,0.30,or 0.60μg mL^-1 of Se as sodium selenite,and Se contents in perfusates were determined at 100 min after perfusion.The results from experiment 1 showed that the Se absorption increased in an asymptotic response(P<0.0001)to post-perfusion time within 120 min in all the small intestinal segments,but increased linearly(P<0.0001)at less than 100 min after perfusion in duodenal and ileal segments,while more than 96.0%of the maximum Se absorption occurred at 100 min after perfusion in each small intestinal segment.In experiment 2,there was no difference(P>0.05)in the Se absorption rate among different ligated small intestinal segments perfused with solutions containing 0.0375–0.15μg mL^-1 of Se,however,the Se absorption rate was higher(P<0.05)in the jejunum than that in the duodenum perfused with solutions containing 0.30–0.60μg mL^-1 of Se.The kinetic curves of Se absorption demonstrated that the Se absorption was a saturated carrier-mediated process in the duodenum,and the maximum absorption rate was 1271 pg min^-1 cm^-1;whereas the Se absorptions were a non-saturated diffusion process in the jejunum and ileum,and the diffusive constants were 2107 and 1777 cm2 min^-1,respectively.The results from the present study indicate that the jejunum is the main Se absorption site,and the Se absorption is a saturated carrier-mediated process in the duodenum,but a non-saturated diffusion process in the jejunum and ileum of broilers.展开更多
基金financially supported by the National Natural Science Foundation of China(31601956)the Agricultural Science and Technology Innovation Program,China(ASTIP-IAS09)the earmarked fund for China Agriculture Research System(CARS-41)。
文摘Selenium(Se)is an essential trace element that has a large number of biological functions for broilers.However,the absorption kinetics of Se from sodium selenite in the small intestine of broilers remains unclear.Therefore,two experiments were conducted with 28-d-old commercial male broilers to study the kinetics of Se absorption in ligated small intestinal segments.In experiment 1,the Se absorption in duodenal,jejunal,and ileal segments at different post-perfusion time points(0,20,40,60,80,100 and 120 min)were compared.In experiment 2,a kinetic study of Se absorption was conducted with the duodenal,jejunal,and ileal loops perfused with solutions containing 0,0.0375,0.075,0.15,0.30,or 0.60μg mL^-1 of Se as sodium selenite,and Se contents in perfusates were determined at 100 min after perfusion.The results from experiment 1 showed that the Se absorption increased in an asymptotic response(P<0.0001)to post-perfusion time within 120 min in all the small intestinal segments,but increased linearly(P<0.0001)at less than 100 min after perfusion in duodenal and ileal segments,while more than 96.0%of the maximum Se absorption occurred at 100 min after perfusion in each small intestinal segment.In experiment 2,there was no difference(P>0.05)in the Se absorption rate among different ligated small intestinal segments perfused with solutions containing 0.0375–0.15μg mL^-1 of Se,however,the Se absorption rate was higher(P<0.05)in the jejunum than that in the duodenum perfused with solutions containing 0.30–0.60μg mL^-1 of Se.The kinetic curves of Se absorption demonstrated that the Se absorption was a saturated carrier-mediated process in the duodenum,and the maximum absorption rate was 1271 pg min^-1 cm^-1;whereas the Se absorptions were a non-saturated diffusion process in the jejunum and ileum,and the diffusive constants were 2107 and 1777 cm2 min^-1,respectively.The results from the present study indicate that the jejunum is the main Se absorption site,and the Se absorption is a saturated carrier-mediated process in the duodenum,but a non-saturated diffusion process in the jejunum and ileum of broilers.
