Studies On The Effect Of Absorption And Expression Of Several Gene Of Manganese From Different Manganese Sources In The Small Intestine Of Broilers

In order to investigate the molecular mechanism of manganese absorption among various Mn sources with different chelation strengths(Qf)in the intestine of broilers;At the age of 14 d,320 birds under manganese deficiency were selected according to the average weight and allotted randomly to 1 of 8 replicate cages(8 birds per replicate cage)for each of 5 treatments.Birds were fed a corn-soybean meal basal diet as the control or the control diet supplemented with 110mg/kg Mn as Mn SO4,Organic Mn with strong chelation strength(OS),Organic Mn with moderate chelation strength(OM),Organic Mn with weak chelation strength(OW),respectively.At 7 and 14 d post-feeding,twenty-four chicks(three birds per cage)from each treatment were selected based on mean body weight to collected the blood from the hepatic portal vein and the mucosa of duodenum,jejunum and ileum.Manganese content in the plasma from the hepatic portal vein blood and gene expression Mn transporters(DMT1 and FPN1),amino acid transporters(B0AT1,LAT1,r BAT,y+LAT1 and EAAT3),peptide transporters(Pep T1)in the small intestine and protein expression of DMT1 and FPN1 were measured.The results showed that:(1)at 21 d of age,plasma Mn contents from the hepatic portal vein plasma Mn contents in the OM and OS group were significantly higher than the Mn SO4 and OW group,and plasma Mn contents in Mn SO4 and OW group were significantly higher than the control(P<0.05),while there was no significant difference between the OS group and the OM group(P>0.05),the OW group and the Mn SO4 group(P>0.05).At 28 d of age,the plasma Mn content was greater in the OS group than that in the OM group(P<0.05),the OM group was higher than the OW group(P<0.05)and the Mn SO4 group(P<0.05),but no significant difference(P>0.05 could be found between the OW group and Mn SO4 group.(2)The levels of DMT1 and FPN1 m RNA in the duodenum of broilers were higher than that in the jejunum and ileum at 7th day of present study.In comparison with the control,the levels of DMT1 and FPN1 m RNA in the duodenum and the expression of DMT1 m RNA in the jejunum were significantly increased with adding manganese(P<0.05),but the DMT1 and FPN1 m RNA levels were found no significance among the treatments at the three segments of the intestine(P>0.05).At 28 d of age,the levels of the DMT1 and FPN1 m RNA in the duodenum and jejunum of broilers was higher than that in the ileum(P<0.05),and the levels of the DMT1 and FPN1 m RNA in the duodenum of broilers was significantly higher than that in the jejunum(P<0.05).In comparison with the control,the levels of the DMT1 m RNA in the duodenum and jejunum and the levels of the FPN1 m RNA in the duodenum increased significantly by adding the different manganese source in the diet(P<0.05),while the DMT1 m RNA expression was no significance in the ileum.The levels of the DMT1 m RNA in the OS and OM group was higher than Mn SO4 and OW group in the duodenum(P<0.05),while there was no difference between OS and OM group(P>0.05),either as Mn SO4 and OW group.(3)No difference was found in the level of the neutral amino acid transporters(B0AT1 and LAT1),basic amino acid transporters(r BAT and y+LAT1),acidic amino acid transporters(EAAT3)and peptide transporters(Pep T1)m RNA in the present study(P>0.05).The levels of the neutral amino acid transporters(B0AT1 and LAT1),basic amino acid transporters(r BAT and y+LAT1)and acidic amino acid transporters(EAAT3)m RNA in the ileum was higher than that in the duodenum and jejunum(P<0.05),while the levels of peptide transporters(Pep T1)m RNA in the duodenum were higher than that in the jejunum and ileum(P<0.05).(4)At 21 d of age,the DMT1 protein expression in the OS group in the duodenum was higher than the other groups(P<0.05),but there was no difference among these groups(P>0.05),either no significance was found in the jejunum and ileum(P>0.05).At 28 d of age,in comparison with the other three groups,the levels of DMT1 protein in the OS and OM group were significantly increased in the duodenum(P<0.05),but no difference was found among these three groups(P>0.05).The levels of FPN1 protein in the groups with adding manganese in the duodenum were higher than the control(P<0.05),while no significance among the five groups in the jejunum and ileum.The results suggested that the DMT1,FPN1 and Pep T1 m RNA was mostly expressed in the duodenum and jejunum of the practical feeding broiler and the most amino acid transporters(except y+LAT1)m RNA was expressed in the distal intestine.The levels of DMT1 in the duodenum and jejunum,FPN1 in the duodenum the level of m RNA increased by adding manganese in the diet in comparison with the control at 21 and 28 d of age.In comparison with the Mn SO4 and OW group,the OS and OM group significantly increased the level of DMT1 m RNA in the duodenum of broilers at 28 d of age.Furthermore,the expression of DMT1 protein in the OS group at 21 and 28 d of age and the OM group at 28 d of age in the duodenum was higher than the other groups.Meanwhile,the levels of FPN1 protein in the duodenum significantly increased with adding manganese than the control at 21 and 28 d of age.In conclusion,the duodenum was the main site of gene expression of DMT1,FPN1 and Pep T1,and the ileum was the main site of that of amino acid transporters in the small intestine of broilers.In addition,organic Mn sources with moderate and strong complex strength showed higher Mn absorption in the small intestine than Mn sulfate and organic Mn source with weak complex strength.It inferred that DMT1 and FPN1 might be involved in the regulation of Mn transport in the small intestine of broilers,while amino acid transporters and peptide transporters might not.